<?php

namespace SilverStripe\Forms;

use SilverStripe\Dev\Debug;

/**
 * Base class for all fields that contain other fields.
 *
 * Implements sequentialisation - so that when we're saving / loading data, we
 * can populate a tabbed form properly. All of the children are stored in
 * $this->children
 */
class CompositeField extends FormField {

	/**
	 * @var FieldList
	 */
	protected $children;

	/**
	 * Set to true when this field is a readonly field
	 */
	protected $readonly;

	/**
	 * @var $columnCount int Toggle different css-rendering for multiple columns
	 * ("onecolumn", "twocolumns", "threecolumns"). The content is determined
	 * by the $children-array, so wrap all items you want to have grouped in a
	 * column inside a CompositeField.
	 * Caution: Please make sure that this variable actually matches the
	 * count of your $children.
	 */
	protected $columnCount = null;

	/**
	 * @var String custom HTML tag to render with, e.g. to produce a <fieldset>.
	 */
	protected $tag = 'div';

	/**
	 * @var String Optional description for this set of fields.
	 * If the {@link $tag} property is set to use a 'fieldset', this will be
	 * rendered as a <legend> tag, otherwise its a 'title' attribute.
	 */
	protected $legend;

	protected $schemaDataType = FormField::SCHEMA_DATA_TYPE_STRUCTURAL;

	public function __construct($children = null) {
		if($children instanceof FieldList) {
			$this->children = $children;
		} elseif(is_array($children)) {
			$this->children = new FieldList($children);
		} else {
			//filter out null/empty items
			$children = array_filter(func_get_args());
			$this->children = new FieldList($children);
		}
		$this->children->setContainerField($this);

		parent::__construct(null, false);
	}

	/**
	 * Merge child field data into this form
	 */
	public function getSchemaDataDefaults() {
		$defaults = parent::getSchemaDataDefaults();
		$children = $this->getChildren();
		if($children && $children->count()) {
			$childSchema = [];
			/** @var FormField $child */
			foreach($children as $child) {
				$childSchema[] = $child->getSchemaData();
			}
			$defaults['children'] = $childSchema;
		}

		$defaults['data']['tag'] = $this->getTag();
		$defaults['data']['legend'] = $this->getLegend();

		return $defaults;
	}

	/**
	 * Returns all the sub-fields, suitable for <% loop FieldList %>
	 *
	 * @return FieldList
	 */
	public function FieldList() {
		return $this->children;
	}

	/**
	 * Accessor method for $this->children
	 *
	 * @return FieldList
	 */
	public function getChildren() {
		return $this->children;
	}

	/**
	 * Returns the name (ID) for the element.
	 * If the CompositeField doesn't have a name, but we still want the ID/name to be set.
	 * This code generates the ID from the nested children.
	 *
	 * @todo this is temporary, and should be removed when FormTemplateHelper is updated to handle ID for CompositeFields with no name
	 *
	 * @return String $name
	 */
	public function getName(){
		if($this->name) {
			return $this->name;
		}

		$fieldList = $this->FieldList();
		$compositeTitle = '';
		$count = 0;
		/** @var FormField $subfield */
		foreach($fieldList as $subfield){
			$compositeTitle .= $subfield->getName();
			if($subfield->getName()) $count++;
		}
		/** @skipUpgrade */
		if($count === 1) {
			$compositeTitle .= 'Group';
		}
		return preg_replace("/[^a-zA-Z0-9]+/", "", $compositeTitle);
	}

	/**
	 * @param FieldList $children
	 * @return $this
	 */
	public function setChildren($children) {
		$this->children = $children;
		return $this;
	}

	/**
	 * @param string $tag
	 * @return $this
	 */
	public function setTag($tag) {
		$this->tag = $tag;

		return $this;
	}

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

	/**
	 * @param string $legend
	 * @return $this
	 */
	public function setLegend($legend) {
		$this->legend = $legend;
		return $this;
	}

