// DualCheck API 封装
// 后端统一响应格式：{code:0, message, data}
// WebSocket 消息格式：{type, data, error}
import 'package:dio/dio.dart';
import 'package:flutter/foundation.dart';

/// 后端地址
const String _baseUrl = kIsWeb
    ? 'http://localhost:8080'
    : 'http://127.0.0.1:8080';

/// WebSocket 地址
const String _wsBaseUrl =
    kIsWeb ? 'ws://localhost:8080' : 'ws://127.0.0.1:8080';

class DualCheckApi {
  DualCheckApi()
      : _dio = Dio(BaseOptions(
          baseUrl: _baseUrl,
          connectTimeout: const Duration(seconds: 10),
          receiveTimeout: const Duration(seconds: 10),
        )) {
    _dio.interceptors.add(InterceptorsWrapper(
      onResponse: (response, handler) {
        final data = response.data;
        if (data is Map<String, dynamic> && data['code'] != 0) {
          handler.reject(DioException(
            requestOptions: response.requestOptions,
            response: response,
            type: DioExceptionType.badResponse,
            error: _BizError(data['code'] as int, data['message'] as String),
          ));
          return;
        }
        handler.next(response);
      },
    ));
  }

  final Dio _dio;

  // ── Create ──

  Future<CreateResp> createSession({required String nickname}) async {
    final res = await _dio.post<Map<String, dynamic>>(
      '/api/v1/dual-check/create',
      data: {'nickname': nickname},
    );
    final d = res.data!['data'] as Map<String, dynamic>;
    return CreateResp(
      sessionId: d['session_id'] as String,
      nickname: d['nickname'] as String,
      ttl: d['ttl_seconds'] as int,
    );
  }

  // ── Submit ──

  Future<SubmitResp> submit({
    required String sessionId,
    required String nickname,
    required String role, // "initiator" | "participant"
    required String text,
  }) async {
    final res = await _dio.post<Map<String, dynamic>>(
      '/api/v1/dual-check/submit',
      data: {
        'session_id': sessionId,
        'nickname': nickname,
        'role': role,
        'text': text,
      },
    );
    final d = res.data!['data'] as Map<String, dynamic>;
    return SubmitResp(
      submitted: d['submitted'] as bool,
      initiatorReady: d['initiator_ready'] as bool,
      match: d['match'] as bool?,
    );
  }

  // ── CheckSession ──

  Future<CheckResp> checkSession(String sessionId) async {
    final res = await _dio.get<Map<String, dynamic>>(
      '/api/v1/dual-check/check/$sessionId',
    );
    final d = res.data!['data'] as Map<String, dynamic>;
    return CheckResp(
      exists: d['exists'] as bool,
      initiatorReady: d['initiator_ready'] as bool,
      participantCount: d['participant_count'] as int,
      ttlSeconds: d['ttl_seconds'] as int,
    );
  }

  // ── GetSession 全量快照 ──

  Future<SessionResp> getSession(String sessionId) async {
    final res = await _dio.get<Map<String, dynamic>>(
      '/api/v1/dual-check/session/$sessionId',
    );
    return parseSession(res.data!['data'] as Map<String, dynamic>);
  }

  // ── SetResubmit 发起方切换"允许参与者重新提交" ──

  Future<SessionResp> setResubmit(String sessionId, {required bool allow}) async {
    final res = await _dio.post<Map<String, dynamic>>(
      '/api/v1/dual-check/session/$sessionId/resubmit',
      data: {'allow': allow},
    );
    return parseSession(res.data!['data'] as Map<String, dynamic>);
  }

  // ── EndSession 发起方主动结束会话 ──

  Future<void> endSession(String sessionId) async {
    await _dio.post('/api/v1/dual-check/session/$sessionId/end');
  }

  static SessionResp parseSession(Map<String, dynamic> d) {
    final parts = (d['participants'] as List)
        .map((p) => ParticipantResp.fromMap(p as Map<String, dynamic>))
        .toList();
    return SessionResp(
      sessionId: d['session_id'] as String,
      initiatorNickname: (d['initiator_nickname'] ?? '') as String,
      initiatorReady: d['initiator_ready'] as bool,
      allowResubmit: (d['allow_resubmit'] as bool?) ?? false,
      participants: parts,
      ttlSeconds: d['ttl_seconds'] as int,
    );
  }

  // ── WS URL ──

  String wsUrl({
    required String sessionId,
    required String role,
    required String nickname,
  }) {
    return '$_wsBaseUrl/api/v1/dual-check/ws'
        '?session_id=${Uri.encodeQueryComponent(sessionId)}'
        '&role=$role'
        '&nickname=${Uri.encodeQueryComponent(nickname)}';
  }
}

// ── 数据模型 ──

class CreateResp {
  final String sessionId;
  final String nickname;
  final int ttl;
  CreateResp({required this.sessionId, required this.nickname, required this.ttl});
}

class SubmitResp {
  final bool submitted;
  final bool initiatorReady;
  final bool? match;
  SubmitResp({required this.submitted, required this.initiatorReady, this.match});
}

class CheckResp {
  final bool exists;
  final bool initiatorReady;
  final int participantCount;
  final int ttlSeconds;
  CheckResp({
    required this.exists,
    required this.initiatorReady,
    required this.participantCount,
    required this.ttlSeconds,
  });
}

class ParticipantResp {
  final String nickname;
  final bool joined;
  final bool submitted;
  final bool? match;
  ParticipantResp({
    required this.nickname,
    required this.joined,
    required this.submitted,
    this.match,
  });
  factory ParticipantResp.fromMap(Map<String, dynamic> m) {
    return ParticipantResp(
      nickname: m['nickname'] as String,
      joined: m['joined'] as bool? ?? true,
      submitted: m['submitted'] as bool,
      match: m['match'] as bool?,
    );
  }
}

class SessionResp {
  final String sessionId;
  final String initiatorNickname;
  final bool initiatorReady;
  final bool allowResubmit;
  final List<ParticipantResp> participants;
  final int ttlSeconds;
  SessionResp({
    required this.sessionId,
    required this.initiatorNickname,
    required this.initiatorReady,
    required this.allowResubmit,
    required this.participants,
    required this.ttlSeconds,
  });
}

// ── WS 消息类型 ──

class WSMessage {
  final String type;
  final Map<String, dynamic> data;
  final String? error;

  WSMessage({required this.type, required this.data, this.error});

  factory WSMessage.fromJson(Map<String, dynamic> json) {
    return WSMessage(
      type: json['type'] as String,
      data: (json['data'] as Map<String, dynamic>?) ?? const {},
      error: json['error'] as String?,
    );
  }
}

// ── 业务错误处理 ──

class _BizError implements Exception {
  _BizError(this.code, this.message);
  final int code;
  final String message;
  @override
  String toString() => '[biz:$code] $message';
}

bool isBizError(DioException e) => e.error is _BizError;
int? bizErrorCode(DioException e) {
  final err = e.error;
  return err is _BizError ? err.code : null;
}
String bizErrorMessage(DioException e) {
  final err = e.error;
  return err is _BizError ? err.message : (e.message ?? '请求失败');
}