From 81a21f68cd6fd302efd0677b25964fa46cba8fcd Mon Sep 17 00:00:00 2001
From: Saophalkun Ponlu <phalkunz@gmail.com>
Date: Thu, 6 Apr 2017 17:23:52 +1200
Subject: [PATCH 01/26] Add 'lang' attribute to front-end date field schema

---
 src/Forms/DateField.php | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Forms/DateField.php b/src/Forms/DateField.php
index b3da3be06..a20614356 100644
--- a/src/Forms/DateField.php
+++ b/src/Forms/DateField.php
@@ -290,6 +290,12 @@ class DateField extends TextField
         return $attributes;
     }
 
+    public function getSchemaDataDefaults()
+    {
+        $defaults = parent::getSchemaDataDefaults();
+        return array_merge($defaults, [ 'lang' => i18n::convert_rfc1766($this->getLocale()) ]);
+    }
+
     public function Type()
     {
         return 'date text';

From 9f8fe88eea52aeb7f649f2c0e253992ab2cd0d44 Mon Sep 17 00:00:00 2001
From: Saophalkun Ponlu <phalkunz@gmail.com>
Date: Wed, 12 Apr 2017 17:11:30 +1200
Subject: [PATCH 02/26] Refactor DateTimeField not to use DateField and
 TimeField

---
 src/Forms/DatetimeField.php                   | 516 ++++++++++++------
 src/ORM/FieldType/DBDatetime.php              |   2 +-
 templates/SilverStripe/Forms/DatetimeField.ss |   7 -
 3 files changed, 347 insertions(+), 178 deletions(-)
 delete mode 100644 templates/SilverStripe/Forms/DatetimeField.ss

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 0ae8b65c6..7cd183d49 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -5,49 +5,77 @@ namespace SilverStripe\Forms;
 use IntlDateFormatter;
 use InvalidArgumentException;
 use SilverStripe\i18n\i18n;
+use SilverStripe\ORM\FieldType\DBDatetime;
 
 /**
- * A composite field for date and time entry,
- * based on {@link DateField} and {@link TimeField}.
- * Usually saves into a single {@link DBDateTime} database column.
- * If you want to save into {@link Date} or {@link Time} columns,
- * please instanciate the fields separately.
- *
- * This field does not implement the <input type="datetime-local"> HTML5 field,
- * but can use date and time HTML5 inputs separately (through {@link DateField->setHTML5()}
- * and {@link TimeField->setHTML5()}.
+ * Form field used for editing date time string
  *
  * # Configuration
  *
- * Individual options are configured either on the DatetimeField, or on individual
- * sub-fields accessed via getDateField() or getTimeField()
- *
- * Example:
- * <code>
- * $field = new DatetimeField('Name', 'Label');
- * $field->getDateField()->setTitle('Select Date');
- * </code>
- *
- * - setLocale(): Sets a custom locale for date / time formatting.
- * - setTimezone(): Set a different timezone for viewing. {@link dataValue()} will still save
+ * - "timezone": Set a different timezone for viewing. {@link dataValue()} will still save
  * the time in PHP's default timezone (date_default_timezone_get()), its only a view setting.
- * Note that the sub-fields ({@link getDateField()} and {@link getTimeField()})
- * are not timezone aware, and will have their values set in local time, rather than server time.
- * - setDateTimeOrder(): An sprintf() template to determine in which order the date and time values will
+ * - "datetimeorder": An sprintf() template to determine in which order the date and time values will
  * be combined. This is necessary as those separate formats are set in their invididual fields.
  */
-class DatetimeField extends FormField
+class DatetimeField extends TextField
 {
 
     /**
-     * @var DateField
+     * @var bool
      */
-    protected $dateField = null;
+    protected $html5 = true;
 
     /**
-     * @var TimeField
+     * Override locale. If empty will default to current locale
+     *
+     * @var string
      */
-    protected $timeField = null;
+    protected $locale = null;
+
+    /**
+     * Min date time
+     *
+     * @var string ISO 8601 date time for min date time
+     */
+    protected $minDatetime = null;
+
+    /**
+     * Max date time
+     *
+     * @var string ISO 860 date time for max date time
+     */
+    protected $maxDatetime = null;
+
+    /**
+     * Override date format. If empty will default to that used by the current locale.
+     *
+     * @var null
+     */
+    protected $datetimeFormat = null;
+
+    /**
+     * Length of this date (full, short, etc).
+     *
+     * @see http://php.net/manual/en/class.intldateformatter.php#intl.intldateformatter-constants
+     * @var int
+     */
+    protected $dateLength = null;
+
+    /**
+     * Length of this time (full, short, etc).
+     *
+     * @see http://php.net/manual/en/class.intldateformatter.php#intl.intldateformatter-constants
+     * @var int
+     */
+    protected $timeLength = null;
+
+    /**
+     * Unparsed value, used exclusively for comparing with internal value
+     * to detect invalid values.
+     *
+     * @var mixed
+     */
+    protected $rawValue = null;
 
     protected $schemaDataType = FormField::SCHEMA_DATA_TYPE_DATETIME;
 
@@ -60,58 +88,124 @@ class DatetimeField extends FormField
 
     public function __construct($name, $title = null, $value = "")
     {
-        $this->timeField = TimeField::create($name . '[time]', false);
-        $this->dateField = DateField::create($name . '[date]', false);
         parent::__construct($name, $title, $value);
     }
 
     public function setForm($form)
     {
         parent::setForm($form);
-        $this->dateField->setForm($form);
-        $this->timeField->setForm($form);
         return $this;
     }
 
     public function setName($name)
     {
         parent::setName($name);
-        $this->dateField->setName($name . '[date]');
-        $this->timeField->setName($name . '[time]');
+        return $this;
+    }
+
+    public function Type()
+    {
+        return 'text datetime';
+    }
+
+    public function getHTML5()
+    {
+        return $this->html5;
+    }
+
+    public function setHTML5($bool)
+    {
+        $this->html5 = $bool;
         return $this;
     }
 
     /**
-     * Sets value from a submitted form array
+     * Assign value posted from form submission
      *
-     * @param array $value Expected submission value is either an empty value,
-     * or an array with the necessary components keyed against 'date' and 'time', each value
-     * localised according to each's localisation setting.
+     * @param mixed $value
      * @param mixed $data
      * @return $this
      */
     public function setSubmittedValue($value, $data = null)
     {
-        // Empty value
-        if (empty($value)) {
+        // Save raw value for later validation
+        $this->rawValue = $value;
+
+        // Null case
+        if (!$value) {
             $this->value = null;
-            $this->dateField->setValue(null);
-            $this->timeField->setValue(null);
             return $this;
         }
 
-        // Validate value is submitted in array format
-        if (!is_array($value)) {
-            throw new InvalidArgumentException("Value is not submitted array");
+        // Parse from submitted value
+        $this->value = $this->localisedToISO8601($value);
+        return $this;
+    }
+
+    /**
+     * Convert date localised in the current locale to ISO 8601 date
+     *
+     * @param string $date
+     * @return string The formatted date, or null if not a valid date
+     */
+    public function localisedToISO8601($datetime)
+    {
+        if (!$datetime) {
+            return null;
+        }
+        $fromFormatter = $this->getFormatter();
+        $toFormatter = $this->getISO8601Formatter();
+        $timestamp = $fromFormatter->parse($datetime);
+        if ($timestamp === false) {
+            return null;
+        }
+        return $toFormatter->format($timestamp) ?: null;
+    }
+
+    /**
+     * Get date formatter with the standard locale / date format
+     *
+     * @throws \LogicException
+     * @return IntlDateFormatter
+     */
+    protected function getFormatter()
+    {
+        if ($this->getHTML5() && $this->datetimeFormat && $this->datetimeFormat !== DBDatetime::ISO_DATE) {
+            throw new \LogicException(
+                'Please opt-out of HTML5 processing of ISO 8601 dates via setHTML5(false) if using setDateFormat()'
+            );
         }
 
-        // Save each field, and convert from array to iso8601 string
-        $this->dateField->setSubmittedValue($value['date'], $value);
-        $this->timeField->setSubmittedValue($value['time'], $value);
+        if ($this->getHTML5() && $this->dateLength) {
+            throw new \LogicException(
+                'Please opt-out of HTML5 processing of ISO 8601 dates via setHTML5(false) if using setDateLength()'
+            );
+        }
 
-        // Combine date components back into iso8601 string for the root value
-        $this->value = $this->dataValue();
-        return $this;
+        if ($this->getHTML5() && $this->locale) {
+            throw new \LogicException(
+                'Please opt-out of HTML5 processing of ISO 8601 dates via setHTML5(false) if using setLocale()'
+            );
+        }
+
+        $formatter = IntlDateFormatter::create(
+            $this->getLocale(),
+            $this->getDateLength(),
+            $this->getTimeLength(),
+            $this->getTimezone()
+        );
+
+        if ($this->getHTML5()) {
+            // Browsers expect ISO 8601 dates, localisation is handled on the client
+            $formatter->setPattern(DBDatetime::ISO_DATETIME);
+        } elseif ($this->datetimeFormat) {
+            // Don't invoke getDateFormat() directly to avoid infinite loop
+            $ok = $formatter->setPattern($this->datetimeFormat);
+            if (!$ok) {
+                throw new InvalidArgumentException("Invalid date format {$this->datetimeFormat}");
+            }
+        }
+        return $formatter;
     }
 
     /**
@@ -165,8 +259,6 @@ class DatetimeField extends FormField
         // Empty value
         if (empty($value)) {
             $this->value = null;
-            $this->dateField->setValue(null);
-            $this->timeField->setValue(null);
             return $this;
         }
         if (is_array($value)) {
@@ -178,8 +270,6 @@ class DatetimeField extends FormField
         $isoFormatter = $this->getISO8601Formatter();
         $timestamp = $isoFormatter->parse($value);
         if ($timestamp === false) {
-            $this->dateField->setSubmittedValue($value);
-            $this->timeField->setValue(null);
             return $this;
         }
 
@@ -197,135 +287,140 @@ class DatetimeField extends FormField
 
         // Set date / time components, which are unaware of their timezone
         list($date, $time) = explode(' ', $value);
-        $this->dateField->setValue($date, $data);
-        $this->timeField->setValue($time, $data);
+        return $this;
+    }
+
+    public function Value()
+    {
+        return $this->iso8601ToLocalised($this->value);
+    }
+
+    /**
+     * Convert an ISO 8601 localised date into the format specified by the
+     * current date format.
+     *
+     * @param string $date
+     * @return string The formatted date, or null if not a valid date
+     */
+    public function iso8601ToLocalised($datetime)
+    {
+        $datetime = $this->tidyISO8601($datetime);
+        if (!$datetime) {
+            return null;
+        }
+        $fromFormatter = $this->getISO8601Formatter();
+        $toFormatter = $this->getFormatter();
+        $timestamp = $fromFormatter->parse($datetime);
+        if ($timestamp === false) {
+            return null;
+        }
+        return $toFormatter->format($timestamp) ?: null;
+    }
+
+    /**
+     * Tidy up iso8601-ish date, or approximation
+     *
+     * @param string $date Date in iso8601 or approximate form
+     * @return string iso8601 date, or null if not valid
+     */
+    public function tidyISO8601($datetime)
+    {
+        if (!$datetime) {
+            return null;
+        }
+        // Re-run through formatter to tidy up (e.g. remove time component)
+        $formatter = $this->getISO8601Formatter();
+        $timestamp = $formatter->parse($datetime);
+        if ($timestamp === false) {
+            // Fallback to strtotime
+            $timestamp = strtotime($datetime, DBDatetime::now()->getTimestamp());
+            if ($timestamp === false) {
+                return null;
+            }
+        }
+        return $formatter->format($timestamp);
+    }
+
+    /**
+     * Get length of the date format to use. One of:
+     *
+     *  - IntlDateFormatter::SHORT
+     *  - IntlDateFormatter::MEDIUM
+     *  - IntlDateFormatter::LONG
+     *  - IntlDateFormatter::FULL
+     *
+     * @see http://php.net/manual/en/class.intldateformatter.php#intl.intldateformatter-constants
+     * @return int
+     */
+    public function getDateLength()
+    {
+        if ($this->dateLength) {
+            return $this->dateLength;
+        }
+        return IntlDateFormatter::MEDIUM;
+    }
+
+    /**
+     * Get length of the date format to use.
+     * Only applicable with {@link setHTML5(false)}.
+     *
+     * @see http://php.net/manual/en/class.intldateformatter.php#intl.intldateformatter-constants
+     *
+     * @param int $length
+     * @return $this
+     */
+    public function setDateLength($length)
+    {
+        $this->dateLength = $length;
         return $this;
     }
 
     /**
-     * localised time value
+     * Get length of the date format to use. One of:
      *
-     * @return string
+     *  - IntlDateFormatter::SHORT
+     *  - IntlDateFormatter::MEDIUM
+     *  - IntlDateFormatter::LONG
+     *  - IntlDateFormatter::FULL
+     *
+     * @see http://php.net/manual/en/class.intldateformatter.php#intl.intldateformatter-constants
+     * @return int
      */
-    public function Value()
+    public function getTimeLength()
     {
-        $date = $this->dateField->Value();
-        $time = $this->timeField->Value();
-        return $this->joinDateTime($date, $time);
+        if ($this->timeLength) {
+            return $this->timeLength;
+        }
+        return IntlDateFormatter::MEDIUM;
     }
 
     /**
-     * @param string $date
-     * @param string $time
-     * @return string
-     */
-    protected function joinDateTime($date, $time)
-    {
-        $format = $this->getDateTimeOrder();
-        return strtr($format, [
-            '{date}' => $date,
-            '{time}' => $time
-        ]);
-    }
-
-    /**
-     * Get ISO8601 formatted string in the local server timezone
+     * Get length of the date format to use.
+     * Only applicable with {@link setHTML5(false)}.
      *
-     * @return string|null
+     * @see http://php.net/manual/en/class.intldateformatter.php#intl.intldateformatter-constants
+     *
+     * @param int $length
+     * @return $this
      */
-    public function dataValue()
+    public function setTimeLength($length)
     {
-        // No date means no value (even if time is specified)
-        $dateDataValue = $this->getDateField()->dataValue();
-        if (empty($dateDataValue)) {
-            return null;
-        }
-
-        // Build iso8601 timestamp from combined date and time
-        $timeDataValue = $this->getTimeField()->dataValue() ?: '00:00:00';
-        $value = $dateDataValue . ' ' . $timeDataValue;
-
-        // If necessary, convert timezone
-        $timezoneFormatter = $this->getTimezoneFormatter();
-        if ($timezoneFormatter) {
-            $timestamp = $timezoneFormatter->parse($value);
-            $isoFormatter = $this->getISO8601Formatter();
-            $value = $isoFormatter->format($timestamp);
-        }
-
-        return $value;
+        $this->timeLength = $length;
+        return $this;
     }
 
     public function setDisabled($bool)
     {
         parent::setDisabled($bool);
-        $this->dateField->setDisabled($bool);
-        $this->timeField->setDisabled($bool);
         return $this;
     }
 
     public function setReadonly($bool)
     {
         parent::setReadonly($bool);
-        $this->dateField->setReadonly($bool);
-        $this->timeField->setReadonly($bool);
         return $this;
     }
 
-    /**
-     * @return DateField
-     */
-    public function getDateField()
-    {
-        return $this->dateField;
-    }
-
-    /**
-     * @param FormField $field
-     */
-    public function setDateField($field)
-    {
-        $expected = $this->getName() . '[date]';
-        if ($field->getName() != $expected) {
-            throw new InvalidArgumentException(sprintf(
-                'Wrong name format for date field: "%s" (expected "%s")',
-                $field->getName(),
-                $expected
-            ));
-        }
-
-        $field->setForm($this->getForm());
-        $field->setValue($this->dateField->dataValue());
-        $this->dateField = $field;
-    }
-
-    /**
-     * @return TimeField
-     */
-    public function getTimeField()
-    {
-        return $this->timeField;
-    }
-
-    /**
-     * @param FormField $field
-     */
-    public function setTimeField($field)
-    {
-        $expected = $this->getName() . '[time]';
-        if ($field->getName() != $expected) {
-            throw new InvalidArgumentException(sprintf(
-                'Wrong name format for time field: "%s" (expected "%s")',
-                $field->getName(),
-                $expected
-            ));
-        }
-
-        $field->setForm($this->getForm());
-        $field->setValue($this->timeField->dataValue());
-        $this->timeField = $field;
-    }
-
     /**
      * Set default locale for this field. If omitted will default to the current locale.
      *
@@ -334,8 +429,7 @@ class DatetimeField extends FormField
      */
     public function setLocale($locale)
     {
-        $this->dateField->setLocale($locale);
-        $this->timeField->setLocale($locale);
+        $this->locale = $locale;
         return $this;
     }
 
@@ -346,16 +440,104 @@ class DatetimeField extends FormField
      */
     public function getLocale()
     {
-        return $this->dateField->getLocale();
+        return $this->locale ?: i18n::get_locale();
     }
 