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

	public function extraClass() {
		/** @skipUpgrade */
		$classes = array('field', 'CompositeField', parent::extraClass());
		if($this->columnCount) $classes[] = 'multicolumn';

		return implode(' ', $classes);
	}

	public function getAttributes() {
		return array_merge(
			parent::getAttributes(),
			array(
				'tabindex' => null,
				'type' => null,
				'value' => null,
				'title' => ($this->tag == 'fieldset') ? null : $this->legend
			)
		);
	}

	/**
	 * Add all of the non-composite fields contained within this field to the
	 * list.
	 *
	 * Sequentialisation is used when connecting the form to its data source
	 *
	 * @param array $list
	 * @param bool $saveableOnly
	 */
	public function collateDataFields(&$list, $saveableOnly = false) {
		foreach($this->children as $field) {
			if(! $field instanceof FormField) {
				continue;
			}
			if($field instanceof CompositeField) {
				$field->collateDataFields($list, $saveableOnly);
			}
			if($saveableOnly) {
				$isIncluded =  ($field->hasData() && !$field->isReadonly() && !$field->isDisabled());
			} else {
				$isIncluded =  ($field->hasData());
			}
			if($isIncluded) {
				$name = $field->getName();
				if($name) {
					$formName = (isset($this->form)) ? $this->form->FormName() : '(unknown form)';
					if(isset($list[$name])) {
						user_error("collateDataFields() I noticed that a field called '$name' appears twice in"
							. " your form: '{$formName}'.  One is a '{$field->class}' and the other is a"
							. " '{$list[$name]->class}'", E_USER_ERROR);
					}
					$list[$name] = $field;
				}
			}
		}
	}

	public function setForm($form) {
		foreach($this->getChildren() as $field) {
			if ($field instanceof FormField) {
				$field->setForm($form);
			}
		}

		parent::setForm($form);
		return $this;
	}


	public function setDisabled($disabled) {
		parent::setDisabled($disabled);
		foreach($this->getChildren() as $child) {
			$child->setDisabled($disabled);
		}
		return $this;
	}

	public function setReadonly($readonly)
	{
		parent::setReadonly($readonly);
		foreach($this->getChildren() as $child) {
			$child->setReadonly($readonly);
		}
		return $this;
	}

	public function setColumnCount($columnCount) {
		$this->columnCount = $columnCount;
		return $this;
	}

	public function getColumnCount() {
		return $this->columnCount;
	}

	public function isComposite() {
		return true;
	}

	public function hasData() {
		return false;
	}

	public function fieldByName($name) {
		return $this->children->fieldByName($name);
	}

	/**
	 * Add a new child field to the end of the set.
	 *
	 * @param FormField
	 */
	public function push(FormField $field) {
		$this->children->push($field);
	}

	/**
	 * Add a new child field to the beginning of the set.
	 *
	 * @param FormField
	 */
	public function unshift(FormField $field) {
		$this->children->unshift($field);
	}

	/**
	 * @uses FieldList->insertBefore()
	 *
	 * @param string $insertBefore
	 * @param FormField $field
	 * @return false|FormField
	 */
	public function insertBefore($insertBefore, $field) {
		return $this->children->insertBefore($insertBefore, $field);
	}

	/**
	 * @uses FieldList->insertAfter()
	 * @param string $insertAfter
	 * @param FormField $field
	 * @return false|FormField
	 */
	public function insertAfter($insertAfter, $field) {
		return $this->children->insertAfter($insertAfter, $field);
	}

