<?php
/**
 * Plugin Updater class.
 *
 * Integrates with WordPress plugin update system to check for and install
 * updates from the license server.
 *
 * @package Magdev\WpBnb\License
 */

declare( strict_types=1 );

namespace Magdev\WpBnb\License;

use Magdev\WcLicensedProductClient\SecureLicenseClient;
use Magdev\WcLicensedProductClient\LicenseClient;
use Magdev\WcLicensedProductClient\Dto\UpdateInfo;
use Symfony\Component\HttpClient\HttpClient;

/**
 * Handles plugin auto-updates from the license server.
 */
final class Updater {

	/**
	 * Singleton instance.
	 *
	 * @var Updater|null
	 */
	private static ?Updater $instance = null;

	/**
	 * Plugin basename (e.g., wp-bnb/wp-bnb.php).
	 *
	 * @var string
	 */
	private string $plugin_basename;

	/**
	 * Plugin slug.
	 *
	 * @var string
	 */
	private string $plugin_slug;

	/**
	 * Current plugin version.
	 *
	 * @var string
	 */
	private string $current_version;

	/**
	 * Cache key for update info.
	 *
	 * @var string
	 */
	private const CACHE_KEY = 'wp_bnb_update_info';

	/**
	 * Cache key for last check timestamp.
	 *
	 * @var string
	 */
	private const LAST_CHECK_KEY = 'wp_bnb_update_last_check';

	/**
	 * Default cache duration in seconds (12 hours).
	 *
	 * @var int
	 */
	private const DEFAULT_CHECK_FREQUENCY = 12;

	// Option keys for update settings.
	public const OPTION_NOTIFICATIONS_ENABLED = 'wp_bnb_update_notifications_enabled';
	public const OPTION_AUTO_INSTALL_ENABLED  = 'wp_bnb_auto_install_enabled';
	public const OPTION_CHECK_FREQUENCY       = 'wp_bnb_update_check_frequency';

	/**
	 * License client instance.
	 *
	 * @var SecureLicenseClient|LicenseClient|null
	 */
	private SecureLicenseClient|LicenseClient|null $client = null;

	/**
	 * Constructor.
	 *
	 * @param string $plugin_file    Full path to the main plugin file.
	 * @param string $current_version Current plugin version.
	 */
	public function __construct( string $plugin_file, string $current_version ) {
		$this->plugin_basename = plugin_basename( $plugin_file );
		$this->plugin_slug     = dirname( $this->plugin_basename );
		$this->current_version = $current_version;
		self::$instance        = $this;
	}

	/**
	 * Get the singleton instance.
	 *
	 * @return Updater|null
	 */
	public static function get_instance(): ?Updater {
		return self::$instance;
	}

	/**
	 * Initialize update hooks.
	 *
	 * @return void
	 */
	public function init(): void {
		// Allow complete disable via constant.
		if ( defined( 'WP_BNB_DISABLE_AUTO_UPDATE' ) && WP_BNB_DISABLE_AUTO_UPDATE ) {
			return;
		}

		// Hook into WordPress update system.
		add_filter( 'pre_set_site_transient_update_plugins', array( $this, 'check_for_updates' ) );
		add_filter( 'plugins_api', array( $this, 'plugin_info' ), 10, 3 );
		add_action( 'upgrader_process_complete', array( $this, 'after_update' ), 10, 2 );

		// Auto-install filter for WordPress background updates.
		add_filter( 'auto_update_plugin', array( $this, 'auto_update_plugin' ), 10, 2 );

		// Clear update cache when license settings change.
		add_action( 'update_option_' . Manager::OPTION_LICENSE_KEY, array( $this, 'clear_cache' ) );
		add_action( 'update_option_' . Manager::OPTION_SERVER_URL, array( $this, 'clear_cache' ) );

		// AJAX handler for manual update check.
		add_action( 'wp_ajax_wp_bnb_check_updates', array( $this, 'ajax_check_updates' ) );
	}

	/**
	 * Check if update notifications are enabled.
	 *
	 * @return bool
	 */
	public static function is_notifications_enabled(): bool {
		return 'yes' === get_option( self::OPTION_NOTIFICATIONS_ENABLED, 'yes' );
	}

	/**
	 * Check if auto-install is enabled.
	 *
	 * @return bool
	 */
	public static function is_auto_install_enabled(): bool {
		return 'yes' === get_option( self::OPTION_AUTO_INSTALL_ENABLED, 'no' );
	}

