<?php
/**
 * MultilingualPress 5 detection service.
 *
 * Detects whether MultilingualPress 5 is installed (active or inactive),
 * reads its plugin metadata, and identifies its database tables.
 *
 * MLP5 must be network-active for migration to proceed. Unlike MLP2,
 * the plugin itself needs to be running so its API is available.
 *
 * @package Robotstxt_Mlp2_Mlp5
 */

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

/**
 * Class Robotstxt_Mlp2_Mlp5_Detector_Mlp5
 *
 * Instantiate once to detect MLP5; all detection results are cached in
 * instance properties to avoid repeated file or database reads.
 *
 * Usage:
 *   $mlp5 = new Robotstxt_Mlp2_Mlp5_Detector_Mlp5();
 *   if ( $mlp5->is_active() ) { ... }
 */
class Robotstxt_Mlp2_Mlp5_Detector_Mlp5 {

	/**
	 * Known plugin basename for MultilingualPress 5 (commercial, Inpsyde).
	 *
	 * @var string
	 */
	const PLUGIN_BASENAME = 'multilingualpress/multilingualpress.php';

	/**
	 * Resolved MLP5 plugin basename, or empty string if not found on disk.
	 *
	 * @var string
	 */
	private string $plugin_file;

	/**
	 * Plugin header data from get_plugin_data(), or empty array if unavailable.
	 *
	 * @var array
	 */
	private array $plugin_data;

	/**
	 * Constructor. Locates the MLP5 plugin file and loads its header data.
	 */
	public function __construct() {
		$this->plugin_file = $this->find_plugin_file();
		$this->plugin_data = $this->plugin_file ? $this->load_plugin_data() : array();
	}

	/**
	 * Whether MultilingualPress 5 is currently network-active.
	 *
	 * MLP5 must be active for migration to proceed; its API tables and
	 * internal state are only available when the plugin is running.
	 *
	 * @return bool
	 */
	public function is_active(): bool {
		if ( ! function_exists( 'is_plugin_active_for_network' ) ) {
			require_once ABSPATH . 'wp-admin/includes/plugin.php';
		}

		return '' !== $this->plugin_file && is_plugin_active_for_network( $this->plugin_file );
	}

	/**
	 * Return the MLP5 version string, or empty string if unavailable.
	 *
	 * @return string
	 */
	public function get_version(): string {
		return isset( $this->plugin_data['Version'] ) ? (string) $this->plugin_data['Version'] : '';
	}

	/**
	 * Return the resolved MLP5 plugin basename, or empty string if not on disk.
	 *
	 * @return string
	 */
	public function get_plugin_file(): string {
		return $this->plugin_file;
	}

	/**
	 * Return the MLP5 site relations table name, or empty string if absent.
	 *
	 * MLP5 uses the same mlp_site_relations table name as MLP2.
	 *
	 * @return string
	 */
	public function get_site_relations_table(): string {
		global $wpdb;

		$table = $wpdb->base_prefix . 'mlp_site_relations';

		return $this->table_exists( $table ) ? $table : '';
	}

	/**
	 * Return the MLP5 relationship groups table name, or empty string if absent.
	 *
	 * MLP5 stores one row per group of related content here (id, type).
	 * The content_relations table references this table via relationship_id.
	 *
	 * @return string
	 */
	public function get_relationships_table(): string {
		global $wpdb;

		$table = $wpdb->base_prefix . 'mlp_relationships';

		return $this->table_exists( $table ) ? $table : '';
	}

	/**
	 * Return the MLP5 content relations table name, or empty string if absent.
	 *
	 * MLP5 uses mlp_content_relations (the newer name introduced in MLP2
	 * late versions and carried forward).
	 *
	 * @return string
	 */
	public function get_content_relations_table(): string {
		global $wpdb;

		$table = $wpdb->base_prefix . 'mlp_content_relations';

		return $this->table_exists( $table ) ? $table : '';
	}

	/**
	 * Return all tables in the database that match the MLP table prefix pattern.
	 *
	 * @return string[] Array of full table names.
	 */
	public function get_all_tables(): array {
		global $wpdb;

		$like = $wpdb->esc_like( $wpdb->base_prefix . 'mlp_' ) . '%';

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$tables = $wpdb->get_col( $wpdb->prepare( 'SHOW TABLES LIKE %s', $like ) );

		return is_array( $tables ) ? $tables : array();
	}

	/**
	 * Check whether a given table exists in the database.
	 *
	 * @param string $table Full table name (including prefix).
	 * @return bool
	 */
	private function table_exists( string $table ): bool {
		global $wpdb;

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		return (string) $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $table ) ) === $table;
	}

	/**
	 * Locate the MLP5 plugin file on disk.
	 *
	 * Checks the known canonical basename first. If not found, scans all
	 * installed plugins for a plugin named "MultilingualPress" with a
	 * version of 3.0.0 or higher (MLP3+ series includes MLP5).
	 *
	 * @return string Plugin basename, or empty string if not found.
	 */
	private function find_plugin_file(): string {
		if ( file_exists( WP_PLUGIN_DIR . '/' . self::PLUGIN_BASENAME ) ) {
			return self::PLUGIN_BASENAME;
		}

		if ( ! function_exists( 'get_plugins' ) ) {
			require_once ABSPATH . 'wp-admin/includes/plugin.php';
		}

		foreach ( get_plugins() as $basename => $data ) {
			if (
				isset( $data['Name'], $data['Version'] ) &&
				'MultilingualPress' === $data['Name'] &&
				version_compare( (string) $data['Version'], '3.0.0', '>=' )
			) {
				return $basename;
			}
		}

		return '';
	}

	/**
	 * Load plugin header data from the MLP5 main file.
	 *
	 * @return array Plugin data from get_plugin_data(), or empty array on failure.
	 */
	private function load_plugin_data(): array {
		if ( ! function_exists( 'get_plugin_data' ) ) {
			require_once ABSPATH . 'wp-admin/includes/plugin.php';
		}

		$path = WP_PLUGIN_DIR . '/' . $this->plugin_file;

		if ( ! file_exists( $path ) ) {
			return array();
		}

		return get_plugin_data( $path, false, false );
	}
}