<?php
/**
 * Yoast SEO: Gralus checks every page with Yoast's own analysis and fixes what it reports. The plugin lists each
 * published page with its Yoast fields (focus keyphrase, SEO title, meta description, slug) and content, and after
 * approval writes the fixes and the new scores, so the dots in WordPress's page list turn green. Undo puts back
 * the previous keyphrase, title, description, content and scores.
 */

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

class Gralus_Yoast {
	const PREVIOUS = '_gralus_yoast_previous';

	public static function register_routes() {
		$auth = array( 'Gralus_Connection', 'verify_request' );
		$ns   = Gralus_Rest::NS;
		register_rest_route( $ns, '/yoast/pages', array( 'methods' => 'POST', 'callback' => array( __CLASS__, 'pages' ), 'permission_callback' => $auth ) );
		register_rest_route( $ns, '/yoast/apply', array( 'methods' => 'POST', 'callback' => array( __CLASS__, 'apply' ), 'permission_callback' => $auth ) );
		register_rest_route( $ns, '/yoast/undo', array( 'methods' => 'POST', 'callback' => array( __CLASS__, 'undo' ), 'permission_callback' => $auth ) );
	}

	public static function active() {
		return defined( 'WPSEO_VERSION' );
	}

	/** Post types Yoast analyses: public ones, without attachments. */
	private static function types() {
		$types = get_post_types( array( 'public' => true ), 'names' );
		unset( $types['attachment'] );
		return array_values( $types );
	}

	/** The page builder that holds the page's real content, if any: its text can't be changed through post_content. */
	public static function builder( $post ) {
		$id      = $post->ID;
		$content = (string) $post->post_content;
		if ( 'builder' === get_post_meta( $id, '_elementor_edit_mode', true ) ) {
			return 'Elementor';
		}
		if ( 'on' === get_post_meta( $id, '_et_pb_use_builder', true ) || false !== strpos( $content, '[et_pb_' ) ) {
			return 'Divi';
		}
		if ( false !== strpos( $content, '[vc_row' ) ) {
			return 'WPBakery';
		}
		if ( get_post_meta( $id, '_fl_builder_enabled', true ) ) {
			return 'Beaver Builder';
		}
		if ( get_post_meta( $id, '_bricks_page_content_2', true ) ) {
			return 'Bricks';
		}
		if ( get_post_meta( $id, 'ct_builder_shortcodes', true ) || get_post_meta( $id, '_ct_builder_json', true ) ) {
			return 'Oxygen';
		}
		return null;
	}

	/** The title and description Yoast prints for the post, with its %%variables%% filled in. */
	private static function resolved( $id ) {
		$out = array( 'title' => '', 'description' => '' );
		if ( function_exists( 'YoastSEO' ) ) {
			try {
				$meta = YoastSEO()->meta->for_post( $id );
				if ( $meta ) {
					$out['title']       = (string) $meta->title;
					$out['description'] = (string) $meta->description;
				}
			} catch ( Throwable $e ) {
				unset( $e );
			}
		}
		return $out;
	}

	/** One page as Gralus needs it for Yoast's analysis. */
	public static function page( $post ) {
		$id       = $post->ID;
		$resolved = self::resolved( $id );
		return array(
			'postId'           => (int) $id,
			'type'             => $post->post_type,
			'url'              => get_permalink( $post ),
			'title'            => get_the_title( $post ),
			'slug'             => $post->post_name,
			'content'          => (string) $post->post_content,
			'contentHash'      => md5( (string) $post->post_content ),
			'builder'          => self::builder( $post ),
			'keyphrase'        => (string) get_post_meta( $id, '_yoast_wpseo_focuskw', true ),
			'seoTitleTemplate' => (string) get_post_meta( $id, '_yoast_wpseo_title', true ),
			'seoTitle'         => $resolved['title'],
			'metaDescription'  => '' !== $resolved['description'] ? $resolved['description'] : (string) get_post_meta( $id, '_yoast_wpseo_metadesc', true ),
			'cornerstone'      => '1' === (string) get_post_meta( $id, '_yoast_wpseo_is_cornerstone', true ),
			'noindex'          => '1' === (string) get_post_meta( $id, '_yoast_wpseo_meta-robots-noindex', true ),
			'yoastSeoScore'    => (int) get_post_meta( $id, '_yoast_wpseo_linkdex', true ),
			'yoastReadability' => (int) get_post_meta( $id, '_yoast_wpseo_content_score', true ),
		);
	}

