import 'dart:convert';

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

import 'api_config.dart';

/// Thrown for any non-2xx response. `errors` is populated for Laravel's
/// standard 422 validation shape (`{"message": ..., "errors": {field: [...]}}`).
class ApiException implements Exception {
  ApiException(this.statusCode, this.message, {this.errors});

  final int statusCode;
  final String message;
  final Map<String, List<String>>? errors;

  bool get isUnauthorized => statusCode == 401;

  @override
  String toString() => message;
}

/// Thin wrapper over `package:http` for the `/api/v1` backend: builds the
/// URL, attaches the bearer token (set by AuthService after login), decodes
/// JSON, and turns non-2xx responses into [ApiException].
class ApiClient {
  String? _token;

  void setToken(String? token) => _token = token;

  Uri _uri(String path) => Uri.parse('${ApiConfig.apiV1Url}$path');

  Map<String, String> get _headers => {
        'Accept': 'application/json',
        'Content-Type': 'application/json',
        if (_token != null) 'Authorization': 'Bearer $_token',
      };

  Future<dynamic> get(String path) async {
    return _handle(await http.get(_uri(path), headers: _headers));
  }

  Future<dynamic> post(String path, [Map<String, dynamic>? body]) async {
    return _handle(await http.post(
      _uri(path),
      headers: _headers,
      body: body == null ? null : jsonEncode(body),
    ));
  }

  Future<dynamic> put(String path, [Map<String, dynamic>? body]) async {
    return _handle(await http.put(
      _uri(path),
      headers: _headers,
      body: body == null ? null : jsonEncode(body),
    ));
  }

  Future<dynamic> delete(String path) async {
    return _handle(await http.delete(_uri(path), headers: _headers));
  }

  dynamic _handle(http.Response response) {
    final ok = response.statusCode >= 200 && response.statusCode < 300;

    if (response.body.isEmpty) {
      if (ok) return null;
      throw ApiException(response.statusCode, 'Ошибка запроса (${response.statusCode})');
    }

    final decoded = jsonDecode(utf8.decode(response.bodyBytes));

    if (ok) return decoded;

    final message = decoded is Map && decoded['message'] is String
        ? decoded['message'] as String
        : 'Ошибка запроса (${response.statusCode})';

    Map<String, List<String>>? errors;
    if (decoded is Map && decoded['errors'] is Map) {
      errors = (decoded['errors'] as Map).map(
        (key, value) => MapEntry(key as String, List<String>.from(value as List)),
      );
    }

    throw ApiException(response.statusCode, message, errors: errors);
  }
}