<?php

namespace SilverStripe\Forms\GridField;

use SilverStripe\Core\Object;
use SilverStripe\Forms\FormField;
use SilverStripe\ORM\DataObject;
use SilverStripe\ORM\FieldType\DBField;
use SilverStripe\View\ArrayData;
use SilverStripe\View\SSViewer;

/**
 * Adds a "level up" link to a GridField table, which is useful when viewing
 * hierarchical data. Requires the managed record to have a "getParent()"
 * method or has_one relationship called "Parent".
 */
class GridFieldLevelup extends Object implements GridField_HTMLProvider {

	/**
	 * @var integer - the record id of the level up to
	 */
	protected $currentID = null;

	/**
	 * sprintf() spec for link to link to parent.
	 * Only supports one variable replacement - the parent ID.
	 * @var string
	 */
	protected $linkSpec = '';

	/**
	 * @var array Extra attributes for the link
	 */
	protected $attributes = array();

	/**
	 *
	 * @param integer $currentID - The ID of the current item; this button will find that item's parent
	 */
	public function __construct($currentID) {
		parent::__construct();
		if($currentID && is_numeric($currentID)) {
			$this->currentID = $currentID;
		}
	}

	public function getHTMLFragments($gridField) {
		$modelClass = $gridField->getModelClass();
		$parentID = 0;

		if(!$this->currentID) {
			return null;
		}

		$modelObj = DataObject::get_by_id($modelClass, $this->currentID);

		$parent = null;
		if($modelObj->hasMethod('getParent')) {
			$parent = $modelObj->getParent();
		} elseif($modelObj->ParentID) {
			$parent = $modelObj->Parent();
		}

		if ($parent) {
			$parentID = $parent->ID;
		}

		// Attributes
		$attrs = array_merge($this->attributes, array(
			'href' => sprintf($this->linkSpec, $parentID),
			'class' => 'cms-panel-link ss-ui-button font-icon-level-up no-text grid-levelup'
		));
		$linkTag = FormField::create_tag('a', $attrs);

		$forTemplate = new ArrayData(array(
			'UpLink' => DBField::create_field('HTMLFragment', $linkTag)
		));

		$template = SSViewer::get_templates_by_class($this, '', __CLASS__);
			return array(
			'before' => $forTemplate->renderWith($template),
		);
	}

	public function setAttributes($attrs) {
		$this->attributes = $attrs;
		return $this;
	}

	public function getAttributes() {
		return $this->attributes;
	}

	public function setLinkSpec($link) {
		$this->linkSpec = $link;
		return $this;
	}

	public function getLinkSpec() {
		return $this->linkSpec;
	}
}