import 'package:audio_session/audio_session.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../app/theme.dart';

/// Where music plays right now, as the phone reports it.
class OutputDevice {
  const OutputDevice(this.label, this.icon);

  final String label;
  final IconData icon;

  static const speaker = OutputDevice('Phone speaker', Icons.speaker_phone_rounded);

  /// Android sends media to the most recently connected external device, so
  /// pick Bluetooth, then wired/USB/car, then the built-in speaker.
  static OutputDevice from(Set<AudioDevice> devices) {
    final outputs = devices.where((d) => d.isOutput).toList();
    int rank(AudioDevice d) {
      final t = d.type.name.toLowerCase();
      if (t.contains('bluetooth') && t != 'bluetoothsco') return 0;
      if (t.contains('car') || t.contains('wired') || t.contains('usb') || t.contains('line')) return 1;
      if (t.contains('hdmi') || t.contains('airplay') || t.contains('dock')) return 2;
      if (t == 'builtinspeaker') return 3;
      return 9;
    }

    outputs.sort((a, b) => rank(a).compareTo(rank(b)));
    if (outputs.isEmpty || rank(outputs.first) >= 3) return speaker;
    final d = outputs.first;
    final t = d.type.name.toLowerCase();
    final name = d.name.trim().isEmpty ? null : d.name.trim();
    if (t.contains('bluetooth')) return OutputDevice(name ?? 'Bluetooth', Icons.bluetooth_audio_rounded);
    if (t.contains('car')) return OutputDevice(name ?? 'Car audio', Icons.directions_car_rounded);
    if (t.contains('wired') || t.contains('line')) return const OutputDevice('Headphones', Icons.headphones_rounded);
    if (t.contains('usb')) return OutputDevice(name ?? 'USB audio', Icons.usb_rounded);
    return OutputDevice(name ?? 'External speaker', Icons.speaker_rounded);
  }
}

final outputDeviceProvider = StreamProvider<OutputDevice>((ref) async* {
  final session = await AudioSession.instance;
  yield OutputDevice.from(await session.getDevices(includeInputs: false));
  yield* session.devicesStream.map(OutputDevice.from);
});

const _channel = MethodChannel('nk/output');

/// Shows where music is playing; tap to choose another speaker or Bluetooth device.
class OutputDeviceButton extends ConsumerWidget {
  const OutputDeviceButton({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final device = ref.watch(outputDeviceProvider).value ?? OutputDevice.speaker;
    final external = device != OutputDevice.speaker;
    final color = external ? NkColors.teaLeaf : NkColors.mutedOnPhoto;
    return TextButton.icon(
      onPressed: () => _choose(context),
      style: TextButton.styleFrom(foregroundColor: color, visualDensity: VisualDensity.compact),
      icon: Icon(device.icon, size: 20),
      label: Text(device.label, maxLines: 1, overflow: TextOverflow.ellipsis),
    );
  }

  Future<void> _choose(BuildContext context) async {
    if (!kIsWeb && defaultTargetPlatform == TargetPlatform.android) {
      try {
        if (await _channel.invokeMethod<bool>('showOutputSwitcher') == true) return;
      } on PlatformException {
        // Fall through to the hint below.
      }
    }
    if (!context.mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(const SnackBar(
      content: Text('Choose a speaker or Bluetooth device from Control Center (swipe down from the top right).'),
    ));
  }
}