<?php
/**
 * Public filter-options endpoint.
 *
 * @package Mapsemble
 */

namespace Mapsemble\Rest;

use Mapsemble\Feed\FilterOptions;
use Mapsemble\Feed\ResponseCache;
use Mapsemble\MapConfigRepository;
use WP_REST_Request;
use WP_REST_Response;

/**
 * GET /wp-json/mapsemble/v1/filter/options
 *
 * `{value: label}` for one mapped filter, top values first. Degrades the
 * same way as the sibling endpoints: unknown map or unmapped filter is an
 * empty 200, a hosted map is a 404, and everything carries CORS `*`.
 */
class FilterOptionsController {

	use HostedMapRefusal;

	/**
	 * Config repository.
	 *
	 * @var MapConfigRepository
	 */
	private MapConfigRepository $repository;

	/**
	 * Option lookups.
	 *
	 * @var FilterOptions
	 */
	private FilterOptions $options;

	/**
	 * Response cache.
	 *
	 * @var ResponseCache
	 */
	private ResponseCache $cache;

	/**
	 * Constructor.
	 *
	 * @param MapConfigRepository $repository Config repository.
	 * @param FilterOptions       $options    Option lookups.
	 * @param ResponseCache       $cache      Response cache (the instance Plugin registered).
	 */
	public function __construct( MapConfigRepository $repository, FilterOptions $options, ResponseCache $cache ) {
		$this->repository = $repository;
		$this->options    = $options;
		$this->cache      = $cache;
	}

	/**
	 * Registers the REST route.
	 */
	public function register_routes(): void {
		register_rest_route(
			'mapsemble/v1',
			'/filter/options',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'handle' ),
				'permission_callback' => '__return_true',
				'args'                => array(
					'mapId'  => array( 'type' => 'string' ),
					'filter' => array( 'type' => 'string' ),
					'search' => array( 'type' => 'string' ),
				),
			)
		);
	}

	/**
	 * Builds the options response.
	 *
	 * @param WP_REST_Request $request The request.
	 */
	public function handle( WP_REST_Request $request ): WP_REST_Response {
		$config = $this->repository->find_by_map_id( (string) $request->get_param( 'mapId' ) );
		if ( null === $config ) {
			return $this->respond( array() );
		}
		if ( $config->is_hosted() ) {
			return $this->hosted_map_refusal();
		}

		$filter = (string) $request->get_param( 'filter' );
		$search = (string) $request->get_param( 'search' );

		return $this->cache->remember(
			'filter/options',
			$config,
			$request,
			array(
				'filter' => $filter,
				'search' => $search,
			),
			fn (): WP_REST_Response => $this->respond( $this->options->options_for( $config, $filter, $search ) )
		);
	}

	/**
	 * Wraps options with the CORS header, as an object even when empty.
	 *
	 * @param array<string, string> $options value => label.
	 */
	private function respond( array $options ): WP_REST_Response {
		$response = new WP_REST_Response( (object) $options );
		$response->header( 'Access-Control-Allow-Origin', '*' );
		return $response;
	}
}