<?php
/**
 * Plugin composition root.
 *
 * @package WPAB
 */

namespace WPAB;

use WPAB\Admin\Admin_Bar;
use WPAB\Admin\Admin_Page;
use WPAB\Admin\Csv_Export;
use WPAB\Admin\Notices;
use WPAB\API\Rest_Controller;
use WPAB\Cache\Cache_Manager;
use WPAB\Compatibility\Compatibility_Checker;
use WPAB\Content\Content_Override;
use WPAB\Database\Migrator;
use WPAB\Experiments\Config_Transfer;
use WPAB\Experiments\Post_Duplicator;
use WPAB\Experiments\Experiment_Repository;
use WPAB\Experiments\Experiment_Service;
use WPAB\Experiments\Goal_Repository;
use WPAB\Experiments\History_Repository;
use WPAB\Experiments\Variant_Repository;
use WPAB\Experiments\Winner_Applier;
use WPAB\Frontend\Tracking_View;
use WPAB\Plugins\Dependency_Validator;
use WPAB\Privacy\Privacy_Service;
use WPAB\Runtime\Frontend_Runtime;
use WPAB\Runtime\Runtime_Index;
use WPAB\Seo\Seo_Guard;
use WPAB\Statistics\Aggregator;
use WPAB\Statistics\Stats_Service;
use WPAB\Statistics\Winner_Detector;
use WPAB\Support\Logger;
use WPAB\Support\Settings;
use WPAB\Themes\Theme_Resolver;
use WPAB\Tracking\Bot_Detector;
use WPAB\Tracking\Tracking_Service;
use WPAB\Variants\Traffic_Allocator;

/**
 * Boots services. A failure here must not take down the front end.
 */
final class Plugin {
	/**
	 * Singleton.
	 *
	 * @var self|null
	 */
	private static ?self $instance = null;

	/**
	 * Tracking service, created during boot.
	 *
	 * @var Tracking_Service|null
	 */
	private ?Tracking_Service $tracking = null;

	/**
	 * Experiment service.
	 *
	 * @var Experiment_Service|null
	 */
	private ?Experiment_Service $experiments = null;

	/**
	 * Instance.
	 *
	 * @return self
	 */
	public static function instance(): self {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Tracking service.
	 *
	 * @return Tracking_Service
	 */
	public function tracking(): Tracking_Service {
		if ( null === $this->tracking ) {
			$this->tracking = new Tracking_Service( new Experiment_Repository(), new Goal_Repository(), new Bot_Detector() );
		}
		return $this->tracking;
	}

	/**
	 * Boot the plugin.
	 */
	public function boot(): void {
		try {
			Activator::install_loader();
			( new Migrator() )->maybe_upgrade();
			$this->ensure_settings();
			$this->ensure_capability();
			$this->ensure_cron();

			$experiments = new Experiment_Repository();
			$variants    = new Variant_Repository();
			$goals       = new Goal_Repository();
			$history     = new History_Repository();
			$themes      = new Theme_Resolver( get_theme_root() );
			$index       = new Runtime_Index( $experiments, $variants, $goals );
			if ( ! is_readable( Runtime_Index::path() ) ) {
				$index->rebuild();
			}
			$service           = new Experiment_Service( $experiments, $variants, $goals, $index, new Traffic_Allocator(), new Dependency_Validator(), $themes );
			$this->experiments = $service;
			$this->tracking    = new Tracking_Service( $experiments, $goals, new Bot_Detector() );
			$stats             = new Stats_Service( new Aggregator( $goals ), new Winner_Detector(), $experiments, $variants );
			$applier           = new Winner_Applier( $experiments, $variants, $history );
			$transfer          = new Config_Transfer( $service );
			$compatibility     = new Compatibility_Checker();
			$compatibility->boot();

			( new Post_Duplicator() )->register();
			( new Frontend_Runtime( $themes ) )->register();
			if ( ! is_admin() ) {
				( new Content_Override( $variants ) )->register();
				( new Tracking_View() )->register();
			}
			( new Cache_Manager() )->register();
			( new Seo_Guard() )->register();
			( new Privacy_Service() )->register();
			( new Rest_Controller( $service, $experiments, $history, $applier, $stats, $this->tracking, $transfer, $themes, $compatibility ) )->register();

			if ( is_admin() ) {
				( new Admin_Page() )->register();
				( new Notices( $experiments, $goals ) )->register();
				( new Csv_Export() )->register();
			}
			( new Admin_Bar() )->register();

			add_action( 'wpab_cron_tick', array( $this, 'cron' ) );
			add_action( 'init', array( $this, 'handle_preview' ), 1 );
			add_action( 'save_post', array( $this, 'refresh_index_for_post' ), 20, 1 );
		} catch ( \Throwable $error ) {
			Logger::exception( $error );
		}
	}

