<?php

namespace SiteSync;

use WP_Error;
use WP_REST_Request;
use WP_REST_Response;

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

/**
 * REST controller for Site Sync plugin.
 *
 * Handles REST API endpoints for synchronization, media, and authentication.
 */
class REST_Controller {
    private const ROUTE_NAMESPACE = 'site-sync/v1';

    /**
     * Settings instance.
     *
     * @var Settings
     */
    private $settings;

    /**
     * Sync_Engine instance.
     *
     * @var Sync_Engine
     */
    private $engine;

    /**
     * REST_Controller constructor.
     *
     * @param Settings    $settings Settings instance.
     * @param Sync_Engine $engine   Sync_Engine instance.
     */
    public function __construct( Settings $settings, Sync_Engine $engine ) {
        $this->settings = $settings;
        $this->engine   = $engine;
    }

    /**
     * Registers REST API hooks for the Site Sync plugin.
     *
     * @return void
     */
    public function hooks(): void {
        add_action( 'rest_api_init', array( $this, 'register_routes' ) );
    }

    /**
     * Registers all REST API routes for the Site Sync plugin.
     *
     * @return void
     */
    public function register_routes(): void {
        register_rest_route(
            self::ROUTE_NAMESPACE,
            '/handshake',
            array(
                'methods'             => 'GET',
                'callback'            => array( $this, 'handshake' ),
                'permission_callback' => '__return_true',
            )
        );

        register_rest_route(
            self::ROUTE_NAMESPACE,
            '/inbox',
            array(
                'methods'             => 'POST',
                'callback'            => array( $this, 'receive_inbox' ),
                'permission_callback' => array( $this, 'check_auth' ),
            )
        );

        register_rest_route(
            self::ROUTE_NAMESPACE,
            '/outbox',
            array(
                'methods'             => 'GET',
                'callback'            => array( $this, 'send_outbox' ),
                'permission_callback' => array( $this, 'check_auth' ),
            )
        );

        register_rest_route(
            self::ROUTE_NAMESPACE,
            '/media',
            array(
                'methods'             => 'POST',
                'callback'            => array( $this, 'handle_media' ),
                'permission_callback' => array( $this, 'check_auth' ),
                'args'                => array(
                    'external_id' => array(
						'required' => true,
						'type'     => 'string',
					),
                    'mime_type'   => array(
						'required' => true,
						'type'     => 'string',
					),
                    'filename'    => array(
						'required' => false,
						'type'     => 'string',
					),
                ),
            )
        );

        register_rest_route(
            self::ROUTE_NAMESPACE,
            '/media',
            array(
                'methods'             => 'GET',
                'callback'            => array( $this, 'send_media' ),
                'permission_callback' => array( $this, 'check_auth' ),
                'args'                => array(
                    'external_id' => array(
                        'required' => true,
                        'type'     => 'string',
                    ),
                ),
            )
        );
    }

    /**
     * Handles the handshake endpoint for the Site Sync plugin.
     *
     * Returns basic site and plugin information for synchronization.
     *
     * @return WP_REST_Response
     */
    public function handshake() {
        $settings = $this->settings->ensure_defaults();

        return new WP_REST_Response(
            array(
                'site_uuid'    => $settings['site_uuid'],
                'schema'       => 'v1',
                'site_url'     => home_url(),
                'version'      => SITE_SYNC_VERSION,
                'capabilities' => array(
                    'content'    => true,
                    'taxonomies' => true,
                    'media'      => true,
                ),
            )
        );
    }

    /**
     * Handles the inbox endpoint for receiving synchronization payloads.
     *
     * @param WP_REST_Request $request The REST request object containing the payload.
     * @return WP_REST_Response The response after processing the inbox payload.
     */
    public function receive_inbox( WP_REST_Request $request ) {
        $payload = $request->get_json_params() ? $request->get_json_params() : array();
        $result  = $this->engine->handle_inbox( $payload );

        return new WP_REST_Response( $result );
    }

    /**
     * Handles the outbox endpoint for sending synchronization payloads.
     *
     * @return WP_REST_Response The response containing the outbox payload.
     */
    public function send_outbox() {
        $result = $this->engine->provide_outbox( true );
        $this->engine->commit_outbox( $result['cursor'], $result['meta']['counts'] ?? array() );

        if ( isset( $result['meta'] ) ) {
            unset( $result['meta'] );
        }

        return new WP_REST_Response( $result );
    }

    /**
     * Handles the media endpoint for receiving and storing media files.
     *
     * @param WP_REST_Request $request The REST request object containing media data.
     * @return WP_REST_Response|WP_Error The response after processing the media upload or WP_Error on failure.
     */
    public function handle_media( WP_REST_Request $request ) {
        $result = $this->engine->receive_media_stream( $request );

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

        return new WP_REST_Response(
            array(
                'status' => 'ok',
                'stored' => $result,
            )
        );
    }

    /**
     * Handles the media endpoint for sending media files.
     *
     * @param WP_REST_Request $request The REST request object containing the external_id parameter.
     * @return WP_REST_Response|WP_Error The response containing the media file or WP_Error on failure.
     */
    public function send_media( WP_REST_Request $request ) {
        $externalId = $request->get_param( 'external_id' );
        $media      = $this->engine->get_media_file( $externalId );

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

        $response = new WP_REST_Response( $media['contents'] );
        $response->set_status( 200 );
        $response->header( 'Content-Type', $media['mime'] );
        $response->header( 'Content-Disposition', 'attachment; filename="' . $media['filename'] . '"' );
        $response->header( 'X-Site-Sync-Checksum', $media['checksum'] );

        return $response;
    }

    /**
     * Checks authentication for REST API requests.
     *
     * @param WP_REST_Request $request The REST request object.
     * @return true|WP_Error True if authentication passes, WP_Error otherwise.
     */
    public function check_auth( WP_REST_Request $request ) {
        $result = Auth::verify( $request, $this->settings );

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

        return true;
    }
}