+    /**
+     * @return string
+     */
+    public function getMinDatetime()
+    {
+        return $this->minDatetime;
+    }
+
+    /**
+     * @param string $minDatetime
+     * @return $this
+     */
+    public function setMinDatetime($minDatetime)
+    {
+        $this->minDatetime = $this->tidyISO8601($minDatetime);
+        return $this;
+    }
+
+    /**
+     * @return string
+     */
+    public function getMaxDatetime()
+    {
+        return $this->maxDatetime;
+    }
+
+    /**
+     * @param string $maxDatetime
+     * @return $this
+     */
+    public function setMaxDatetime($maxDatetime)
+    {
+        $this->maxDatetime = $this->tidyISO8601($maxDatetime);
+        return $this;
+    }
+
+    /**
+     * @param Validator $validator
+     * @return bool
+     */
     public function validate($validator)
     {
-        $dateValid = $this->dateField->validate($validator);
-        $timeValid = $this->timeField->validate($validator);
+        // Don't validate empty fields
+        if (empty($this->rawValue)) {
+            return true;
+        }
 
-        // Validate if both subfields are valid
-        return $dateValid && $timeValid;
+        // We submitted a value, but it couldn't be parsed
+        if (empty($this->value)) {
+            $validator->validationError(
+                $this->name,
+                _t(
+                    'DateField.VALIDDATEFORMAT2',
+                    "Please enter a valid date format ({format})",
+                    ['format' => $this->getDateFormat()]
+                )
+            );
+            return false;
+        }
+
+        // Check min date
+        $min = $this->getMinDatetime();
+        if ($min) {
+            $oops = strtotime($this->value) < strtotime($min);
+            if ($oops) {
+                $validator->validationError(
+                    $this->name,
+                    _t(
+                        'DateField.VALIDDATEMINDATE',
+                        "Your date has to be newer or matching the minimum allowed date ({date})",
+                        ['date' => $this->iso8601ToLocalised($min)]
+                    )
+                );
+                return false;
+            }
+        }
+
+        // Check max date
+        $max = $this->getMaxDatetime();
+        if ($max) {
+            $oops = strtotime($this->value) > strtotime($max);
+            if ($oops) {
+                $validator->validationError(
+                    $this->name,
+                    _t(
+                        'DateField.VALIDDATEMAXDATE',
+                        "Your date has to be older or matching the maximum allowed date ({date})",
+                        ['date' => $this->iso8601ToLocalised($max)]
+                    )
+                );
+                return false;
+            }
+        }
+
+        return true;
     }
 
     public function performReadonlyTransformation()
@@ -365,12 +547,6 @@ class DatetimeField extends FormField
         return $field;
     }
 
-    public function __clone()
-    {
-        $this->dateField = clone $this->dateField;
-        $this->timeField = clone $this->timeField;
-    }
-
     /**
      * @return string
      */
diff --git a/src/ORM/FieldType/DBDatetime.php b/src/ORM/FieldType/DBDatetime.php
index 291b31d46..159e43c8b 100644
--- a/src/ORM/FieldType/DBDatetime.php
+++ b/src/ORM/FieldType/DBDatetime.php
@@ -37,7 +37,7 @@ class DBDatetime extends DBDate implements TemplateGlobalProvider
     /**
      * Standard ISO format string for date and time in CLDR standard format
      */
-    const ISO_DATETIME = 'y-MM-dd HH:mm:ss';
+    const ISO_DATETIME = 'y-MM-dd\'T\'HH:mm:ss';
 
     /**
      * Returns the standard localised date
diff --git a/templates/SilverStripe/Forms/DatetimeField.ss b/templates/SilverStripe/Forms/DatetimeField.ss
deleted file mode 100644
index 90a7836ea..000000000
--- a/templates/SilverStripe/Forms/DatetimeField.ss
+++ /dev/null
@@ -1,7 +0,0 @@
-<div id="$ID" class="form__fieldgroup<% if $extraClass %> $extraClass<% end_if %>">
-	$DateField.SmallFieldHolder
-	$TimeField.SmallFieldHolder
-	<% if $TimeZone %>
-		$TimezoneField.Field
-	<% end_if %>
-</div>

From 4a7066294028be2f65ab8ececae18efd441790fa Mon Sep 17 00:00:00 2001
From: Saophalkun Ponlu <phalkunz@gmail.com>
Date: Wed, 12 Apr 2017 22:39:23 +1200
Subject: [PATCH 03/26] Pass html5 flag to front-end

---
 src/Forms/DateField.php     |  5 ++++-
 src/Forms/DatetimeField.php | 11 +++++++++++
 src/Forms/TimeField.php     |  8 ++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/Forms/DateField.php b/src/Forms/DateField.php
index a20614356..adff7afb1 100644
--- a/src/Forms/DateField.php
+++ b/src/Forms/DateField.php
@@ -293,7 +293,10 @@ class DateField extends TextField
     public function getSchemaDataDefaults()
     {
         $defaults = parent::getSchemaDataDefaults();
-        return array_merge($defaults, [ 'lang' => i18n::convert_rfc1766($this->getLocale()) ]);
+        return array_merge($defaults, [
+            'lang' => i18n::convert_rfc1766($this->getLocale()),
+            'html5' => $this->getHTML5()
+        ]);
     }
 
     public function Type()
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 7cd183d49..7e91300e8 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -103,6 +103,14 @@ class DatetimeField extends TextField
         return $this;
     }
 
+    public function getSchemaDataDefaults()
+    {
+        $defaults = parent::getSchemaDataDefaults();
+        return array_merge($defaults, [
+            'html5' => $this->getHTML5()
+        ]);
+    }
+
     public function Type()
     {
         return 'text datetime';
@@ -256,6 +264,9 @@ class DatetimeField extends TextField
      */
     public function setValue($value, $data = null)
     {
+        // Save raw value for later validation
+        $this->rawValue = $value;
+
         // Empty value
         if (empty($value)) {
             $this->value = null;
diff --git a/src/Forms/TimeField.php b/src/Forms/TimeField.php
index 94d480236..85c377e17 100644
--- a/src/Forms/TimeField.php
+++ b/src/Forms/TimeField.php
@@ -231,6 +231,14 @@ class TimeField extends TextField
         return $attributes;
     }
 
+    public function getSchemaDataDefaults()
+    {
+        $defaults = parent::getSchemaDataDefaults();
+        return array_merge($defaults, [
+            'html5' => $this->getHTML5()
+        ]);
+    }
+
     public function Type()
     {
         return 'time text';

From 9d7eef7cf3de62c5b1c50ee74b54c3ac521c3a2b Mon Sep 17 00:00:00 2001
From: Saophalkun Ponlu <phalkunz@gmail.com>
Date: Thu, 20 Apr 2017 10:54:41 +1200
Subject: [PATCH 04/26] Fix datetime field validation for the refactor

---
 src/Forms/DatetimeField.php | 59 +++++++++++++++++++++++++++++++++----
 1 file changed, 54 insertions(+), 5 deletions(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 7e91300e8..e14473770 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -103,6 +103,21 @@ class DatetimeField extends TextField
         return $this;
     }
 
+    public function getAttributes()
+    {
+        $attributes = parent::getAttributes();
+
+        $attributes['lang'] = i18n::convert_rfc1766($this->getLocale());
+
+        if ($this->getHTML5()) {
+            $attributes['type'] = 'datetime-local';
+            $attributes['min'] = $this->getMinDatetime();
+            $attributes['max'] = $this->getMaxDatetime();
+        }
+
+        return $attributes;
+    }
+
     public function getSchemaDataDefaults()
     {
         $defaults = parent::getSchemaDataDefaults();
@@ -178,9 +193,9 @@ class DatetimeField extends TextField
      */
     protected function getFormatter()
     {
-        if ($this->getHTML5() && $this->datetimeFormat && $this->datetimeFormat !== DBDatetime::ISO_DATE) {
+        if ($this->getHTML5() && $this->datetimeFormat && $this->datetimeFormat !== DBDatetime::ISO_DATETIME) {
             throw new \LogicException(
-                'Please opt-out of HTML5 processing of ISO 8601 dates via setHTML5(false) if using setDateFormat()'
+                'Please opt-out of HTML5 processing of ISO 8601 dates via setHTML5(false) if using setDatetimeFormat()'
             );
         }
 
@@ -216,6 +231,43 @@ class DatetimeField extends TextField
         return $formatter;
     }
 
+    /**
+     * Get date format in CLDR standard format
+     *
+     * This can be set explicitly. If not, this will be generated from the current locale
+     * with the current date length.
+     *
+     * @see http://userguide.icu-project.org/formatparse/datetime#TOC-Date-Field-Symbol-Table
+     */
+    public function getDateFormat()
+    {
+        if ($this->getHTML5()) {
+            // Browsers expect ISO 8601 dates, localisation is handled on the client
+            $this->setDatetimeFormat(DBDatetime::ISO_DATETIME);
+        }
+
+        if ($this->datetimeFormat) {
+            return $this->datetimeFormat;
+        }
+
+        // Get from locale
+        return $this->getFormatter()->getPattern();
+    }
+
+    /**
+     * Set date format in CLDR standard format.
+     * Only applicable with {@link setHTML5(false)}.
+     *
+     * @see http://userguide.icu-project.org/formatparse/datetime#TOC-Date-Field-Symbol-Table
+     * @param string $format
+     * @return $this
+     */
+    public function setDatetimeFormat($format)
+    {
+        $this->datetimeFormat = $format;
+        return $this;
+    }
+
     /**
      * Get formatter for converting to the target timezone, if timezone is set
      * Can return null if no timezone set
@@ -295,9 +347,6 @@ class DatetimeField extends TextField
         if ($timezoneFormatter) {
             $value = $timezoneFormatter->format($timestamp);
         }
-
-        // Set date / time components, which are unaware of their timezone
-        list($date, $time) = explode(' ', $value);
         return $this;
     }
 

From dba1f61f133f22cba1ecd1fe07f4838a61a1486d Mon Sep 17 00:00:00 2001
From: Saophalkun Ponlu <phalkunz@gmail.com>
Date: Thu, 20 Apr 2017 15:08:44 +1200
Subject: [PATCH 05/26] Fix tests related to date time

---
 src/Forms/DatetimeField.php           |  33 ++------
 src/ORM/FieldType/DBDatetime.php      |  20 +----
 tests/php/Forms/DatetimeFieldTest.php | 117 ++++----------------------
 tests/php/Forms/FormSchemaTest.php    |   2 +
 tests/php/ORM/DBDatetimeTest.php      |   8 +-
 5 files changed, 32 insertions(+), 148 deletions(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index e14473770..a1db12a64 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -10,12 +10,14 @@ use SilverStripe\ORM\FieldType\DBDatetime;
 /**
  * Form field used for editing date time string
  *
+ * # Localization
+ *
+ * See {@link DateField}
+ *
  * # Configuration
  *
  * - "timezone": Set a different timezone for viewing. {@link dataValue()} will still save
  * the time in PHP's default timezone (date_default_timezone_get()), its only a view setting.
- * - "datetimeorder": An sprintf() template to determine in which order the date and time values will
- * be combined. This is necessary as those separate formats are set in their invididual fields.
  */
 class DatetimeField extends TextField
 {
@@ -162,6 +164,7 @@ class DatetimeField extends TextField
 
         // Parse from submitted value
         $this->value = $this->localisedToISO8601($value);
+
         return $this;
     }
 
@@ -222,7 +225,7 @@ class DatetimeField extends TextField
             // Browsers expect ISO 8601 dates, localisation is handled on the client
             $formatter->setPattern(DBDatetime::ISO_DATETIME);
         } elseif ($this->datetimeFormat) {
-            // Don't invoke getDateFormat() directly to avoid infinite loop
+            // Don't invoke getDatetimeFormat() directly to avoid infinite loop
             $ok = $formatter->setPattern($this->datetimeFormat);
             if (!$ok) {
                 throw new InvalidArgumentException("Invalid date format {$this->datetimeFormat}");
@@ -239,7 +242,7 @@ class DatetimeField extends TextField
      *
      * @see http://userguide.icu-project.org/formatparse/datetime#TOC-Date-Field-Symbol-Table
      */
-    public function getDateFormat()
+    public function getDatetimeFormat()
     {
         if ($this->getHTML5()) {
             // Browsers expect ISO 8601 dates, localisation is handled on the client
@@ -557,7 +560,7 @@ class DatetimeField extends TextField
                 _t(
                     'DateField.VALIDDATEFORMAT2',
                     "Please enter a valid date format ({format})",
-                    ['format' => $this->getDateFormat()]
+                    ['format' => $this->getDatetimeFormat()]
                 )
             );
             return false;
@@ -636,24 +639,4 @@ class DatetimeField extends TextField
         $this->timezone = $timezone;
         return $this;
     }
-
-    /**
-     * @return string
-     */
-    public function getDateTimeOrder()
-    {
-        return $this->dateTimeOrder;
-    }
-
-    /**
-     * Set date time order format string. Use {date} and {time} as placeholders.
-     *
-     * @param string $dateTimeOrder
-     * @return $this
-     */
-    public function setDateTimeOrder($dateTimeOrder)
-    {
-        $this->dateTimeOrder = $dateTimeOrder;
-        return $this;
-    }
 }
diff --git a/src/ORM/FieldType/DBDatetime.php b/src/ORM/FieldType/DBDatetime.php
index 159e43c8b..1630c1ebc 100644
--- a/src/ORM/FieldType/DBDatetime.php
+++ b/src/ORM/FieldType/DBDatetime.php
@@ -132,32 +132,18 @@ class DBDatetime extends DBDate implements TemplateGlobalProvider
     public function scaffoldFormField($title = null, $params = null)
     {
         $field = DatetimeField::create($this->name, $title);
-        $dateFormat = $field->getDateField()->getDateFormat();
-        $timeFormat = $field->getTimeField()->getTimeFormat();
+        $dateTimeFormat = $field->getDatetimeFormat();
 
         // Set date formatting hints and example
-        $date = static::now()->Format($dateFormat);
+        $date = static::now()->Format($dateTimeFormat);
         $field
-            ->getDateField()
             ->setDescription(_t(
                 'FormField.EXAMPLE',
                 'e.g. {format}',
                 'Example format',
                 [ 'format' => $date ]
             ))
-            ->setAttribute('placeholder', $dateFormat);
-
-        // Set time formatting hints and example
-        $time = static::now()->Format($timeFormat);
-        $field
-            ->getTimeField()
-            ->setDescription(_t(
-                'FormField.EXAMPLE',
-                'e.g. {format}',
-                'Example format',
-                [ 'format' => $time ]
-            ))
-            ->setAttribute('placeholder', $timeFormat);
+            ->setAttribute('placeholder', $dateTimeFormat);
 
         return $field;
     }
diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index f0736f44a..02dccca14 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -37,26 +37,18 @@ class DatetimeFieldTest extends SapphireTest
         $form = $this->getMockForm();
         $form->Fields()->push($dateTimeField);
 
-        $dateTimeField->setSubmittedValue([
-            'date' => '2003-03-29',
-            'time' => '23:59:38'
-        ]);
+        $dateTimeField->setSubmittedValue('2003-03-29T23:59:38');
         $validator = new RequiredFields();
         $this->assertTrue($dateTimeField->validate($validator));
         $m = new Model();
         $form->saveInto($m);
-        $this->assertEquals('2003-03-29 23:59:38', $m->MyDatetime);
+        $this->assertEquals('2003-03-29T23:59:38', $m->MyDatetime);
     }
 
     public function testFormSaveIntoLocalised()
     {
         $dateTimeField = new DatetimeField('MyDatetime');
-
-        $dateTimeField->getDateField()
-            ->setHTML5(false)
-            ->setLocale('en_NZ');
-
-        $dateTimeField->getTimeField()
+        $dateTimeField
             ->setHTML5(false)
             ->setLocale('en_NZ');
 
@@ -64,15 +56,12 @@ class DatetimeFieldTest extends SapphireTest
         $form->Fields()->push($dateTimeField);
 
         // en_NZ standard format
-        $dateTimeField->setSubmittedValue([
-            'date' => '29/03/2003',
-            'time' => '11:59:38 pm'
-        ]);
+        $dateTimeField->setSubmittedValue('29/03/2003 11:59:38 pm');
         $validator = new RequiredFields();
         $this->assertTrue($dateTimeField->validate($validator));
         $m = new Model();
         $form->saveInto($m);
-        $this->assertEquals('2003-03-29 23:59:38', $m->MyDatetime);
+        $this->assertEquals('2003-03-29T23:59:38', $m->MyDatetime);
     }
 
     public function testDataValue()
@@ -119,33 +108,23 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertEquals($f->dataValue(), '2003-03-29 23:59:38');
     }
 
-    public function testSetValueWithArray()
+    public function testSetValue()
     {
         $datetimeField = new DatetimeField('Datetime', 'Datetime');
-        $datetimeField->setSubmittedValue([
-            'date' => '2003-03-29',
-            'time' => '23:00:00'
-        ]);
+        $datetimeField->setSubmittedValue('2003-03-29 23:00:00');
         $this->assertEquals($datetimeField->dataValue(), '2003-03-29 23:00:00');
     }
 
-    public function testSetValueWithArrayLocalised()
+    public function testSetValueWithLocalised()
     {
         $datetimeField = new DatetimeField('Datetime', 'Datetime');
 
