import 'dart:convert';
import 'dart:io';

import '../../../domain/models/server_config.dart';

class ApiException implements Exception {
  const ApiException(this.statusCode, this.message);
  final int statusCode;
  final String message;

  @override
  String toString() => 'ApiException $statusCode: $message';
}

abstract class LocaliserdClient {
  const LocaliserdClient({required this.config, this.token});

  final ServerConfig config;

  /// Null for unauthenticated clients (session, onboarding setup).
  final String? token;

  Uri _uri(String path) => Uri(
        scheme: 'http',
        host: config.host,
        port: config.port,
        path: path,
      );

  Future<dynamic> get(String path) => _request('GET', path);
  Future<dynamic> post(String path, [Object? body]) => _request('POST', path, body);
  Future<dynamic> put(String path, [Object? body]) => _request('PUT', path, body);
  Future<dynamic> patch(String path, [Object? body]) => _request('PATCH', path, body);
  Future<void> delete(String path) => _request('DELETE', path).then((_) {});

  /// Like [delete] but returns the response body (for endpoints that do so).
  Future<dynamic> deleteBody(String path) => _request('DELETE', path);

  Future<dynamic> _request(String method, String path, [Object? body]) async {
    final http = HttpClient();
    try {
      final request = await http.openUrl(method, _uri(path));
      request.headers.contentType = ContentType.json;
      if (token != null) {
        request.headers.set(HttpHeaders.authorizationHeader, 'Bearer $token');
      }
      if (body != null) request.write(jsonEncode(body));

      final response = await request.close();
      if (response.statusCode == 204) return null;

      final responseBody = await response.transform(utf8.decoder).join();
      if (response.statusCode >= 400) {
        final parsed = responseBody.isNotEmpty
            ? jsonDecode(responseBody) as Map<String, dynamic>?
            : null;
        throw ApiException(
          response.statusCode,
          parsed?['error']?.toString() ?? responseBody,
        );
      }

      return responseBody.isEmpty ? null : jsonDecode(responseBody);
    } finally {
      http.close();
    }
  }
}