	/** Body: { offset?: int, limit?: int } or { ids: int[] }. Published pages of every public type, oldest first, with the site's language. */
	public static function pages( WP_REST_Request $request ) {
		if ( ! self::active() ) {
			return new WP_Error( 'gralus_no_yoast', 'Yoast SEO is not active on this site.', array( 'status' => 409 ) );
		}
		$p      = $request->get_json_params();
		$offset = max( 0, (int) ( $p['offset'] ?? 0 ) );
		$limit  = max( 1, min( 50, (int) ( $p['limit'] ?? 25 ) ) );
		$ids    = isset( $p['ids'] ) && is_array( $p['ids'] ) ? array_slice( array_filter( array_map( 'intval', $p['ids'] ) ), 0, 50 ) : array();
		$args   = array(
			'post_type'      => self::types(),
			'post_status'    => 'publish',
			'posts_per_page' => $limit,
			'offset'         => $offset,
			'orderby'        => 'ID',
			'order'          => 'ASC',
			'has_password'   => false,
		);
		if ( $ids ) {
			// Specific pages (to fix them from what is on the site now).
			$args['post__in']       = $ids;
			$args['posts_per_page'] = count( $ids );
			$args['offset']         = 0;
		}
		$q = new WP_Query( $args );
		return array(
			'yoastVersion' => WPSEO_VERSION,
			'locale'       => get_locale(),
			'total'        => (int) $q->found_posts,
			'pages'        => array_map( array( __CLASS__, 'page' ), $q->posts ),
		);
	}

	/**
	 * Body: { postId, contentHash, keyphrase?, seoTitle?, metaDescription?, content?, scores: { seo, readability } }.
	 * Fields left out are not touched. New content is refused when the page changed since Gralus read it.
	 */
	public static function apply( WP_REST_Request $request ) {
		$p    = $request->get_json_params();
		$id   = (int) ( $p['postId'] ?? 0 );
		$post = $id ? get_post( $id ) : null;
		if ( ! $post || 'publish' !== $post->post_status ) {
			return new WP_Error( 'gralus_not_found', 'The page was not found.', array( 'status' => 404 ) );
		}
		if ( isset( $p['content'] ) && md5( (string) $post->post_content ) !== (string) ( $p['contentHash'] ?? '' ) ) {
			return new WP_Error( 'gralus_changed', 'The page was edited since Gralus checked it. Check it again, then write the fix again.', array( 'status' => 409 ) );
		}
		$previous = array(
			'keyphrase'       => (string) get_post_meta( $id, '_yoast_wpseo_focuskw', true ),
			'seoTitle'        => (string) get_post_meta( $id, '_yoast_wpseo_title', true ),
			'metaDescription' => (string) get_post_meta( $id, '_yoast_wpseo_metadesc', true ),
			'linkdex'         => (string) get_post_meta( $id, '_yoast_wpseo_linkdex', true ),
			'contentScore'    => (string) get_post_meta( $id, '_yoast_wpseo_content_score', true ),
		);
		if ( isset( $p['keyphrase'] ) ) {
			update_post_meta( $id, '_yoast_wpseo_focuskw', sanitize_text_field( (string) $p['keyphrase'] ) );
		}
		if ( isset( $p['seoTitle'] ) || isset( $p['metaDescription'] ) ) {
			Gralus_Seo_Meta::set_exact( $id, isset( $p['seoTitle'] ) ? (string) $p['seoTitle'] : null, isset( $p['metaDescription'] ) ? (string) $p['metaDescription'] : null );
		}
		if ( isset( $p['scores']['seo'] ) ) {
			update_post_meta( $id, '_yoast_wpseo_linkdex', (string) max( 0, min( 100, (int) $p['scores']['seo'] ) ) );
		}
		if ( isset( $p['scores']['readability'] ) ) {
			update_post_meta( $id, '_yoast_wpseo_content_score', (string) max( 0, min( 100, (int) $p['scores']['readability'] ) ) );
		}
		if ( isset( $p['content'] ) ) {
			$previous['content'] = (string) $post->post_content;
			if ( function_exists( 'wp_save_post_revision' ) ) {
				wp_save_post_revision( $id );
			}
			// Gralus changes only text blocks (cleaned to plain tags) and sends every other block exactly as it was,
			// so the content is saved as-is: kses would strip the author's own embeds and scripts.
			kses_remove_filters();
			$r = wp_update_post( wp_slash( array( 'ID' => $id, 'post_content' => (string) $p['content'] ) ), true );
			kses_init_filters();
			if ( is_wp_error( $r ) ) {
				return new WP_Error( 'gralus_save_failed', $r->get_error_message(), array( 'status' => 500 ) );
			}
		} else {
			self::touch( $id );
		}
		$all            = get_post_meta( $id, self::PREVIOUS, true );
		$all            = is_array( $all ) ? $all : array();
		$key            = preg_replace( '/[^a-zA-Z0-9-]/', '', (string) ( $p['fixId'] ?? 'last' ) );
		$all[ $key ]    = $previous;
		update_post_meta( $id, self::PREVIOUS, $all );
		return array( 'ok' => true, 'url' => get_permalink( $id ), 'contentHash' => md5( (string) get_post( $id )->post_content ) );
	}