-        $datetimeField->getDateField()
-            ->setHTML5(false)
-            ->setLocale('en_NZ');
-
-        $datetimeField->getTimeField()
+        $datetimeField
             ->setHTML5(false)
             ->setLocale('en_NZ');
 
         // Values can only be localized (= non-ISO) in array notation
-        $datetimeField->setSubmittedValue([
-            'date' => '29/03/2003',
-            'time' => '11:00:00 pm'
-        ]);
+        $datetimeField->setSubmittedValue('29/03/2003 11:00:00 pm');
         $this->assertEquals($datetimeField->dataValue(), '2003-03-29 23:00:00');
     }
 
@@ -167,11 +146,7 @@ class DatetimeFieldTest extends SapphireTest
         // Berlin and Auckland have 12h time difference in northern hemisphere winter
         $datetimeField = new DatetimeField('Datetime', 'Datetime');
 
-        $datetimeField->getDateField()
-            ->setHTML5(false)
-            ->setLocale('en_NZ');
-
-        $datetimeField->getTimeField()
+        $datetimeField
             ->setHTML5(false)
             ->setLocale('en_NZ');
 
@@ -182,8 +157,7 @@ class DatetimeFieldTest extends SapphireTest
             $datetimeField->Value(),
             'User value is formatted, and in user timezone'
         );
-        $this->assertEquals('25/12/2003', $datetimeField->getDateField()->Value());
-        $this->assertEquals('11:59:59 AM', $datetimeField->getTimeField()->Value());
+
         $this->assertEquals(
             '2003-12-24 23:59:59',
             $datetimeField->dataValue(),
@@ -197,81 +171,22 @@ class DatetimeFieldTest extends SapphireTest
         // Berlin and Auckland have 12h time difference in northern hemisphere summer, but Berlin and Moscow only 2h.
         $datetimeField = new DatetimeField('Datetime', 'Datetime');
 
-        $datetimeField->getDateField()
-            ->setHTML5(false)
-            ->setLocale('en_NZ');
-
-        $datetimeField->getTimeField()
+        $datetimeField
             ->setHTML5(false)
             ->setLocale('en_NZ');
 
         $datetimeField->setTimezone('Europe/Moscow');
-        $datetimeField->setSubmittedValue([
-            // pass in default format, at user time (Moscow)
-            'date' => '24/06/2003',
-            'time' => '11:59:59 pm',
-        ]);
+        // pass in default format, at user time (Moscow)
+        $datetimeField->setSubmittedValue('24/06/2003 11:59:59 pm');
         $this->assertTrue($datetimeField->validate(new RequiredFields()));
         $this->assertEquals('2003-06-24 21:59:59', $datetimeField->dataValue(), 'Data value matches server timezone');
     }
 
-    public function testSetDateField()
-    {
-        $form = $this->getMockForm();
-        $field = new DatetimeField('Datetime', 'Datetime');
-        $field->setForm($form);
-        $field->setSubmittedValue([
-            'date' => '2003-06-24',
-            'time' => '23:59:59',
-        ]);
-        $dateField = new DateField('Datetime[date]');
-        $field->setDateField($dateField);
-
-        $this->assertEquals(
-            $dateField->getForm(),
-            $form,
-            'Sets form on new field'
-        );
-
-        $this->assertEquals(
-            '2003-06-24',
-            $dateField->dataValue(),
-            'Sets existing value on new field'
-        );
-    }
-
-    public function testSetTimeField()
-    {
-        $form = $this->getMockForm();
-        $field = new DatetimeField('Datetime', 'Datetime');
-        $field->setForm($form);
-        $field->setSubmittedValue([
-            'date' => '2003-06-24',
-            'time' => '23:59:59',
-        ]);
-        $timeField = new TimeField('Datetime[time]');
-        $field->setTimeField($timeField);
-
-        $this->assertEquals(
-            $timeField->getForm(),
-            $form,
-            'Sets form on new field'
-        );
-
-        $this->assertEquals(
-            '23:59:59',
-            $timeField->dataValue(),
-            'Sets existing value on new field'
-        );
-    }
-
     public function testGetName()
     {
         $field = new DatetimeField('Datetime');
 
         $this->assertEquals('Datetime', $field->getName());
-        $this->assertEquals('Datetime[date]', $field->getDateField()->getName());
-        $this->assertEquals('Datetime[time]', $field->getTimeField()->getName());
     }
 
     public function testSetName()
@@ -279,8 +194,6 @@ class DatetimeFieldTest extends SapphireTest
         $field = new DatetimeField('Datetime', 'Datetime');
         $field->setName('CustomDatetime');
         $this->assertEquals('CustomDatetime', $field->getName());
-        $this->assertEquals('CustomDatetime[date]', $field->getDateField()->getName());
-        $this->assertEquals('CustomDatetime[time]', $field->getTimeField()->getName());
     }
 
     protected function getMockForm()
diff --git a/tests/php/Forms/FormSchemaTest.php b/tests/php/Forms/FormSchemaTest.php
index 3073482f2..fb5b8659a 100644
--- a/tests/php/Forms/FormSchemaTest.php
+++ b/tests/php/Forms/FormSchemaTest.php
@@ -462,6 +462,8 @@ class FormSchemaTest extends SapphireTest
                         'extraClass' => 'date text',
                         'description' => null,
                         'rightTitle' => null,
+                        'html5' => true,
+                        'lang' => 'en-US',
                         'leftTitle' => null,
                         'readOnly' => false,
                         'disabled' => false,
diff --git a/tests/php/ORM/DBDatetimeTest.php b/tests/php/ORM/DBDatetimeTest.php
index 428e56b03..bfb2ab032 100644
--- a/tests/php/ORM/DBDatetimeTest.php
+++ b/tests/php/ORM/DBDatetimeTest.php
@@ -29,7 +29,7 @@ class DBDatetimeTest extends SapphireTest
     public function testNowWithMockDate()
     {
         // Test setting
-        $mockDate = '2001-12-31 22:10:59';
+        $mockDate = '2001-12-31T22:10:59';
         DBDatetime::set_mock_now($mockDate);
         $systemDatetime = DBDatetime::create_field('Datetime', date('Y-m-d H:i:s'));
         $nowDatetime = DBDatetime::now();
@@ -55,10 +55,10 @@ class DBDatetimeTest extends SapphireTest
         $this->assertNull($date->getValue(), 'Boolean FALSE evaluates to NULL');
 
         $date = DBDatetime::create_field('Datetime', '0');
-        $this->assertEquals('1970-01-01 00:00:00', $date->getValue(), 'String zero is UNIX epoch time');
+        $this->assertEquals('1970-01-01T00:00:00', $date->getValue(), 'String zero is UNIX epoch time');
 
         $date = DBDatetime::create_field('Datetime', 0);
-        $this->assertEquals('1970-01-01 00:00:00', $date->getValue(), 'Numeric zero is UNIX epoch time');
+        $this->assertEquals('1970-01-01T00:00:00', $date->getValue(), 'Numeric zero is UNIX epoch time');
     }
 
     public function testExtendedDateTimes()
@@ -98,7 +98,7 @@ class DBDatetimeTest extends SapphireTest
     public function testURLDateTime()
     {
         $date = DBDatetime::create_field('Datetime', '2001-12-31 22:10:59');
-        $this->assertEquals('2001-12-31%2022%3A10%3A59', $date->URLDateTime());
+        $this->assertEquals('2001-12-31T22%3A10%3A59', $date->URLDateTime());
     }
 
     public function testAgoInPast()

From 507add8566a480a59201e40ba271d06fcdcfcb89 Mon Sep 17 00:00:00 2001
From: Saophalkun Ponlu <phalkunz@gmail.com>
Date: Fri, 21 Apr 2017 12:04:44 +1200
Subject: [PATCH 06/26] Update changelogs

---
 docs/en/04_Changelogs/4.0.0.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/docs/en/04_Changelogs/4.0.0.md b/docs/en/04_Changelogs/4.0.0.md
index c0266346a..f2cc7ea88 100644
--- a/docs/en/04_Changelogs/4.0.0.md
+++ b/docs/en/04_Changelogs/4.0.0.md
@@ -1397,8 +1397,13 @@ The below methods have been added or had their functionality updated to `DBDate`
 * `getFormatter` method added, which returns a locale-specific date/time formatter.
 
 `DBTime` specific changes:
+
 * Added `DBTime::FormatFromSettings`
 
+`DBDatetim` specific changes:
+
+* Changed `ISO_DATETIME`'s pattern from '`y-MM-dd HH:mm:ss`' to '`y-MM-dd\'T\'HH:mm:ss`'
+
 #### <a name="overview-orm-removed"></a>ORM Removed API
 
 * `DataObject::db` removed and replaced with `DataObjectSchema::fieldSpec` and `DataObjectSchema::fieldSpecs`
@@ -1670,6 +1675,12 @@ New `DatetimeField` methods replace `getConfig()` / `setConfig()`:
 * `getLocale()` / `setLocale()`
 * `datavaluefield` config is removed as internal data value is now fixed to ISO 8601 format
 
+The `DatetimeField` has changed behaviour:
+
+* It no longer relies on `DateField` and `TimeField`
+* Anything related to `DateField` and `TimeField` have been removed, e.g. `DatetimeField::getDateField()`
+* Added `getHTML5()` / `setHTML5()`
+
 New `DateField` methods replace `getConfig()` / `setConfig()`:
 
 * `getDateFormat()` / `setDateFormat()`

From d2132e85db8c906b57c258ee5909ca8a61cd2e96 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Wed, 26 Apr 2017 13:48:48 +1200
Subject: [PATCH 07/26] More specific localisations

---
 lang/en.yml                 |  4 ++++
 src/Forms/DatetimeField.php | 16 ++++++++--------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/lang/en.yml b/lang/en.yml
index 58f12af3e..384af5f54 100644
--- a/lang/en.yml
+++ b/lang/en.yml
@@ -57,6 +57,10 @@ en:
     VALIDDATEFORMAT2: 'Please enter a valid date format ({format})'
     VALIDDATEMAXDATE: 'Your date has to be older or matching the maximum allowed date ({date})'
     VALIDDATEMINDATE: 'Your date has to be newer or matching the minimum allowed date ({date})'
+  DatetimeField:
+      VALIDDATETIMEFORMAT: 'Please enter a valid date and time format ({format})'
+      VALIDDATEMAXDATETIME: 'Your date has to be older or matching the maximum allowed date and time ({datetime})'
+      VALIDDATEMINDATETIME: 'Your date has to be newer or matching the minimum allowed date and time ({datetime})'
   Director:
     INVALID_REQUEST: 'Invalid request'
   DropdownField:
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index a1db12a64..9c9b6b8b7 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -558,8 +558,8 @@ class DatetimeField extends TextField
             $validator->validationError(
                 $this->name,
                 _t(
-                    'DateField.VALIDDATEFORMAT2',
-                    "Please enter a valid date format ({format})",
+                    'DatetimeField.VALIDDATETIMEFORMAT',
+                    "Please enter a valid date and time format ({format})",
                     ['format' => $this->getDatetimeFormat()]
                 )
             );
@@ -574,9 +574,9 @@ class DatetimeField extends TextField
                 $validator->validationError(
                     $this->name,
                     _t(
-                        'DateField.VALIDDATEMINDATE',
-                        "Your date has to be newer or matching the minimum allowed date ({date})",
-                        ['date' => $this->iso8601ToLocalised($min)]
+                        'DatetimeField.VALIDDATETIMEMINDATE',
+                        "Your date has to be newer or matching the minimum allowed date and time ({datetime})",
+                        ['datetime' => $this->iso8601ToLocalised($min)]
                     )
                 );
                 return false;
@@ -591,9 +591,9 @@ class DatetimeField extends TextField
                 $validator->validationError(
                     $this->name,
                     _t(
-                        'DateField.VALIDDATEMAXDATE',
-                        "Your date has to be older or matching the maximum allowed date ({date})",
-                        ['date' => $this->iso8601ToLocalised($max)]
+                        'DatetimeField.VALIDDATEMAXDATETIME',
+                        "Your date has to be older or matching the maximum allowed date and time ({datetime})",
+                        ['datetime' => $this->iso8601ToLocalised($max)]
                     )
                 );
                 return false;

From e97783b05708fd72449605f41b7e7226b4e90a28 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Wed, 26 Apr 2017 13:49:29 +1200
Subject: [PATCH 08/26] Better second handling

---
 src/Forms/DatetimeField.php           | 8 ++++++++
 src/Forms/TimeField.php               | 2 +-
 tests/php/Forms/DatetimeFieldTest.php | 4 ++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 9c9b6b8b7..9557e6689 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -182,6 +182,14 @@ class DatetimeField extends TextField
         $fromFormatter = $this->getFormatter();
         $toFormatter = $this->getISO8601Formatter();
         $timestamp = $fromFormatter->parse($datetime);
+
+        // Try to parse time without seconds, since that's a valid HTML5 submission format
+        // See https://html.spec.whatwg.org/multipage/infrastructure.html#times
+        if ($timestamp === false && $this->getHTML5()) {
+            $fromFormatter->setPattern(str_replace(':ss', '', $fromFormatter->getPattern()));
+            $timestamp = $fromFormatter->parse($datetime);
+        }
+
         if ($timestamp === false) {
             return null;
         }
diff --git a/src/Forms/TimeField.php b/src/Forms/TimeField.php
index 85c377e17..26085cb6a 100644
--- a/src/Forms/TimeField.php
+++ b/src/Forms/TimeField.php
@@ -389,7 +389,7 @@ class TimeField extends TextField
         // Try to parse time without seconds, since that's a valid HTML5 submission format
         // See https://html.spec.whatwg.org/multipage/infrastructure.html#times
         if ($timestamp === false && $this->getHTML5()) {
-            $fromFormatter->setPattern('HH:mm');
+            $fromFormatter->setPattern(str_replace(':ss', '', DBTime::ISO_TIME));
             $timestamp = $fromFormatter->parse($time);
         }
 
diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index 02dccca14..13e31619a 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -136,6 +136,10 @@ class DatetimeFieldTest extends SapphireTest
         $f = new DatetimeField('Datetime', 'Datetime', '2003-03-29 00:00:00');
         $this->assertTrue($f->validate(new RequiredFields()));
 
+        $f = (new DatetimeField('Datetime', 'Datetime'))
+            ->setSubmittedValue('2003-03-29 00:00');
+        $this->assertTrue($f->validate(new RequiredFields()), 'Leaving out seconds (like many browsers)');
+
         $f = new DatetimeField('Datetime', 'Datetime', 'wrong');
         $this->assertFalse($f->validate(new RequiredFields()));
     }

From a279d00e81432ca253315c59aab82dafe07074ca Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Wed, 26 Apr 2017 13:49:40 +1200
Subject: [PATCH 09/26] Min/max validations

---
 tests/php/Forms/DatetimeFieldTest.php | 73 +++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index 13e31619a..fa685ad4f 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -13,6 +13,7 @@ use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\FormAction;
 use SilverStripe\Forms\Form;
 use SilverStripe\i18n\i18n;
+use SilverStripe\ORM\FieldType\DBDatetime;
 
 class DatetimeFieldTest extends SapphireTest
 {
@@ -144,6 +145,78 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertFalse($f->validate(new RequiredFields()));
     }
 
+    public function testValidateMinDate()
+    {
+        $dateField = new DatetimeField('Datetime');
+        $dateField->setMinDatetime('2009-03-31 23:00:00');
+        $dateField->setValue('2009-03-31 23:00:01');
+        $this->assertTrue($dateField->validate(new RequiredFields()), 'Time above min datetime');
+
+        $dateField = new DatetimeField('Datetime');
+        $dateField->setMinDatetime('2009-03-31 23:00:00');
+        $dateField->setValue('2009-03-31 22:00:00');
+        $this->assertFalse($dateField->validate(new RequiredFields()), 'Time below min datetime');
+
+        $dateField = new DatetimeField('Datetime');
+        $dateField->setMinDatetime('2009-03-31 23:00:00');
+        $dateField->setValue('2009-03-31 23:00:00');
+        $this->assertTrue($dateField->validate(new RequiredFields()), 'Date and time matching min datetime');
+
+        $dateField = new DatetimeField('Datetime');
+        $dateField->setMinDatetime('2009-03-31 23:00:00');
+        $dateField->setValue('2008-03-31 23:00:00');
+        $this->assertFalse($dateField->validate(new RequiredFields()), 'Date below min datetime');
+    }
+
+    public function testValidateMinDateStrtotime()
+    {
+        $f = new DatetimeField('Datetime');
+        $f->setMinDatetime('-7 days');
+        $f->setValue(strftime('%Y-%m-%d %T', strtotime('-8 days', DBDatetime::now()->getTimestamp())));
+        $this->assertFalse($f->validate(new RequiredFields()), 'Date below min datetime, with strtotime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setMinDatetime('-7 days');
+        $f->setValue(strftime('%Y-%m-%d %T', strtotime('-7 days', DBDatetime::now()->getTimestamp())));
+        $this->assertTrue($f->validate(new RequiredFields()), 'Date matching min datetime, with strtotime');
+    }
+
+    public function testValidateMaxDateStrtotime()
+    {
+        $f = new DatetimeField('Datetime');
+        $f->setMaxDatetime('7 days');
+        $f->setValue(strftime('%Y-%m-%d %T', strtotime('8 days', DBDatetime::now()->getTimestamp())));
+        $this->assertFalse($f->validate(new RequiredFields()), 'Date above max date, with strtotime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setMaxDatetime('7 days');
+        $f->setValue(strftime('%Y-%m-%d %T', strtotime('7 days', DBDatetime::now()->getTimestamp())));
+        $this->assertTrue($f->validate(new RequiredFields()), 'Date matching max date, with strtotime');
+    }
+
+    public function testValidateMaxDate()
+    {
+        $f = new DatetimeField('Datetime');
+        $f->setMaxDatetime('2009-03-31 23:00:00');
+        $f->setValue('2009-03-31 22:00:00');
+        $this->assertTrue($f->validate(new RequiredFields()), 'Time below max datetime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setMaxDatetime('2009-03-31 23:00:00');
+        $f->setValue('2010-03-31 23:00:01');
+        $this->assertFalse($f->validate(new RequiredFields()), 'Time above max datetime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setMaxDatetime('2009-03-31 23:00:00');
+        $f->setValue('2009-03-31 23:00:00');
+        $this->assertTrue($f->validate(new RequiredFields()), 'Date and time matching max datetime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setMaxDatetime('2009-03-31 23:00:00');
+        $f->setValue('2010-03-31 23:00:00');
+        $this->assertFalse($f->validate(new RequiredFields()), 'Date above max datetime');
+    }
+
     public function testTimezoneSetLocalised()
     {
         date_default_timezone_set('Europe/Berlin');

