<?php

namespace DeliciousBrains\WPMDB\Common\Queue;

use DeliciousBrains\WPMDB\Common\FormData\FormData;
use DeliciousBrains\WPMDB\Common\MigrationState\MigrationStateManager;
use DeliciousBrains\WPMDB\Common\MigrationState\StateDataContainer;
use DeliciousBrains\WPMDB\Common\Properties\Properties;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\Backup_Table_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\Core_File_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\File_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\Media_File_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\MUPlugin_File_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\Other_File_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\Plugin_File_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\Root_File_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\Table_Job;
use DeliciousBrains\WPMDB\Common\Queue\Jobs\Theme_File_Job;
use DeliciousBrains\WPMDB\Common\Util\Util;
use DeliciousBrains\WPMDB\Data\Stage;
use WP_Error;
use wpdb;

/**
 * @phpstan-import-type StageName from Stage
 */
class Manager {
	public $queue;
	public $worker;
	public $connection;
	public $prefix;
	public $jobs_table;
	public $failures_table;

	/**
	 * @var wpdb
	 */
	public $wpdb;

	/**
	 * @var Properties
	 */
	private $properties;

	/**
	 * @var StateDataContainer
	 */
	private $state_data_container;

	/**
	 * @var MigrationStateManager
	 */
	private $migration_state_manager;

	/**
	 * @var FormData
	 */
	private $form_data;

	function __construct(
		Properties $properties,
		StateDataContainer $state_data_container,
		MigrationStateManager $migration_state_manager,
		FormData $form_data
	) {
		$this->wpdb                    = $GLOBALS['wpdb'];
		$this->properties              = $properties;
		$this->state_data_container    = $state_data_container;
		$this->migration_state_manager = $migration_state_manager;
		$this->form_data               = $form_data;

		$this->prefix         = $this->properties->temp_prefix;
		$this->jobs_table     = $this->prefix . "queue_jobs";
		$this->failures_table = $this->prefix . "queue_failures";

		$allowed_job_classes = [
			Backup_Table_Job::class,
			Table_Job::class,
			Media_File_Job::class,
			Theme_File_Job::class,
			Plugin_File_Job::class,
			MUPlugin_File_Job::class,
			Other_File_Job::class,
			Core_File_Job::class,
			Root_File_Job::class,
			File_Job::class,
		];

		$this->connection = new Connection( $GLOBALS['wpdb'], $allowed_job_classes, $properties->temp_prefix );
		$this->queue      = new Queue( $this->connection );
		$this->worker     = new Worker( $this->connection, 1 );
	}

	public function register() {
		add_filter( 'wpmdb_initiate_migration', [ $this, 'ensure_tables_exist' ] );
		add_action( 'wpmdb_always_exclude_table', [ $this, 'filter_always_exclude_table' ] );
		add_action( 'wpmdb_migration_complete', [ $this, 'do_cleanup' ] );
		add_action( 'wpmdb_cancellation', [ $this, 'do_cleanup' ] );
	}

	/**
	 * Adds a file to the jobs queue.
	 *
	 * @param array     $file
	 * @param StageName $stage
	 *
	 * @return int|WP_Error
	 */
	public function enqueue_file( $file, $stage ) {
		switch ( $stage ) {
			case Stage::MEDIA_FILES:
				$result = $this->enqueue_job( new Jobs\Media_File_Job( $file ) );
				break;
			case Stage::THEMES:
				$result = $this->enqueue_job( new Jobs\Theme_File_Job( $file ) );
				break;
			case Stage::PLUGINS:
				$result = $this->enqueue_job( new Jobs\Plugin_File_Job( $file ) );
				break;
			case Stage::MUPLUGINS:
				$result = $this->enqueue_job( new Jobs\MUPlugin_File_Job( $file ) );
				break;
			case Stage::OTHERS:
				$result = $this->enqueue_job( new Jobs\Other_File_Job( $file ) );
				break;
			case Stage::CORE:
				$result = $this->enqueue_job( new Jobs\Core_File_Job( $file ) );
				break;
			case Stage::ROOT:
				$result = $this->enqueue_job( new Jobs\Root_File_Job( $file ) );
				break;
			default:
				$result = $this->enqueue_job( new Jobs\File_Job( $file ) );
		}

		return $result;
	}

	/**
	 * Adds a table to the jobs queue.
	 *
	 * @param string $table
	 *
	 * @return int|WP_Error
	 */
	public function enqueue_table( $table ) {
		return $this->enqueue_job( new Jobs\Table_Job( $table ) );
	}

	/**
	 * Adds a table backup to the jobs queue.
	 *
	 * @param string $table
	 *
	 * @return int|WP_Error
	 */
	public function enqueue_backup_table( $table ) {
		return $this->enqueue_job( new Jobs\Backup_Table_Job( $table ) );
	}

	/**
	 * Adds a job to the queue.
	 *
	 * @param Job $job
	 *
	 * @return int|WP_Error
	 */
	public function enqueue_job( Job $job ) {
		return $this->queue->push( $job );
	}

	function process() {
		return $this->worker->process();
	}

	/**
	 * Ensure the queue tables exist.
	 *
	 * @param array $state_data
	 *
	 * @return array|WP_Error
	 */
	public function ensure_tables_exist( $state_data ) {
		// ***+=== @TODO - revisit usage of parse_migration_form_data
		$form_data = $this->form_data->parse_and_save_migration_form_data( $state_data['form_data'] );

