<?php
/**
 * Unified JSON-LD Schema Graph, Local SEO, Google Merchant Product & E-E-A-T Builder.
 *
 * Outputs a single deduplicated `@graph` script in `wp_head` using WordPress's
 * native `wp_print_inline_script_tag()` and strict `JSON_HEX_TAG` encoding.
 *
 * @package ModulusTools\SEO\Modules
 */

namespace ModulusTools\SEO\Modules;

use ModulusTools\SEO\Core;

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

/**
 * Class Schema_Graph
 */
class Schema_Graph {

	/**
	 * Constructor.
	 */
	public function __construct() {
		add_action( 'wp_head', array( $this, 'output_schema_graph' ), 5 );
		add_action( 'show_user_profile', array( $this, 'render_user_eeat_fields' ) );
		add_action( 'edit_user_profile', array( $this, 'render_user_eeat_fields' ) );
		add_action( 'personal_options_update', array( $this, 'save_user_eeat_fields' ) );
		add_action( 'edit_user_profile_update', array( $this, 'save_user_eeat_fields' ) );
	}

	/**
	 * Outputs the unified JSON-LD `@graph` in `wp_head` via `wp_print_inline_script_tag()`.
	 *
	 * @return void
	 */
	public function output_schema_graph(): void {
		if ( is_admin() || is_feed() ) {
			return;
		}

		$settings = get_option( 'modulustools_seo_settings', array() );
		$site_url = home_url( '/' );
		$org_id   = $site_url . '#organization';
		$web_id   = $site_url . '#website';

		$graph = array();

		$has_local = ! empty( $settings['local_street'] ) || ! empty( $settings['local_phone'] );
		$org_type  = $has_local && ! empty( $settings['local_business_type'] )
			? array( 'Organization', $settings['local_business_type'] )
			: 'Organization';

		$org_node = array(
			'@type' => $org_type,
			'@id'   => $org_id,
			'name'  => ! empty( $settings['organization_name'] ) ? $settings['organization_name'] : get_bloginfo( 'name' ),
			'url'   => $site_url,
		);
		if ( ! empty( $settings['organization_logo'] ) ) {
			$org_node['logo'] = array(
				'@type' => 'ImageObject',
				'url'   => $settings['organization_logo'],
			);
		}
		if ( ! empty( $settings['local_phone'] ) ) {
			$org_node['telephone']  = $settings['local_phone'];
			$org_node['priceRange'] = $settings['local_price_range'] ?? '$$';
		}
		if ( ! empty( $settings['local_street'] ) || ! empty( $settings['local_city'] ) ) {
			$org_node['address'] = array(
				'@type'           => 'PostalAddress',
				'streetAddress'   => $settings['local_street'] ?? '',
				'addressLocality' => $settings['local_city'] ?? '',
				'addressRegion'   => $settings['local_region'] ?? '',
				'postalCode'      => $settings['local_postal'] ?? '',
				'addressCountry'  => $settings['local_country'] ?? '',
			);
		}
		if ( ! empty( $settings['local_lat'] ) && ! empty( $settings['local_lng'] ) ) {
			$org_node['geo'] = array(
				'@type'     => 'GeoCoordinates',
				'latitude'  => $settings['local_lat'],
				'longitude' => $settings['local_lng'],
			);
		}
		if ( ! empty( $settings['local_opening_hours'] ) && $has_local ) {
			$org_node['openingHours'] = $settings['local_opening_hours'];
		}
		$graph[] = $org_node;

		$graph[] = array(
			'@type'           => 'WebSite',
			'@id'             => $web_id,
			'url'             => $site_url,
			'name'            => get_bloginfo( 'name' ),
			'publisher'       => array( '@id' => $org_id ),
			'potentialAction' => array(
				'@type'       => 'SearchAction',
				'target'      => array(
					'@type'       => 'EntryPoint',
					'urlTemplate' => $site_url . '?s={search_term_string}',
				),
				'query-input' => 'required name=search_term_string',
			),
		);

		$crumbs = Frontend_Head::get_breadcrumb_items();
		if ( count( $crumbs ) > 1 ) {
			$item_list = array();
			foreach ( $crumbs as $idx => $crumb ) {
				$item_list[] = array(
					'@type'    => 'ListItem',
					'position' => $idx + 1,
					'name'     => $crumb['name'],
					'item'     => $crumb['url'],
				);
			}
			$graph[] = array(
				'@type'           => 'BreadcrumbList',
				'@id'             => get_permalink() . '#breadcrumb',
				'itemListElement' => $item_list,
			);
		}

		if ( is_singular() ) {
			$post = get_queried_object();
			if ( $post instanceof \WP_Post ) {
				$meta        = Core::get_meta( (int) $post->ID, 'post' );
				$schema_type = $meta && ! empty( $meta->schema_type ) ? $meta->schema_type : 'Article';
				$permalink   = (string) get_permalink( $post->ID );
				$author_id   = (int) $post->post_author;
				$person_id   = $site_url . '#/schema/person/' . $author_id;

