<?php
/**
 * Store-level AI readiness health check.
 *
 * Produces an actionable checklist describing how ready the whole store is for
 * AI discovery and agentic commerce. Powers the onboarding wizard's status
 * step and the dashboard health card, and is exposed via the REST API.
 *
 * @package AICommerce\Analytics
 */

declare(strict_types=1);

namespace AICommerce\Analytics;

/**
 * Runs a set of store-wide readiness checks.
 */
class SiteHealth {

	/**
	 * Status constants.
	 */
	public const STATUS_PASS = 'pass';
	public const STATUS_WARN = 'warn';
	public const STATUS_FAIL = 'fail';
	public const STATUS_INFO = 'info';

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

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

	/**
	 * Run all checks and return a structured report.
	 *
	 * @return array{
	 *     score: int,
	 *     grade: string,
	 *     summary: array{pass: int, warn: int, fail: int, total: int},
	 *     checks: array<int, array<string, mixed>>
	 * }
	 */
	public function run(): array {
		$checks = array(
			$this->check_woocommerce(),
			$this->check_permalinks(),
			$this->check_site_public(),
			$this->check_schema_enabled(),
			$this->check_site_schema_enabled(),
			$this->check_products_published(),
			$this->check_product_identifiers(),
			$this->check_default_brand(),
			$this->check_feeds_generated(),
			$this->check_llms_txt(),
			$this->check_crawler_activity(),
			$this->check_onboarding(),
		);

		/**
		 * Filters the store health checks.
		 *
		 * @param array<int, array<string, mixed>> $checks The check results.
		 * @param SiteHealth                        $health The health instance.
		 */
		$checks = (array) apply_filters( 'aicommerce_site_health_checks', $checks, $this );

		$summary = array(
			'pass'  => 0,
			'warn'  => 0,
			'fail'  => 0,
			'total' => 0,
		);

		foreach ( $checks as $check ) {
			if ( ! isset( $check['status'] ) || self::STATUS_INFO === $check['status'] ) {
				continue;
			}
			++$summary['total'];
			if ( isset( $summary[ $check['status'] ] ) ) {
				++$summary[ $check['status'] ];
			}
		}

		$score = $summary['total'] > 0
			? (int) round( ( ( $summary['pass'] + ( $summary['warn'] * 0.5 ) ) / $summary['total'] ) * 100 )
			: 0;

		return array(
			'score'   => $score,
			'grade'   => $this->grade( $score ),
			'summary' => $summary,
			'checks'  => array_values( $checks ),
		);
	}

	/**
	 * Build a single check result.
	 *
	 * @param string $id      Check identifier.
	 * @param string $label   Human label.
	 * @param string $status  One of the STATUS_* constants.
	 * @param string $message Guidance message.
	 * @param array  $extra   Extra fields (e.g., action_url).
	 *
	 * @return array<string, mixed>
	 */
	private function result( string $id, string $label, string $status, string $message, array $extra = array() ): array {
		return array_merge(
			array(
				'id'      => $id,
				'label'   => $label,
				'status'  => $status,
				'message' => $message,
			),
			$extra
		);
	}

	/**
	 * Convert a numeric score into a letter grade.
	 *
	 * @param int $score The 0-100 score.
	 *
	 * @return string
	 */
	private function grade( int $score ): string {
		if ( $score >= 90 ) {
			return 'A';
		}
		if ( $score >= 75 ) {
			return 'B';
		}
		if ( $score >= 60 ) {
			return 'C';
		}
		if ( $score >= 40 ) {
			return 'D';
		}
		return 'F';
	}

