<?php

/**
 * Handles polymorphic relation for commentlist
 *
 * Uses elements of PolymorphicHasManyList in 3.2
 *
 * @author dmooyman
 */
class CommentList extends HasManyList {

	/**
	 * Retrieve the name of the class this relation is filtered by
	 *
	 * @return string
	 */
	public function getForeignClass() {
		return $this->dataQuery->getQueryParam('Foreign.Class');
	}

	public function __construct($parentClassName) {
		parent::__construct('Comment', 'ParentID');


		// Ensure underlying DataQuery globally references the class filter
		$this->dataQuery->setQueryParam('Foreign.Class', $parentClassName);

		// For queries with multiple foreign IDs (such as that generated by
		// DataList::relation) the filter must be generalised to filter by subclasses
		$classNames = Convert::raw2sql(ClassInfo::subclassesFor($parentClassName));
		$this->dataQuery->where(sprintf(
			"\"BaseClass\" IN ('%s')", implode("', '", $classNames)
		));
	}

	/**
	 * Adds the item to this relation.
	 * 
	 * @param Comment $item The comment to be added
	 */
	public function add($item) {
		// Check item given
		if(is_numeric($item)) {
			$item = Comment::get()->byID($item);
		}
		if(!($item instanceof Comment)) {
			throw new InvalidArgumentException("CommentList::add() expecting a Comment object, or ID value");
		}
		
		// Validate foreignID
		$foreignID = $this->getForeignID();
		if(!$foreignID || is_array($foreignID)) {
			throw new InvalidArgumentException("CommentList::add() can't be called until a single foreign ID is set");
		}

		$item->ParentID = $foreignID;
		$item->BaseClass = $this->getForeignClass();
		$item->write();
	}
	/**
	 * Remove a Comment from this relation by clearing the foreign key. Does not actually delete the comment.
	 *
	 * @param Comment $item The Comment to be removed
	 */
	public function remove($item) {
		// Check item given
		if(is_numeric($item)) {
			$item = Comment::get()->byID($item);
		}
		if(!($item instanceof Comment)) {
			throw new InvalidArgumentException("CommentList::remove() expecting a Comment object, or ID",
				E_USER_ERROR);
		}
		
		// Don't remove item with unrelated class key
		$foreignClass = $this->getForeignClass();
		$classNames = ClassInfo::subclassesFor($foreignClass);
		if(!in_array($item->BaseClass, $classNames)) return;
		
		// Don't remove item which doesn't belong to this list
		$foreignID = $this->getForeignID();
		if(	empty($foreignID)
			|| (is_array($foreignID) && in_array($item->ParentID, $foreignID))
			|| $foreignID == $item->ParentID
		) {
			$item->ParentID = null;
			$item->BaseClass = null;
			$item->write();
		}
	}
}