<?php

namespace SilverStripe\Forms;

use SilverStripe\Core\Convert;
use SilverStripe\Core\Injector\Injector;
use SilverStripe\i18n\i18n;
use InvalidArgumentException;
use Zend_Locale;
use Zend_Date;

require_once 'Zend/Date.php';

/**
 * Form field to display an editable date string,
 * either in a single `<input type="text">` field,
 * or in three separate fields for day, month and year.
 *
 * # Configuration
 *
 * - 'showcalendar' (boolean): Determines if a calendar picker is shown.
 *    By default, jQuery UI datepicker is used (see {@link DateField_View_JQuery}).
 * - 'jslocale' (string): Overwrites the "Locale" value set in this class.
 *    Only useful in combination with {@link DateField_View_JQuery}.
 * - 'dmyfields' (boolean): Show three input fields for day, month and year separately.
 *    CAUTION: Might not be useable in combination with 'showcalendar', depending on the used javascript library
 * - 'dmyseparator' (string): HTML markup to separate day, month and year fields.
 *    Only applicable with 'dmyfields'=TRUE. Use 'dateformat' to influence date representation with 'dmyfields'=FALSE.
 * - 'dmyplaceholders': Show HTML5 placehoder text to allow identification of the three separate input fields
 * - 'dateformat' (string): Date format compatible with Zend_Date.
 *    Usually set to default format for {@link locale} through {@link Zend_Locale_Format::getDateFormat()}.
 * - 'datavalueformat' (string): Internal ISO format string used by {@link dataValue()} to save the
 *    date to a database.
 * - 'min' (string): Minimum allowed date value (in ISO format, or strtotime() compatible).
 *    Example: '2010-03-31', or '-7 days'
 * - 'max' (string): Maximum allowed date value (in ISO format, or strtotime() compatible).
 *    Example: '2010-03-31', or '1 year'
 *
 * Depending which UI helper is used, further namespaced configuration options are available.
 * For the default jQuery UI, all options prefixed/namespaced with "jQueryUI." will be respected as well.
 * Example: <code>$myDateField->setConfig('jQueryUI.showWeek', true);</code>
 * See http://docs.jquery.com/UI/Datepicker for details.
 *
 * Caution: The form field does not include any JavaScript or CSS when used outside of the CMS context,
 * since the required frontend dependencies are included through CMS bundling.
 *
 * # Localization
 *
 * The field will get its default locale from {@link i18n::get_locale()}, and set the `dateformat`
 * configuration accordingly. Changing the locale through {@link setLocale()} will not update the
 * `dateformat` configuration automatically.
 *
 * See http://doc.silverstripe.org/framework/en/topics/i18n for more information about localizing form fields.
 *
 * # Usage
 *
 * ## Example: German dates with separate fields for day, month, year
 *
 *   $f = new DateField('MyDate');
 *   $f->setLocale('de_DE');
 *   $f->setConfig('dmyfields', true);
 *
 * # Validation
 *
 * Caution: JavaScript validation is only supported for the 'en_NZ' locale at the moment,
 * it will be disabled automatically for all other locales.
 */
class DateField extends TextField {

	protected $schemaDataType = FormField::SCHEMA_DATA_TYPE_DATE;

	/**
	 * @config
	 * @var array
	 */
	private static $default_config = array(
		'showcalendar' => false,
		'jslocale' => null,
		'dmyfields' => false,
		'dmyseparator' => '&nbsp;<span class="separator">/</span>&nbsp;',
		'dmyplaceholders' => true,
		'dateformat' => null,
		'datavalueformat' => 'yyyy-MM-dd',
		'min' => null,
		'max' => null,
	);

	/**
	 * @var array
	 */
	protected $config;

	/**
	 * @var String
	 */
	protected $locale = null;

	/**
	 * @var Zend_Date Just set if the date is valid.
	 * {@link $value} will always be set to aid validation,
	 * and might contain invalid values.
	 */
	protected $valueObj = null;

	public function __construct($name, $title = null, $value = null) {
		if(!$this->locale) {
			$this->locale = i18n::get_locale();
		}

