<?php
/**
 * Connects the job runner to WordPress and Action Scheduler.
 *
 * @package Fitzaro
 */

namespace Fitzaro\Job;

use Fitzaro\Image\Sanitizer;
use Fitzaro\Prompt\TypeResolver;
use Fitzaro\Prompt\VariantAttributes;
use Fitzaro\Provider\Registry;
use Fitzaro\Settings;
use Fitzaro\Storage\Storage;

defined( 'ABSPATH' ) || exit;

/**
 * The only class in the job module that touches WordPress globals; Runner itself stays pure.
 */
final class Jobs {

	/**
	 * Registers the queue hooks.
	 */
	public static function register(): void {
		add_action( ActionSchedulerQueue::RUN_HOOK, array( self::class, 'run' ) );
		add_action( ActionSchedulerQueue::POLL_HOOK, array( self::class, 'poll' ) );
		add_action( ActionSchedulerQueue::REAP_HOOK, array( self::class, 'reap' ) );
		add_action( ActionSchedulerQueue::CLEANUP_HOOK, array( self::class, 'cleanup' ) );
		add_action( 'action_scheduler_init', array( ActionSchedulerQueue::class, 'ensure_recurring' ) );
	}

	/**
	 * Creates a queued request and puts it on the queue. Returns its UUID.
	 *
	 * @param array<string, mixed> $fields See Requests::create().
	 */
	public static function submit( array $fields ): string {
		$id = self::requests()->create( $fields );
		( new ActionSchedulerQueue() )->run_now( $id );

		return $id;
	}

	/**
	 * Action Scheduler callback.
	 *
	 * @param mixed $id Request UUID.
	 */
	public static function run( $id ): void {
		$runner = self::runner();
		if ( null === $runner ) {
			self::fail_without_storage( (string) $id );
			return;
		}

		// A generation can take minutes; hosts often stop PHP after 30 seconds. Ignored where disabled.
		if ( function_exists( 'set_time_limit' ) ) {
			@set_time_limit( Runner::LEASE_SECONDS ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged, Squiz.PHP.DiscouragedFunctions.Discouraged -- Only raised for this background job. Warns where the function is disabled; the job then runs with the host's limit.
		}

		$runner->run( (string) $id );
	}

	/**
	 * Action Scheduler callback.
	 *
	 * @param mixed $id Request UUID.
	 */
	public static function poll( $id ): void {
		$runner = self::runner();
		if ( null === $runner ) {
			self::fail_without_storage( (string) $id );
			return;
		}

		$runner->poll( (string) $id );
	}

	/**
	 * Action Scheduler callback.
	 */
	public static function reap(): void {
		$runner = self::runner();
		if ( null !== $runner ) {
			$runner->reap();
		}
	}

	/**
	 * Action Scheduler callback: deletes expired photos, results and rows.
	 */
	public static function cleanup(): void {
		$files = Storage::store();
		if ( null !== $files ) {
			( new Cleanup( self::requests(), $files, Settings::retention(), 'time' ) )->run();
		}
	}

	/**
	 * Request storage.
	 */
	public static function requests(): Requests {
		global $wpdb;

		return new WpdbRequests( $wpdb );
	}

	/**
	 * A runner wired to WordPress, or null when there is nowhere to store results.
	 */
	private static function runner(): ?Runner {
		$files = Storage::store();
		if ( null === $files ) {
			return null;
		}

		return new Runner(
			self::requests(),
			array( Registry::class, 'get' ),
			new ProductInputBuilder( $files, array( self::class, 'product_image' ), array( TypeResolver::class, 'for_product' ), array( VariantAttributes::class, 'for_variation' ), new Sanitizer() ),
			$files,
			new ActionSchedulerQueue(),
			'time',
			array( self::class, 'announce' )
		);
	}

	/**
	 * Bytes of the image shown for a product or variation, or null.
	 *
	 * @param int $product_id   Product ID.
	 * @param int $variation_id Variation ID, 0 for none.
	 */
	public static function product_image( int $product_id, int $variation_id ): ?string {
		$product = wc_get_product( $variation_id > 0 ? $variation_id : $product_id );
		if ( ! $product instanceof \WC_Product ) {
			return null;
		}

		// A variation without its own image returns the parent's.
		$file = get_attached_file( (int) $product->get_image_id() );
		if ( ! is_string( $file ) || '' === $file || ! is_readable( $file ) ) {
			return null;
		}

		$bytes = file_get_contents( $file ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- A local media file; WP_Filesystem can need credentials a background job does not have.

		return false === $bytes ? null : $bytes;
	}

	/**
	 * Turns runner events into actions other code (and Fitzaro Pro) can hook into.
	 *
	 * @param string $event 'completed' or 'failed'.
	 * @param string $id    Request UUID.
	 * @param string $code  Error code when failed.
	 */
	public static function announce( string $event, string $id, string $code ): void {
		if ( 'completed' === $event ) {
			/**
			 * Fires when a try-on result is ready.
			 *
			 * @since 1.0.0
			 *
			 * @param string $id Request UUID.
			 */
			do_action( 'fitzaro/job/completed', $id );
			return;
		}

		/**
		 * Fires when a try-on request fails.
		 *
		 * @since 1.0.0
		 *
		 * @param string $id   Request UUID.
		 * @param string $code Error code (a ProviderError or JobError constant).
		 */
		do_action( 'fitzaro/job/failed', $id, $code );
	}

	/**
	 * Fails a request when the storage folder disappeared.
	 *
	 * @param string $id Request UUID.
	 */
	private static function fail_without_storage( string $id ): void {
		if ( self::requests()->fail( $id, JobError::INTERNAL, gmdate( 'Y-m-d H:i:s' ) ) ) {
			self::announce( 'failed', $id, JobError::INTERNAL );
		}
	}
}