import 'dart:async';

import 'package:flutter/services.dart';

import '../models/bluetooth_device_info.dart';
import '../models/bluetooth_power_state.dart';
import '../models/gps_speed.dart';
import '../models/location_reading.dart';
import '../models/obd_state.dart';

class TelemetryException implements Exception {
  TelemetryException(this.message, {this.code});

  final String message;

  /// Stable native error code, when one was supplied.
  final String? code;

  @override
  String toString() => message;
}

/// Bluetooth OBD and location boundary. Kept separate from LauncherPlatform so
/// package/launcher fakes do not need telemetry methods.
abstract class TelemetryPlatform {
  Future<List<BluetoothDeviceInfo>> listBondedDevices();

  Future<BluetoothPowerState> bluetoothState();

  Future<bool> openBluetoothSettings();

  Future<bool> ensureBluetoothPermission();

  Future<bool> ensureLocationPermission();

  Future<LocationReading> getLocation();

  Future<void> connectObd(String address);

  Future<void> disconnectObd();

  Future<ObdState> getObdState();

  /// Starts GPS speed updates only when precise location is already allowed.
  Future<bool> startGpsSpeed();

  Future<void> stopGpsSpeed();

  Future<GpsSpeed> getGpsSpeed();
}

class NativeTelemetryBridge implements TelemetryPlatform {
  static const _channel = MethodChannel('com.wasp.cardash_launcher/telemetry');

  static const _listTimeout = Duration(seconds: 6);
  static const _stateTimeout = Duration(seconds: 3);
  static const _permissionTimeout = Duration(seconds: 30);
  static const _connectTimeout = Duration(seconds: 5);
  static const _disconnectTimeout = Duration(seconds: 3);
  static const _obdStateTimeout = Duration(seconds: 2);
  static const _settingsTimeout = Duration(seconds: 3);

  @override
  Future<List<BluetoothDeviceInfo>> listBondedDevices() async {
    try {
      final raw = await _channel
          .invokeMethod<dynamic>('listBondedDevices')
          .timeout(_listTimeout);
      if (raw is! List) return const [];
      return raw
          .whereType<Map>()
          .map(BluetoothDeviceInfo.fromMap)
          .where((device) => device.address.isNotEmpty)
          .toList(growable: false);
    } on TimeoutException {
      throw TelemetryException('Bluetooth is not responding.', code: 'timeout');
    } on PlatformException catch (error) {
      throw TelemetryException(
        error.message ?? 'Could not list Bluetooth devices.',
        code: error.code,
      );
    } on MissingPluginException {
      throw TelemetryException('The telemetry bridge is unavailable.');
    }
  }

  @override
  Future<BluetoothPowerState> bluetoothState() async {
    try {
      final raw = await _channel
          .invokeMethod<String>('bluetoothState')
          .timeout(_stateTimeout);
      return BluetoothPowerState.fromWire(raw);
    } on TimeoutException {
      return BluetoothPowerState.unknown;
    } on PlatformException {
      return BluetoothPowerState.unavailable;
    } on MissingPluginException {
      return BluetoothPowerState.unavailable;
    }
  }

  @override
  Future<bool> openBluetoothSettings() async {
    try {
      return await _channel
              .invokeMethod<bool>('openBluetoothSettings')
              .timeout(_settingsTimeout) ??
          false;
    } on TimeoutException {
      return false;
    } on PlatformException {
      return false;
    } on MissingPluginException {
      return false;
    }
  }

  @override
  Future<bool> ensureBluetoothPermission() async {
    try {
      return await _channel
              .invokeMethod<bool>('ensureBluetoothPermission')
              .timeout(_permissionTimeout) ??
          false;
    } on TimeoutException {
      throw TelemetryException(
        'Bluetooth permission request timed out.',
        code: 'timeout',
      );
    } on PlatformException {
      return false;
    } on MissingPluginException {
      return false;
    }
  }

  @override
  Future<bool> ensureLocationPermission() async {
    try {
      return await _channel
              .invokeMethod<bool>('ensureLocationPermission')
              .timeout(_permissionTimeout) ??
          false;
    } on TimeoutException {
      return false;
    } on PlatformException {
      return false;
    } on MissingPluginException {
      return false;
    }
  }

  @override
  Future<LocationReading> getLocation() async {
    try {
      final raw = await _channel
          .invokeMethod<dynamic>('getLocation')
          .timeout(const Duration(seconds: 20));
      if (raw is! Map) {
        throw TelemetryException('Could not read the current location.');
      }
      return LocationReading.fromMap(raw);
    } on TimeoutException {
      throw TelemetryException('Could not read the current location.');
    } on PlatformException catch (error) {
      throw TelemetryException(
        error.message ?? 'Could not read location.',
        code: error.code,
      );
    } on MissingPluginException {
      throw TelemetryException('The telemetry bridge is unavailable.');
    }
  }

  @override
  Future<void> connectObd(String address) async {
    try {
      await _channel
          .invokeMethod<dynamic>('connectObd', {'address': address})
          .timeout(_connectTimeout);
    } on TimeoutException {
      throw TelemetryException('Bluetooth is not responding.', code: 'timeout');
    } on PlatformException catch (error) {
      throw TelemetryException(
        error.message ?? 'Could not connect to OBD.',
        code: error.code,
      );
    } on MissingPluginException {
      throw TelemetryException('The telemetry bridge is unavailable.');
    }
  }

  @override
  Future<void> disconnectObd() async {
    try {
      await _channel
          .invokeMethod<dynamic>('disconnectObd')
          .timeout(_disconnectTimeout);
    } on TimeoutException {
      // The native stop is best effort; never hold up the UI for it.
    } on PlatformException {
      // Nothing useful to do when already disconnected.
    } on MissingPluginException {
      // No-op outside Android.
    }
  }

  @override
  Future<bool> startGpsSpeed() async {
    try {
      return await _channel
              .invokeMethod<bool>('startGpsSpeed')
              .timeout(const Duration(seconds: 3)) ??
          false;
    } on TimeoutException {
      return false;
    } on PlatformException {
      return false;
    } on MissingPluginException {
      return false;
    }
  }

  @override
  Future<void> stopGpsSpeed() async {
    try {
      await _channel
          .invokeMethod<dynamic>('stopGpsSpeed')
          .timeout(const Duration(seconds: 2));
    } on TimeoutException {
      // Best effort.
    } on PlatformException {
      // Nothing useful to do when already stopped.
    } on MissingPluginException {
      // No-op outside Android.
    }
  }

  @override
  Future<GpsSpeed> getGpsSpeed() async {
    try {
      final raw = await _channel
          .invokeMethod<dynamic>('getGpsSpeed')
          .timeout(const Duration(seconds: 2));
      return raw is Map ? GpsSpeed.fromMap(raw) : const GpsSpeed();
    } on TimeoutException {
      return const GpsSpeed();
    } on PlatformException {
      return const GpsSpeed();
    } on MissingPluginException {
      return const GpsSpeed();
    }
  }

  @override
  Future<ObdState> getObdState() async {
    try {
      final raw = await _channel
          .invokeMethod<dynamic>('getObdState')
          .timeout(_obdStateTimeout);
      return raw is Map ? ObdState.fromMap(raw) : const ObdState();
    } on TimeoutException {
      throw TelemetryException('OBD state is not responding.', code: 'timeout');
    } on PlatformException {
      return const ObdState();
    } on MissingPluginException {
      return const ObdState();
    }
  }
}