From 1ec2abe75f9f3541fa8866361e20a3d939249358 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Wed, 26 Apr 2017 13:49:59 +1200
Subject: [PATCH 10/26] Fixed timezone and normalised ISO handling
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

A few observations:
- ISO says “T” is optional (https://en.wikipedia.org/wiki/ISO_8601#cite_note-21),
- WHATWG says in the HTML5 spec that it’s optional (https://html.spec.whatwg.org/multipage/infrastructure.html#local-dates-and-times)
- W3C says it’s reqiured in 1997 (https://www.w3.org/TR/NOTE-datetime), but then later says it’s optional in its HTML5 spec (https://www.w3.org/TR/html5/infrastructure.html#floating-dates-and-times).
- Chrome doesn’t parse values with whitespace separators (requires "T")
- DataObject DBDatetime values and database columns use whitespace separators (and will have many devs relying on this format)
- MySQL only supports whitespace separators (https://dev.mysql.com/doc/refman/5.7/en/datetime.html)
- SQLite can parse both ways (https://sqlite.org/lang_datefunc.html)

So the goal here is to retain ORM/database compatibility with 3.x (whitespace separator),
while exposing "T" separators to the browser in HTML5 mode.

Regarding timezones, this fixes a regression where setValue() would not actually
apply the timezone (last $value assignment is ineffective now that sub fields are removed).
---
 docs/en/04_Changelogs/4.0.0.md        |  12 +--
 src/Forms/DatetimeField.php           | 119 +++++++++++++++++---------
 src/ORM/FieldType/DBDatetime.php      |  11 ++-
 tests/php/Forms/DatetimeFieldTest.php |  57 ++++++++++--
 4 files changed, 144 insertions(+), 55 deletions(-)

diff --git a/docs/en/04_Changelogs/4.0.0.md b/docs/en/04_Changelogs/4.0.0.md
index f2cc7ea88..32549d376 100644
--- a/docs/en/04_Changelogs/4.0.0.md
+++ b/docs/en/04_Changelogs/4.0.0.md
@@ -1400,10 +1400,6 @@ The below methods have been added or had their functionality updated to `DBDate`
 
 * Added `DBTime::FormatFromSettings`
 
-`DBDatetim` specific changes:
-
-* Changed `ISO_DATETIME`'s pattern from '`y-MM-dd HH:mm:ss`' to '`y-MM-dd\'T\'HH:mm:ss`'
-
 #### <a name="overview-orm-removed"></a>ORM Removed API
 
 * `DataObject::db` removed and replaced with `DataObjectSchema::fieldSpec` and `DataObjectSchema::fieldSpecs`
@@ -1677,8 +1673,12 @@ New `DatetimeField` methods replace `getConfig()` / `setConfig()`:
 
 The `DatetimeField` has changed behaviour:
 
-* It no longer relies on `DateField` and `TimeField`
-* Anything related to `DateField` and `TimeField` have been removed, e.g. `DatetimeField::getDateField()`
+* It uses a combined input instead of a composite from `DateField` and `TimeField`
+  Consequently, `getDateField()` and `getTimeField()` have been removed.
+* It returns [ISO 8601 normalised dates](https://html.spec.whatwg.org/multipage/infrastructure.html#local-dates-and-times)
+  by default in `Value()`, which include a "T" separator between date and time. 
+  This is required to allow HTML5 input. Either use `setHTML5(false)` to set your custom format,
+  or use `dataValue()` to retrieve a whitespace separated representation. 
 * Added `getHTML5()` / `setHTML5()`
 
 New `DateField` methods replace `getConfig()` / `setConfig()`:
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 9557e6689..86e00209d 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -8,16 +8,10 @@ use SilverStripe\i18n\i18n;
 use SilverStripe\ORM\FieldType\DBDatetime;
 
 /**
- * Form field used for editing date time string
- *
- * # Localization
- *
- * See {@link DateField}
- *
- * # Configuration
- *
- * - "timezone": Set a different timezone for viewing. {@link dataValue()} will still save
- * the time in PHP's default timezone (date_default_timezone_get()), its only a view setting.
+ * Form field used for editing date time strings.
+ * By default, the field handles strings in normalised ISO 8601 format,
+ * for example 2017-04-26T23:59:59. The "T" separator can be replaced with a whitespace for value setting.
+ * Data is passed on via {@link dataValue()} with whitespace separators.
  */
 class DatetimeField extends TextField
 {
@@ -79,6 +73,9 @@ class DatetimeField extends TextField
      */
     protected $rawValue = null;
 
+    /**
+     * @inheritDoc
+     */
     protected $schemaDataType = FormField::SCHEMA_DATA_TYPE_DATETIME;
 
     /**
@@ -88,10 +85,12 @@ class DatetimeField extends TextField
      */
     protected $dateTimeOrder = '{date} {time}';
 
-    public function __construct($name, $title = null, $value = "")
-    {
-        parent::__construct($name, $title, $value);
-    }
+    /**
+     * Custom timezone
+     *
+     * @var string
+     */
+    protected $timezone = null;
 
     public function setForm($form)
     {
@@ -171,7 +170,7 @@ class DatetimeField extends TextField
     /**
      * Convert date localised in the current locale to ISO 8601 date
      *
-     * @param string $date
+     * @param string $datetime
      * @return string The formatted date, or null if not a valid date
      */
     public function localisedToISO8601($datetime)
@@ -181,6 +180,13 @@ class DatetimeField extends TextField
         }
         $fromFormatter = $this->getFormatter();
         $toFormatter = $this->getISO8601Formatter();
+
+        // Remove 'T' date and time separator before parsing (required by W3C HTML5 fields)
+        if ($this->getHTML5()) {
+            $datetime = str_replace('T', ' ', $datetime);
+        }
+
+        // Try to parse time with seconds
         $timestamp = $fromFormatter->parse($datetime);
 
         // Try to parse time without seconds, since that's a valid HTML5 submission format
@@ -204,7 +210,7 @@ class DatetimeField extends TextField
      */
     protected function getFormatter()
     {
-        if ($this->getHTML5() && $this->datetimeFormat && $this->datetimeFormat !== DBDatetime::ISO_DATETIME) {
+        if ($this->getHTML5() && $this->datetimeFormat && $this->datetimeFormat !== DBDatetime::ISO_DATETIME_NORMALISED) {
             throw new \LogicException(
                 'Please opt-out of HTML5 processing of ISO 8601 dates via setHTML5(false) if using setDatetimeFormat()'
             );
@@ -230,8 +236,9 @@ class DatetimeField extends TextField
         );
 
         if ($this->getHTML5()) {
-            // Browsers expect ISO 8601 dates, localisation is handled on the client
-            $formatter->setPattern(DBDatetime::ISO_DATETIME);
+            // Browsers expect ISO 8601 dates, localisation is handled on the client.
+            // Add 'T' date and time separator to create W3C compliant format
+            $formatter->setPattern(DBDatetime::ISO_DATETIME_NORMALISED);
         } elseif ($this->datetimeFormat) {
             // Don't invoke getDatetimeFormat() directly to avoid infinite loop
             $ok = $formatter->setPattern($this->datetimeFormat);
@@ -254,7 +261,7 @@ class DatetimeField extends TextField
     {
         if ($this->getHTML5()) {
             // Browsers expect ISO 8601 dates, localisation is handled on the client
-            $this->setDatetimeFormat(DBDatetime::ISO_DATETIME);
+            $this->setDatetimeFormat(DBDatetime::ISO_DATETIME_NORMALISED);
         }
 
         if ($this->datetimeFormat) {
@@ -295,6 +302,11 @@ class DatetimeField extends TextField
         // Build new formatter with the altered timezone
         $formatter = clone $this->getISO8601Formatter();
         $formatter->setTimeZone($timezone);
+
+        // ISO8601 date with a standard "T" separator (W3C standard).
+        // Note we omit timezone from this format, and we assume server TZ always.
+        $formatter->setPattern(DBDatetime::ISO_DATETIME_NORMALISED);
+
         return $formatter;
     }
 
@@ -312,9 +324,11 @@ class DatetimeField extends TextField
             date_default_timezone_get() // Default to server timezone
         );
         $formatter->setLenient(false);
-        // CLDR iso8601 date.
-        // Note we omit timezone from this format, and we assume server TZ always.
-        $formatter->setPattern('y-MM-dd HH:mm:ss');
+
+        // Note we omit timezone from this format, and we always assume server TZ
+        // ISO8601 date with a standard "T" separator (W3C standard).
+        $formatter->setPattern(DBDatetime::ISO_DATETIME_NORMALISED);
+
         return $formatter;
     }
 
@@ -343,6 +357,14 @@ class DatetimeField extends TextField
         // If invalid, assign for later validation failure
         $isoFormatter = $this->getISO8601Formatter();
         $timestamp = $isoFormatter->parse($value);
+
+        // Retry without "T" separator
+        if (!$timestamp) {
+            $isoFallbackFormatter = $this->getISO8601Formatter();
+            $isoFallbackFormatter->setPattern(DBDatetime::ISO_DATETIME);
+            $timestamp = $isoFallbackFormatter->parse($value);
+        }
+
         if ($timestamp === false) {
             return $this;
         }
@@ -353,11 +375,6 @@ class DatetimeField extends TextField
         // Save value
         $this->value = $value;
 
-        // Shift iso date into timezone before assignment to subfields
-        $timezoneFormatter = $this->getTimezoneFormatter();
-        if ($timezoneFormatter) {
-            $value = $timezoneFormatter->format($timestamp);
-        }
         return $this;
     }
 
@@ -366,12 +383,40 @@ class DatetimeField extends TextField
         return $this->iso8601ToLocalised($this->value);
     }
 
+    public function dataValue()
+    {
+        return $this->iso8601ToDataValue($this->value);
+    }
+
     /**
-     * Convert an ISO 8601 localised date into the format specified by the
-     * current date format.
+     * Convert an ISO 8601 localised datetime into a saveable representation.
      *
-     * @param string $date
-     * @return string The formatted date, or null if not a valid date
+     * @param string $datetime
+     * @return string The formatted date and time, or null if not a valid date and time
+     */
+    public function iso8601ToDataValue($datetime)
+    {
+        $fromFormatter = $this->getISO8601Formatter();
+        $toFormatter = $this->getFormatter();
+
+        // Set default timezone (avoid shifting data values into user timezone)
+        $toFormatter->setTimezone(date_default_timezone_get());
+
+        // Send to data object without "T" separator
+        $toFormatter->setPattern(DBDatetime::ISO_DATETIME);
+
+        $timestamp = $fromFormatter->parse($datetime);
+        if ($timestamp === false) {
+            return null;
+        }
+        return $toFormatter->format($timestamp) ?: null;
+    }
+
+    /**
+     * Convert an ISO 8601 localised datetime into the format specified by the current format.
+     *
+     * @param string $datetime
+     * @return string The formatted date and time, or null if not a valid date and time
      */
     public function iso8601ToLocalised($datetime)
     {
@@ -385,13 +430,14 @@ class DatetimeField extends TextField
         if ($timestamp === false) {
             return null;
         }
+
         return $toFormatter->format($timestamp) ?: null;
     }
 
     /**
      * Tidy up iso8601-ish date, or approximation
      *
-     * @param string $date Date in iso8601 or approximate form
+     * @param string $date Date in ISO 8601 or approximate form
      * @return string iso8601 date, or null if not valid
      */
     public function tidyISO8601($datetime)
@@ -523,7 +569,7 @@ class DatetimeField extends TextField
     }
 
     /**
-     * @param string $minDatetime
+     * @param string $minDatetime A string in ISO 8601 format
      * @return $this
      */
     public function setMinDatetime($minDatetime)
@@ -626,13 +672,6 @@ class DatetimeField extends TextField
         return $this->timezone;
     }
 
-    /**
-     * Custom timezone
-     *
-     * @var string
-     */
-    protected $timezone = null;
-
     /**
      * @param string $timezone
      * @return $this
diff --git a/src/ORM/FieldType/DBDatetime.php b/src/ORM/FieldType/DBDatetime.php
index 1630c1ebc..c52dbc8d8 100644
--- a/src/ORM/FieldType/DBDatetime.php
+++ b/src/ORM/FieldType/DBDatetime.php
@@ -35,9 +35,16 @@ use InvalidArgumentException;
 class DBDatetime extends DBDate implements TemplateGlobalProvider
 {
     /**
-     * Standard ISO format string for date and time in CLDR standard format
+     * Standard ISO format string for date and time in CLDR standard format,
+     * with a whitespace separating date and time (common database representation, e.g. in MySQL).
      */
-    const ISO_DATETIME = 'y-MM-dd\'T\'HH:mm:ss';
+    const ISO_DATETIME = 'y-MM-dd HH:mm:ss';
+
+    /**
+     * Standard ISO format string for date and time in CLDR standard format,
+     * with a "T" separator between date and time (W3C standard, e.g. for HTML5 datetime-local fields).
+     */
+    const ISO_DATETIME_NORMALISED = 'y-MM-dd\'T\'HH:mm:ss';
 
     /**
      * Returns the standard localised date
diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index fa685ad4f..df4e517f8 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -43,7 +43,7 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertTrue($dateTimeField->validate($validator));
         $m = new Model();
         $form->saveInto($m);
-        $this->assertEquals('2003-03-29T23:59:38', $m->MyDatetime);
+        $this->assertEquals('2003-03-29 23:59:38', $m->MyDatetime);
     }
 
     public function testFormSaveIntoLocalised()
@@ -62,7 +62,7 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertTrue($dateTimeField->validate($validator));
         $m = new Model();
         $form->saveInto($m);
-        $this->assertEquals('2003-03-29T23:59:38', $m->MyDatetime);
+        $this->assertEquals('2003-03-29 23:59:38', $m->MyDatetime);
     }
 
     public function testDataValue()
@@ -107,13 +107,21 @@ class DatetimeFieldTest extends SapphireTest
         $f = new DatetimeField('Datetime', 'Datetime');
         $f->setValue('2003-03-29 23:59:38');
         $this->assertEquals($f->dataValue(), '2003-03-29 23:59:38');
+
+        $f = new DatetimeField('Datetime', 'Datetime');
+        $f->setValue('2003-03-29T23:59:38');
+        $this->assertEquals($f->dataValue(), '2003-03-29 23:59:38', 'Normalised ISO');
     }
 
-    public function testSetValue()
+    public function testSubmittedValue()
     {
         $datetimeField = new DatetimeField('Datetime', 'Datetime');
         $datetimeField->setSubmittedValue('2003-03-29 23:00:00');
         $this->assertEquals($datetimeField->dataValue(), '2003-03-29 23:00:00');
+
+        $datetimeField = new DatetimeField('Datetime', 'Datetime');
+        $datetimeField->setSubmittedValue('2003-03-29T23:00:00');
+        $this->assertEquals($datetimeField->dataValue(), '2003-03-29 23:00:00', 'Normalised ISO');
     }
 
     public function testSetValueWithLocalised()
@@ -134,6 +142,9 @@ class DatetimeFieldTest extends SapphireTest
         $f = new DatetimeField('Datetime', 'Datetime', '2003-03-29 23:59:38');
         $this->assertTrue($f->validate(new RequiredFields()));
 
+        $f = new DatetimeField('Datetime', 'Datetime', '2003-03-29T23:59:38');
+        $this->assertTrue($f->validate(new RequiredFields()), 'Normalised ISO');
+
         $f = new DatetimeField('Datetime', 'Datetime', '2003-03-29 00:00:00');
         $this->assertTrue($f->validate(new RequiredFields()));
 