	/**
	 * Check that WooCommerce is active.
	 *
	 * @return array<string, mixed>
	 */
	private function check_woocommerce(): array {
		if ( class_exists( 'WooCommerce' ) ) {
			$version = defined( 'WC_VERSION' ) ? WC_VERSION : '';
			return $this->result(
				'woocommerce',
				__( 'WooCommerce active', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				$version
					? sprintf( /* translators: %s: WooCommerce version. */ __( 'WooCommerce %s is active.', 'ai-discoverability-kit' ), $version )
					: __( 'WooCommerce is active.', 'ai-discoverability-kit' )
			);
		}

		return $this->result(
			'woocommerce',
			__( 'WooCommerce active', 'ai-discoverability-kit' ),
			self::STATUS_FAIL,
			__( 'WooCommerce is required for product schema and feeds.', 'ai-discoverability-kit' )
		);
	}

	/**
	 * Check pretty permalinks (required for /llms.txt and manifest endpoints).
	 *
	 * @return array<string, mixed>
	 */
	private function check_permalinks(): array {
		$structure = (string) get_option( 'permalink_structure', '' );

		if ( '' !== $structure ) {
			return $this->result(
				'permalinks',
				__( 'Pretty permalinks', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				__( 'Pretty permalinks are enabled — discovery endpoints will work.', 'ai-discoverability-kit' )
			);
		}

		return $this->result(
			'permalinks',
			__( 'Pretty permalinks', 'ai-discoverability-kit' ),
			self::STATUS_FAIL,
			__( 'Enable pretty permalinks so /llms.txt and the AI manifest are reachable.', 'ai-discoverability-kit' ),
			array( 'action_url' => admin_url( 'options-permalink.php' ) )
		);
	}

	/**
	 * Check the site is publicly visible to crawlers.
	 *
	 * @return array<string, mixed>
	 */
	private function check_site_public(): array {
		if ( '1' === (string) get_option( 'blog_public', '1' ) ) {
			return $this->result(
				'site_public',
				__( 'Search engine visibility', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				__( 'Your site is visible to search engines and AI crawlers.', 'ai-discoverability-kit' )
			);
		}

		return $this->result(
			'site_public',
			__( 'Search engine visibility', 'ai-discoverability-kit' ),
			self::STATUS_FAIL,
			__( 'Search engine visibility is discouraged in Settings → Reading; AI crawlers will be blocked.', 'ai-discoverability-kit' ),
			array( 'action_url' => admin_url( 'options-reading.php' ) )
		);
	}

	/**
	 * Check product schema injection is enabled.
	 *
	 * @return array<string, mixed>
	 */
	private function check_schema_enabled(): array {
		if ( get_option( 'aicommerce_schema_enabled', true ) ) {
			return $this->result(
				'schema_enabled',
				__( 'Product schema output', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				__( 'JSON-LD product schema is being injected on product pages.', 'ai-discoverability-kit' )
			);
		}

		return $this->result(
			'schema_enabled',
			__( 'Product schema output', 'ai-discoverability-kit' ),
			self::STATUS_WARN,
			__( 'Product schema output is turned off in Tyralix AI Discoverability settings.', 'ai-discoverability-kit' )
		);
	}

	/**
	 * Check site-level schema is enabled.
	 *
	 * @return array<string, mixed>
	 */
	private function check_site_schema_enabled(): array {
		if ( get_option( 'aicommerce_site_schema_enabled', true ) ) {
			return $this->result(
				'site_schema_enabled',
				__( 'Store schema output', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				__( 'Organization, WebSite and OnlineStore schema are output on your home page.', 'ai-discoverability-kit' )
			);
		}

		return $this->result(
			'site_schema_enabled',
			__( 'Store schema output', 'ai-discoverability-kit' ),
			self::STATUS_WARN,
			__( 'Store-level schema is turned off; AI models get less context about your brand.', 'ai-discoverability-kit' )
		);
	}

