<?php
/**
 * Extend the REST API functionality for VideoPress users.
 *
 * @package Jetpack
 */

/**
 * Add per-attachment VideoPress data.
 *
 * { # Attachment Object
 *   ...
 *   jetpack_videopress_guid: (string) VideoPress identifier
 *   ...
 * }
 *
 * @since 7.1.0
 */
class WPCOM_REST_API_V2_Attachment_VideoPress_Field extends WPCOM_REST_API_V2_Field_Controller {
	/**
	 * The REST Object Type to which the jetpack_videopress_guid field will be added.
	 *
	 * @var string
	 */
	protected $object_type = 'attachment';

	/**
	 * The name of the REST API field to add.
	 *
	 * @var string $field_name
	 */
	protected $field_name = 'jetpack_videopress_guid';

	/**
	 * Registers the jetpack_videopress field and adds a filter to remove it for attachments that are not videos.
	 */
	public function register_fields() {
		parent::register_fields();

		add_filter( 'rest_prepare_attachment', array( $this, 'remove_field_for_non_videos' ), 10, 2 );
	}

	/**
	 * Defines data structure and what elements are visible in which contexts
	 */
	public function get_schema() {
		return array(
			'$schema'     => 'http://json-schema.org/draft-04/schema#',
			'title'       => $this->field_name,
			'type'        => 'string',
			'context'     => array( 'view', 'edit' ),
			'readonly'    => true,
			'description' => __( 'Unique VideoPress ID', 'jetpack' ),
		);
	}

	/**
	 * Getter: Retrieve current VideoPress data for a given attachment.
	 *
	 * @param array           $attachment Response from the attachment endpoint.
	 * @param WP_REST_Request $request Request to the attachment endpoint.
	 *
	 * @return string
	 */
	public function get( $attachment, $request ) {
		if ( defined( 'IS_WPCOM' ) && IS_WPCOM ) {
			$blog_id = get_current_blog_id();
		} else {
			$blog_id = Jetpack_Options::get_option( 'id' );
		}

		$post_id = absint( $attachment['id'] );

		$videopress_guid = $this->get_videopress_guid( $post_id, $blog_id );

		if ( ! $videopress_guid ) {
			return '';
		}

		return $videopress_guid;
	}

	/**
	 * Gets the VideoPress GUID for a given attachment.
	 *
	 * This is pulled out into a separate method to support unit test mocking.
	 *
	 * @param int $attachment_id Attachment ID.
	 * @param int $blog_id Blog ID.
	 *
	 * @return string
	 */
	public function get_videopress_guid( $attachment_id, $blog_id ) {
		return video_get_info_by_blogpostid( $blog_id, $attachment_id )->guid;
	}

	/**
	 * Checks if the given attachment is a video.
	 *
	 * @param object $attachment The attachment object.
	 *
	 * @return false|int
	 */
	public function is_video( $attachment ) {
		return wp_startswith( $attachment->post_mime_type, 'video/' );
	}

	/**
	 * Removes the jetpack_videopress_guid field from the response if the
	 * given attachment is not a video.
	 *
	 * @param WP_REST_Response $response Response from the attachment endpoint.
	 * @param WP_Post          $attachment The original attachment object.
	 *
	 * @return mixed
	 */
	public function remove_field_for_non_videos( $response, $attachment ) {
		if ( ! $this->is_video( $attachment ) ) {
			unset( $response->data[ $this->field_name ] );
		}

		return $response;
	}

	/**
	 * Setter: It does nothing since `jetpack_videopress` is a read-only field.
	 *
	 * @param mixed           $value The new value for the field.
	 * @param WP_Post         $object The attachment object.
	 * @param WP_REST_Request $request The request object.
	 *
	 * @return null
	 */
	public function update( $value, $object, $request ) {
		return null;
	}

	/**
	 * Permission Check for the field's getter. Delegate the responsibility to the
	 * attachment endpoint, so it always returns true.
	 *
	 * @param mixed           $object Response from the attachment endpoint.
	 * @param WP_REST_Request $request Request to the attachment endpoint.
	 *
	 * @return true
	 */
	public function get_permission_check( $object, $request ) {
		return true;
	}

	/**
	 * Permission Check for the field's setter. Delegate the responsibility to the
	 * attachment endpoint, so it always returns true.
	 *
	 * @param mixed           $value The new value for the field.
	 * @param WP_Post         $object The attachment object.
	 * @param WP_REST_Request $request Request to the attachment endpoint.
	 *
	 * @return true
	 */
	public function update_permission_check( $value, $object, $request ) {
		return true;
	}
}

if (
	( method_exists( 'Jetpack', 'is_active' ) && Jetpack::is_active() ) ||
	( defined( 'IS_WPCOM' ) && IS_WPCOM )
) {
	wpcom_rest_api_v2_load_plugin( 'WPCOM_REST_API_V2_Attachment_VideoPress_Field' );
}
