import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:wakelock_plus/wakelock_plus.dart';

import 'package:external_cam/frame_server.dart';
import 'package:external_cam/jpeg_encoder.dart';

class CameraScreen extends StatefulWidget {
  const CameraScreen({super.key});

  @override
  State<CameraScreen> createState() => _CameraScreenState();
}

class _CameraScreenState extends State<CameraScreen> {
  CameraController? _controller;
  final _server = FrameServer();
  final _beacon = DiscoveryBeacon();
  bool _isStreaming = false;
  bool _isProcessing = false;
  bool _flashOn = false;
  String _error = '';
  List<String> _addresses = [];
  List<CameraDescription> _cameras = [];
  int _cameraIndex = 0;
  int _fps = 0;
  int _frameCount = 0;
  double _zoom = 1.0;
  double _minZoom = 1.0;
  double _maxZoom = 1.0;
  int _quality = 50;
  Timer? _fpsTimer;
  StreamSubscription<String>? _commandSub;
  StreamSubscription<void>? _connectSub;

  @override
  void initState() {
    super.initState();
    _init();
  }

  Future<void> _init() async {
    try {
      if (!await Permission.camera.request().isGranted) {
        setState(() => _error = 'Camera permission required');
        return;
      }

      _cameras = await availableCameras();
      if (_cameras.isEmpty) {
        setState(() => _error = 'No cameras found');
        return;
      }

      await _initCamera(_cameras[_cameraIndex]);
      await _startServer();
    } catch (error) {
      setState(() => _error = error.toString());
    }
  }

  Future<void> _initCamera(CameraDescription camera) async {
    await _controller?.dispose();
    _flashOn = false;
    _zoom = 1.0;
    final controller = CameraController(
      camera,
      ResolutionPreset.high,
      enableAudio: false,
      imageFormatGroup: ImageFormatGroup.yuv420,
    );
    await controller.initialize();
    if (!mounted) return;

    _controller = controller;
    _minZoom = await controller.getMinZoomLevel();
    _maxZoom = await controller.getMaxZoomLevel();
    setState(() {});
  }

  Future<void> _startServer() async {
    await _server.start();
    await _beacon.start();
    _addresses = await _networkAddresses();

    _commandSub = _server.commands.listen(_handleCommand);
    _connectSub = _server.clientConnected.listen((_) => _broadcastState());

    _fpsTimer = Timer.periodic(const Duration(seconds: 1), (_) {
      if (!mounted) return;
      setState(() {
        _fps = _frameCount;
        _frameCount = 0;
      });
    });

    setState(() {});
    _startStreaming();
  }

  void _handleCommand(String command) {
    if (command.startsWith('zoom:')) {
      final level = double.tryParse(command.substring(5));
      if (level != null) _setZoom(level);
      return;
    }
    if (command.startsWith('quality:')) {
      final q = int.tryParse(command.substring(8));
      if (q != null) _setQuality(q);
      return;
    }
    switch (command) {
      case 'switch_camera':
        _switchCamera();
      case 'toggle_flash':
        _toggleFlash();
    }
  }

  void _broadcastState() {
    if (_cameras.isEmpty) return;
    final camera = _cameras[_cameraIndex];
    _server.sendText(
      jsonEncode({
        'cameras': _cameras.length,
        'current': _cameraIndex,
        'flash': _flashOn,
        'lens': camera.lensDirection.name,
        'name': camera.name,
        'zoom': _zoom,
        'minZoom': _minZoom,
        'maxZoom': _maxZoom,
        'quality': _quality,
      }),
    );
  }

  void _startStreaming() {
    if (_isStreaming || _controller == null) return;
    _controller!.startImageStream(_onFrame);
    _isStreaming = true;
    WakelockPlus.enable();
  }

  void _stopStreaming() {
    if (!_isStreaming || _controller == null) return;
    _controller!.stopImageStream();
    _isStreaming = false;
  }

  void _onFrame(CameraImage image) {
    if (_isProcessing || _server.clientCount == 0) return;
    _isProcessing = true;

    encodeJpeg(image, quality: _quality).then((jpeg) {
      if (jpeg != null) {
        _server.sendFrame(jpeg);
        _frameCount++;
      }
    }).whenComplete(() {
      _isProcessing = false;
    });
  }