	/**
	 * Check that at least one product is published.
	 *
	 * @return array<string, mixed>
	 */
	private function check_products_published(): array {
		$counts = wp_count_posts( 'product' );
		$count  = $counts ? (int) $counts->publish : 0;

		if ( $count > 0 ) {
			return $this->result(
				'products',
				__( 'Published products', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				sprintf(
					/* translators: %d: number of products. */
					_n( '%d published product found.', '%d published products found.', $count, 'ai-discoverability-kit' ),
					$count
				)
			);
		}

		return $this->result(
			'products',
			__( 'Published products', 'ai-discoverability-kit' ),
			self::STATUS_WARN,
			__( 'No published products yet — publish products to generate schema and feeds.', 'ai-discoverability-kit' )
		);
	}

	/**
	 * Check how many products have GTIN/brand identifiers.
	 *
	 * @return array<string, mixed>
	 */
	private function check_product_identifiers(): array {
		$counts = wp_count_posts( 'product' );
		$total  = $counts ? (int) $counts->publish : 0;

		if ( 0 === $total ) {
			return $this->result(
				'identifiers',
				__( 'Product identifiers', 'ai-discoverability-kit' ),
				self::STATUS_INFO,
				__( 'Publish products to start tracking identifier coverage.', 'ai-discoverability-kit' )
			);
		}

		// Count published products that have a GTIN or brand meta value.
		// Core table names only; no user input in the query.
		// phpcs:disable WordPress.DB, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$with_ids = (int) $this->wpdb->get_var(
			"SELECT COUNT(DISTINCT p.ID)
			 FROM {$this->wpdb->posts} p
			 INNER JOIN {$this->wpdb->postmeta} pm ON pm.post_id = p.ID
			 WHERE p.post_type = 'product'
			   AND p.post_status = 'publish'
			   AND pm.meta_key IN ( '_aicommerce_gtin', '_aicommerce_brand' )
			   AND pm.meta_value <> ''"
		);
		// phpcs:enable WordPress.DB, PluginCheck.Security.DirectDB.UnescapedDBParameter

		$pct = $total > 0 ? (int) round( ( $with_ids / $total ) * 100 ) : 0;

		if ( $pct >= 80 ) {
			$status = self::STATUS_PASS;
		} elseif ( $pct >= 30 ) {
			$status = self::STATUS_WARN;
		} else {
			$status = self::STATUS_FAIL;
		}

		return $this->result(
			'identifiers',
			__( 'Product identifiers', 'ai-discoverability-kit' ),
			$status,
			sprintf(
				/* translators: 1: percentage, 2: count with identifiers, 3: total. */
				__( '%1$d%% of products (%2$d of %3$d) have a brand or GTIN. Identifiers improve AI matching.', 'ai-discoverability-kit' ),
				$pct,
				$with_ids,
				$total
			),
			array( 'coverage' => $pct )
		);
	}

	/**
	 * Check a default brand is configured.
	 *
	 * @return array<string, mixed>
	 */
	private function check_default_brand(): array {
		$brand = (string) get_option( 'aicommerce_default_brand', '' );

		if ( '' !== trim( $brand ) ) {
			return $this->result(
				'default_brand',
				__( 'Default brand', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				sprintf( /* translators: %s: brand name. */ __( 'Default brand set to "%s".', 'ai-discoverability-kit' ), $brand )
			);
		}

		return $this->result(
			'default_brand',
			__( 'Default brand', 'ai-discoverability-kit' ),
			self::STATUS_WARN,
			__( 'Set a default brand so products without one still expose brand data.', 'ai-discoverability-kit' )
		);
	}

	/**
	 * Check whether product feeds have been generated.
	 *
	 * @return array<string, mixed>
	 */
	private function check_feeds_generated(): array {
		$upload_dir = wp_upload_dir();
		$feed_dir   = trailingslashit( $upload_dir['basedir'] ) . 'aicommerce/feeds/';
		$found      = array();

		foreach ( array( 'google-feed.xml', 'openai-feed.json', 'bing-feed.xml', 'perplexity-feed.json' ) as $file ) {
			if ( file_exists( $feed_dir . $file ) ) {
				$found[] = $file;
			}
		}

		if ( ! empty( $found ) ) {
			return $this->result(
				'feeds',
				__( 'Product feeds', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				sprintf(
					/* translators: %d: number of feeds. */
					_n( '%d product feed generated.', '%d product feeds generated.', count( $found ), 'ai-discoverability-kit' ),
					count( $found )
				)
			);
		}

		return $this->result(
			'feeds',
			__( 'Product feeds', 'ai-discoverability-kit' ),
			self::STATUS_WARN,
			__( 'No product feeds generated yet — generate feeds so AI shopping agents can index your catalog.', 'ai-discoverability-kit' )
		);
	}