		$stages = $form_data['current_migration']['stages'];

		$allowed_migration_types = [
			Stage::FIND_REPLACE,
			Stage::TABLES,
			Stage::THEME_FILES,
			Stage::PLUGIN_FILES,
			Stage::MUPLUGIN_FILES,
			Stage::OTHER_FILES,
			Stage::CORE_FILES,
			Stage::MEDIA_FILES,
			Stage::ROOT_FILES,
		];

		if (
			empty( array_intersect( $stages, $allowed_migration_types ) )
		) {
			return $state_data;
		}

		$result = $this->create_tables( true );

		if ( is_wp_error( $result ) ) {
			return $result;
		}

		return $state_data;
	}

	/**
	 * Create the job and failures tables.
	 *
	 * @param bool $drop
	 *
	 * @return bool|WP_Error
	 */
	public function create_tables( $drop = false ) {
		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		$this->wpdb->hide_errors();
		$charset_collate = $this->wpdb->get_charset_collate();

		$sql = "
			CREATE TABLE IF NOT EXISTS {$this->jobs_table} (
				id bigint(20) NOT NULL AUTO_INCREMENT,
				job longtext NOT NULL,
				attempts tinyint(3) NOT NULL DEFAULT 0,
				reserved_at datetime DEFAULT NULL,
				available_at datetime NOT NULL,
				created_at datetime NOT NULL,
				PRIMARY KEY  (id)
			) $charset_collate;
		";

		if ( $drop ) {
			$this->wpdb->query( "DROP TABLE IF EXISTS {$this->jobs_table}" );
		}

		if ( ! $this->wpdb->query( $sql ) ) {
			$msg = sprintf(
				__( 'Could not create queue jobs table, error: %s', 'wp-migrate-db' ),
				$this->wpdb->last_error
			);

			return new WP_Error( 'create-jobs-table-error', $msg );
		}

		$sql = "
			CREATE TABLE IF NOT EXISTS {$this->failures_table} (
				id bigint(20) NOT NULL AUTO_INCREMENT,
				job longtext NOT NULL,
				error text DEFAULT NULL,
				failed_at datetime NOT NULL,
				PRIMARY KEY  (id)
			) $charset_collate;
		";

		if ( $drop ) {
			$this->wpdb->query( "DROP TABLE IF EXISTS {$this->failures_table}" );
		}

		if ( ! $this->wpdb->query( $sql ) ) {
			$msg = sprintf(
				__( 'Could not create queue failures table, error: %s', 'wp-migrate-db' ),
				$this->wpdb->last_error
			);

			return new WP_Error( 'create-jobs-table-error', $msg );
		}

		return true;
	}

	/**
	 * Drop the queue manager's custom tables.
	 *
	 * @return void
	 */
	public function drop_tables() {
		$this->wpdb->hide_errors();

		$sql = "DROP TABLE IF EXISTS {$this->jobs_table}";
		$this->wpdb->query( $sql );

		$sql = "DROP TABLE IF EXISTS {$this->failures_table}";
		$this->wpdb->query( $sql );
	}

	/**
	 * Wrapper for DatabaseConnection::jobs()
	 *
	 * @return int
	 */

	public function count_jobs() {
		return $this->connection->jobs();
	}

	/**
	 *
	 * @param     $count
	 * @param int $offset
	 *
	 * @return array|null|object
	 *
	 */
	public function delete_data_from_queue( $count = 99999999 ) {
		$raw_sql = "
			DELETE FROM {$this->jobs_table}
			WHERE reserved_at IS NULL
			AND available_at <= %s
			ORDER BY id ASC
			LIMIT %d
        ";

		$sql = $this->wpdb->prepare( $raw_sql, Util::sql_formatted_datetime(), $count );

		return $this->wpdb->query( $sql );
	}

	public function truncate_queue() {
		$sql = "TRUNCATE TABLE {$this->jobs_table}";

		$results = $this->wpdb->query( $sql );

		return $results;
	}

	/**
	 * Get list of jobs in queue
	 *
	 * @param int  $limit
	 * @param int  $offset
	 * @param bool $raw if true, method will return serialized instead of instantiated objects
	 *
	 * @return array|WP_Error
	 */
	public function list_jobs( $limit = 9999999, $offset = 0, $raw = false ) {
		return $this->connection->list_jobs( $limit, $offset, $raw );
	}

	/**
	 * Filter the list of tables that should be excluded from any migration operations.
	 *
	 * @param array $tables
	 *
	 * @return array
	 */
	public function filter_always_exclude_table( $tables ) {
		return array_merge(
			$tables,
			array( $this->jobs_table, $this->failures_table )
		);
	}

	/**
	 * When a migration completes or cancels, cleanup.
	 *
	 * @return void
	 */
	public function do_cleanup() {
		// Currently just cleanup the custom tables.
		$this->drop_tables();
	}
}