				$graph[]     = $this->build_author_eeat_node( $author_id, $person_id );
				$entity_node = $this->build_singular_entity_node( $post, $meta, $schema_type, $permalink, $person_id, $org_id, $web_id );
				$graph[]     = $entity_node;

				$auto_faq = $this->extract_faq_node_from_content( $post->post_content, $permalink );
				if ( ! empty( $auto_faq ) && 'FAQPage' !== $schema_type ) {
					$graph[] = $auto_faq;
				}
			}
		}

		$payload = array(
			'@context' => 'https://schema.org',
			'@graph'   => $graph,
		);

		$encoded_json = wp_json_encode( $payload, JSON_HEX_TAG | JSON_HEX_AMP | JSON_HEX_APOS | JSON_HEX_QUOT );
		if ( is_string( $encoded_json ) && '' !== $encoded_json ) {
			wp_print_inline_script_tag(
				$encoded_json,
				array(
					'type'  => 'application/ld+json',
					'class' => 'modulustools-schema-graph',
				)
			);
		}
	}

	/**
	 * Builds the Author `Person` Schema node enriched with E-E-A-T user metadata.
	 *
	 * @param int    $user_id   WordPress User ID.
	 * @param string $person_id Schema `@id` URI.
	 * @return array<string, mixed>
	 */
	private function build_author_eeat_node( int $user_id, string $person_id ): array {
		$user = get_userdata( $user_id );
		$node = array(
			'@type' => 'Person',
			'@id'   => $person_id,
			'name'  => $user ? $user->display_name : get_bloginfo( 'name' ),
			'url'   => get_author_posts_url( $user_id ),
		);

		if ( $user && ! empty( $user->description ) ) {
			$node['description'] = $user->description;
		}

		$job_title   = get_user_meta( $user_id, 'modulustools_eeat_job_title', true );
		$credentials = get_user_meta( $user_id, 'modulustools_eeat_credentials', true );
		$alumni_of   = get_user_meta( $user_id, 'modulustools_eeat_alumni_of', true );
		$knows_about = get_user_meta( $user_id, 'modulustools_eeat_knows_about', true );
		$same_as_raw = get_user_meta( $user_id, 'modulustools_eeat_same_as', true );

		if ( ! empty( $job_title ) ) {
			$node['jobTitle'] = $job_title;
		}
		if ( ! empty( $credentials ) ) {
			$node['hasCredential'] = array(
				'@type'              => 'EducationalOccupationalCredential',
				'credentialCategory' => $credentials,
			);
		}
		if ( ! empty( $alumni_of ) ) {
			$node['alumniOf'] = array(
				'@type' => 'CollegeOrUniversity',
				'name'  => $alumni_of,
			);
		}
		if ( ! empty( $knows_about ) ) {
			$topics = array_filter( array_map( 'trim', explode( ',', (string) $knows_about ) ) );
			if ( ! empty( $topics ) ) {
				$node['knowsAbout'] = array_values( $topics );
			}
		}
		if ( ! empty( $same_as_raw ) ) {
			$links = array_filter( array_map( 'esc_url_raw', array_map( 'trim', explode( "\n", (string) $same_as_raw ) ) ) );
			if ( ! empty( $links ) ) {
				$node['sameAs'] = array_values( $links );
			}
		}

		return $node;
	}

	/**
	 * Builds the primary singular Schema node.
	 *
	 * @param \WP_Post    $post        Current post object.
	 * @param object|null $meta        Custom table row.
	 * @param string      $schema_type Entity type.
	 * @param string      $permalink   Canonical URL.
	 * @param string      $person_id   Author `@id`.
	 * @param string      $org_id      Organization `@id`.
	 * @param string      $web_id      WebSite `@id`.
	 * @return array<string, mixed>
	 */
	private function build_singular_entity_node( \WP_Post $post, ?object $meta, string $schema_type, string $permalink, string $person_id, string $org_id, string $web_id ): array {
		$headline    = $meta && ! empty( $meta->title ) ? $meta->title : get_the_title( $post );
		$description = $meta && ! empty( $meta->description ) ? $meta->description : wp_trim_words( wp_strip_all_tags( $post->post_content ), 28 );
		$settings    = get_option( 'modulustools_seo_settings', array() );