		$this->config = $this->config()->default_config;
		if(!$this->getConfig('dateformat')) {
			$this->setConfig('dateformat', i18n::config()->get('date_format'));
		}

		foreach ($this->config()->default_config AS $defaultK => $defaultV) {
			if ($defaultV) {
				if ($defaultK=='locale') {
					$this->locale = $defaultV;
				} else {
					$this->setConfig($defaultK, $defaultV);
			}
		}
		}

		parent::__construct($name, $title, $value);
	}

	public function FieldHolder($properties = array()) {
		if ($this->getConfig('showcalendar')) {
			// TODO Replace with properly extensible view helper system
			$d = DateField_View_JQuery::create($this);
			if(!$d->regionalSettingsExist()) {
				$dateformat = $this->getConfig('dateformat');

				// if no localefile is present, the jQuery DatePicker
				// month- and daynames will default to English, so the date
				// will not pass Zend validatiobn. We provide a fallback
				if (preg_match('/(MMM+)|(EEE+)/', $dateformat)) {
					$this->setConfig('dateformat', $this->getConfig('datavalueformat'));
				}
			}
			$d->onBeforeRender();
		}
		$html = parent::FieldHolder();

		if(!empty($d)) {
			$html = $d->onAfterRender($html);
		}
		return $html;
	}

	function SmallFieldHolder($properties = array()){
		$d = DateField_View_JQuery::create($this);
		$d->onBeforeRender();
		$html = parent::SmallFieldHolder($properties);
		$html = $d->onAfterRender($html);
		return $html;
	}

	public function Field($properties = array()) {
		$config = array(
			'showcalendar' => $this->getConfig('showcalendar'),
			'isoDateformat' => $this->getConfig('dateformat'),
			'jquerydateformat' => DateField_View_JQuery::convert_iso_to_jquery_format($this->getConfig('dateformat')),
			'min' => $this->getConfig('min'),
			'max' => $this->getConfig('max')
		);

		// Add other jQuery UI specific, namespaced options (only serializable, no callbacks etc.)
		// TODO Move to DateField_View_jQuery once we have a properly extensible HTML5 attribute system for FormField
		$jqueryUIConfig = array();
		foreach($this->getConfig() as $k => $v) {
			if(preg_match('/^jQueryUI\.(.*)/', $k, $matches)) $jqueryUIConfig[$matches[1]] = $v;
		}
		if ($jqueryUIConfig)
			$config['jqueryuiconfig'] =  Convert::array2json(array_filter($jqueryUIConfig));
		$config = array_filter($config);
		foreach($config as $k => $v) $this->setAttribute('data-' . $k, $v);

		// Three separate fields for day, month and year
		if($this->getConfig('dmyfields')) {
			// values
			$valArr = ($this->valueObj) ? $this->valueObj->toArray() : null;

			// fields
			$fieldNames = Zend_Locale::getTranslationList('Field', $this->locale);
			$fieldDay = NumericField::create($this->name . '[day]', false, ($valArr) ? $valArr['day'] : null)
				->addExtraClass('day')
				->setAttribute('placeholder', $this->getConfig('dmyplaceholders') ? $fieldNames['day'] : null)
				->setMaxLength(2);

			$fieldMonth = NumericField::create($this->name . '[month]', false, ($valArr) ? $valArr['month'] : null)
				->addExtraClass('month')
				->setAttribute('placeholder', $this->getConfig('dmyplaceholders') ? $fieldNames['month'] : null)
				->setMaxLength(2);

			$fieldYear = NumericField::create($this->name . '[year]', false, ($valArr) ? $valArr['year'] : null)
				->addExtraClass('year')
				->setAttribute('placeholder', $this->getConfig('dmyplaceholders') ? $fieldNames['year'] : null)
				->setMaxLength(4);

			// order fields depending on format
			$sep = $this->getConfig('dmyseparator');
			$format = $this->getConfig('dateformat');
			$fields = array();
			$fields[stripos($format, 'd')] = $fieldDay->Field();
			$fields[stripos($format, 'm')] = $fieldMonth->Field();
			$fields[stripos($format, 'y')] = $fieldYear->Field();
			ksort($fields);
			$html = implode($sep, $fields);

