import 'dart:async';
import 'dart:io';
import 'package:dio/dio.dart';
import 'package:flutter/foundation.dart';
import 'package:twilio_voice/twilio_voice.dart';
import 'api_client.dart';

class VoiceService {
  final ApiClient _api;
  Timer? _tokenRefreshTimer;
  String? _identity;
  String? _deviceToken;
  StreamSubscription? _eventSubscription;

  final StreamController<CallEvent> _callEventController =
      StreamController<CallEvent>.broadcast();
  Stream<CallEvent> get callEvents => _callEventController.stream;

  VoiceService(this._api);

  Future<void> initialize({String? deviceToken}) async {
    _deviceToken = deviceToken;
    debugPrint('VoiceService.initialize: deviceToken=${deviceToken != null ? "present (${deviceToken.length} chars)" : "NULL"}');

    // Request permissions (Android telecom requires these)
    await TwilioVoice.instance.requestMicAccess();
    if (!kIsWeb && Platform.isAndroid) {
      await TwilioVoice.instance.requestReadPhoneStatePermission();
      await TwilioVoice.instance.requestReadPhoneNumbersPermission();
      await TwilioVoice.instance.requestCallPhonePermission();
      await TwilioVoice.instance.requestManageOwnCallsPermission();
      // Register phone account with Android telecom
      // (enabling is handled by dashboard UI with a user-friendly dialog)
      await TwilioVoice.instance.registerPhoneAccount();
    }

    // Fetch token and register
    await _fetchAndRegisterToken();

    // Listen for call events (only once)
    _eventSubscription ??= TwilioVoice.instance.callEventsListener.listen((event) {
      if (!_callEventController.isClosed) {
        _callEventController.add(event);
      }
    });

    // Refresh token every 50 minutes
    _tokenRefreshTimer?.cancel();
    _tokenRefreshTimer = Timer.periodic(
      const Duration(minutes: 50),
      (_) => _fetchAndRegisterToken(),
    );
  }

  Future<void> _fetchAndRegisterToken() async {
    try {
      final response = await _api.dio.get('/voice/token');
      final data = response.data;
      final token = data['token'] as String;
      _identity = data['identity'] as String;
      await TwilioVoice.instance.setTokens(
        accessToken: token,
        deviceToken: _deviceToken ?? 'no-fcm',
      );
    } catch (e) {
      debugPrint('VoiceService._fetchAndRegisterToken error: $e');
      if (e is DioException) debugPrint('  response: ${e.response?.data}');
    }
  }

  String? get identity => _identity;

  Future<void> answer() async {
    await TwilioVoice.instance.call.answer();
  }

  Future<void> reject() async {
    await TwilioVoice.instance.call.hangUp();
  }

  Future<void> hangUp() async {
    await TwilioVoice.instance.call.hangUp();
  }

  Future<void> toggleMute(bool mute) async {
    await TwilioVoice.instance.call.toggleMute(mute);
  }

  Future<void> toggleSpeaker(bool speaker) async {
    await TwilioVoice.instance.call.toggleSpeaker(speaker);
  }

  Future<bool> makeCall(String to, {String? callerId}) async {
    try {
      final extraOptions = <String, dynamic>{};
      if (callerId != null && callerId.isNotEmpty) {
        extraOptions['CallerId'] = callerId;
      }
      debugPrint('VoiceService.makeCall: to=$to, from=$_identity, extras=$extraOptions');
      final result = await TwilioVoice.instance.call.place(
        to: to,
        from: _identity ?? '',
        extraOptions: extraOptions,
      ) ?? false;
      debugPrint('VoiceService.makeCall: result=$result');
      return result;
    } catch (e) {
      debugPrint('VoiceService.makeCall error: $e');
      return false;
    }
  }

  Future<void> sendDigits(String digits) async {
    await TwilioVoice.instance.call.sendDigits(digits);
  }

  Future<List<Map<String, dynamic>>> getQueueCalls(int queueId) async {
    final response = await _api.dio.get('/queues/$queueId/calls');
    return List<Map<String, dynamic>>.from(response.data['calls'] ?? []);
  }

  Future<void> acceptQueueCall(String callSid) async {
    await _api.dio.post('/calls/$callSid/accept', data: {
      'client_identity': _identity,
    });
  }

  Future<void> holdCall(String callSid) async {
    await _api.dio.post('/calls/$callSid/hold');
  }

  Future<void> unholdCall(String callSid) async {
    await _api.dio.post('/calls/$callSid/unhold');
  }

  Future<void> transferCall(String callSid, String target) async {
    await _api.dio.post('/calls/$callSid/transfer', data: {'target': target});
  }

  void dispose() {
    _tokenRefreshTimer?.cancel();
    _eventSubscription?.cancel();
    _eventSubscription = null;
    _callEventController.close();
  }
}