<?php
/**
 * GZIP module.
 *
 * Owns the gzip_enabled setting. On flip → writes / removes Apache /
 * LiteSpeed `.htaccess` rules via the static XSpeed\Gzip helper. On
 * nginx (or any server xSpeed can't auto-configure), the panel shows
 * the manual snippet via ui_notices().
 *
 * Tier: Free. See SETTINGS.md for the contract this module satisfies.
 *
 * @package XSpeed
 */

declare(strict_types=1);

namespace XSpeed\Modules\Gzip;

defined( 'ABSPATH' ) || exit;

use XSpeed\Gzip as LegacyGzip;
use XSpeed\Module;
use XSpeed\Server;
use XSpeed\Settings_Manager;

final class GzipModule extends Module {

	public const SLUG    = 'gzip';
	public const TIER    = self::TIER_FREE;
	public const VERSION = '1.1.0';

	public function ui_metadata(): array {
		return array(
			'label'       => 'GZIP',
			'icon'        => 'Layers',
			'description' => 'Compress responses to reduce transfer size.',
		);
	}

	public function settings_schema(): array {
		return array(
			'gzip_enabled' => array(
				'type'        => 'bool',
				'default'     => false,
				'label'       => 'Enable GZIP Compression',
				'description' => 'On Apache / LiteSpeed we write the .htaccess rules automatically. On nginx the snippet below must be added to your server config.',
			),
		);
	}

	/**
	 * 1.1.0: drain gzip_enabled from the legacy xspeed_options blob into
	 * this module's option. Idempotent — a re-run with the legacy key
	 * already gone is a no-op.
	 */
	public function migrations(): array {
		return array(
			'1.1.0' => static function ( array $opts ): array {
				$legacy = get_option( 'xspeed_options', array() );
				if ( ! is_array( $legacy ) || ! array_key_exists( 'gzip_enabled', $legacy ) ) {
					return $opts;
				}
				$opts['gzip_enabled'] = (bool) $legacy['gzip_enabled'];
				unset( $legacy['gzip_enabled'] );
				update_option( 'xspeed_options', $legacy );
				return $opts;
			},
		);
	}

	public function cli_commands(): array {
		return array(
			array(
				'name'      => 'xspeed gzip',
				'callback'  => array( $this, 'cli_handler' ),
				'shortdesc' => 'Show GZIP status (server type, active, mode).',
				'synopsis'  => array(),
			),
		);
	}

	/**
	 * Conditional notice published to the module's panel via
	 * Module::ui_notices(). When gzip is enabled and the server can't
	 * auto-configure (nginx / unknown / IIS), we surface a copy-able
	 * snippet so the user can wire it up.
	 */
	public function ui_notices(): array {
		$opts = Settings_Manager::get( self::SLUG );
		if ( empty( $opts['gzip_enabled'] ) ) {
			return array();
		}
		// Probe the live response — works regardless of server type
		// (Apache, nginx, anything). If gzip is actually being served,
		// nothing else matters: hide the notice. Mirror's BrowserCache's
		// probe_headers_present() pattern.
		if ( LegacyGzip::probe_active() ) {
			return array();
		}
		// Probe says NOT active and gzip is enabled — surface the right
		// notice per server topology.
		if ( 'auto' === Server::gzip_mode() ) {
			// Apache/LiteSpeed but probe failed — .htaccess write must
			// have been blocked, or another plugin is overriding. Tell
			// the user something is wrong, no snippet (we can't fix it
			// without their server access).
			return array(
				array(
					'tone'  => 'warn',
					'title' => __( 'GZIP enabled but not active on the server', 'xspeed' ),
					'body'  => __( 'xSpeed wrote the .htaccess rules but the response still isn\'t gzipped. Your server may have AllowOverride disabled, another caching plugin overriding, or mod_deflate missing. Ask your host to enable GZIP on Apache.', 'xspeed' ),
				),
			);
		}
		// Manual server (nginx, IIS, unknown) — probe failed because
		// the user hasn't pasted the snippet (or hasn't reloaded nginx).
		$type = Server::type();
		if ( 'nginx' === $type ) {
			return array(
				array(
					'tone'  => 'warn',
					'title' => __( 'GZIP requires server config on nginx', 'xspeed' ),
					'body'  => __( 'xSpeed can only auto-configure GZIP on Apache and LiteSpeed (via .htaccess). The directives are included in the unified server-block snippet on the Cache panel — copy + paste it once into your nginx vhost (or container nginx config) and reload nginx.', 'xspeed' ),
				),
			);
		}
		// IIS / unknown server fallback — keep the legacy "paste this"
		// notice until a non-nginx unified-snippet surface ships.
		return array(
			array(
				'tone'    => 'warn',
				'title'   => __( 'GZIP requires server config on this server', 'xspeed' ),
				'body'    => __( 'xSpeed can only auto-configure GZIP on Apache and LiteSpeed (via .htaccess). Paste the snippet below into your server config and reload.', 'xspeed' ),
				'snippet' => LegacyGzip::nginx_snippet(),
			),
		);
	}

