// DualCheck API 封装
import 'dart:convert';
import 'package:flutter/foundation.dart' show kIsWeb;

import 'package:dio/dio.dart';

// ── URL ──
const String _baseUrl =
    kIsWeb ? 'http://localhost:8080' : 'http://127.0.0.1:8080';
const String _wsBaseUrl =
    kIsWeb ? 'ws://localhost:8080' : 'ws://127.0.0.1:8080';

class DualCheckApi {
  DualCheckApi._();
  static final DualCheckApi instance = DualCheckApi._();

  final Dio _dio = Dio(BaseOptions(
    baseUrl: _baseUrl,
    contentType: 'application/json',
    connectTimeout: const Duration(seconds: 5),
    receiveTimeout: const Duration(seconds: 10),
    sendTimeout: const Duration(seconds: 10),
  ))
    ..interceptors.add(_BizErrorInterceptor());

  // ── Create ──

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

  // ── Join 参与者加入登记 ──

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

  // ── SetIgnoreWs 发起方切换"忽略首尾空白" ──

  Future<SessionResp> setIgnoreWs(String sessionId, {required bool ignore}) async {
    final res = await _dio.post<Map<String, dynamic>>(
      '/api/v1/dual-check/ignore-ws',
      data: {'session_id': sessionId, 'ignore': ignore},
    );
    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/end', data: {'session_id': sessionId});
  }

  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,
      ignoreWs: (d['ignore_ws'] as bool?) ?? false,
      participants: parts,
      ttlSeconds: d['ttl_seconds'] as int,
    );
  }

  // ── WS URL ──

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

// ── Dio 拦截器：把后端业务错误转成 DioException ──

class _BizErrorInterceptor extends Interceptor {
  @override
  void onResponse(Response response, ResponseInterceptorHandler handler) {
    final data = response.data;
    if (data is Map<String, dynamic>) {
      final code = data['code'];
      if (code != null && code != 0) {
        final msg = data['message']?.toString() ?? '请求失败';
        handler.reject(DioException(
          requestOptions: response.requestOptions,
          response: response,
          error: _BizError(code as int, msg),
          type: DioExceptionType.badResponse,
        ));
        return;
      }
    }
    handler.next(response);
  }
}

class _BizError {
  final int code;
  final String message;
  const _BizError(this.code, this.message);
  @override
  String toString() => 'BusinessError($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');
}

// ── 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) => ParticipantResp(
        nickname: m['nickname'] as String,
        joined: (m['joined'] as bool?) ?? true,
        submitted: (m['submitted'] as bool?) ?? false,
        match: m['match'] as bool?,
      );
}

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

  SessionResp copyWith({
    String? sessionId,
    String? initiatorNickname,
    bool? initiatorReady,
    bool? allowResubmit,
    bool? ignoreWs,
    List<ParticipantResp>? participants,
    int? ttlSeconds,
  }) =>
      SessionResp(
        sessionId: sessionId ?? this.sessionId,
        initiatorNickname: initiatorNickname ?? this.initiatorNickname,
        initiatorReady: initiatorReady ?? this.initiatorReady,
        allowResubmit: allowResubmit ?? this.allowResubmit,
        ignoreWs: ignoreWs ?? this.ignoreWs,
        participants: participants ?? this.participants,
        ttlSeconds: ttlSeconds ?? this.ttlSeconds,
      );
}

// ── WS 消息解析 ──

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(String raw) {
    try {
      final m = jsonDecode(raw) as Map<String, dynamic>;
      return WSMessage(
        type: m['type'] as String? ?? '',
        data: (m['data'] as Map<String, dynamic>?) ?? {},
        error: (m['error'] as String?) ?? '',
      );
    } catch (_) {
      return WSMessage(type: '', data: {});
    }
  }
}