<?php
/**
 * Ranktim - JSON-LD schema output.
 *
 * Renders the structured data saved during article import for Ranktim posts.
 *
 * @package Ranktim
 */

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

class Ranktim_Schema {

	/** Post meta key that stores the prepared Article/BlogPosting JSON-LD. */
	const META_KEY = '_ranktim_json_ld';

	/** Attach the schema renderer to WordPress. */
	public function register(): void {
		add_action( 'wp_head', array( $this, 'render' ), 20 );
	}

	/** Render JSON-LD in the document head for imported Ranktim posts only. */
	public function render(): void {
		if ( ! is_singular( 'post' ) ) {
			return;
		}

		$post_id = get_queried_object_id();
		if ( ! $post_id || ! get_post_meta( $post_id, '_ranktim_item_id', true ) ) {
			return;
		}

		$schema = get_post_meta( $post_id, self::META_KEY, true );
		if ( is_string( $schema ) ) {
			$decoded = json_decode( $schema, true );
			$schema  = is_array( $decoded ) ? $decoded : array();
		}

		if ( empty( $schema ) || ! is_array( $schema ) ) {
			$schema = $this->build_runtime_fallback_schema( $post_id );
			if ( empty( $schema ) ) {
				return;
			}
			update_post_meta( $post_id, self::META_KEY, $schema );
		}

		$json = wp_json_encode(
			$schema,
			JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_HEX_TAG | JSON_HEX_AMP | JSON_HEX_APOS | JSON_HEX_QUOT
		);

		if ( ! $json ) {
			return;
		}

		// Printed through the core helper so the tag goes through WordPress'
		// script-tag filters. $json is already safely encoded for ld+json.
		wp_print_inline_script_tag( $json, array( 'type' => 'application/ld+json' ) );
	}

	/**
	 * Generate schema for older Ranktim posts imported before JSON-LD meta existed.
	 */
	private function build_runtime_fallback_schema( int $post_id ): array {
		$permalink = get_permalink( $post_id );
		if ( ! $permalink ) {
			return array();
		}

		$description = get_post_meta( $post_id, '_ranktim_meta_description', true );
		if ( ! is_string( $description ) || '' === trim( $description ) ) {
			$description = get_the_excerpt( $post_id );
		}

		$author_id = (int) get_post_field( 'post_author', $post_id );
		$author    = $author_id > 0 ? get_the_author_meta( 'display_name', $author_id ) : '';
		$image     = get_the_post_thumbnail_url( $post_id, 'full' );
		$keywords  = $this->get_runtime_keywords( $post_id );

		$schema = array(
			'@context'         => 'https://schema.org',
			'@type'            => 'BlogPosting',
			'headline'         => wp_strip_all_tags( get_the_title( $post_id ) ),
			'author'           => array(
				'@type' => 'Person',
				'name'  => $author ? $author : get_bloginfo( 'name' ),
			),
			'publisher'        => array(
				'@type' => 'Organization',
				'name'  => get_bloginfo( 'name' ),
				'url'   => home_url( '/' ),
			),
			'datePublished'    => get_post_time( 'c', false, $post_id ),
			'dateModified'     => get_post_modified_time( 'c', false, $post_id ),
			'url'              => $permalink,
			'mainEntityOfPage' => array(
				'@type' => 'WebPage',
				'@id'   => $permalink,
			),
		);

		if ( is_string( $description ) && '' !== trim( $description ) ) {
			$schema['description'] = trim( wp_strip_all_tags( $description ) );
		}
		if ( is_string( $image ) && '' !== trim( $image ) ) {
			$schema['image'] = array( esc_url_raw( $image ) );
		}
		if ( ! empty( $keywords ) ) {
			$schema['keywords'] = $keywords;
		}

		return $schema;
	}

	/**
	 * Read Ranktim keyword meta stored during article import.
	 */
	private function get_runtime_keywords( int $post_id ): array {
		$keywords = array();
		$primary  = get_post_meta( $post_id, '_ranktim_primary_keyword', true );

		if ( is_string( $primary ) && '' !== trim( $primary ) ) {
			$keywords[] = sanitize_text_field( $primary );
		}

		$secondary = get_post_meta( $post_id, '_ranktim_secondary_keywords', true );
		if ( is_array( $secondary ) ) {
			foreach ( $secondary as $keyword ) {
				if ( is_string( $keyword ) && '' !== trim( $keyword ) ) {
					$keywords[] = sanitize_text_field( $keyword );
				}
			}
		}

		return array_values( array_unique( $keywords ) );
	}
}