<?php

namespace SilverStripe\Forms\GridField;

use SilverStripe\ORM\ArrayList;
use SilverStripe\Core\Object;

/**
 * Encapsulates a collection of components following the
 * {@link GridFieldComponent} interface. While the {@link GridField} itself
 * has some configuration in the form of setters, most of the details are
 * dealt with through components.
 *
 * For example, you would add a {@link GridFieldPaginator} component to enable
 * pagination on the listed records, and configure it through
 * {@link GridFieldPaginator->setItemsPerPage()}.
 *
 * In order to reduce the amount of custom code required, the framework
 * provides some default configurations for common use cases:
 *
 * - {@link GridFieldConfig_Base} (added by default to GridField)
 * - {@link GridFieldConfig_RecordEditor}
 * - {@link GridFieldConfig_RelationEditor}
 */
class GridFieldConfig extends Object {

	/**
	 * @var ArrayList
	 */
	protected $components = null;


	/**
	 *
	 */
	public function __construct() {
		parent::__construct();
		$this->components = new ArrayList();
	}

	/**
	 * @param GridFieldComponent $component
	 * @param string $insertBefore The class of the component to insert this one before
	 * @return $this
	 */
	public function addComponent(GridFieldComponent $component, $insertBefore = null) {
		if($insertBefore) {
			$existingItems = $this->getComponents();
			$this->components = new ArrayList;
			$inserted = false;
			foreach($existingItems as $existingItem) {
				if(!$inserted && $existingItem instanceof $insertBefore) {
					$this->components->push($component);
					$inserted = true;
				}
				$this->components->push($existingItem);
			}
			if(!$inserted) $this->components->push($component);
		} else {
			$this->getComponents()->push($component);
		}
		return $this;
	}

	/**
	 * @param GridFieldComponent $component,... One or more components
	 * @return $this
	 */
	public function addComponents($component = null) {
		$components = func_get_args();
		foreach($components as $component) {
			$this->addComponent($component);
		}
		return $this;
	}

	/**
	 * @param GridFieldComponent $component
	 * @return $this
	 */
	public function removeComponent(GridFieldComponent $component) {
		$this->getComponents()->remove($component);
		return $this;
	}

	/**
	 * @param string $type Class name or interface
	 * @return $this
	 */
	public function removeComponentsByType($type) {
		$components = $this->getComponentsByType($type);
		foreach($components as $component) {
			$this->removeComponent($component);
		}
		return $this;
	}

	/**
	 * @return ArrayList Of GridFieldComponent
	 */
	public function getComponents() {
		if(!$this->components) {
			$this->components = new ArrayList();
		}
		return $this->components;
	}

	/**
	 * Returns all components extending a certain class, or implementing a certain interface.
	 *
	 * @param string $type Class name or interface
	 * @return ArrayList Of GridFieldComponent
	 */
	public function getComponentsByType($type) {
		$components = new ArrayList();
		foreach($this->components as $component) {
			if($component instanceof $type) $components->push($component);
		}
		return $components;
	}

	/**
	 * Returns the first available component with the given class or interface.
	 *
	 * @param string $type ClassName
	 * @return GridFieldComponent
	 */
	public function getComponentByType($type) {
		foreach($this->components as $component) {
			if($component instanceof $type) {
				return $component;
			}
		}
		return null;
	}
}