@@ -166,6 +177,11 @@ class DatetimeFieldTest extends SapphireTest
         $dateField->setMinDatetime('2009-03-31 23:00:00');
         $dateField->setValue('2008-03-31 23:00:00');
         $this->assertFalse($dateField->validate(new RequiredFields()), 'Date below min datetime');
+
+        $dateField = new DatetimeField('Datetime');
+        $dateField->setMinDatetime('2009-03-31T23:00:00');
+        $dateField->setValue('2009-03-31T23:00:01');
+        $this->assertTrue($dateField->validate(new RequiredFields()), 'Time above min datetime with normalised ISO');
     }
 
     public function testValidateMinDateStrtotime()
@@ -215,9 +231,14 @@ class DatetimeFieldTest extends SapphireTest
         $f->setMaxDatetime('2009-03-31 23:00:00');
         $f->setValue('2010-03-31 23:00:00');
         $this->assertFalse($f->validate(new RequiredFields()), 'Date above max datetime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setMaxDatetime('2009-03-31T23:00:00');
+        $f->setValue('2009-03-31T22:00:00');
+        $this->assertTrue($f->validate(new RequiredFields()), 'Time below max datetime with normalised ISO');
     }
 
-    public function testTimezoneSetLocalised()
+    public function testTimezoneSetValueLocalised()
     {
         date_default_timezone_set('Europe/Berlin');
         // Berlin and Auckland have 12h time difference in northern hemisphere winter
@@ -230,7 +251,7 @@ class DatetimeFieldTest extends SapphireTest
         $datetimeField->setTimezone('Pacific/Auckland');
         $datetimeField->setValue('2003-12-24 23:59:59');
         $this->assertEquals(
-            '25/12/2003 11:59:59 AM',
+            '25/12/2003, 11:59:59 AM',
             $datetimeField->Value(),
             'User value is formatted, and in user timezone'
         );
@@ -238,11 +259,32 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertEquals(
             '2003-12-24 23:59:59',
             $datetimeField->dataValue(),
-            'Data value is unformatted, and in server timezone'
+            'Data value is in ISO format, and in server timezone'
         );
     }
 
-    public function testTimezoneFromConfigLocalised()
+    public function testTimezoneSetValueWithHtml5()
+    {
+        date_default_timezone_set('Europe/Berlin');
+        // Berlin and Auckland have 12h time difference in northern hemisphere winter
+        $datetimeField = new DatetimeField('Datetime', 'Datetime');
+
+        $datetimeField->setTimezone('Pacific/Auckland');
+        $datetimeField->setValue('2003-12-24 23:59:59');
+        $this->assertEquals(
+            '2003-12-25T11:59:59',
+            $datetimeField->Value(),
+            'User value is in normalised ISO format and in user timezone'
+        );
+
+        $this->assertEquals(
+            '2003-12-24 23:59:59',
+            $datetimeField->dataValue(),
+            'Data value is in ISO format, and in server timezone'
+        );
+    }
+
+    public function testTimezoneSetSubmittedValueLocalised()
     {
         date_default_timezone_set('Europe/Berlin');
         // Berlin and Auckland have 12h time difference in northern hemisphere summer, but Berlin and Moscow only 2h.
@@ -285,4 +327,5 @@ class DatetimeFieldTest extends SapphireTest
             )
         );
     }
+
 }

From a73abbfcb834dc740207d86bab20d7009ee60beb Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 09:18:38 +1200
Subject: [PATCH 11/26] unit test cleanup

---
 docs/en/04_Changelogs/4.0.0.md        |  1 +
 tests/php/Forms/DatetimeFieldTest.php | 31 ++++++++++++---------------
 tests/php/ORM/DBDatetimeTest.php      |  8 +++----
 3 files changed, 19 insertions(+), 21 deletions(-)

diff --git a/docs/en/04_Changelogs/4.0.0.md b/docs/en/04_Changelogs/4.0.0.md
index 32549d376..ea1a357bc 100644
--- a/docs/en/04_Changelogs/4.0.0.md
+++ b/docs/en/04_Changelogs/4.0.0.md
@@ -1679,6 +1679,7 @@ The `DatetimeField` has changed behaviour:
   by default in `Value()`, which include a "T" separator between date and time. 
   This is required to allow HTML5 input. Either use `setHTML5(false)` to set your custom format,
   or use `dataValue()` to retrieve a whitespace separated representation. 
+* It no longer accepts `setValue()` as an array with 'date' and 'time' keys
 * Added `getHTML5()` / `setHTML5()`
 
 New `DateField` methods replace `getConfig()` / `setConfig()`:
diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index df4e517f8..08dfdab88 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -80,12 +80,11 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertEquals($f->dataValue(), null);
     }
 
-    // /**
-    //  * @expectedException InvalidArgumentException
-    //  */
-    // public function testConstructorWithLocalizedDateString() {
-    // 	$f = new DatetimeField('Datetime', 'Datetime', '29/03/2003 23:59:38');
-    // }
+    public function testConstructorWithLocalizedDateSetsNullValue()
+    {
+        $f = new DatetimeField('Datetime', 'Datetime', '29/03/2003 23:59:38');
+        $this->assertNull($f->Value());
+    }
 
     public function testConstructorWithIsoDate()
     {
@@ -94,14 +93,6 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertEquals($f->dataValue(), '2003-03-29 23:59:38');
     }
 
-    // /**
-    //  * @expectedException InvalidArgumentException
-    //  */
-    // public function testSetValueWithDateString() {
-    // 	$f = new DatetimeField('Datetime', 'Datetime');
-    // 	$f->setValue('29/03/2003');
-    // }
-
     public function testSetValueWithDateTimeString()
     {
         $f = new DatetimeField('Datetime', 'Datetime');
@@ -132,9 +123,15 @@ class DatetimeFieldTest extends SapphireTest
             ->setHTML5(false)
             ->setLocale('en_NZ');
 
-        // Values can only be localized (= non-ISO) in array notation
         $datetimeField->setSubmittedValue('29/03/2003 11:00:00 pm');
         $this->assertEquals($datetimeField->dataValue(), '2003-03-29 23:00:00');
+
+        // Some localisation packages exclude the ',' in default medium format
+        $this->assertRegExp(
+            '#29/03/2003(,)? 11:00:00 (AM|am)#',
+            $datetimeField->Value(),
+            'User value is formatted, and in user timezone'
+        );
     }
 
     public function testValidate()
@@ -246,12 +243,12 @@ class DatetimeFieldTest extends SapphireTest
 
         $datetimeField
             ->setHTML5(false)
-            ->setLocale('en_NZ');
+            ->setDatetimeFormat('dd/MM/y HH:mm:ss');
 
         $datetimeField->setTimezone('Pacific/Auckland');
         $datetimeField->setValue('2003-12-24 23:59:59');
         $this->assertEquals(
-            '25/12/2003, 11:59:59 AM',
+            '25/12/2003 11:59:59',
             $datetimeField->Value(),
             'User value is formatted, and in user timezone'
         );
diff --git a/tests/php/ORM/DBDatetimeTest.php b/tests/php/ORM/DBDatetimeTest.php
index bfb2ab032..428e56b03 100644
--- a/tests/php/ORM/DBDatetimeTest.php
+++ b/tests/php/ORM/DBDatetimeTest.php
@@ -29,7 +29,7 @@ class DBDatetimeTest extends SapphireTest
     public function testNowWithMockDate()
     {
         // Test setting
-        $mockDate = '2001-12-31T22:10:59';
+        $mockDate = '2001-12-31 22:10:59';
         DBDatetime::set_mock_now($mockDate);
         $systemDatetime = DBDatetime::create_field('Datetime', date('Y-m-d H:i:s'));
         $nowDatetime = DBDatetime::now();
@@ -55,10 +55,10 @@ class DBDatetimeTest extends SapphireTest
         $this->assertNull($date->getValue(), 'Boolean FALSE evaluates to NULL');
 
         $date = DBDatetime::create_field('Datetime', '0');
-        $this->assertEquals('1970-01-01T00:00:00', $date->getValue(), 'String zero is UNIX epoch time');
+        $this->assertEquals('1970-01-01 00:00:00', $date->getValue(), 'String zero is UNIX epoch time');
 
         $date = DBDatetime::create_field('Datetime', 0);
-        $this->assertEquals('1970-01-01T00:00:00', $date->getValue(), 'Numeric zero is UNIX epoch time');
+        $this->assertEquals('1970-01-01 00:00:00', $date->getValue(), 'Numeric zero is UNIX epoch time');
     }
 
     public function testExtendedDateTimes()
@@ -98,7 +98,7 @@ class DBDatetimeTest extends SapphireTest
     public function testURLDateTime()
     {
         $date = DBDatetime::create_field('Datetime', '2001-12-31 22:10:59');
-        $this->assertEquals('2001-12-31T22%3A10%3A59', $date->URLDateTime());
+        $this->assertEquals('2001-12-31%2022%3A10%3A59', $date->URLDateTime());
     }
 
     public function testAgoInPast()

From 958736502a9b29145d9726b7077d2a959d837ab6 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 10:32:22 +1200
Subject: [PATCH 12/26] =?UTF-8?q?Removed=20=E2=80=9CT=E2=80=9D=20str=5Frep?=
 =?UTF-8?q?lace,=20more=20comments?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/Forms/DatetimeField.php           | 20 ++++++++++----------
 tests/php/Forms/DatetimeFieldTest.php |  2 +-
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 86e00209d..aeda8cbcf 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -9,8 +9,8 @@ use SilverStripe\ORM\FieldType\DBDatetime;
 
 /**
  * Form field used for editing date time strings.
- * By default, the field handles strings in normalised ISO 8601 format,
- * for example 2017-04-26T23:59:59. The "T" separator can be replaced with a whitespace for value setting.
+ * In the default HTML5 mode, the field expects form submissions
+ * in normalised ISO 8601 format, for example 2017-04-26T23:59:59 (with a "T" separator).
  * Data is passed on via {@link dataValue()} with whitespace separators.
  */
 class DatetimeField extends TextField
@@ -144,7 +144,8 @@ class DatetimeField extends TextField
     }
 
     /**
-     * Assign value posted from form submission
+     * Assign value posted from form submission, based on {@link $datetimeFormat}.
+     * When $html5=true, this needs to be normalised ISO format (with "T" separator).
      *
      * @param mixed $value
      * @param mixed $data
@@ -168,7 +169,8 @@ class DatetimeField extends TextField
     }
 
     /**
-     * Convert date localised in the current locale to ISO 8601 date
+     * Convert date localised in the current locale to ISO 8601 date.
+     * Note that "localised" could also mean ISO format when $html5=true.
      *
      * @param string $datetime
      * @return string The formatted date, or null if not a valid date
@@ -181,11 +183,6 @@ class DatetimeField extends TextField
         $fromFormatter = $this->getFormatter();
         $toFormatter = $this->getISO8601Formatter();
 
-        // Remove 'T' date and time separator before parsing (required by W3C HTML5 fields)
-        if ($this->getHTML5()) {
-            $datetime = str_replace('T', ' ', $datetime);
-        }
-
         // Try to parse time with seconds
         $timestamp = $fromFormatter->parse($datetime);
 
@@ -333,7 +330,10 @@ class DatetimeField extends TextField
     }
 
     /**
-     * Assign value from iso8601 string
+     * Assign value based on {@link $datetimeFormat}.
+     *
+     * When $html5=true, assign value from ISO 8601 normalised string (with a "T" separator).
+     * Falls back to an ISO 8601 string (with a whitespace separator).
      *
      * @param mixed $value
      * @param mixed $data
diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index 08dfdab88..6499a2914 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -128,7 +128,7 @@ class DatetimeFieldTest extends SapphireTest
 
         // Some localisation packages exclude the ',' in default medium format
         $this->assertRegExp(
-            '#29/03/2003(,)? 11:00:00 (AM|am)#',
+            '#29/03/2003(,)? 11:00:00 (PM|pm)#',
             $datetimeField->Value(),
             'User value is formatted, and in user timezone'
         );

From d3afa0c3b5211db2b70afc55c3961ba0174e4559 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 10:59:44 +1200
Subject: [PATCH 13/26] Remove array check since setSubmittedValue() no longer
 supports it

---
 src/Forms/DateField.php     | 4 ----
 src/Forms/DatetimeField.php | 3 ---
 2 files changed, 7 deletions(-)

diff --git a/src/Forms/DateField.php b/src/Forms/DateField.php
index adff7afb1..dd86aed6f 100644
--- a/src/Forms/DateField.php
+++ b/src/Forms/DateField.php
@@ -338,10 +338,6 @@ class DateField extends TextField
             return $this;
         }
 
-        if (is_array($value)) {
-            throw new InvalidArgumentException("Use setSubmittedValue to assign by array");
-        }
-
         // Re-run through formatter to tidy up (e.g. remove time component)
         $this->value = $this->tidyISO8601($value);
         return $this;
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index aeda8cbcf..52b802dc3 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -349,9 +349,6 @@ class DatetimeField extends TextField
             $this->value = null;
             return $this;
         }
-        if (is_array($value)) {
-            throw new InvalidArgumentException("Use setSubmittedValue to assign by array");
-        };
 
         // Validate iso 8601 date
         // If invalid, assign for later validation failure

From 655b047d8057f1187e66a1dcfc0fd99f007ec3c9 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 11:09:43 +1200
Subject: [PATCH 14/26] Removed superfluous methods

---
 src/Forms/DatetimeField.php | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 52b802dc3..e4d50f2c7 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -92,18 +92,6 @@ class DatetimeField extends TextField
      */
     protected $timezone = null;
 
-    public function setForm($form)
-    {
-        parent::setForm($form);
-        return $this;
-    }
-
-    public function setName($name)
-    {
-        parent::setName($name);
-        return $this;
-    }
-
     public function getAttributes()
     {
         $attributes = parent::getAttributes();

From 14b3468eeee992835a0d7df972c1f32f5821d66e Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 11:09:59 +1200
Subject: [PATCH 15/26] Removed setting format in getter
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

That’s already handled in getFormatter()
---
 src/Forms/DatetimeField.php | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index e4d50f2c7..836a3ae82 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -244,11 +244,6 @@ class DatetimeField extends TextField
      */
     public function getDatetimeFormat()
     {
-        if ($this->getHTML5()) {
-            // Browsers expect ISO 8601 dates, localisation is handled on the client
-            $this->setDatetimeFormat(DBDatetime::ISO_DATETIME_NORMALISED);
-        }
-
         if ($this->datetimeFormat) {
             return $this->datetimeFormat;
         }

From b852a76334d17ea60a37456c972760ddaab5124c Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 11:47:04 +1200
Subject: [PATCH 16/26] Consistent schema keys

---
 src/Forms/DateField.php     | 6 +++++-
 src/Forms/DatetimeField.php | 7 ++++++-
 src/Forms/TimeField.php     | 5 ++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/Forms/DateField.php b/src/Forms/DateField.php
index dd86aed6f..33e4a9c22 100644
--- a/src/Forms/DateField.php
+++ b/src/Forms/DateField.php
@@ -295,7 +295,11 @@ class DateField extends TextField
         $defaults = parent::getSchemaDataDefaults();
         return array_merge($defaults, [
             'lang' => i18n::convert_rfc1766($this->getLocale()),
-            'html5' => $this->getHTML5()
+            'data' => array_merge($defaults['data'], [
+                'html5' => $this->getHTML5(),
+                'min' => $this->getMinDate(),
+                'max' => $this->getMaxDate()
+            ])
         ]);
     }
 
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 836a3ae82..9003b4f58 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -111,7 +111,12 @@ class DatetimeField extends TextField
     {
         $defaults = parent::getSchemaDataDefaults();
         return array_merge($defaults, [
-            'html5' => $this->getHTML5()
+            'lang' => i18n::convert_rfc1766($this->getLocale()),
+            'data' => array_merge($defaults['data'], [
+                'html5' => $this->getHTML5(),
+                'min' => $this->getMinDate(),
+                'max' => $this->getMaxDate()
+            ])
         ]);
     }
 
diff --git a/src/Forms/TimeField.php b/src/Forms/TimeField.php
index 26085cb6a..ff430031b 100644
--- a/src/Forms/TimeField.php
+++ b/src/Forms/TimeField.php
@@ -235,7 +235,10 @@ class TimeField extends TextField
     {
         $defaults = parent::getSchemaDataDefaults();
         return array_merge($defaults, [
-            'html5' => $this->getHTML5()
+            'lang' => i18n::convert_rfc1766($this->getLocale()),
+            'data' => array_merge($defaults['data'], [
+                'html5' => $this->getHTML5(),
+            ])
         ]);
     }
 

From 9b41350f64cbfceb7f4c9037ffe3de67371fef1a Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 11:53:34 +1200
Subject: [PATCH 17/26] More min/max setter tests

---
 tests/php/Forms/DatetimeFieldTest.php | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index 6499a2914..9d33b39f3 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -153,6 +153,30 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertFalse($f->validate(new RequiredFields()));
     }
 
