// api_client.dart — 统一鉴权 HTTP 客户端。
//
// 职责:为受 JWT 保护的端点(/v1/me、/v1/me/devices、/v1/plans、/v1/usage、
// /v1/redeem、/v1/ads/unlock 等)提供 GET/POST/DELETE 封装,自动:
//   - 注入 Authorization: Bearer <access token>
//   - 401 时调用 [refresh] 刷新令牌,成功则用新令牌重试一次
//   - 错误统一包装为 AuthApiException(message_zh/en),UI 复用既有错误模型
import 'dart:convert';

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

import 'auth_api.dart' show AuthApiException;

/// 取当前 access token(可空表示未登录)。
typedef TokenGetter = String? Function();

/// 触发刷新;成功返回 true(调用方应已写入新令牌)。
typedef TokenRefresher = Future<bool> Function();

class ApiClient {
  ApiClient({
    required this.baseUrl,
    required this.getToken,
    required this.refresh,
    http.Client? client,
  }) : _client = client ?? http.Client();

  final String baseUrl;
  final TokenGetter getToken;
  final TokenRefresher refresh;
  final http.Client _client;

  /// GET → 解析为 JSON 对象。
  Future<Map<String, dynamic>> getJson(String path) async =>
      _decodeObj(await _send(() => _req('GET', path)));

  /// POST → 解析为 JSON 对象(空响应体返回空 map)。
  Future<Map<String, dynamic>> postJson(String path, [Map<String, dynamic>? body]) async =>
      _decodeObj(await _send(() => _req('POST', path, body)));

  /// DELETE(无响应体)。
  Future<void> delete(String path) async {
    await _send(() => _req('DELETE', path));
  }

  // ── 内部 ──────────────────────────────────────────────────────────

  /// 发送 + 401 自动刷新重试一次;非 2xx 抛 AuthApiException。
  Future<http.Response> _send(Future<http.Response> Function() build) async {
    http.Response resp;
    try {
      resp = await build();
      if (resp.statusCode == 401 && await refresh()) {
        resp = await build();
      }
    } on AuthApiException {
      rethrow;
    } on Exception catch (e) {
      throw AuthApiException(
        statusCode: -1,
        messageZh: '网络请求失败，请检查连接后重试',
        messageEn: 'Network error: $e',
      );
    }
    if (resp.statusCode < 200 || resp.statusCode >= 300) _throwFromResponse(resp);
    return resp;
  }

  Future<http.Response> _req(String method, String path, [Map<String, dynamic>? body]) {
    final uri = Uri.parse('$baseUrl$path');
    final headers = <String, String>{'Content-Type': 'application/json'};
    final t = getToken();
    if (t != null && t.isNotEmpty) headers['Authorization'] = 'Bearer $t';
    final Future<http.Response> f;
    switch (method) {
      case 'GET':
        f = _client.get(uri, headers: headers);
      case 'DELETE':
        f = _client.delete(uri, headers: headers);
      default:
        f = _client.post(uri, headers: headers, body: body == null ? null : jsonEncode(body));
    }
    return f.timeout(const Duration(seconds: 15));
  }

  Map<String, dynamic> _decodeObj(http.Response r) {
    if (r.body.isEmpty) return <String, dynamic>{};
    return jsonDecode(r.body) as Map<String, dynamic>;
  }

  Never _throwFromResponse(http.Response resp) {
    String zh = '操作失败 (HTTP ${resp.statusCode})';
    String en = 'Request failed (HTTP ${resp.statusCode})';
    String? code;
    try {
      final b = jsonDecode(resp.body) as Map<String, dynamic>;
      zh = b['message_zh'] as String? ?? zh;
      en = b['message_en'] as String? ?? en;
      code = b['code'] as String?;
    } catch (_) {}
    throw AuthApiException(statusCode: resp.statusCode, messageZh: zh, messageEn: en, code: code);
  }

  void dispose() => _client.close();
}