<?php
/**
 * GET|DELETE /jobs/<id> and POST /jobs/<id>/cancel.
 *
 * @package Transtrix
 */

namespace Transtrix\Rest\Controllers;

use Transtrix\Runner\Job_Store;
use WP_REST_Request;

defined( 'ABSPATH' ) || exit;

/**
 * The endpoint the UI polls while a job runs.
 */
class Jobs extends Controller {

	/**
	 * Phases during which a job refuses to be cancelled.
	 *
	 * Mirrors Steppable::uncancellable_phases(). Kept as a constant here so the
	 * cancel route does not have to instantiate the task to answer a question
	 * about it.
	 */
	const UNCANCELLABLE_PHASES = array( 'swap' );

	/**
	 * Register routes.
	 *
	 * @return void
	 */
	public function register_routes(): void {
		register_rest_route(
			self::NAMESPACE_V1,
			'/jobs/(?P<id>[A-Za-z0-9_.]+)',
			array(
				array(
					'methods'             => 'GET',
					'callback'            => array( $this, 'get_job' ),
					'permission_callback' => array( $this, 'permission_check' ),
					'args'                => $this->job_id_arg(),
				),
				array(
					'methods'             => 'DELETE',
					'callback'            => array( $this, 'delete_job' ),
					'permission_callback' => array( $this, 'permission_check' ),
					'args'                => $this->job_id_arg(),
				),
			)
		);

		register_rest_route(
			self::NAMESPACE_V1,
			'/jobs/(?P<id>[A-Za-z0-9_.]+)/cancel',
			array(
				array(
					'methods'             => 'POST',
					'callback'            => array( $this, 'cancel_job' ),
					'permission_callback' => array( $this, 'permission_check' ),
					'args'                => $this->job_id_arg(),
				),
			)
		);
	}

	/**
	 * One job's status.
	 *
	 * @param WP_REST_Request $request The request.
	 * @return \WP_REST_Response|\WP_Error
	 */
	public function get_job( WP_REST_Request $request ) {
		$record = Job_Store::get( (string) $request['id'] );

		if ( null === $record ) {
			return $this->error( 'transtrix_job_not_found', __( 'That export or import no longer exists. It may have been deleted from History.', 'transtrix' ), 404 );
		}

		if ( ! $this->may_touch( $record ) ) {
			return $this->full_site_forbidden();
		}

		return rest_ensure_response( $record );
	}

	/**
	 * Remove a finished job from History, with its stored package.
	 *
	 * @param WP_REST_Request $request The request.
	 * @return \WP_REST_Response|\WP_Error
	 */
	public function delete_job( WP_REST_Request $request ) {
		if ( ! $this->may_touch( Job_Store::get( (string) $request['id'] ) ) ) {
			return $this->full_site_forbidden();
		}

		if ( ! Job_Store::delete( (string) $request['id'] ) ) {
			return $this->error( 'transtrix_job_not_deletable', __( 'This is still running or was already deleted. If it is running, stop it first.', 'transtrix' ), 409 );
		}

		return rest_ensure_response( array( 'deleted' => true ) );
	}

	/**
	 * Cancel a job that has not finished.
	 *
	 * @param WP_REST_Request $request The request.
	 * @return \WP_REST_Response|\WP_Error
	 */
	public function cancel_job( WP_REST_Request $request ) {
		$job_id = (string) $request['id'];
		$record = Job_Store::get( $job_id );

		if ( ! $this->may_touch( $record ) ) {
			return $this->full_site_forbidden();
		}

		// A whole-site restore that has started swapping tables into place
		// cannot be stopped half way: the swap is one statement, and the only
		// way back from a partial database is the restore point taken before
		// it started. Offering a cancel button here would be a lie.
		if ( null !== $record && ! empty( $record['phase'] ) && in_array( $record['phase'], self::UNCANCELLABLE_PHASES, true ) ) {
			return $this->error(
				'transtrix_job_past_no_return',
				__( 'This restore is writing the site into place and can no longer be stopped.', 'transtrix' ),
				409
			);
		}

		$record = Job_Store::cancel( $job_id );

		if ( null === $record ) {
			return $this->error( 'transtrix_job_not_cancellable', __( 'That has already finished, so there is nothing to cancel.', 'transtrix' ), 409 );
		}

		return rest_ensure_response( $record );
	}

	/**
	 * Whether the current user may act on a job. Whole-site jobs are admin-only.
	 *
	 * @param array<string, mixed>|null $record The job record, or null.
	 * @return bool
	 */
	private function may_touch( ?array $record ): bool {
		return null === $record || ( ( 'full-site' !== ( $record['kind'] ?? '' ) || $this->can_access_full_site() ) && $this->owns_job( $record ) );
	}

	/**
	 * The job id argument.
	 *
	 * @return array<string,array<string,mixed>>
	 */
	private function job_id_arg(): array {
		return array(
			'id' => array(
				'description'       => __( 'Job id.', 'transtrix' ),
				'type'              => 'string',
				'required'          => true,
				'sanitize_callback' => static function ( $value ) {
					return preg_replace( '/[^A-Za-z0-9_.]/', '', (string) $value );
				},
				'validate_callback' => static function ( $value ) {
					return 1 === preg_match( '/^[A-Za-z0-9_.]{1,64}$/', (string) $value );
				},
			),
		);
	}
}