			// dmyfields doesn't work with showcalendar
			$this->setConfig('showcalendar',false);
		}
		// Default text input field
		else {
			$html = parent::Field();
		}

		return $html;
	}

	public function Type() {
		return 'date text';
	}

	/**
	 * Sets the internal value to ISO date format.
	 *
	 * @param mixed $val
	 * @return $this
	 */
	public function setValue($val) {
		$locale = new Zend_Locale($this->locale);

		if(empty($val)) {
			$this->value = null;
			$this->valueObj = null;
		} else {
			if($this->getConfig('dmyfields')) {
				// Setting in correct locale
				if(is_array($val) && $this->validateArrayValue($val)) {
					// set() gets confused with custom date formats when using array notation
					if(!(empty($val['day']) || empty($val['month']) || empty($val['year']))) {
						$this->valueObj = new Zend_Date($val, null, $locale);
						$this->value = $this->valueObj->toArray();
					} else {
						$this->value = $val;
						$this->valueObj = null;
					}
				}
				// load ISO date from database (usually through Form->loadDataForm())
				else if(!empty($val) && Zend_Date::isDate($val, $this->getConfig('datavalueformat'), $locale)) {
					$this->valueObj = new Zend_Date($val, $this->getConfig('datavalueformat'), $locale);
					$this->value = $this->valueObj->toArray();
				}
				else {
					$this->value = $val;
					$this->valueObj = null;
				}
			} else {
				// Setting in correct locale.
				// Caution: Its important to have this check *before* the ISO date fallback,
				// as some dates are falsely detected as ISO by isDate(), e.g. '03/04/03'
				// (en_NZ for 3rd of April, definetly not yyyy-MM-dd)
				if(!empty($val) && Zend_Date::isDate($val, $this->getConfig('dateformat'), $locale)) {
					$this->valueObj = new Zend_Date($val, $this->getConfig('dateformat'), $locale);
					$this->value = $this->valueObj->get($this->getConfig('dateformat'), $locale);

				}
				// load ISO date from database (usually through Form->loadDataForm())
				else if(!empty($val) && Zend_Date::isDate($val, $this->getConfig('datavalueformat'))) {
					$this->valueObj = new Zend_Date($val, $this->getConfig('datavalueformat'));
					$this->value = $this->valueObj->get($this->getConfig('dateformat'), $locale);
				}
				else {
					$this->value = $val;
					$this->valueObj = null;
				}
			}
		}

		return $this;
	}

	/**
	 * @return String ISO 8601 date, suitable for insertion into database
	 */
	public function dataValue() {
		if($this->valueObj) {
			return $this->valueObj->toString($this->getConfig('datavalueformat'));
		} else {
			return null;
		}
	}

	public function performReadonlyTransformation() {
		$field = $this->castedCopy('SilverStripe\\Forms\\DateField_Disabled');
		$field->setValue($this->dataValue());
		$field->readonly = true;

		return $field;
	}

	/**
	 * @param mixed $class
	 * @return FormField
	 */
	public function castedCopy($class) {
		/** @var FormField $copy */
		$copy = Injector::inst()->create($class, $this->name);
		if($copy->hasMethod('setConfig')) {
			/** @var DateField $copy */
			$config = $this->getConfig();
			foreach($config as $k => $v) {
				$copy->setConfig($k, $v);
			}
		}

		return parent::castedCopy($copy);
	}

	/**
	 * Validate an array with expected keys 'day', 'month' and 'year.
	 * Used because Zend_Date::isDate() doesn't provide this.
	 *
	 * @param array $val
	 * @return bool
	 */
	public function validateArrayValue($val) {
		if(!is_array($val)) {
			return false;
		}

		// Validate against Zend_Date,
		// but check for empty array keys (they're included in standard form submissions)
		return (
			array_key_exists('year', $val)
			&& (!$val['year'] || Zend_Date::isDate($val['year'], 'yyyy', $this->locale))
			&& array_key_exists('month', $val)
			&& (!$val['month'] || Zend_Date::isDate($val['month'], 'MM', $this->locale))
			&& array_key_exists('day', $val)
			&& (!$val['day'] || Zend_Date::isDate($val['day'], 'dd', $this->locale))
		);
	}