		if ( 'Product' === $schema_type ) {
			$brand_name   = $meta && ! empty( $meta->product_brand ) ? $meta->product_brand : ( $settings['organization_name'] ?? get_bloginfo( 'name' ) );
			$return_days  = absint( $settings['merchant_return_days'] ?? 30 );
			$product_node = array(
				'@type'       => 'Product',
				'@id'         => $permalink . '#product',
				'name'        => $headline,
				'description' => $description,
				'url'         => $permalink,
				'brand'       => array(
					'@type' => 'Brand',
					'name'  => $brand_name,
				),
			);

			if ( $meta && ! empty( $meta->product_gtin ) ) {
				$product_node['gtin'] = $meta->product_gtin;
			}
			if ( $meta && ! empty( $meta->product_mpn ) ) {
				$product_node['mpn'] = $meta->product_mpn;
			}

			if ( has_post_thumbnail( $post->ID ) ) {
				$product_node['image'] = (string) get_the_post_thumbnail_url( $post->ID, 'full' );
			}

			$offer = array(
				'@type'                   => 'Offer',
				'url'                     => $permalink,
				'priceCurrency'           => function_exists( 'get_woocommerce_currency' ) ? get_woocommerce_currency() : 'USD',
				'price'                   => '0.00',
				'availability'            => 'https://schema.org/InStock',
				'hasMerchantReturnPolicy' => array(
					'@type'                => 'MerchantReturnPolicy',
					'returnPolicyCategory' => 'https://schema.org/MerchantReturnFiniteReturnWindow',
					'merchantReturnDays'   => $return_days,
					'returnMethod'         => 'https://schema.org/ReturnByMail',
				),
			);

			if ( function_exists( 'wc_get_product' ) ) {
				$wc_product = wc_get_product( $post->ID );
				if ( $wc_product ) {
					$product_node['sku']   = $wc_product->get_sku();
					$offer['price']        = $wc_product->get_price();
					$offer['availability'] = $wc_product->is_in_stock() ? 'https://schema.org/InStock' : 'https://schema.org/OutOfStock';
				}
			}

			$product_node['offers'] = $offer;
			return $product_node;
		}

		$node = array(
			'@type'            => $schema_type,
			'@id'              => $permalink . '#primaryentity',
			'headline'         => $headline,
			'description'      => $description,
			'url'              => $permalink,
			'datePublished'    => get_the_date( DATE_W3C, $post ),
			'dateModified'     => get_the_modified_date( DATE_W3C, $post ),
			'author'           => array( '@id' => $person_id ),
			'publisher'        => array( '@id' => $org_id ),
			'isPartOf'         => array( '@id' => $web_id ),
			'mainEntityOfPage' => $permalink,
		);

		if ( has_post_thumbnail( $post->ID ) ) {
			$node['image'] = (string) get_the_post_thumbnail_url( $post->ID, 'full' );
		}

		if ( $meta && ! empty( $meta->eeat_reviewed_by ) ) {
			$node['reviewedBy'] = array(
				'@type' => 'Person',
				'name'  => $meta->eeat_reviewed_by,
			);
		}

		if ( $meta && ! empty( $meta->eeat_citations ) ) {
			$citations = array_filter( array_map( 'esc_url_raw', array_map( 'trim', explode( "\n", (string) $meta->eeat_citations ) ) ) );
			if ( ! empty( $citations ) ) {
				$node['citation'] = array_values( $citations );
			}
		}

		return $node;
	}

	/**
	 * Automatically extracts Question-and-Answer H2/H3 blocks into a `FAQPage` graph node.
	 *
	 * @param string $content   Post HTML content.
	 * @param string $permalink Post URL.
	 * @return array<string, mixed>
	 */
	private function extract_faq_node_from_content( string $content, string $permalink ): array {
		if ( ! preg_match_all( '/<h[23][^>]*>(.*?\?)<\/h[23]>\s*<p>(.*?)<\/p>/is', $content, $matches, PREG_SET_ORDER ) ) {
			return array();
		}

		$questions = array();
		foreach ( $matches as $match ) {
			$q_text = trim( wp_strip_all_tags( $match[1] ) );
			$a_text = trim( wp_strip_all_tags( $match[2] ) );
			if ( '' !== $q_text && '' !== $a_text ) {
				$questions[] = array(
					'@type'          => 'Question',
					'name'           => $q_text,
					'acceptedAnswer' => array(
						'@type' => 'Answer',
						'text'  => $a_text,
					),
				);
			}
		}

		if ( empty( $questions ) ) {
			return array();
		}

		return array(
			'@type'      => 'FAQPage',
			'@id'        => $permalink . '#faq',
			'mainEntity' => $questions,
		);
	}

