<?php
/**
 * AI Commerce manifest endpoint.
 *
 * Serves /.well-known/ai-commerce.json — a machine-readable manifest
 * that tells AI agents where to find product feeds, store policies,
 * and crawling permissions.
 *
 * @package AICommerce\Crawler
 */

declare(strict_types=1);

namespace AICommerce\Crawler;

use AICommerce\Feed\FeedFileManager;

/**
 * Registers and serves the /.well-known/ai-commerce.json endpoint.
 */
class ManifestEndpoint {

	/**
	 * Feed file manager.
	 *
	 * @var FeedFileManager
	 */
	private FeedFileManager $file_manager;

	/**
	 * WordPress database abstraction.
	 *
	 * @var \wpdb
	 */
	private \wpdb $wpdb;

	/**
	 * Constructor.
	 *
	 * @param FeedFileManager $file_manager Feed file manager.
	 * @param \wpdb           $wpdb         WordPress database instance.
	 */
	public function __construct( FeedFileManager $file_manager, \wpdb $wpdb ) {
		$this->file_manager = $file_manager;
		$this->wpdb         = $wpdb;
	}

	/**
	 * Register the rewrite rule for /.well-known/ai-commerce.json.
	 *
	 * @return void
	 */
	public function register_rewrite_rule(): void {
		add_rewrite_rule(
			'^\.well-known/ai-commerce\.json$',
			'index.php?aicommerce_manifest=1',
			'top'
		);
	}

	/**
	 * Add the query var for the manifest endpoint.
	 *
	 * @param array $vars Existing query vars.
	 *
	 * @return array Modified query vars.
	 */
	public function add_query_var( array $vars ): array {
		$vars[] = 'aicommerce_manifest';
		return $vars;
	}

	/**
	 * Serve the manifest if the query var is set.
	 *
	 * @return void
	 */
	public function maybe_serve(): void {
		if ( ! get_query_var( 'aicommerce_manifest' ) ) {
			return;
		}

		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
		@header( 'Content-Type: application/json; charset=utf-8' );
		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
		@header( 'Cache-Control: public, max-age=3600' );
		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
		@header( 'Access-Control-Allow-Origin: *' );

		$data = $this->build_manifest();

		/**
		 * Filters the ai-commerce.json manifest data.
		 *
		 * @param array $data The manifest data.
		 */
		$data = apply_filters( 'aicommerce/manifest/data', $data );

		// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
		echo wp_json_encode( $data, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT );
		exit;
	}

	/**
	 * Build the manifest data structure.
	 *
	 * @return array The manifest data.
	 */
	public function build_manifest(): array {
		$feeds_data = $this->get_feed_status();

		// Only expose a contact email if the admin has explicitly opted in to a
		// public one. The WordPress admin email is private and never published.
		$public_email = sanitize_email( (string) get_option( 'aicommerce_llms_contact_email', '' ) );
		/** This filter is documented in src/Crawler/LlmsTxtGenerator.php */
		$public_email = (string) apply_filters( 'aicommerce_llms_contact_email', $public_email );
		$contact_email = ( '' !== $public_email && is_email( $public_email ) ) ? $public_email : null;

		// WooCommerce is optional: guard all WC-only calls so the public manifest
		// endpoint never fatals on a site without WooCommerce.
		$currency = function_exists( 'get_woocommerce_currency' ) ? get_woocommerce_currency() : null;

		$total_products = 0;
		if ( post_type_exists( 'product' ) ) {
			$counts         = wp_count_posts( 'product' );
			$total_products = isset( $counts->publish ) ? (int) $counts->publish : 0;
		}

		return array(
			'version'       => '1.0',
			'merchant'      => array(
				'name'          => get_bloginfo( 'name' ),
				'url'           => home_url(),
				'logo'          => get_site_icon_url( 512 ) ?: null,
				'contact_email' => $contact_email,
				'currency'      => $currency,
			),
			'catalog'       => array(
				'total_products'     => $total_products,
				'feeds'              => $this->build_feeds_section( $feeds_data ),
				'schema_markup'      => true,
				'ai_readiness_score' => $this->get_average_readiness_score(),
			),
			'policies'      => array(
				'return_policy_url'  => get_option( 'aicommerce_return_policy_url' ) ?: null,
				'privacy_policy_url' => get_privacy_policy_url() ?: null,
				'terms_url'          => get_option( 'aicommerce_terms_url' ) ?: null,
			),
			'crawling'      => array(
				'allowed_bots' => array( 'GPTBot', 'Google-Extended', 'PerplexityBot', 'ClaudeBot' ),
				'sitemap_url'  => $this->get_sitemap_url(),
			),
			'mcp_endpoint'  => rest_url( 'aicommerce/v1/mcp' ),
			'mcp_discovery' => home_url( '/.well-known/mcp.json' ),
			'generated_at'  => current_time( 'c' ),
		);
	}

	/**
	 * Build the feeds section of the manifest.
	 *
	 * @param array $feeds_data Feed status data from the database.
	 *
	 * @return array Feeds section.
	 */
	private function build_feeds_section( array $feeds_data ): array {
		$feed_configs = array(
			'google'     => array(
				'format'    => 'xml/rss2+g',
				'extension' => 'xml',
			),
			'openai'     => array(
				'format'    => 'json',
				'extension' => 'json',
			),
			'bing'       => array(
				'format'    => 'xml/rss2+g',
				'extension' => 'xml',
			),
			'perplexity' => array(
				'format'    => 'json',
				'extension' => 'json',
			),
		);

		$feeds = array();

		foreach ( $feed_configs as $type => $config ) {
			$status   = $feeds_data[ $type ] ?? null;
			$has_file = $status && 'complete' === ( $status['status'] ?? '' );
			$filename = $type . '-feed.' . $config['extension'];

			$feeds[ $type ] = array(
				'url'        => $has_file ? $this->file_manager->get_feed_url( $filename ) : null,
				'format'     => $config['format'],
				'updated_at' => $status['generated_at'] ?? null,
			);
		}

		return $feeds;
	}

	/**
	 * Get feed status from the database.
	 *
	 * @return array Feed status indexed by feed_type.
	 */
	private function get_feed_status(): array {
		$feed_table = $this->wpdb->prefix . 'aicommerce_feeds';

		// Safe: internal $wpdb->prefix table names; user values use placeholders.
		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$rows = $this->wpdb->get_results(
			"SELECT feed_type, status, file_url, generated_at FROM {$feed_table}",
			ARRAY_A
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter

		$status = array();
		foreach ( ( $rows ?: array() ) as $row ) {
			$status[ $row['feed_type'] ] = $row;
		}

		return $status;
	}

	/**
	 * Get average AI readiness score across products.
	 *
	 * Returns cached average from the readiness_cache table, or null.
	 *
	 * @return int|null Average score or null if not available.
	 */
	private function get_average_readiness_score(): ?int {
		$cache_table = $this->wpdb->prefix . 'aicommerce_readiness_cache';

		// Safe: internal $wpdb->prefix table names; user values use placeholders.
		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$avg = $this->wpdb->get_var(
			"SELECT AVG(score) FROM {$cache_table}"
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter

		return null !== $avg ? (int) round( (float) $avg ) : null;
	}

	/**
	 * Get the sitemap URL.
	 *
	 * @return string Sitemap URL.
	 */
	private function get_sitemap_url(): string {
		if ( function_exists( 'get_sitemap_url' ) ) {
			$url = get_sitemap_url( 'index' );
			if ( $url ) {
				return $url;
			}
		}

		return home_url( '/wp-sitemap.xml' );
	}
}