	/**
	 * Get the update check frequency in hours.
	 *
	 * @return int
	 */
	public static function get_check_frequency(): int {
		$frequency = (int) get_option( self::OPTION_CHECK_FREQUENCY, self::DEFAULT_CHECK_FREQUENCY );
		// Clamp between 1 and 168 hours (1 week).
		return max( 1, min( 168, $frequency ) );
	}

	/**
	 * Get cache duration in seconds based on check frequency.
	 *
	 * @return int
	 */
	private function get_cache_duration(): int {
		return self::get_check_frequency() * 3600;
	}

	/**
	 * Filter for WordPress auto-update system.
	 *
	 * @param bool|null $update Whether to update the plugin.
	 * @param object    $item   The plugin update object.
	 * @return bool|null
	 */
	public function auto_update_plugin( $update, object $item ) {
		// Only affect our plugin.
		if ( ! isset( $item->plugin ) || $item->plugin !== $this->plugin_basename ) {
			return $update;
		}

		// Check if auto-install is enabled and license is valid.
		if ( self::is_auto_install_enabled() && Manager::is_license_valid() ) {
			return true;
		}

		return $update;
	}

	/**
	 * Get current plugin version.
	 *
	 * @return string
	 */
	public function get_current_version(): string {
		return $this->current_version;
	}

	/**
	 * Get last update check timestamp.
	 *
	 * @return int
	 */
	public static function get_last_check(): int {
		return (int) get_option( self::LAST_CHECK_KEY, 0 );
	}

	/**
	 * AJAX handler: Check for updates.
	 *
	 * @return void
	 */
	public function ajax_check_updates(): void {
		check_ajax_referer( 'wp_bnb_admin_nonce', 'nonce' );

		if ( ! current_user_can( 'update_plugins' ) ) {
			wp_send_json_error( array(
				'message' => __( 'You do not have permission to check for updates.', 'wp-bnb' ),
			) );
		}

		$update_info = $this->get_cached_update_info( true );

		if ( null === $update_info ) {
			wp_send_json_success( array(
				'update_available' => false,
				'current_version'  => $this->current_version,
				'message'          => __( 'Could not check for updates. Please verify your license configuration.', 'wp-bnb' ),
			) );
		}

		$response = array(
			'update_available' => $update_info->updateAvailable && version_compare( $this->current_version, $update_info->version ?? '', '<' ),
			'current_version'  => $this->current_version,
			'latest_version'   => $update_info->version ?? $this->current_version,
			'last_check'       => time(),
		);

		if ( $response['update_available'] ) {
			$response['message']   = sprintf(
				/* translators: %s: New version number */
				__( 'A new version (%s) is available.', 'wp-bnb' ),
				$update_info->version
			);
			$response['changelog'] = $update_info->changelog ?? '';
		} else {
			$response['message'] = __( 'You are running the latest version.', 'wp-bnb' );
		}

		wp_send_json_success( $response );
	}

	/**
	 * Initialize the license client.
	 *
	 * @return bool
	 */
	private function init_client(): bool {
		if ( null !== $this->client ) {
			return true;
		}

		$server_url    = Manager::get_server_url();
		$server_secret = Manager::get_server_secret();

		if ( empty( $server_url ) ) {
			return false;
		}

		try {
			if ( ! empty( $server_secret ) ) {
				$this->client = new SecureLicenseClient(
					httpClient: HttpClient::create(),
					baseUrl: $server_url,
					serverSecret: $server_secret,
				);
			} else {
				$this->client = new LicenseClient(
					httpClient: HttpClient::create(),
					baseUrl: $server_url,
				);
			}
			return true;
		} catch ( \Throwable $e ) {
			return false;
		}
	}

	/**
	 * Check for plugin updates.
	 *
	 * @param object $transient The update_plugins transient.
	 * @return object Modified transient.
	 */
	public function check_for_updates( object $transient ): object {
		if ( empty( $transient->checked ) ) {
			return $transient;
		}

		// Respect notifications enabled setting.
		if ( ! self::is_notifications_enabled() ) {
			return $transient;
		}

		$update_info = $this->get_update_info();

		if ( null === $update_info || ! $update_info->updateAvailable ) {
			return $transient;
		}

		// Compare versions.
		if ( version_compare( $this->current_version, $update_info->version ?? '', '>=' ) ) {
			return $transient;
		}