+    public function testSetMinDate()
+    {
+        $f = (new DatetimeField('Datetime'))->setMinDatetime('2009-03-31T23:00:00');
+        $this->assertEquals($f->getMinDatetime(), '2009-03-31T23:00:00', 'Retains normalised ISO');
+
+        $f = (new DatetimeField('Datetime'))->setMinDatetime('2009-03-31 23:00:00');
+        $this->assertEquals($f->getMinDatetime(), '2009-03-31T23:00:00', 'Converts ISO to normalised ISO');
+
+        $f = (new DatetimeField('Datetime'))->setMinDatetime('invalid');
+        $this->assertNull($f->getMinDatetime(), 'Ignores invalid values');
+    }
+
+    public function testSetMaxDate()
+    {
+        $f = (new DatetimeField('Datetime'))->setMaxDatetime('2009-03-31T23:00:00');
+        $this->assertEquals($f->getMaxDatetime(), '2009-03-31T23:00:00', 'Retains normalised ISO');
+
+        $f = (new DatetimeField('Datetime'))->setMaxDatetime('2009-03-31 23:00:00');
+        $this->assertEquals($f->getMaxDatetime(), '2009-03-31T23:00:00', 'Converts ISO to normalised ISO');
+
+        $f = (new DatetimeField('Datetime'))->setMaxDatetime('invalid');
+        $this->assertNull($f->getMaxDatetime(), 'Ignores invalid values');
+    }
+
     public function testValidateMinDate()
     {
         $dateField = new DatetimeField('Datetime');

From de8abe11675941ee9c5bfa49f491155dd8f22293 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 11:53:43 +1200
Subject: [PATCH 18/26] API rename

---
 src/Forms/DateField.php           | 62 +++++++++++++---------
 src/Forms/DatetimeField.php       | 87 ++++++++++++++++++-------------
 src/Forms/TimeField.php           | 46 ++++++++--------
 tests/php/Forms/DateFieldTest.php | 19 ++++---
 4 files changed, 126 insertions(+), 88 deletions(-)

diff --git a/src/Forms/DateField.php b/src/Forms/DateField.php
index 33e4a9c22..9d698e012 100644
--- a/src/Forms/DateField.php
+++ b/src/Forms/DateField.php
@@ -194,7 +194,7 @@ class DateField extends TextField
         }
 
         // Get from locale
-        return $this->getFormatter()->getPattern();
+        return $this->getFrontendFormatter()->getPattern();
     }
 
     /**
@@ -217,7 +217,7 @@ class DateField extends TextField
      * @throws \LogicException
      * @return IntlDateFormatter
      */
-    protected function getFormatter()
+    protected function getFrontendFormatter()
     {
         if ($this->getHTML5() && $this->dateFormat && $this->dateFormat !== DBDate::ISO_DATE) {
             throw new \LogicException(
@@ -261,7 +261,7 @@ class DateField extends TextField
      *
      * @return IntlDateFormatter
      */
-    protected function getISO8601Formatter()
+    protected function getInternalFormatter()
     {
         $locale = i18n::config()->uninherited('default_locale');
         $formatter = IntlDateFormatter::create(
@@ -327,10 +327,19 @@ class DateField extends TextField
         }
 
         // Parse from submitted value
-        $this->value = $this->localisedToISO8601($value);
+        $this->value = $this->frontendToInternal($value);
         return $this;
     }
 
+    /**
+     * Assign value based on {@link $datetimeFormat}, which might be localised.
+     *
+     * When $html5=true, assign value from ISO 8601 string.
+     *
+     * @param mixed $value
+     * @param mixed $data
+     * @return $this
+     */
     public function setValue($value, $data = null)
     {
         // Save raw value for later validation
@@ -343,13 +352,13 @@ class DateField extends TextField
         }
 
         // Re-run through formatter to tidy up (e.g. remove time component)
-        $this->value = $this->tidyISO8601($value);
+        $this->value = $this->tidyInternal($value);
         return $this;
     }
 
     public function Value()
     {
-        return $this->iso8601ToLocalised($this->value);
+        return $this->internalToFrontend($this->value);
     }
 
     public function performReadonlyTransformation()
@@ -394,7 +403,7 @@ class DateField extends TextField
                     _t(
                         'DateField.VALIDDATEMINDATE',
                         "Your date has to be newer or matching the minimum allowed date ({date})",
-                        ['date' => $this->iso8601ToLocalised($min)]
+                        ['date' => $this->internalToFrontend($min)]
                     )
                 );
                 return false;
@@ -411,7 +420,7 @@ class DateField extends TextField
                     _t(
                         'DateField.VALIDDATEMAXDATE',
                         "Your date has to be older or matching the maximum allowed date ({date})",
-                        ['date' => $this->iso8601ToLocalised($max)]
+                        ['date' => $this->internalToFrontend($max)]
                     )
                 );
                 return false;
@@ -466,7 +475,7 @@ class DateField extends TextField
      */
     public function setMinDate($minDate)
     {
-        $this->minDate = $this->tidyISO8601($minDate);
+        $this->minDate = $this->tidyInternal($minDate);
         return $this;
     }
 
@@ -484,23 +493,24 @@ class DateField extends TextField
      */
     public function setMaxDate($maxDate)
     {
-        $this->maxDate = $this->tidyISO8601($maxDate);
+        $this->maxDate = $this->tidyInternal($maxDate);
         return $this;
     }
 
     /**
-     * Convert date localised in the current locale to ISO 8601 date
+     * Convert frontend date to the internal representation (ISO 8601).
+     * The frontend date is also in ISO 8601 when $html5=true.
      *
      * @param string $date
      * @return string The formatted date, or null if not a valid date
      */
-    public function localisedToISO8601($date)
+    protected function frontendToInternal($date)
     {
         if (!$date) {
             return null;
         }
-        $fromFormatter = $this->getFormatter();
-        $toFormatter = $this->getISO8601Formatter();
+        $fromFormatter = $this->getFrontendFormatter();
+        $toFormatter = $this->getInternalFormatter();
         $timestamp = $fromFormatter->parse($date);
         if ($timestamp === false) {
             return null;
@@ -509,20 +519,21 @@ class DateField extends TextField
     }
 
     /**
-     * Convert an ISO 8601 localised date into the format specified by the
-     * current date format.
+     * Convert the internal date representation (ISO 8601) to a format used by the frontend,
+     * as defined by {@link $dateFormat}. With $html5=true, the frontend date will also be
+     * in ISO 8601.
      *
      * @param string $date
      * @return string The formatted date, or null if not a valid date
      */
-    public function iso8601ToLocalised($date)
+    protected function internalToFrontend($date)
     {
-        $date = $this->tidyISO8601($date);
+        $date = $this->tidyInternal($date);
         if (!$date) {
             return null;
         }
-        $fromFormatter = $this->getISO8601Formatter();
-        $toFormatter = $this->getFormatter();
+        $fromFormatter = $this->getInternalFormatter();
+        $toFormatter = $this->getFrontendFormatter();
         $timestamp = $fromFormatter->parse($date);
         if ($timestamp === false) {
             return null;
@@ -531,18 +542,19 @@ class DateField extends TextField
     }
 
     /**
-     * Tidy up iso8601-ish date, or approximation
+     * Tidy up the internal date representation (ISO 8601),
+     * and fall back to strtotime() if there's parsing errors.
      *
-     * @param string $date Date in iso8601 or approximate form
-     * @return string iso8601 date, or null if not valid
+     * @param string $date Date in ISO 8601 or approximate form
+     * @return string ISO 8601 date, or null if not valid
      */
-    public function tidyISO8601($date)
+    protected function tidyInternal($date)
     {
         if (!$date) {
             return null;
         }
         // Re-run through formatter to tidy up (e.g. remove time component)
-        $formatter = $this->getISO8601Formatter();
+        $formatter = $this->getInternalFormatter();
         $timestamp = $formatter->parse($date);
         if ($timestamp === false) {
             // Fallback to strtotime
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 9003b4f58..c551f1a31 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -156,25 +156,25 @@ class DatetimeField extends TextField
         }
 
         // Parse from submitted value
-        $this->value = $this->localisedToISO8601($value);
+        $this->value = $this->frontendToInternal($value);
 
         return $this;
     }
 
     /**
-     * Convert date localised in the current locale to ISO 8601 date.
-     * Note that "localised" could also mean ISO format when $html5=true.
+     * Convert frontend date to the internal representation (ISO 8601).
+     * The frontend date is also in ISO 8601 when $html5=true.
      *
      * @param string $datetime
      * @return string The formatted date, or null if not a valid date
      */
-    public function localisedToISO8601($datetime)
+    public function frontendToInternal($datetime)
     {
         if (!$datetime) {
             return null;
         }
-        $fromFormatter = $this->getFormatter();
-        $toFormatter = $this->getISO8601Formatter();
+        $fromFormatter = $this->getFrontendFormatter();
+        $toFormatter = $this->getInternalFormatter();
 
         // Try to parse time with seconds
         $timestamp = $fromFormatter->parse($datetime);
@@ -198,7 +198,7 @@ class DatetimeField extends TextField
      * @throws \LogicException
      * @return IntlDateFormatter
      */
-    protected function getFormatter()
+    protected function getFrontendFormatter()
     {
         if ($this->getHTML5() && $this->datetimeFormat && $this->datetimeFormat !== DBDatetime::ISO_DATETIME_NORMALISED) {
             throw new \LogicException(
@@ -254,7 +254,7 @@ class DatetimeField extends TextField
         }
 
         // Get from locale
-        return $this->getFormatter()->getPattern();
+        return $this->getFrontendFormatter()->getPattern();
     }
 
     /**
@@ -285,7 +285,7 @@ class DatetimeField extends TextField
         }
 
         // Build new formatter with the altered timezone
-        $formatter = clone $this->getISO8601Formatter();
+        $formatter = clone $this->getInternalFormatter();
         $formatter->setTimeZone($timezone);
 
         // ISO8601 date with a standard "T" separator (W3C standard).
@@ -300,7 +300,7 @@ class DatetimeField extends TextField
      *
      * @return IntlDateFormatter
      */
-    protected function getISO8601Formatter()
+    protected function getInternalFormatter()
     {
         $formatter = IntlDateFormatter::create(
             i18n::config()->uninherited('default_locale'),
@@ -311,14 +311,13 @@ class DatetimeField extends TextField
         $formatter->setLenient(false);
 
         // Note we omit timezone from this format, and we always assume server TZ
-        // ISO8601 date with a standard "T" separator (W3C standard).
         $formatter->setPattern(DBDatetime::ISO_DATETIME_NORMALISED);
 
         return $formatter;
     }
 
     /**
-     * Assign value based on {@link $datetimeFormat}.
+     * Assign value based on {@link $datetimeFormat}, which might be localised.
      *
      * When $html5=true, assign value from ISO 8601 normalised string (with a "T" separator).
      * Falls back to an ISO 8601 string (with a whitespace separator).
@@ -340,14 +339,14 @@ class DatetimeField extends TextField
 
         // Validate iso 8601 date
         // If invalid, assign for later validation failure
-        $isoFormatter = $this->getISO8601Formatter();
-        $timestamp = $isoFormatter->parse($value);
+        $internalFormatter = $this->getInternalFormatter();
+        $timestamp = $internalFormatter->parse($value);
 
         // Retry without "T" separator
         if (!$timestamp) {
-            $isoFallbackFormatter = $this->getISO8601Formatter();
-            $isoFallbackFormatter->setPattern(DBDatetime::ISO_DATETIME);
-            $timestamp = $isoFallbackFormatter->parse($value);
+            $fallbackFormatter = $this->getInternalFormatter();
+            $fallbackFormatter->setPattern(DBDatetime::ISO_DATETIME);
+            $timestamp = $fallbackFormatter->parse($value);
         }
 
         if ($timestamp === false) {
@@ -355,7 +354,7 @@ class DatetimeField extends TextField
         }
 
         // Cleanup date
-        $value = $isoFormatter->format($timestamp);
+        $value = $internalFormatter->format($timestamp);
 
         // Save value
         $this->value = $value;
@@ -363,14 +362,27 @@ class DatetimeField extends TextField
         return $this;
     }
 
+    /**
+     * Returns the frontend representation of the field value,
+     * according to the defined {@link dateFormat}.
+     * With $html5=true, this will be in ISO 8601 format.
+     *
+     * @return string
+     */
     public function Value()
     {
-        return $this->iso8601ToLocalised($this->value);
+        return $this->internalToFrontend($this->value);
     }
 
+    /**
+     * Returns the field value in the internal representation (ISO 8601),
+     * suitable for insertion into the data object.
+     *
+     * @return string
+     */
     public function dataValue()
     {
-        return $this->iso8601ToDataValue($this->value);
+        return $this->internalToDataValue($this->value);
     }
 
     /**
@@ -379,10 +391,10 @@ class DatetimeField extends TextField
      * @param string $datetime
      * @return string The formatted date and time, or null if not a valid date and time
      */
-    public function iso8601ToDataValue($datetime)
+    public function internalToDataValue($datetime)
     {
-        $fromFormatter = $this->getISO8601Formatter();
-        $toFormatter = $this->getFormatter();
+        $fromFormatter = $this->getInternalFormatter();
+        $toFormatter = $this->getFrontendFormatter();
 
         // Set default timezone (avoid shifting data values into user timezone)
         $toFormatter->setTimezone(date_default_timezone_get());
@@ -398,19 +410,21 @@ class DatetimeField extends TextField
     }
 
     /**
-     * Convert an ISO 8601 localised datetime into the format specified by the current format.
+     * Convert the internal date representation (ISO 8601) to a format used by the frontend,
+     * as defined by {@link $dateFormat}. With $html5=true, the frontend date will also be
+     * in ISO 8601.
      *
      * @param string $datetime
      * @return string The formatted date and time, or null if not a valid date and time
      */
-    public function iso8601ToLocalised($datetime)
+    public function internalToFrontend($datetime)
     {
-        $datetime = $this->tidyISO8601($datetime);
+        $datetime = $this->tidyInternal($datetime);
         if (!$datetime) {
             return null;
         }
-        $fromFormatter = $this->getISO8601Formatter();
-        $toFormatter = $this->getFormatter();
+        $fromFormatter = $this->getInternalFormatter();
+        $toFormatter = $this->getFrontendFormatter();
         $timestamp = $fromFormatter->parse($datetime);
         if ($timestamp === false) {
             return null;
@@ -420,18 +434,19 @@ class DatetimeField extends TextField
     }
 
     /**
-     * Tidy up iso8601-ish date, or approximation
+     * Tidy up the internal date representation (ISO 8601),
+     * and fall back to strtotime() if there's parsing errors.
      *
      * @param string $date Date in ISO 8601 or approximate form
-     * @return string iso8601 date, or null if not valid
+     * @return string ISO 8601 date, or null if not valid
      */
-    public function tidyISO8601($datetime)
+    public function tidyInternal($datetime)
     {
         if (!$datetime) {
             return null;
         }
         // Re-run through formatter to tidy up (e.g. remove time component)
-        $formatter = $this->getISO8601Formatter();
+        $formatter = $this->getInternalFormatter();
         $timestamp = $formatter->parse($datetime);
         if ($timestamp === false) {
             // Fallback to strtotime
@@ -559,7 +574,7 @@ class DatetimeField extends TextField
      */
     public function setMinDatetime($minDatetime)
     {
-        $this->minDatetime = $this->tidyISO8601($minDatetime);
+        $this->minDatetime = $this->tidyInternal($minDatetime);
         return $this;
     }
 
@@ -577,7 +592,7 @@ class DatetimeField extends TextField
      */
     public function setMaxDatetime($maxDatetime)
     {
-        $this->maxDatetime = $this->tidyISO8601($maxDatetime);
+        $this->maxDatetime = $this->tidyInternal($maxDatetime);
         return $this;
     }
 
@@ -615,7 +630,7 @@ class DatetimeField extends TextField
                     _t(
                         'DatetimeField.VALIDDATETIMEMINDATE',
                         "Your date has to be newer or matching the minimum allowed date and time ({datetime})",
-                        ['datetime' => $this->iso8601ToLocalised($min)]
+                        ['datetime' => $this->internalToFrontend($min)]
                     )
                 );
                 return false;
@@ -632,7 +647,7 @@ class DatetimeField extends TextField
                     _t(
                         'DatetimeField.VALIDDATEMAXDATETIME',
                         "Your date has to be older or matching the maximum allowed date and time ({datetime})",
-                        ['datetime' => $this->iso8601ToLocalised($max)]
+                        ['datetime' => $this->internalToFrontend($max)]
                     )
                 );
                 return false;
diff --git a/src/Forms/TimeField.php b/src/Forms/TimeField.php
index ff430031b..4cfa187ac 100644
--- a/src/Forms/TimeField.php
+++ b/src/Forms/TimeField.php
@@ -103,7 +103,7 @@ class TimeField extends TextField
         }
 
         // Get from locale
-        return $this->getFormatter()->getPattern();
+        return $this->getFrontendFormatter()->getPattern();
     }
 
     /**
@@ -159,7 +159,7 @@ class TimeField extends TextField
      *
      * @return IntlDateFormatter
      */
-    protected function getFormatter()
+    protected function getFrontendFormatter()
     {
         if ($this->getHTML5() && $this->timeFormat && $this->timeFormat !== DBTime::ISO_TIME) {
             throw new \LogicException(
@@ -204,7 +204,7 @@ class TimeField extends TextField
      *
      * @return IntlDateFormatter
      */
-    protected function getISO8601Formatter()
+    protected function getInternalFormatter()
     {
         $formatter = IntlDateFormatter::create(
             i18n::config()->uninherited('default_locale'),
@@ -260,7 +260,7 @@ class TimeField extends TextField
         $this->rawValue = $value;
 
