<?php
/**
 * REST endpoint that the block-editor UI calls to perform a workflow transition.
 *
 * @package OST\EditorialWorkflow
 */

namespace OST\EditorialWorkflow;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * POST /ost-editorial-workflow/v1/transition
 */
class Rest {

	const NAMESPACE_V1 = 'ost-editorial-workflow/v1';

	/**
	 * Transition engine.
	 *
	 * @var Transitions
	 */
	private $transitions;

	/**
	 * Workflow service.
	 *
	 * @var Workflow
	 */
	private $workflow;

	/**
	 * Constructor.
	 *
	 * @param Transitions $transitions Transition engine.
	 * @param Workflow    $workflow    Workflow service.
	 */
	public function __construct( Transitions $transitions, Workflow $workflow ) {
		$this->transitions = $transitions;
		$this->workflow    = $workflow;
	}

	/**
	 * Register hooks.
	 *
	 * @return void
	 */
	public function register_hooks() {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	/**
	 * Register the transition route.
	 *
	 * @return void
	 */
	public function register_routes() {
		register_rest_route(
			self::NAMESPACE_V1,
			'/transition',
			array(
				'methods'             => \WP_REST_Server::CREATABLE,
				'callback'            => array( $this, 'transition' ),
				'permission_callback' => array( $this, 'can_transition' ),
				'args'                => array(
					'post'   => array(
						'required'          => true,
						'type'              => 'integer',
						'sanitize_callback' => 'absint',
					),
					'action' => array(
						'required'          => true,
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_key',
					),
					'note'   => array(
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_textarea_field',
					),
				),
			)
		);
	}

	/**
	 * Permission: the user must be able to edit the target post.
	 *
	 * @param \WP_REST_Request $request Request.
	 * @return bool
	 */
	public function can_transition( $request ) {
		return current_user_can( 'edit_post', (int) $request['post'] );
	}

	/**
	 * Handle the transition and return the new state.
	 *
	 * @param \WP_REST_Request $request Request.
	 * @return \WP_REST_Response|\WP_Error
	 */
	public function transition( $request ) {
		$post_id = (int) $request['post'];
		$result  = $this->transitions->handle( $post_id, (string) $request['action'], (string) $request['note'] );

		if ( is_wp_error( $result ) ) {
			return $result;
		}

		$post     = get_post( $post_id );
		$workflow = $this->workflow->for_post( $post );

		return rest_ensure_response(
			array(
				'status'       => $result,
				'status_label' => $workflow ? $this->workflow->status_label( $workflow, $result ) : $result,
				'actions'      => array_values( $this->workflow->allowed_actions( $post ) ),
			)
		);
	}
}