		// Add to update response.
		$transient->response[ $this->plugin_basename ] = (object) array(
			'slug'         => $update_info->slug ?? $this->plugin_slug,
			'plugin'       => $this->plugin_basename,
			'new_version'  => $update_info->version,
			'url'          => $update_info->homepage ?? '',
			'package'      => $update_info->downloadUrl,
			'icons'        => $update_info->icons ?? array(),
			'tested'       => $update_info->tested ?? '',
			'requires'     => $update_info->requires ?? '',
			'requires_php' => $update_info->requiresPhp ?? '',
		);

		return $transient;
	}

	/**
	 * Provide plugin information for the details modal.
	 *
	 * @param false|object|array $result The result object or array.
	 * @param string             $action The API action being performed.
	 * @param object             $args   Plugin API arguments.
	 * @return false|object
	 */
	public function plugin_info( $result, string $action, object $args ) {
		if ( 'plugin_information' !== $action ) {
			return $result;
		}

		if ( ! isset( $args->slug ) || $args->slug !== $this->plugin_slug ) {
			return $result;
		}

		$update_info = $this->get_update_info();

		if ( null === $update_info ) {
			return $result;
		}

		$plugin_info = (object) array(
			'name'          => $update_info->name ?? 'WP BnB Manager',
			'slug'          => $update_info->slug ?? $this->plugin_slug,
			'version'       => $update_info->version ?? $this->current_version,
			'author'        => '<a href="https://src.bundespruefstelle.ch/magdev">Marco Graetsch</a>',
			'homepage'      => $update_info->homepage ?? 'https://src.bundespruefstelle.ch/magdev/wp-bnb',
			'requires'      => $update_info->requires ?? '6.0',
			'tested'        => $update_info->tested ?? '',
			'requires_php'  => $update_info->requiresPhp ?? '8.3',
			'last_updated'  => $update_info->lastUpdated?->format( 'Y-m-d' ) ?? '',
			'download_link' => $update_info->downloadUrl ?? '',
			'sections'      => $update_info->sections ?? array(
				'description' => __( 'A comprehensive Bed & Breakfast management plugin for WordPress.', 'wp-bnb' ),
				'changelog'   => $update_info->changelog ?? '',
			),
		);

		if ( ! empty( $update_info->icons ) ) {
			$plugin_info->icons = $update_info->icons;
		}

		return $plugin_info;
	}

	/**
	 * Clear update cache after upgrade.
	 *
	 * @param \WP_Upgrader $upgrader   WP_Upgrader instance.
	 * @param array        $hook_extra Extra arguments passed to hooked filters.
	 * @return void
	 */
	public function after_update( \WP_Upgrader $upgrader, array $hook_extra ): void {
		if ( ! isset( $hook_extra['plugins'] ) || ! is_array( $hook_extra['plugins'] ) ) {
			return;
		}

		if ( in_array( $this->plugin_basename, $hook_extra['plugins'], true ) ) {
			$this->clear_cache();
		}
	}

	/**
	 * Get update info from cache or server.
	 *
	 * @param bool $force_refresh Force refresh from server.
	 * @return UpdateInfo|null
	 */
	public function get_cached_update_info( bool $force_refresh = false ): ?UpdateInfo {
		if ( ! $force_refresh ) {
			$cached = get_transient( self::CACHE_KEY );
			if ( false !== $cached && $cached instanceof UpdateInfo ) {
				return $cached;
			}
		}

		// Check if license is configured.
		$license_key = Manager::get_license_key();
		if ( empty( $license_key ) ) {
			return null;
		}

		if ( ! $this->init_client() ) {
			return null;
		}

		try {
			$domain      = $this->get_current_domain();
			$update_info = $this->client->checkForUpdates(
				licenseKey: $license_key,
				domain: $domain,
				pluginSlug: $this->plugin_slug,
				currentVersion: $this->current_version,
			);

			// Cache the result and update last check timestamp.
			set_transient( self::CACHE_KEY, $update_info, $this->get_cache_duration() );
			update_option( self::LAST_CHECK_KEY, time() );

			return $update_info;
		} catch ( \Throwable $e ) {
			// Silently fail and return null - don't break WordPress.
			return null;
		}
	}

	/**
	 * Get update info from cache or server (alias for WordPress update system).
	 *
	 * @param bool $force_refresh Force refresh from server.
	 * @return UpdateInfo|null
	 */
	private function get_update_info( bool $force_refresh = false ): ?UpdateInfo {
		return $this->get_cached_update_info( $force_refresh );
	}

	/**
	 * Get current domain.
	 *
	 * @return string
	 */
	private function get_current_domain(): string {
		$site_url = get_site_url();
		$parsed   = wp_parse_url( $site_url );
		return $parsed['host'] ?? '';
	}

	/**
	 * Clear the update cache.
	 *
	 * @return void
	 */
	public function clear_cache(): void {
		delete_transient( self::CACHE_KEY );
	}
}