         // Parse from submitted value
-        $this->value = $this->localisedToISO8601($value);
+        $this->value = $this->frontendToInternal($value);
         return $this;
     }
 
@@ -283,13 +283,13 @@ class TimeField extends TextField
         }
 
         // Re-run through formatter to tidy up (e.g. remove date component)
-        $this->value = $this->tidyISO8601($value);
+        $this->value = $this->tidyInternal($value);
         return $this;
     }
 
     public function Value()
     {
-        $localised = $this->iso8601ToLocalised($this->value);
+        $localised = $this->internalToFrontend($this->value);
         if ($localised) {
             return $localised;
         }
@@ -305,7 +305,7 @@ class TimeField extends TextField
      */
     public function getMidnight()
     {
-        $formatter = $this->getFormatter();
+        $formatter = $this->getFrontendFormatter();
         $timestamp = $this->withTimezone($this->getTimezone(), function () {
             return strtotime('midnight');
         });
@@ -375,18 +375,19 @@ class TimeField extends TextField
     }
 
     /**
-     * Convert time localised in the current locale to ISO 8601 time
+     * Convert frontend time to the internal representation (ISO 8601).
+     * The frontend time is also in ISO 8601 when $html5=true.
      *
      * @param string $time
      * @return string The formatted time, or null if not a valid time
      */
-    public function localisedToISO8601($time)
+    protected function frontendToInternal($time)
     {
         if (!$time) {
             return null;
         }
-        $fromFormatter = $this->getFormatter();
-        $toFormatter = $this->getISO8601Formatter();
+        $fromFormatter = $this->getFrontendFormatter();
+        $toFormatter = $this->getInternalFormatter();
         $timestamp = $fromFormatter->parse($time);
 
         // Try to parse time without seconds, since that's a valid HTML5 submission format
@@ -405,19 +406,21 @@ class TimeField extends TextField
     }
 
     /**
-     * Format iso time to localised form
+     * Convert the internal time representation (ISO 8601) to a format used by the frontend,
+     * as defined by {@link $timeFormat}. With $html5=true, the frontend time will also be
+     * in ISO 8601.
      *
      * @param string $time
      * @return string
      */
-    public function iso8601ToLocalised($time)
+    protected function internalToFrontend($time)
     {
-        $time = $this->tidyISO8601($time);
+        $time = $this->tidyInternal($time);
         if (!$time) {
             return null;
         }
-        $fromFormatter = $this->getISO8601Formatter();
-        $toFormatter = $this->getFormatter();
+        $fromFormatter = $this->getInternalFormatter();
+        $toFormatter = $this->getFrontendFormatter();
         $timestamp = $fromFormatter->parse($time);
         if ($timestamp === false) {
             return null;
@@ -428,18 +431,19 @@ class TimeField extends TextField
 
 
     /**
-     * Tidy up iso8601-ish time, or approximation
+     * Tidy up the internal time representation (ISO 8601),
+     * and fall back to strtotime() if there's parsing errors.
      *
-     * @param string $time Time in iso8601 or approximate form
-     * @return string iso8601 time, or null if not valid
+     * @param string $time Time in ISO 8601 or approximate form
+     * @return string ISO 8601 time, or null if not valid
      */
-    public function tidyISO8601($time)
+    protected function tidyInternal($time)
     {
         if (!$time) {
             return null;
         }
         // Re-run through formatter to tidy up (e.g. remove date component)
-        $formatter = $this->getISO8601Formatter();
+        $formatter = $this->getInternalFormatter();
         $timestamp = $formatter->parse($time);
         if ($timestamp === false) {
             // Fallback to strtotime
diff --git a/tests/php/Forms/DateFieldTest.php b/tests/php/Forms/DateFieldTest.php
index 676ae58eb..7843a02c0 100644
--- a/tests/php/Forms/DateFieldTest.php
+++ b/tests/php/Forms/DateFieldTest.php
@@ -94,15 +94,22 @@ class DateFieldTest extends SapphireTest
         $this->assertEquals('2003-03-29', $f->dataValue());
     }
 
-    public function testTidyISO8601()
+    public function testSetValue()
     {
-        $f = new DateField('Date', 'Date');
-        $this->assertEquals(null, $f->tidyISO8601('notadate'));
-        $this->assertEquals('2011-01-31', $f->tidyISO8601('-1 day'));
-        $this->assertEquals(null, $f->tidyISO8601('29/03/2003'));
+        $f = (new DateField('Date', 'Date'))->setValue('notadate');
+        $this->assertNull($f->Value(), 'Invalid input ignored');
+
+        $f = (new DateField('Date', 'Date'))->setValue('-1 day');
+        $this->assertEquals($f->Value(), '2011-01-31', 'Relative dates accepted');
+
+        $f = (new DateField('Date', 'Date'))->setValue('2011-01-31');
+        $this->assertEquals($f->Value(), '2011-01-31', 'ISO format accepted');
+
+        $f = (new DateField('Date', 'Date'))->setValue('2011-01-31 23:59:59');
+        $this->assertEquals($f->Value(), '2011-01-31', 'ISO format with time accepted');
     }
 
-    public function testSetValueWithDateString()
+    public function testSetValueWithLocalisedDateString()
     {
         $f = new DateField('Date', 'Date');
         $f->setHTML5(false);

From f01a20d5c4b46715e07ddcaa673aa8025f9890a0 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 11:56:18 +1200
Subject: [PATCH 19/26] Only used normalised ISO on HTML5

---
 src/Forms/DatetimeField.php | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index c551f1a31..e97679927 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -311,7 +311,13 @@ class DatetimeField extends TextField
         $formatter->setLenient(false);
 
         // Note we omit timezone from this format, and we always assume server TZ
-        $formatter->setPattern(DBDatetime::ISO_DATETIME_NORMALISED);
+        if ($this->getHTML5()) {
+            // ISO8601 date with a standard "T" separator (W3C standard).
+            $formatter->setPattern(DBDatetime::ISO_DATETIME_NORMALISED);
+        } else {
+            // ISO8601 date with a whitespace separator
+            $formatter->setPattern(DBDatetime::ISO_DATETIME);
+        }
 
         return $formatter;
     }

From 628fd216adce2fff3bbf136f15c1435e5cf670c6 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 11:56:23 +1200
Subject: [PATCH 20/26] PHPDoc fixes

---
 src/Forms/DatetimeField.php | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index e97679927..a5520bdc6 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -107,6 +107,9 @@ class DatetimeField extends TextField
         return $attributes;
     }
 
+    /**
+     * @inheritDoc
+     */
     public function getSchemaDataDefaults()
     {
         $defaults = parent::getSchemaDataDefaults();
@@ -120,16 +123,26 @@ class DatetimeField extends TextField
         ]);
     }
 
+    /**
+     * @inheritDoc
+     */
     public function Type()
     {
         return 'text datetime';
     }
 
+    /**
+     * @return bool
+     */
     public function getHTML5()
     {
         return $this->html5;
     }
 
+    /**
+     * @param $bool
+     * @return $this
+     */
     public function setHTML5($bool)
     {
         $this->html5 = $bool;

From 60706c8efd2ea22884eaede36a6deaee3829902e Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 14:59:11 +1200
Subject: [PATCH 21/26] Store $value in ISO and server timezone consistently,
 fix min/max timezone handling

---
 src/Forms/DatetimeField.php           | 108 +++++---------------
 tests/php/Forms/DatetimeFieldTest.php | 141 +++++++++++++++++++++++---
 2 files changed, 151 insertions(+), 98 deletions(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index a5520bdc6..03da92f68 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -12,6 +12,7 @@ use SilverStripe\ORM\FieldType\DBDatetime;
  * In the default HTML5 mode, the field expects form submissions
  * in normalised ISO 8601 format, for example 2017-04-26T23:59:59 (with a "T" separator).
  * Data is passed on via {@link dataValue()} with whitespace separators.
+ * The {@link $value} property is always in ISO 8601 format, in the server timezone.
  */
 class DatetimeField extends TextField
 {
@@ -31,14 +32,14 @@ class DatetimeField extends TextField
     /**
      * Min date time
      *
-     * @var string ISO 8601 date time for min date time
+     * @var string ISO 8601 date time in server timezone
      */
     protected $minDatetime = null;
 
     /**
      * Max date time
      *
-     * @var string ISO 860 date time for max date time
+     * @var string ISO 860 date time in server timezone
      */
     protected $maxDatetime = null;
 
@@ -100,8 +101,8 @@ class DatetimeField extends TextField
 
         if ($this->getHTML5()) {
             $attributes['type'] = 'datetime-local';
-            $attributes['min'] = $this->getMinDatetime();
-            $attributes['max'] = $this->getMaxDatetime();
+            $attributes['min'] = $this->internalToFrontend($this->getMinDatetime());
+            $attributes['max'] = $this->internalToFrontend($this->getMaxDatetime());
         }
 
         return $attributes;
@@ -117,8 +118,8 @@ class DatetimeField extends TextField
             'lang' => i18n::convert_rfc1766($this->getLocale()),
             'data' => array_merge($defaults['data'], [
                 'html5' => $this->getHTML5(),
-                'min' => $this->getMinDate(),
-                'max' => $this->getMaxDate()
+                'min' => $this->internalToFrontend($this->getMinDatetime()),
+                'max' => $this->internalToFrontend($this->getMaxDatetime())
             ])
         ]);
     }
@@ -177,6 +178,8 @@ class DatetimeField extends TextField
     /**
      * Convert frontend date to the internal representation (ISO 8601).
      * The frontend date is also in ISO 8601 when $html5=true.
+     * Assumes the value is in the defined {@link $timezone} (if one is set),
+     * and adjusts for server timezone.
      *
      * @param string $datetime
      * @return string The formatted date, or null if not a valid date
@@ -284,59 +287,35 @@ class DatetimeField extends TextField
         return $this;
     }
 
-    /**
-     * Get formatter for converting to the target timezone, if timezone is set
-     * Can return null if no timezone set
-     *
-     * @return IntlDateFormatter|null
-     */
-    protected function getTimezoneFormatter()
-    {
-        $timezone = $this->getTimezone();
-        if (!$timezone) {
-            return null;
-        }
-
-        // Build new formatter with the altered timezone
-        $formatter = clone $this->getInternalFormatter();
-        $formatter->setTimeZone($timezone);
-
-        // ISO8601 date with a standard "T" separator (W3C standard).
-        // Note we omit timezone from this format, and we assume server TZ always.
-        $formatter->setPattern(DBDatetime::ISO_DATETIME_NORMALISED);
-
-        return $formatter;
-    }
-
     /**
      * Get a date formatter for the ISO 8601 format
      *
+     * @param String $timezone Optional timezone identifier (defaults to server timezone)
      * @return IntlDateFormatter
      */
-    protected function getInternalFormatter()
+    protected function getInternalFormatter($timezone = null)
     {
+        if (!$timezone) {
+            $timezone = date_default_timezone_get(); // Default to server timezone
+        }
+
         $formatter = IntlDateFormatter::create(
             i18n::config()->uninherited('default_locale'),
             IntlDateFormatter::MEDIUM,
             IntlDateFormatter::MEDIUM,
-            date_default_timezone_get() // Default to server timezone
+            $timezone
         );
         $formatter->setLenient(false);
 
         // Note we omit timezone from this format, and we always assume server TZ
-        if ($this->getHTML5()) {
-            // ISO8601 date with a standard "T" separator (W3C standard).
-            $formatter->setPattern(DBDatetime::ISO_DATETIME_NORMALISED);
-        } else {
-            // ISO8601 date with a whitespace separator
-            $formatter->setPattern(DBDatetime::ISO_DATETIME);
-        }
+        $formatter->setPattern(DBDatetime::ISO_DATETIME);
 
         return $formatter;
     }
 
     /**
      * Assign value based on {@link $datetimeFormat}, which might be localised.
+     * The value needs to be in the server timezone.
      *
      * When $html5=true, assign value from ISO 8601 normalised string (with a "T" separator).
      * Falls back to an ISO 8601 string (with a whitespace separator).
@@ -393,41 +372,6 @@ class DatetimeField extends TextField
         return $this->internalToFrontend($this->value);
     }
 
-    /**
-     * Returns the field value in the internal representation (ISO 8601),
-     * suitable for insertion into the data object.
-     *
-     * @return string
-     */
-    public function dataValue()
-    {
-        return $this->internalToDataValue($this->value);
-    }
-
-    /**
-     * Convert an ISO 8601 localised datetime into a saveable representation.
-     *
-     * @param string $datetime
-     * @return string The formatted date and time, or null if not a valid date and time
-     */
-    public function internalToDataValue($datetime)
-    {
-        $fromFormatter = $this->getInternalFormatter();
-        $toFormatter = $this->getFrontendFormatter();
-
-        // Set default timezone (avoid shifting data values into user timezone)
-        $toFormatter->setTimezone(date_default_timezone_get());
-
-        // Send to data object without "T" separator
-        $toFormatter->setPattern(DBDatetime::ISO_DATETIME);
-
-        $timestamp = $fromFormatter->parse($datetime);
-        if ($timestamp === false) {
-            return null;
-        }
-        return $toFormatter->format($timestamp) ?: null;
-    }
-
     /**
      * Convert the internal date representation (ISO 8601) to a format used by the frontend,
      * as defined by {@link $dateFormat}. With $html5=true, the frontend date will also be
@@ -580,7 +524,7 @@ class DatetimeField extends TextField
     }
 
     /**
-     * @return string
+     * @return string Date in ISO 8601 format, in server timezone.
      */
     public function getMinDatetime()
     {
@@ -588,7 +532,7 @@ class DatetimeField extends TextField
     }
 
     /**
-     * @param string $minDatetime A string in ISO 8601 format
+     * @param string $minDatetime A string in ISO 8601 format, in server timezone.
      * @return $this
      */
     public function setMinDatetime($minDatetime)
@@ -598,7 +542,7 @@ class DatetimeField extends TextField
     }
 
     /**
-     * @return string
+     * @return string Date in ISO 8601 format, in server timezone.
      */
     public function getMaxDatetime()
     {
@@ -606,7 +550,7 @@ class DatetimeField extends TextField
     }
 
     /**
-     * @param string $maxDatetime
+     * @param string $maxDatetime A string in ISO 8601 format, in server timezone.
      * @return $this
      */
     public function setMaxDatetime($maxDatetime)
@@ -639,7 +583,7 @@ class DatetimeField extends TextField
             return false;
         }
 
-        // Check min date
+        // Check min date (in server timezone)
         $min = $this->getMinDatetime();
         if ($min) {
             $oops = strtotime($this->value) < strtotime($min);
@@ -656,7 +600,7 @@ class DatetimeField extends TextField
             }
         }
 
-        // Check max date
+        // Check max date (in server timezone)
         $max = $this->getMaxDatetime();
         if ($max) {
             $oops = strtotime($this->value) > strtotime($max);
@@ -700,9 +644,9 @@ class DatetimeField extends TextField
         if ($this->value && $timezone !== $this->timezone) {
             throw new \BadMethodCallException("Can't change timezone after setting a value");
         }
-        // Note: DateField has no timezone option, and TimeField::setTimezone
-        // should be ignored
+
         $this->timezone = $timezone;
+
         return $this;
     }
 }
diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index 9d33b39f3..e8bcdcc69 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -74,6 +74,17 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertEquals('2003-03-29 23:59:38', $f->dataValue(), 'From date/time string');
     }
 
+    public function testDataValueWithTimezone()
+    {
+        // Berlin and Auckland have 12h time difference in northern hemisphere winter
+        date_default_timezone_set('Europe/Berlin');
+
+        $f = new DatetimeField('Datetime');
+        $f->setTimezone('Pacific/Auckland');
+        $f->setSubmittedValue('2003-01-30T23:59:38'); // frontend timezone (Auckland)
+        $this->assertEquals('2003-01-30 11:59:38', $f->dataValue()); // server timezone (Berlin)
+    }
+
     public function testConstructorWithoutArgs()
     {
         $f = new DatetimeField('Datetime');
@@ -97,11 +108,11 @@ class DatetimeFieldTest extends SapphireTest
     {
         $f = new DatetimeField('Datetime', 'Datetime');
         $f->setValue('2003-03-29 23:59:38');
-        $this->assertEquals($f->dataValue(), '2003-03-29 23:59:38');
+        $this->assertEquals($f->dataValue(), '2003-03-29 23:59:38', 'Accepts ISO');
 
         $f = new DatetimeField('Datetime', 'Datetime');
         $f->setValue('2003-03-29T23:59:38');
-        $this->assertEquals($f->dataValue(), '2003-03-29 23:59:38', 'Normalised ISO');
+        $this->assertNull($f->dataValue(), 'Rejects normalised ISO');
     }
 
     public function testSubmittedValue()
@@ -140,13 +151,13 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertTrue($f->validate(new RequiredFields()));
 
         $f = new DatetimeField('Datetime', 'Datetime', '2003-03-29T23:59:38');
-        $this->assertTrue($f->validate(new RequiredFields()), 'Normalised ISO');
+        $this->assertFalse($f->validate(new RequiredFields()), 'Normalised ISO');
 
