<?php
/**
 * "Add to page" from the Embed dialog: append or prepend a player block to an
 * existing page, or create a new page that contains it.
 *
 * REST: POST streamsera/v1/embed/page { player, page_id?, title?, status?, position? }.
 *
 * @package StreamSera
 */

namespace StreamSera\Modules;

use WP_Error;
use WP_REST_Request;
use WP_REST_Response;

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

/**
 * Embed-to-page module.
 */
class Embed_Page {

	const NS = 'streamsera/v1';

	/**
	 * Hook in.
	 */
	public function register() {
		add_action( 'rest_api_init', array( $this, 'routes' ) );
	}

	/**
	 * Routes.
	 */
	public function routes() {
		register_rest_route(
			self::NS,
			'/embed/page',
			array(
				'methods'             => 'POST',
				'permission_callback' => array( $this, 'can_embed' ),
				'callback'            => array( $this, 'handle' ),
				'args'                => array(
					'player'   => array(
						'type'              => 'integer',
						'required'          => true,
						'sanitize_callback' => 'absint',
						'validate_callback' => 'rest_validate_request_arg',
					),
					'page_id'  => array(
						'type'              => 'integer',
						'sanitize_callback' => 'absint',
						'validate_callback' => 'rest_validate_request_arg',
					),
					'title'    => array(
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_text_field',
						'validate_callback' => 'rest_validate_request_arg',
					),
					'status'   => array(
						'type' => 'string',
						'enum' => array( 'draft', 'publish' ),
					),
					'position' => array(
						'type' => 'string',
						'enum' => array( 'append', 'prepend' ),
					),
				),
			)
		);
	}

	/**
	 * REST permission: add a player to a page (users who can edit pages).
	 *
	 * @return bool
	 */
	public function can_embed() {
		return current_user_can( 'edit_pages' );
	}

	/**
	 * Block markup (or the shortcode when the block is not registered).
	 *
	 * @param int $player_id Player.
	 * @return string
	 */
	public static function markup( $player_id ) {
		$player_id = absint( $player_id );
		if ( class_exists( '\WP_Block_Type_Registry' ) && \WP_Block_Type_Registry::get_instance()->is_registered( 'streamsera/player' ) ) {
			return '<!-- wp:streamsera/player {"playerId":' . $player_id . '} /-->';
		}
		return '<!-- wp:shortcode -->[streamsera id="' . $player_id . '"]<!-- /wp:shortcode -->';
	}

	/**
	 * Whether the current user may publish posts of a type (publish_pages for pages).
	 *
	 * @param string $post_type Post type.
	 * @return bool
	 */
	private static function can_publish( $post_type ) {
		$type = get_post_type_object( $post_type );
		$cap  = $type && isset( $type->cap->publish_posts ) ? $type->cap->publish_posts : ( 'page' === $post_type ? 'publish_pages' : 'publish_posts' );
		return current_user_can( $cap );
	}

	/**
	 * Add the player to a page or create one.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function handle( WP_REST_Request $request ) {
		$player_id = absint( $request['player'] );
		$player    = $player_id ? get_post( $player_id ) : null;
		// Published players, or drafts / private players the user may edit; never someone else's draft.
		if ( ! $player || 'streamsera_player' !== $player->post_type || ( 'publish' !== $player->post_status && ! current_user_can( 'edit_post', $player_id ) ) ) {
			return new WP_Error( 'streamsera_no_player', __( 'Player not found.', 'streamsera' ), array( 'status' => 404 ) );
		}
		$position = 'prepend' === $request['position'] ? 'prepend' : 'append';
		$markup   = self::markup( $player_id );
		$page_id  = absint( $request['page_id'] );

		if ( $page_id ) {
			$page = get_post( $page_id );
			if ( ! $page || ! in_array( $page->post_type, array( 'page', 'post' ), true ) ) {
				return new WP_Error( 'streamsera_no_page', __( 'Page not found.', 'streamsera' ), array( 'status' => 404 ) );
			}
			if ( ! current_user_can( 'edit_post', $page_id ) ) {
				return new WP_Error( 'streamsera_forbidden', __( 'You cannot edit that page.', 'streamsera' ), array( 'status' => 403 ) );
			}
			// Changing live content needs the publish capability of that post type too.
			if ( 'publish' === $page->post_status && ! self::can_publish( $page->post_type ) ) {
				return new WP_Error( 'streamsera_forbidden', __( 'You cannot change published content.', 'streamsera' ), array( 'status' => 403 ) );
			}
			$content = (string) $page->post_content;
			if ( false !== strpos( $content, '"playerId":' . $player_id . '}' ) || false !== strpos( $content, 'id="' . $player_id . '"' ) ) {
				// Already there: don't add it twice.
				$already = true;
			} else {
				$already = false;
				$content = 'prepend' === $position
					? $markup . "\n\n" . $content
					: rtrim( $content ) . "\n\n" . $markup;
				// wp_update_post() expects slashed data (it unslashes): keep backslashes in the page content.
				$result = wp_update_post(
					wp_slash(
						array(
							'ID'           => $page_id,
							'post_content' => $content,
						)
					),
					true
				);
				if ( is_wp_error( $result ) ) {
					return $result;
				}
			}
			$status = $page->post_status;
		} else {
			$title  = sanitize_text_field( (string) $request['title'] );
			$status = 'draft' === $request['status'] ? 'draft' : 'publish';
			if ( 'publish' === $status && ! self::can_publish( 'page' ) ) {
				return new WP_Error( 'streamsera_forbidden', __( 'You cannot publish pages. Create the page as a draft instead.', 'streamsera' ), array( 'status' => 403 ) );
			}
			if ( '' === $title ) {
				$title = streamsera_plain_title( $player );
			}
			$page_id = wp_insert_post(
				wp_slash(
					array(
						'post_type'    => 'page',
						'post_title'   => $title,
						'post_status'  => $status,
						'post_content' => $markup,
					)
				),
				true
			);
			if ( is_wp_error( $page_id ) ) {
				return $page_id;
			}
			$already = false;
		}

		/**
		 * Fires after a player was added to a page from the Embed dialog.
		 *
		 * @param int    $page_id   Page.
		 * @param int    $player_id Player.
		 * @param string $position  append|prepend.
		 */
		do_action( 'streamsera_embed_added_to_page', $page_id, $player_id, $position );

		return new WP_REST_Response(
			array(
				'id'        => (int) $page_id,
				'title'     => streamsera_plain_title( $page_id ),
				'status'    => $status,
				'already'   => $already,
				'edit_link' => get_edit_post_link( $page_id, 'raw' ),
				'view_link' => 'publish' === $status ? get_permalink( $page_id ) : get_preview_post_link( $page_id ),
			)
		);
	}
}