<?php
/**
 * SEO title, meta description and schema markup for AiM posts.
 *
 * The Application Password path writes these straight into WordPress. The
 * plugin path carried none of them, so plugin-connected sites published posts
 * with no structured data at all (AIM-4461). They arrive as DATA in the
 * /pending payload, are stored as post meta, and are printed in the page head.
 * JSON-LD can't travel in the post content: wp_kses_post() strips script tags.
 *
 * @package AiM_Blog_Engine
 */

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

/**
 * Stores and prints the SEO fields of posts that came from AiM.
 */
class Aim_Be_Seo {

	const META_TITLE       = '_aim_seo_title';
	const META_DESCRIPTION = '_aim_seo_description';
	const META_SCHEMA      = '_aim_schema';
	const META_LOCAL       = '_aim_schema_local_business';

	/**
	 * Register the front-end hooks.
	 */
	public static function init() {
		add_action( 'wp_head', array( __CLASS__, 'print_head' ), 5 );
		add_filter( 'pre_get_document_title', array( __CLASS__, 'document_title' ), 20 );
	}

	/**
	 * Save the payload's SEO fields on the post. A field the payload doesn't
	 * carry (an older AiM server) leaves what is stored alone.
	 *
	 * @param int   $post_id Local post id.
	 * @param array $item    Post payload from /pending.
	 */
	public static function store( $post_id, $item ) {
		if ( isset( $item['seo_title'] ) ) {
			update_post_meta( $post_id, self::META_TITLE, sanitize_text_field( $item['seo_title'] ) );
		}
		if ( isset( $item['seo_description'] ) ) {
			update_post_meta( $post_id, self::META_DESCRIPTION, sanitize_textarea_field( $item['seo_description'] ) );
		}
		if ( isset( $item['schema'] ) && is_array( $item['schema'] ) ) {
			// Re-encoded from the decoded payload, so only JSON is ever stored.
			$schema = array_values( array_filter( $item['schema'], 'is_array' ) );
			update_post_meta( $post_id, self::META_SCHEMA, wp_slash( wp_json_encode( $schema ) ) );
		}
		if ( array_key_exists( 'schema_local_business', $item ) ) {
			$local = is_array( $item['schema_local_business'] ) ? wp_json_encode( $item['schema_local_business'] ) : '';
			update_post_meta( $post_id, self::META_LOCAL, wp_slash( $local ) );
		}
		self::fill_seo_plugin( $post_id, $item );
	}

	/**
	 * Fill Yoast or Rank Math's own fields, as the Application Password path
	 * does, but only where they are still empty: a title the member wrote in
	 * their SEO plugin is theirs.
	 *
	 * @param int   $post_id Local post id.
	 * @param array $item    Post payload from /pending.
	 */
	private static function fill_seo_plugin( $post_id, $item ) {
		$plugin = self::seo_plugin();
		$fields = array();
		if ( 'yoast' === $plugin ) {
			$fields = array(
				'_yoast_wpseo_title'    => 'seo_title',
				'_yoast_wpseo_metadesc' => 'seo_description',
				'_yoast_wpseo_focuskw'  => 'focus_keyword',
			);
		} elseif ( 'rankmath' === $plugin ) {
			$fields = array(
				'rank_math_title'         => 'seo_title',
				'rank_math_description'   => 'seo_description',
				'rank_math_focus_keyword' => 'focus_keyword',
			);
		}
		foreach ( $fields as $meta_key => $field ) {
			if ( empty( $item[ $field ] ) || '' !== (string) get_post_meta( $post_id, $meta_key, true ) ) {
				continue;
			}
			update_post_meta( $post_id, $meta_key, sanitize_text_field( $item[ $field ] ) );
		}
	}

	/**
	 * The SEO plugin running on this site, if any.
	 *
	 * @return string 'yoast', 'rankmath', 'other' or 'none'.
	 */
	public static function seo_plugin() {
		if ( defined( 'WPSEO_VERSION' ) ) {
			return 'yoast';
		}
		if ( class_exists( 'RankMath' ) || defined( 'RANK_MATH_VERSION' ) ) {
			return 'rankmath';
		}
		if ( defined( 'SEOPRESS_VERSION' ) || defined( 'AIOSEO_VERSION' ) || class_exists( 'The_SEO_Framework\\Load' ) ) {
			return 'other';
		}
		return 'none';
	}

	/**
	 * The AiM post being viewed, or 0.
	 *
	 * @return int
	 */
	private static function current_aim_post() {
		if ( ! is_singular( 'post' ) ) {
			return 0;
		}
		$post_id = get_queried_object_id();
		return ( $post_id && get_post_meta( $post_id, '_aim_blog_id', true ) ) ? (int) $post_id : 0;
	}

	/**
	 * Print the schema, and the meta description when no SEO plugin prints one.
	 */
	public static function print_head() {
		$post_id = self::current_aim_post();
		if ( ! $post_id ) {
			return;
		}
		$plugin = self::seo_plugin();

		if ( 'none' === $plugin ) {
			$description = (string) get_post_meta( $post_id, self::META_DESCRIPTION, true );
			if ( '' !== $description ) {
				echo '<meta name="description" content="' . esc_attr( $description ) . '" />' . "\n";
			}
		}

		$blocks = json_decode( (string) get_post_meta( $post_id, self::META_SCHEMA, true ), true );
		$blocks = is_array( $blocks ) ? $blocks : array();
		// An SEO plugin owns the site's organization schema; a copy on every post
		// is wrong. Article, FAQ and breadcrumb stay, as on the other path.
		if ( 'none' === $plugin ) {
			$local = json_decode( (string) get_post_meta( $post_id, self::META_LOCAL, true ), true );
			if ( is_array( $local ) ) {
				$blocks[] = $local;
			}
		}
		foreach ( $blocks as $block ) {
			if ( ! is_array( $block ) ) {
				continue;
			}
			// JSON_HEX_TAG turns < and > into escapes, so nothing in the data can
			// close the script element.
			echo '<script type="application/ld+json">' . wp_json_encode( $block, JSON_HEX_TAG | JSON_HEX_AMP | JSON_UNESCAPED_SLASHES ) . '</script>' . "\n";
		}
	}

	/**
	 * Use the SEO title for the browser tab and search result when no SEO
	 * plugin manages titles.
	 *
	 * @param string $title Title another filter already chose, or ''.
	 * @return string
	 */
	public static function document_title( $title ) {
		if ( '' !== $title || 'none' !== self::seo_plugin() ) {
			return $title;
		}
		$post_id = self::current_aim_post();
		if ( ! $post_id ) {
			return $title;
		}
		$seo_title = (string) get_post_meta( $post_id, self::META_TITLE, true );
		return '' !== $seo_title ? $seo_title : $title;
	}
}

Aim_Be_Seo::init();