-        $f = new DatetimeField('Datetime', 'Datetime', '2003-03-29 00:00:00');
-        $this->assertTrue($f->validate(new RequiredFields()));
+        $f = new DatetimeField('Datetime', 'Datetime', '2003-03-29');
+        $this->assertFalse($f->validate(new RequiredFields()), 'Leaving out time');
 
         $f = (new DatetimeField('Datetime', 'Datetime'))
-            ->setSubmittedValue('2003-03-29 00:00');
+            ->setSubmittedValue('2003-03-29T00:00');
         $this->assertTrue($f->validate(new RequiredFields()), 'Leaving out seconds (like many browsers)');
 
         $f = new DatetimeField('Datetime', 'Datetime', 'wrong');
@@ -156,10 +167,10 @@ class DatetimeFieldTest extends SapphireTest
     public function testSetMinDate()
     {
         $f = (new DatetimeField('Datetime'))->setMinDatetime('2009-03-31T23:00:00');
-        $this->assertEquals($f->getMinDatetime(), '2009-03-31T23:00:00', 'Retains normalised ISO');
+        $this->assertEquals($f->getMinDatetime(), '2009-03-31 23:00:00', 'Retains ISO');
 
         $f = (new DatetimeField('Datetime'))->setMinDatetime('2009-03-31 23:00:00');
-        $this->assertEquals($f->getMinDatetime(), '2009-03-31T23:00:00', 'Converts ISO to normalised ISO');
+        $this->assertEquals($f->getMinDatetime(), '2009-03-31 23:00:00', 'Converts normalised ISO to ISO');
 
         $f = (new DatetimeField('Datetime'))->setMinDatetime('invalid');
         $this->assertNull($f->getMinDatetime(), 'Ignores invalid values');
@@ -168,10 +179,10 @@ class DatetimeFieldTest extends SapphireTest
     public function testSetMaxDate()
     {
         $f = (new DatetimeField('Datetime'))->setMaxDatetime('2009-03-31T23:00:00');
-        $this->assertEquals($f->getMaxDatetime(), '2009-03-31T23:00:00', 'Retains normalised ISO');
+        $this->assertEquals($f->getMaxDatetime(), '2009-03-31 23:00:00', 'Retains ISO');
 
         $f = (new DatetimeField('Datetime'))->setMaxDatetime('2009-03-31 23:00:00');
-        $this->assertEquals($f->getMaxDatetime(), '2009-03-31T23:00:00', 'Converts ISO to normalised ISO');
+        $this->assertEquals($f->getMaxDatetime(), '2009-03-31 23:00:00', 'Converts normalised ISO to ISO');
 
         $f = (new DatetimeField('Datetime'))->setMaxDatetime('invalid');
         $this->assertNull($f->getMaxDatetime(), 'Ignores invalid values');
@@ -198,11 +209,36 @@ class DatetimeFieldTest extends SapphireTest
         $dateField->setMinDatetime('2009-03-31 23:00:00');
         $dateField->setValue('2008-03-31 23:00:00');
         $this->assertFalse($dateField->validate(new RequiredFields()), 'Date below min datetime');
+    }
+
+    public function testValidateMinDateWithSubmittedValueAndTimezone()
+    {
+        // Berlin and Auckland have 12h time difference in northern hemisphere winter
+        date_default_timezone_set('Europe/Berlin');
 
         $dateField = new DatetimeField('Datetime');
-        $dateField->setMinDatetime('2009-03-31T23:00:00');
-        $dateField->setValue('2009-03-31T23:00:01');
-        $this->assertTrue($dateField->validate(new RequiredFields()), 'Time above min datetime with normalised ISO');
+        $dateField->setTimezone('Pacific/Auckland');
+        $dateField->setMinDatetime('2009-01-30 23:00:00'); // server timezone (Berlin)
+        $dateField->setSubmittedValue('2009-01-31T11:00:01'); // frontend timezone (Auckland)
+        $this->assertTrue($dateField->validate(new RequiredFields()), 'Time above min datetime');
+
+        $dateField = new DatetimeField('Datetime');
+        $dateField->setTimezone('Pacific/Auckland');
+        $dateField->setMinDatetime('2009-01-30 23:00:00');
+        $dateField->setSubmittedValue('2009-01-31T10:00:00');
+        $this->assertFalse($dateField->validate(new RequiredFields()), 'Time below min datetime');
+
+        $dateField = new DatetimeField('Datetime');
+        $dateField->setTimezone('Pacific/Auckland');
+        $dateField->setMinDatetime('2009-01-30 23:00:00');
+        $dateField->setSubmittedValue('2009-01-31T11:00:00');
+        $this->assertTrue($dateField->validate(new RequiredFields()), 'Date and time matching min datetime');
+
+        $dateField = new DatetimeField('Datetime');
+        $dateField->setTimezone('Pacific/Auckland');
+        $dateField->setMinDatetime('2009-01-30 23:00:00');
+        $dateField->setSubmittedValue('2008-01-31T11:00:00');
+        $this->assertFalse($dateField->validate(new RequiredFields()), 'Date below min datetime');
     }
 
     public function testValidateMinDateStrtotime()
@@ -252,11 +288,36 @@ class DatetimeFieldTest extends SapphireTest
         $f->setMaxDatetime('2009-03-31 23:00:00');
         $f->setValue('2010-03-31 23:00:00');
         $this->assertFalse($f->validate(new RequiredFields()), 'Date above max datetime');
+    }
+
+    public function testValidateMaxDateWithSubmittedValueAndTimezone()
+    {
+        // Berlin and Auckland have 12h time difference in northern hemisphere winter
+        date_default_timezone_set('Europe/Berlin');
 
         $f = new DatetimeField('Datetime');
-        $f->setMaxDatetime('2009-03-31T23:00:00');
-        $f->setValue('2009-03-31T22:00:00');
-        $this->assertTrue($f->validate(new RequiredFields()), 'Time below max datetime with normalised ISO');
+        $f->setTimezone('Pacific/Auckland');
+        $f->setMaxDatetime('2009-01-31 23:00:00'); // server timezone (Berlin)
+        $f->setSubmittedValue('2009-01-31T10:00:00'); // frontend timezone (Auckland)
+        $this->assertTrue($f->validate(new RequiredFields()), 'Time below max datetime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setTimezone('Pacific/Auckland');
+        $f->setMaxDatetime('2009-01-31 23:00:00');
+        $f->setSubmittedValue('2010-01-31T11:00:01');
+        $this->assertFalse($f->validate(new RequiredFields()), 'Time above max datetime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setTimezone('Pacific/Auckland');
+        $f->setMaxDatetime('2009-01-31 23:00:00');
+        $f->setSubmittedValue('2009-01-31T11:00:00');
+        $this->assertTrue($f->validate(new RequiredFields()), 'Date and time matching max datetime');
+
+        $f = new DatetimeField('Datetime');
+        $f->setTimezone('Pacific/Auckland');
+        $f->setMaxDatetime('2009-01-31 23:00:00');
+        $f->setSubmittedValue('2010-01-31T11:00:00');
+        $this->assertFalse($f->validate(new RequiredFields()), 'Date above max datetime');
     }
 
     public function testTimezoneSetValueLocalised()
@@ -336,6 +397,54 @@ class DatetimeFieldTest extends SapphireTest
         $this->assertEquals('CustomDatetime', $field->getName());
     }
 
+    public function testSchemaDataDefaultsIncludesMinMax()
+    {
+        $field = new DatetimeField('Datetime');
+        $field->setMinDatetime('2009-03-31 23:00:00');
+        $field->setMaxDatetime('2010-03-31 23:00:00');
+        $defaults = $field->getSchemaDataDefaults();
+        $this->assertEquals($defaults['data']['min'], '2009-03-31T23:00:00');
+        $this->assertEquals($defaults['data']['max'], '2010-03-31T23:00:00');
+    }
+
+    public function testSchemaDataDefaultsAdjustsMinMaxToTimezone()
+    {
+        date_default_timezone_set('Europe/Berlin');
+        // Berlin and Auckland have 12h time difference in northern hemisphere summer, but Berlin and Moscow only 2h.
+
+        $field = new DatetimeField('Datetime');
+        $field->setTimezone('Pacific/Auckland');
+        $field->setMinDatetime('2009-01-31 11:00:00'); // server timezone
+        $field->setMaxDatetime('2010-01-31 11:00:00'); // server timezone
+        $defaults = $field->getSchemaDataDefaults();
+        $this->assertEquals($defaults['data']['min'], '2009-01-31T23:00:00'); // frontend timezone
+        $this->assertEquals($defaults['data']['max'], '2010-01-31T23:00:00'); // frontend timezone
+    }
+
+    public function testAttributesIncludesMinMax()
+    {
+        $field = new DatetimeField('Datetime');
+        $field->setMinDatetime('2009-03-31 23:00:00');
+        $field->setMaxDatetime('2010-03-31 23:00:00');
+        $attrs = $field->getAttributes();
+        $this->assertEquals($attrs['min'], '2009-03-31T23:00:00');
+        $this->assertEquals($attrs['max'], '2010-03-31T23:00:00');
+    }
+
+    public function testAttributesAdjustsMinMaxToTimezone()
+    {
+        date_default_timezone_set('Europe/Berlin');
+        // Berlin and Auckland have 12h time difference in northern hemisphere summer, but Berlin and Moscow only 2h.
+
+        $field = new DatetimeField('Datetime');
+        $field->setTimezone('Pacific/Auckland');
+        $field->setMinDatetime('2009-01-31 11:00:00'); // server timezone
+        $field->setMaxDatetime('2010-01-31 11:00:00'); // server timezone
+        $attrs = $field->getAttributes();
+        $this->assertEquals($attrs['min'], '2009-01-31T23:00:00'); // frontend timezone
+        $this->assertEquals($attrs['max'], '2010-01-31T23:00:00'); // frontend timezone
+    }
+
     protected function getMockForm()
     {
         /** @skipUpgrade */

From 94b49e3e28b66295e15137b4ffb97ec021a389ab Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 15:36:11 +1200
Subject: [PATCH 22/26] Removed unused field

---
 src/Forms/DatetimeField.php | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 03da92f68..7a7ff97fd 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -79,13 +79,6 @@ class DatetimeField extends TextField
      */
     protected $schemaDataType = FormField::SCHEMA_DATA_TYPE_DATETIME;
 
-    /**
-     * Date time order
-     *
-     * @var string
-     */
-    protected $dateTimeOrder = '{date} {time}';
-
     /**
      * Custom timezone
      *

From cbe534c67523bb5e0bdb019e353a1efa6c35b345 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 15:36:18 +1200
Subject: [PATCH 23/26] Fixed component capitalisation

---
 src/Forms/FormField.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Forms/FormField.php b/src/Forms/FormField.php
index ac60eb425..076fb0f52 100644
--- a/src/Forms/FormField.php
+++ b/src/Forms/FormField.php
@@ -70,7 +70,7 @@ class FormField extends RequestHandler
     const SCHEMA_DATA_TYPE_DATE = 'Date';
 
     /** @see $schemaDataType */
-    const SCHEMA_DATA_TYPE_DATETIME = 'DateTime';
+    const SCHEMA_DATA_TYPE_DATETIME = 'Datetime';
 
     /** @see $schemaDataType */
     const SCHEMA_DATA_TYPE_TIME = 'Time';

From a2ee6a76a0dfed5bb738852c932d04a91545614c Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 21:44:28 +1200
Subject: [PATCH 24/26] Fixed formschematest

---
 tests/php/Forms/FormSchemaTest.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/php/Forms/FormSchemaTest.php b/tests/php/Forms/FormSchemaTest.php
index fb5b8659a..fbc56b050 100644
--- a/tests/php/Forms/FormSchemaTest.php
+++ b/tests/php/Forms/FormSchemaTest.php
@@ -462,7 +462,6 @@ class FormSchemaTest extends SapphireTest
                         'extraClass' => 'date text',
                         'description' => null,
                         'rightTitle' => null,
-                        'html5' => true,
                         'lang' => 'en-US',
                         'leftTitle' => null,
                         'readOnly' => false,
@@ -474,8 +473,9 @@ class FormSchemaTest extends SapphireTest
                             ],
                         'attributes' =>
                             [],
-                        'data' =>
-                            [],
+                        'data' => [
+                            'html5' => true,
+                        ],
                     ],
                     [
                         'name' => 'Number',

From 22f232ed4d6c82d649b02d0fea26978726659646 Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Thu, 27 Apr 2017 21:44:52 +1200
Subject: [PATCH 25/26] Mark up <time> in validation errors

Allow better localisation of values in JS
---
 src/Forms/DateField.php     | 25 +++++++++++++++++++++----
 src/Forms/DatetimeField.php | 25 +++++++++++++++++++++----
 2 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/src/Forms/DateField.php b/src/Forms/DateField.php
index 9d698e012..8ed22d84c 100644
--- a/src/Forms/DateField.php
+++ b/src/Forms/DateField.php
@@ -7,6 +7,7 @@ use SilverStripe\i18n\i18n;
 use InvalidArgumentException;
 use SilverStripe\ORM\FieldType\DBDate;
 use SilverStripe\ORM\FieldType\DBDatetime;
+use SilverStripe\ORM\ValidationResult;
 
 /**
  * Form used for editing a date stirng
@@ -403,8 +404,16 @@ class DateField extends TextField
                     _t(
                         'DateField.VALIDDATEMINDATE',
                         "Your date has to be newer or matching the minimum allowed date ({date})",
-                        ['date' => $this->internalToFrontend($min)]
-                    )
+                        [
+                            'date' => sprintf(
+                                '<time datetime="%s">%s</time>',
+                                $min,
+                                $this->internalToFrontend($min)
+                            )
+                        ]
+                    ),
+                    ValidationResult::TYPE_ERROR,
+                    ValidationResult::CAST_HTML
                 );
                 return false;
             }
@@ -420,8 +429,16 @@ class DateField extends TextField
                     _t(
                         'DateField.VALIDDATEMAXDATE',
                         "Your date has to be older or matching the maximum allowed date ({date})",
-                        ['date' => $this->internalToFrontend($max)]
-                    )
+                        [
+                            'date' => sprintf(
+                                '<time datetime="%s">%s</time>',
+                                $max,
+                                $this->internalToFrontend($max)
+                            )
+                        ]
+                    ),
+                    ValidationResult::TYPE_ERROR,
+                    ValidationResult::CAST_HTML
                 );
                 return false;
             }
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 7a7ff97fd..02295b319 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -6,6 +6,7 @@ use IntlDateFormatter;
 use InvalidArgumentException;
 use SilverStripe\i18n\i18n;
 use SilverStripe\ORM\FieldType\DBDatetime;
+use SilverStripe\ORM\ValidationResult;
 
 /**
  * Form field used for editing date time strings.
@@ -586,8 +587,16 @@ class DatetimeField extends TextField
                     _t(
                         'DatetimeField.VALIDDATETIMEMINDATE',
                         "Your date has to be newer or matching the minimum allowed date and time ({datetime})",
-                        ['datetime' => $this->internalToFrontend($min)]
-                    )
+                        [
+                            'datetime' => sprintf(
+                                '<time datetime="%s">%s</time>',
+                                $min,
+                                $this->internalToFrontend($min)
+                            )
+                        ]
+                    ),
+                    ValidationResult::TYPE_ERROR,
+                    ValidationResult::CAST_HTML
                 );
                 return false;
             }
@@ -603,8 +612,16 @@ class DatetimeField extends TextField
                     _t(
                         'DatetimeField.VALIDDATEMAXDATETIME',
                         "Your date has to be older or matching the maximum allowed date and time ({datetime})",
-                        ['datetime' => $this->internalToFrontend($max)]
-                    )
+                        [
+                            'datetime' => sprintf(
+                                '<time datetime="%s">%s</time>',
+                                $max,
+                                $this->internalToFrontend($max)
+                            )
+                        ]
+                    ),
+                    ValidationResult::TYPE_ERROR,
+                    ValidationResult::CAST_HTML
                 );
                 return false;
             }

From daed727accb205c5a8fc46026c03539707aa2d2c Mon Sep 17 00:00:00 2001
From: Ingo Schommer <ingo@silverstripe.com>
Date: Fri, 28 Apr 2017 08:30:59 +1200
Subject: [PATCH 26/26] Fixed form schema validation

---
 tests/php/Forms/DatetimeFieldTest.php | 1 -
 tests/php/Forms/FormSchemaTest.php    | 2 ++
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/php/Forms/DatetimeFieldTest.php b/tests/php/Forms/DatetimeFieldTest.php
index e8bcdcc69..6cb8057d9 100644
--- a/tests/php/Forms/DatetimeFieldTest.php
+++ b/tests/php/Forms/DatetimeFieldTest.php
@@ -457,5 +457,4 @@ class DatetimeFieldTest extends SapphireTest
             )
         );
     }
-
 }
diff --git a/tests/php/Forms/FormSchemaTest.php b/tests/php/Forms/FormSchemaTest.php
index fbc56b050..7bd29161c 100644
--- a/tests/php/Forms/FormSchemaTest.php
+++ b/tests/php/Forms/FormSchemaTest.php
@@ -475,6 +475,8 @@ class FormSchemaTest extends SapphireTest
                             [],
                         'data' => [
                             'html5' => true,
+                            'min' => null,
+                            'max' => null
                         ],
                     ],
                     [