	/**
	 * Informational check: is /llms.txt configured to serve?
	 *
	 * @return array<string, mixed>
	 */
	private function check_llms_txt(): array {
		$structure = (string) get_option( 'permalink_structure', '' );

		if ( '' === $structure ) {
			return $this->result(
				'llms_txt',
				__( 'llms.txt endpoint', 'ai-discoverability-kit' ),
				self::STATUS_WARN,
				__( 'Enable pretty permalinks so /llms.txt is served.', 'ai-discoverability-kit' )
			);
		}

		return $this->result(
			'llms_txt',
			__( 'llms.txt endpoint', 'ai-discoverability-kit' ),
			self::STATUS_PASS,
			sprintf(
				/* translators: %s: llms.txt URL. */
				__( 'Your AI guide is available at %s.', 'ai-discoverability-kit' ),
				home_url( '/llms.txt' )
			),
			array( 'url' => home_url( '/llms.txt' ) )
		);
	}

	/**
	 * Informational check: recent AI crawler activity.
	 *
	 * @return array<string, mixed>
	 */
	private function check_crawler_activity(): array {
		$table = $this->wpdb->prefix . 'aicommerce_crawler_log';

		// Table name is built from $wpdb->prefix; the date filter is prepared.
		// phpcs:disable WordPress.DB, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$exists = $this->wpdb->get_var(
			$this->wpdb->prepare( 'SHOW TABLES LIKE %s', $table )
		);

		if ( $table !== $exists ) {
			return $this->result(
				'crawler_activity',
				__( 'AI crawler activity', 'ai-discoverability-kit' ),
				self::STATUS_INFO,
				__( 'Crawler monitoring will begin once AI bots visit your store.', 'ai-discoverability-kit' )
			);
		}

		$since = gmdate( 'Y-m-d H:i:s', time() - ( 30 * DAY_IN_SECONDS ) );

		$visits = (int) $this->wpdb->get_var(
			$this->wpdb->prepare( "SELECT COUNT(*) FROM {$table} WHERE request_time >= %s", $since )
		);
		// phpcs:enable WordPress.DB, PluginCheck.Security.DirectDB.UnescapedDBParameter

		return $this->result(
			'crawler_activity',
			__( 'AI crawler activity', 'ai-discoverability-kit' ),
			self::STATUS_INFO,
			sprintf(
				/* translators: %d: number of crawler visits. */
				_n( '%d AI crawler visit in the last 30 days.', '%d AI crawler visits in the last 30 days.', $visits, 'ai-discoverability-kit' ),
				$visits
			),
			array( 'visits_30d' => $visits )
		);
	}

	/**
	 * Check onboarding completion.
	 *
	 * @return array<string, mixed>
	 */
	private function check_onboarding(): array {
		if ( get_option( 'aicommerce_onboarding_complete', false ) ) {
			return $this->result(
				'onboarding',
				__( 'Setup wizard', 'ai-discoverability-kit' ),
				self::STATUS_PASS,
				__( 'You have completed the setup wizard.', 'ai-discoverability-kit' )
			);
		}

		return $this->result(
			'onboarding',
			__( 'Setup wizard', 'ai-discoverability-kit' ),
			self::STATUS_WARN,
			__( 'Finish the setup wizard to configure schema, feeds and crawler rules.', 'ai-discoverability-kit' )
		);
	}
}