	/**
	 * Remove a field from this CompositeField by Name.
	 * The field could also be inside a CompositeField.
	 *
	 * @param string $fieldName The name of the field
	 * @param boolean $dataFieldOnly If this is true, then a field will only
	 * be removed if it's a data field.  Dataless fields, such as tabs, will
	 * be left as-is.
	 */
	public function removeByName($fieldName, $dataFieldOnly = false) {
		$this->children->removeByName($fieldName, $dataFieldOnly);
	}

	public function replaceField($fieldName, $newField) {
		return $this->children->replaceField($fieldName, $newField);
	}

	public function rootFieldList() {
		if(is_object($this->containerFieldList)) return $this->containerFieldList->rootFieldList();
		else return $this->children;
	}

	public function __clone() {
		/** {@see FieldList::__clone(}} */
		$this->setChildren(clone $this->children);
	}

	/**
	 * Return a readonly version of this field. Keeps the composition but returns readonly
	 * versions of all the child {@link FormField} objects.
	 *
	 * @return CompositeField
	 */
	public function performReadonlyTransformation() {
		$newChildren = new FieldList();
		$clone = clone $this;
		if($clone->getChildren()) foreach($clone->getChildren() as $child) {
			/** @var FormField $child */
			$child = $child->transform(new ReadonlyTransformation());
			$newChildren->push($child);
		}

		$clone->setChildren($newChildren);
		$clone->setReadonly(true);
		$clone->addExtraClass($this->extraClass());
		$clone->setDescription($this->getDescription());

		return $clone;
	}

	/**
	 * Return a disabled version of this field. Keeps the composition but returns disabled
	 * versions of all the child {@link FormField} objects.
	 *
	 * @return CompositeField
	 */
	public function performDisabledTransformation() {
		$newChildren = new FieldList();
		$clone = clone $this;
		if($clone->getChildren()) foreach($clone->getChildren() as $child) {
			/** @var FormField $child */
			$child = $child->transform(new DisabledTransformation());
			$newChildren->push($child);
		}

		$clone->setChildren($newChildren);
		$clone->setDisabled(true);
		$clone->addExtraClass($this->extraClass());
		$clone->setDescription($this->getDescription());
		foreach($this->attributes as $k => $v) {
			$clone->setAttribute($k, $v);
		}

		return $clone;
	}

	public function IsReadonly() {
		return $this->readonly;
	}

	/**
	 * Find the numerical position of a field within
	 * the children collection. Doesn't work recursively.
	 *
	 * @param string|FormField
	 * @return int Position in children collection (first position starts with 0). Returns FALSE if the field can't
	 *             be found.
	 */
	public function fieldPosition($field) {
		if(is_string($field)) {
			$field = $this->fieldByName($field);
		}
		if(!$field) {
			return false;
		}

		$i = 0;
		foreach($this->children as $child) {
			/** @var FormField $child */
			if($child->getName() == $field->getName()) {
				return $i;
			}
			$i++;
		}

		return false;
	}

	/**
	 * Transform the named field into a readonly feld.
	 *
	 * @param string|FormField
	 * @return bool
	 */
	public function makeFieldReadonly($field) {
		$fieldName = ($field instanceof FormField) ? $field->getName() : $field;

		// Iterate on items, looking for the applicable field
		foreach($this->children as $i => $item) {
			if($item instanceof CompositeField) {
				if($item->makeFieldReadonly($fieldName)) {
					return true;
				};
			} elseif($item instanceof FormField && $item->getName() == $fieldName) {
				// Once it's found, use FormField::transform to turn the field into a readonly version of itself.
				$this->children->replaceField($fieldName, $item->transform(new ReadonlyTransformation()));

				// A true results indicates that the field was found
				return true;
			}
		}
		return false;
	}

	public function debug() {
		$result = "$this->class ($this->name) <ul>";
		foreach($this->children as $child) {
			$result .= "<li>" . Debug::text($child) . "&nbsp;</li>";
		}
		$result .= "</ul>";
		return $result;
	}

	/**
	 * Validate this field
	 *
	 * @param Validator $validator
	 * @return bool
	 */
	public function validate($validator) {
		$valid = true;
		foreach($this->children as $child){
			/** @var FormField $child */
			$valid = ($child && $child->validate($validator) && $valid);
		}
		return $valid;
	}

}