	/**
	 * Cron: schedules, aggregation, retention.
	 */
	public function cron(): void {
		try {
			if ( $this->experiments instanceof Experiment_Service ) {
				$this->experiments->sync_schedules();
			}
			$goals = new Goal_Repository();
			( new Aggregator( $goals ) )->run( 2000 );
			( new Privacy_Service() )->prune();
		} catch ( \Throwable $error ) {
			Logger::exception( $error );
		}
	}

	/**
	 * Authorized preview and assignment reset. Query parameters do nothing for other visitors.
	 */
	public function handle_preview(): void {
		$can = is_user_logged_in() && ( current_user_can( Settings::capability() ) || current_user_can( 'manage_options' ) );
		if ( ! $can ) {
			return;
		}

		if ( isset( $_GET['wpab_preview'] ) ) {
			$nonce = isset( $_GET['_wpnonce'] ) ? sanitize_text_field( wp_unslash( (string) $_GET['_wpnonce'] ) ) : '';
			if ( ! wp_verify_nonce( $nonce, 'wpab_preview' ) ) {
				wp_die( esc_html__( 'Invalid preview request.', 'jm-split-tester' ) );
			}
			$raw = sanitize_text_field( wp_unslash( (string) $_GET['wpab_preview'] ) );
			if ( preg_match( '/^(\d+):(\d+)$/', $raw, $matches ) ) {
				$token = \WPAB\Runtime\sign_preview( (int) $matches[1], (int) $matches[2], time() + 900, \WPAB\Runtime\runtime_secret() );
				setcookie(
					\WPAB\Runtime\PREVIEW_COOKIE,
					$token,
					array(
						'expires'  => time() + 900,
						'path'     => '/',
						'secure'   => is_ssl(),
						'httponly' => true,
						'samesite' => 'Lax',
					)
				);
			}
			wp_safe_redirect( remove_query_arg( 'wpab_preview' ) );
			exit;
		}

		if ( isset( $_GET['wpab_reset'] ) ) {
			$nonce = isset( $_GET['_wpnonce'] ) ? sanitize_text_field( wp_unslash( (string) $_GET['_wpnonce'] ) ) : '';
			if ( ! wp_verify_nonce( $nonce, 'wpab_reset' ) ) {
				wp_die( esc_html__( 'Invalid reset request.', 'jm-split-tester' ) );
			}
			$names      = array( \WPAB\Runtime\VISITOR_COOKIE, \WPAB\Runtime\PREVIEW_COOKIE );
			$experiment = absint( wp_unslash( $_GET['wpab_reset'] ) );
			if ( $experiment > 0 ) {
				$names[] = \WPAB\Runtime\assignment_cookie_name( $experiment );
			}
			foreach ( $names as $name ) {
				setcookie(
					$name,
					'',
					array(
						'expires'  => time() - 3600,
						'path'     => '/',
						'secure'   => is_ssl(),
						'samesite' => 'Lax',
					)
				);
			}
			wp_safe_redirect( remove_query_arg( 'wpab_reset' ) );
			exit;
		}
	}

	/**
	 * Keep the runtime path index aligned with permalink changes.
	 *
	 * @param int $post_id Post ID.
	 */
	public function refresh_index_for_post( int $post_id ): void {
		if ( null === $this->experiments ) {
			return;
		}
		foreach ( ( new Experiment_Repository() )->live_candidates() as $experiment ) {
			if ( (int) $experiment['post_id'] === $post_id ) {
				( new Runtime_Index( new Experiment_Repository(), new Variant_Repository(), new Goal_Repository() ) )->rebuild();
				return;
			}
		}
	}

	/**
	 * Default option.
	 */
	private function ensure_settings(): void {
		if ( false === get_option( Settings::OPTION, false ) ) {
			add_option( Settings::OPTION, Settings::defaults(), '', false );
		}
	}

	/**
	 * Grant the capability to administrators.
	 */
	private function ensure_capability(): void {
		$role = get_role( 'administrator' );
		if ( $role instanceof \WP_Role && ! $role->has_cap( Settings::capability() ) ) {
			$role->add_cap( Settings::capability() );
		}
	}

	/**
	 * Five-minute cron for status flips, aggregation, and retention.
	 */
	private function ensure_cron(): void {
		add_filter(
			'cron_schedules',
			static function ( array $schedules ): array {
				$schedules['wpab_fifteen_minutes'] = array(
					'interval' => 15 * MINUTE_IN_SECONDS,
					'display'  => __( 'Every fifteen minutes', 'jm-split-tester' ),
				);
				return $schedules;
			}
		);
		$scheduled = wp_get_scheduled_event( 'wpab_cron_tick' );
		if ( ! $scheduled instanceof \stdClass || 'wpab_fifteen_minutes' !== $scheduled->schedule ) {
			wp_clear_scheduled_hook( 'wpab_cron_tick' );
			wp_schedule_event( time() + MINUTE_IN_SECONDS, 'wpab_fifteen_minutes', 'wpab_cron_tick' );
		}
	}
}