	/**
	 * Renders E-E-A-T Author Credential fields on the WordPress User Profile screen.
	 *
	 * @param \WP_User $user User object.
	 * @return void
	 */
	public function render_user_eeat_fields( \WP_User $user ): void {
		wp_nonce_field( 'modulustools_save_user_eeat', 'modulustools_user_eeat_nonce' );
		?>
		<h2><?php esc_html_e( 'ModulusTools SEO — Author E-E-A-T Schema Credentials', 'modulustools-seo-suite' ); ?></h2>
		<p class="description"><?php esc_html_e( 'Injects verified author credentials into the JSON-LD Person graph for E-E-A-T structured data.', 'modulustools-seo-suite' ); ?></p>
		<table class="form-table" role="presentation">
			<tr>
				<th><label for="modulustools_eeat_job_title"><?php esc_html_e( 'Professional Job Title', 'modulustools-seo-suite' ); ?></label></th>
				<td><input type="text" name="modulustools_eeat_job_title" id="modulustools_eeat_job_title" value="<?php echo esc_attr( (string) get_user_meta( $user->ID, 'modulustools_eeat_job_title', true ) ); ?>" class="regular-text" placeholder="Senior Technical SEO Architect" /></td>
			</tr>
			<tr>
				<th><label for="modulustools_eeat_credentials"><?php esc_html_e( 'Academic / Professional Credentials', 'modulustools-seo-suite' ); ?></label></th>
				<td><input type="text" name="modulustools_eeat_credentials" id="modulustools_eeat_credentials" value="<?php echo esc_attr( (string) get_user_meta( $user->ID, 'modulustools_eeat_credentials', true ) ); ?>" class="regular-text" placeholder="M.S. Computer Science" /></td>
			</tr>
			<tr>
				<th><label for="modulustools_eeat_alumni_of"><?php esc_html_e( 'Alma Mater (alumniOf)', 'modulustools-seo-suite' ); ?></label></th>
				<td><input type="text" name="modulustools_eeat_alumni_of" id="modulustools_eeat_alumni_of" value="<?php echo esc_attr( (string) get_user_meta( $user->ID, 'modulustools_eeat_alumni_of', true ) ); ?>" class="regular-text" /></td>
			</tr>
			<tr>
				<th><label for="modulustools_eeat_knows_about"><?php esc_html_e( 'Areas of Expertise (knowsAbout, comma-separated)', 'modulustools-seo-suite' ); ?></label></th>
				<td><input type="text" name="modulustools_eeat_knows_about" id="modulustools_eeat_knows_about" value="<?php echo esc_attr( (string) get_user_meta( $user->ID, 'modulustools_eeat_knows_about', true ) ); ?>" class="regular-text" /></td>
			</tr>
			<tr>
				<th><label for="modulustools_eeat_same_as"><?php esc_html_e( 'Verified Profile URLs (sameAs, one URL per line)', 'modulustools-seo-suite' ); ?></label></th>
				<td><textarea name="modulustools_eeat_same_as" id="modulustools_eeat_same_as" rows="4" class="regular-text"><?php echo esc_textarea( (string) get_user_meta( $user->ID, 'modulustools_eeat_same_as', true ) ); ?></textarea></td>
			</tr>
		</table>
		<?php
	}

	/**
	 * Saves E-E-A-T Author Credential fields on User Profile update with direct sanitization.
	 *
	 * @param int $user_id User ID.
	 * @return void
	 */
	public function save_user_eeat_fields( int $user_id ): void {
		if ( ! isset( $_POST['modulustools_user_eeat_nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['modulustools_user_eeat_nonce'] ) ), 'modulustools_save_user_eeat' ) ) {
			return;
		}
		if ( ! current_user_can( 'edit_user', $user_id ) ) {
			return;
		}

		$text_fields = array(
			'modulustools_eeat_job_title',
			'modulustools_eeat_credentials',
			'modulustools_eeat_alumni_of',
			'modulustools_eeat_knows_about',
		);

		foreach ( $text_fields as $meta_key ) {
			if ( isset( $_POST[ $meta_key ] ) ) {
				update_user_meta( $user_id, $meta_key, sanitize_text_field( wp_unslash( $_POST[ $meta_key ] ) ) );
			}
		}

		if ( isset( $_POST['modulustools_eeat_same_as'] ) ) {
			update_user_meta( $user_id, 'modulustools_eeat_same_as', sanitize_textarea_field( wp_unslash( $_POST['modulustools_eeat_same_as'] ) ) );
		}
	}
}