import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;

import '../../../errors/server_exception.dart';
import '../../../http_errors.dart';
import '../../nextcloud_ocs.dart';
import 'get_chat_params.dart';
import 'get_chat_response.dart';

/// GETs a chat page outside [TalkApi], which treats non-2xx as errors: here
/// HTTP 304 (nothing new / no older messages) is a normal outcome and yields
/// `null`.
Future<GetChatResponse?> fetchChatPage({
  required String label,
  required String chatToken,
  required GetChatParams params,
  Duration? timeout,
  bool parseOffIsolate = false,
}) async {
  final uri = NextcloudOcs.uri(
    'apps/spreed/api/v1/chat/$chatToken',
    queryParameters: params.toJson(),
  );
  final headers = NextcloudOcs.headers();

  final response = (await sendGuarded('$label $uri', () {
    final request = http.get(uri, headers: headers);
    return timeout == null ? request : request.timeout(timeout);
  }))!;

  final status = response.statusCode;
  if (status == 304) return null;
  if (status >= 200 && status < 300) {
    final parsed = parseOffIsolate
        ? await compute(_parseChatResponse, response.body)
        : _parseChatResponse(response.body);
    return parsed..headers = response.headers;
  }
  throw ServerException(
    statusCode: status,
    technicalDetails: '$label $uri: HTTP $status',
  );
}

GetChatResponse _parseChatResponse(String body) =>
    GetChatResponse.fromJson(NextcloudOcs.decode(body));