	/**
	 * @param Validator $validator
	 * @return bool
	 */
	public function validate($validator) {
		// Don't validate empty fields
		if(empty($this->value)) {
			return true;
		}

		// date format
		if($this->getConfig('dmyfields')) {
			$valid = (!$this->value || $this->validateArrayValue($this->value));
		} else {
			$valid = (Zend_Date::isDate($this->value, $this->getConfig('dateformat'), $this->locale));
		}
		if(!$valid) {
			$validator->validationError(
				$this->name,
				_t(
					'DateField.VALIDDATEFORMAT2', "Please enter a valid date format ({format})",
					array('format' => $this->getConfig('dateformat'))
				),
				"validation"
			);
			return false;
		}

		// min/max - Assumes that the date value was valid in the first place
		if($min = $this->getConfig('min')) {
			// ISO or strtotime()
			if(Zend_Date::isDate($min, $this->getConfig('datavalueformat'))) {
				$minDate = new Zend_Date($min, $this->getConfig('datavalueformat'));
			} else {
				$minDate = new Zend_Date(strftime('%Y-%m-%d', strtotime($min)), $this->getConfig('datavalueformat'));
			}
			if(!$this->valueObj || (!$this->valueObj->isLater($minDate) && !$this->valueObj->equals($minDate))) {
				$validator->validationError(
					$this->name,
					_t(
						'DateField.VALIDDATEMINDATE',
						"Your date has to be newer or matching the minimum allowed date ({date})",
						array('date' => $minDate->toString($this->getConfig('dateformat')))
					),
					"validation"
				);
				return false;
			}
		}
		if($max = $this->getConfig('max')) {
			// ISO or strtotime()
			if(Zend_Date::isDate($min, $this->getConfig('datavalueformat'))) {
				$maxDate = new Zend_Date($max, $this->getConfig('datavalueformat'));
			} else {
				$maxDate = new Zend_Date(strftime('%Y-%m-%d', strtotime($max)), $this->getConfig('datavalueformat'));
			}
			if(!$this->valueObj || (!$this->valueObj->isEarlier($maxDate) && !$this->valueObj->equals($maxDate))) {
				$validator->validationError(
					$this->name,
					_t('DateField.VALIDDATEMAXDATE',
						"Your date has to be older or matching the maximum allowed date ({date})",
						array('date' => $maxDate->toString($this->getConfig('dateformat')))
					),
					"validation"
				);
				return false;
			}
		}

		return true;
	}

	/**
	 * @return string
	 */
	public function getLocale() {
		return $this->locale;
	}

	/**
	 * Caution: Will not update the 'dateformat' config value.
	 *
	 * @param string $locale
	 * @return $this
	 */
	public function setLocale($locale) {
		$this->locale = $locale;
		return $this;
	}

	/**
	 * @param string $name
	 * @param mixed $val
	 * @return $this
	 */
	public function setConfig($name, $val) {
		switch($name) {
			case 'min':
				$format = $this->getConfig('datavalueformat');
				if($val && !Zend_Date::isDate($val, $format) && !strtotime($val)) {
					throw new InvalidArgumentException(
						sprintf('Date "%s" is not a valid minimum date format (%s) or strtotime() argument',
						$val, $format));
				}
				break;
			case 'max':
				$format = $this->getConfig('datavalueformat');
				if($val && !Zend_Date::isDate($val, $format) && !strtotime($val)) {
					throw new InvalidArgumentException(
						sprintf('Date "%s" is not a valid maximum date format (%s) or strtotime() argument',
						$val, $format));
				}
				break;
		}

		$this->config[$name] = $val;
		return $this;
	}

	/**
	 * @param String $name Optional, returns the whole configuration array if empty
	 * @return mixed|array
	 */
	public function getConfig($name = null) {
		if($name) {
			return isset($this->config[$name]) ? $this->config[$name] : null;
		} else {
			return $this->config;
		}
	}
}