	/**
	 * Module booting: seed per-module option from legacy if needed,
	 * then register the change hook that flips Apache / LiteSpeed
	 * .htaccess rules whenever gzip_enabled is toggled. This handler
	 * fires on writes to xspeed_module_gzip (not the legacy blob).
	 */
	public function boot(): void {
		$this->seed_from_legacy_if_needed();
		add_action( 'update_option_xspeed_module_gzip', array( __CLASS__, 'on_settings_change' ), 10, 2 );
		add_action( 'add_option_xspeed_module_gzip', array( __CLASS__, 'on_settings_added' ), 10, 2 );
	}

	/**
	 * Detect the gzip_enabled flip on write and apply / remove the
	 * .htaccess rules. Idempotent — re-running with the same state is a
	 * no-op inside LegacyGzip::apply().
	 */
	public static function on_settings_change( $old, $new ): void {
		$old_gzip = is_array( $old ) ? ! empty( $old['gzip_enabled'] ) : false;
		$new_gzip = is_array( $new ) ? ! empty( $new['gzip_enabled'] ) : false;
		if ( $old_gzip !== $new_gzip ) {
			LegacyGzip::apply( $new_gzip );
			// Settings just changed — current "probe says active" answer
			// is stale. Drop the transient so the next dashboard load
			// re-checks the live response.
			delete_transient( 'xspeed_gzip_active' );
		}
	}

	/**
	 * The very first write (option doesn't exist yet) hits add_option
	 * instead of update_option. Treat it as old=false → new=current.
	 */
	public static function on_settings_added( $name, $value ): void {
		$enabled = is_array( $value ) ? ! empty( $value['gzip_enabled'] ) : false;
		if ( $enabled ) {
			LegacyGzip::apply( true );
		}
	}

	public function activate(): void {
		$this->seed_from_legacy_if_needed();
	}

	private function seed_from_legacy_if_needed(): void {
		if ( null !== get_option( 'xspeed_module_gzip', null ) ) {
			return;
		}
		$legacy = get_option( 'xspeed_options', array() );
		if ( ! is_array( $legacy ) || ! array_key_exists( 'gzip_enabled', $legacy ) ) {
			return;
		}
		update_option(
			'xspeed_module_gzip',
			array(
				'_version'     => self::VERSION,
				'gzip_enabled' => (bool) $legacy['gzip_enabled'],
			)
		);
		unset( $legacy['gzip_enabled'] );
		update_option( 'xspeed_options', $legacy );
	}

	public function cli_handler( array $args, array $assoc ): void {
		$opts = Settings_Manager::get( self::SLUG );
		\WP_CLI::log( 'enabled       ' . ( $opts['gzip_enabled'] ? 'true' : 'false' ) );
		\WP_CLI::log( 'server        ' . Server::type() );
		\WP_CLI::log( 'mode          ' . Server::gzip_mode() );
		\WP_CLI::log( 'active        ' . ( LegacyGzip::probe_active() ? 'true' : 'false' ) );
		\WP_CLI::log( 'nginx_snippet ' . LegacyGzip::nginx_snippet() );
	}

	/**
	 * GZIP directives for the unified nginx server-block snippet. Null
	 * when the module is disabled.
	 */
	public function nginx_directives(): ?string {
		$opts = Settings_Manager::get( self::SLUG );
		if ( empty( $opts['gzip_enabled'] ) ) {
			return null;
		}
		$snippet = LegacyGzip::nginx_snippet();
		return is_string( $snippet ) && '' !== $snippet ? $snippet : null;
	}
}