	/** Save the post unchanged, so Yoast rebuilds its own copy of the fields (its indexables) from the new values. */
	private static function touch( $id ) {
		clean_post_cache( $id );
		// Saving re-runs the content filters; without kses removed, a signed request (no logged-in user) would strip embeds.
		kses_remove_filters();
		wp_update_post( array( 'ID' => $id ) );
		kses_init_filters();
	}

	/** Body: { postId, fixId }. Puts back what the fix replaced. */
	public static function undo( WP_REST_Request $request ) {
		$p    = $request->get_json_params();
		$id   = (int) ( $p['postId'] ?? 0 );
		$key  = preg_replace( '/[^a-zA-Z0-9-]/', '', (string) ( $p['fixId'] ?? 'last' ) );
		$all  = $id ? get_post_meta( $id, self::PREVIOUS, true ) : null;
		$prev = is_array( $all ) && isset( $all[ $key ] ) ? $all[ $key ] : null;
		if ( ! $prev ) {
			return new WP_Error( 'gralus_no_previous', 'The previous values were not found on the site.', array( 'status' => 404 ) );
		}
		$meta = array(
			'_yoast_wpseo_focuskw'       => $prev['keyphrase'],
			'_yoast_wpseo_title'         => $prev['seoTitle'],
			'_yoast_wpseo_metadesc'      => $prev['metaDescription'],
			'_yoast_wpseo_linkdex'       => $prev['linkdex'],
			'_yoast_wpseo_content_score' => $prev['contentScore'],
		);
		foreach ( $meta as $k => $v ) {
			if ( '' === (string) $v ) {
				delete_post_meta( $id, $k );
			} else {
				update_post_meta( $id, $k, $v );
			}
		}
		if ( isset( $prev['content'] ) ) {
			if ( function_exists( 'wp_save_post_revision' ) ) {
				wp_save_post_revision( $id );
			}
			kses_remove_filters();
			wp_update_post( wp_slash( array( 'ID' => $id, 'post_content' => (string) $prev['content'] ) ) );
			kses_init_filters();
		} else {
			self::touch( $id );
		}
		unset( $all[ $key ] );
		if ( $all ) {
			update_post_meta( $id, self::PREVIOUS, $all );
		} else {
			delete_post_meta( $id, self::PREVIOUS );
		}
		return array( 'ok' => true );
	}
}