import 'dart:typed_data';

import 'package:http/http.dart';

import 'package:pkpass/pkpass.dart';
import 'package:pkpass/pkpass_web_wervice/utils/http_date.dart';
import 'web_service_error.dart';

/// PassKit WebService implementation
///
/// A Representational State Transfer (REST)–style web service protocol is used
/// to communicate with your server about changes to passes, and to fetch the
/// latest version of a pass when it has changed.
///
/// https://developer.apple.com/library/archive/documentation/PassKit/Reference/PassKit_WebService/WebService.html#//apple_ref/doc/uid/TP40011988
class PkPassWebService {
  static const _apiVersion = 'v1';
  static Client? _client;

  /// The [PassMetadata] to check for updates.
  final PassMetadata metadata;

  /// An optional [Client] used for any http requests
  final Client? client;

  const PkPassWebService(this.metadata, {this.client});

  PassWebService get webService {
    final service = metadata.webService;
    if (service == null) noWebServiceProvided();
    return service;
  }

  Client get httpClient {
    final client = this.client;
    if (client != null) return client;
    return _client ??= Client();
  }

  /// Getting the Latest Version of a Pass
  ///
  /// Requests the latest version of the current PkPass file
  ///
  /// [modifiedSince] should be provided in order to support "304 Not Modified"
  Future<Uint8List?> getLatestVersion([DateTime? modifiedSince]) async {
    final identifier = metadata.passTypeIdentifier;
    final serial = metadata.serialNumber;
    final endpoint = '/$_apiVersion/passes/$identifier/$serial';

    final response = await httpClient.get(
      Uri.parse(webService.webServiceURL.toString() + endpoint),
      headers: {
        if (modifiedSince != null)
          'If-Modified-Since': HttpDate.format(modifiedSince),
        'Authorization': 'ApplePass ${webService.authenticationToken}',
      },
    );
    switch (response.statusCode) {
      case 200:
        return response.bodyBytes;
      case 304:
        return null;
      default:
        throw WebServiceResponseError(response);
    }
  }

  Never noWebServiceProvided() => throw WebServiceUnavailable();
}