  Future<List<String>> _networkAddresses() async {
    final interfaces = await NetworkInterface.list();
    final results = <String>[];
    for (final iface in interfaces) {
      for (final addr in iface.addresses) {
        if (addr.type != InternetAddressType.IPv4 || addr.isLoopback) continue;
        results.add('${addr.address} (${iface.name})');
      }
    }
    return results;
  }

  Future<void> _switchCamera() async {
    if (_cameras.length < 2) return;
    _stopStreaming();
    _cameraIndex = (_cameraIndex + 1) % _cameras.length;
    await _initCamera(_cameras[_cameraIndex]);
    _startStreaming();
    _broadcastState();
  }

  Future<void> _setZoom(double level) async {
    final controller = _controller;
    if (controller == null) return;

    _zoom = level.clamp(_minZoom, _maxZoom);
    await controller.setZoomLevel(_zoom);
    setState(() {});
    _broadcastState();
  }

  void _setQuality(int value) {
    _quality = value.clamp(10, 100);
    setState(() {});
    _broadcastState();
  }

  Future<void> _toggleFlash() async {
    final controller = _controller;
    if (controller == null) return;

    try {
      _stopStreaming();
      _flashOn = !_flashOn;
      await controller.setFlashMode(
        _flashOn ? FlashMode.torch : FlashMode.off,
      );
    } catch (_) {
      _flashOn = false;
    } finally {
      _startStreaming();
      setState(() {});
      _broadcastState();
    }
  }

  @override
  void dispose() {
    _fpsTimer?.cancel();
    _commandSub?.cancel();
    _connectSub?.cancel();
    _stopStreaming();
    _controller?.dispose();
    _beacon.stop();
    _server.stop();
    WakelockPlus.disable();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    if (_error.isNotEmpty) {
      return Scaffold(
        appBar: AppBar(title: const Text('Camera')),
        body: Center(
          child: Padding(
            padding: const EdgeInsets.all(32),
            child: Text(_error, textAlign: TextAlign.center),
          ),
        ),
      );
    }

    return Scaffold(
      backgroundColor: Colors.black,
      body: Stack(
        fit: StackFit.expand,
        children: [
          if (_controller?.value.isInitialized ?? false)
            Center(child: CameraPreview(_controller!)),
          SafeArea(
            child: Column(
              children: [_buildInfoBar(), const Spacer(), _buildControls()],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildInfoBar() {
    final addressText =
        _addresses.isNotEmpty ? _addresses.join('\n') : 'No network';

    return Container(
      margin: const EdgeInsets.all(16),
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
      decoration: BoxDecoration(
        color: Colors.black54,
        borderRadius: BorderRadius.circular(8),
      ),
      child: Row(
        children: [
          Icon(
            Icons.circle,
            color: _server.clientCount > 0 ? Colors.green : Colors.red,
            size: 12,
          ),
          const SizedBox(width: 10),
          Expanded(
            child: Text(addressText, style: const TextStyle(fontSize: 13)),
          ),
          Text('${_server.clientCount} viewers  $_fps fps'),
        ],
      ),
    );
  }

  Widget _buildControls() {
    return Padding(
      padding: const EdgeInsets.all(24),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: [
          IconButton.filled(
            onPressed: () => Navigator.pop(context),
            icon: const Icon(Icons.arrow_back),
            iconSize: 28,
          ),
          if (_cameras.length > 1)
            IconButton.filled(
              onPressed: _switchCamera,
              icon: const Icon(Icons.flip_camera_android),
              iconSize: 28,
            ),
          IconButton.filled(
            onPressed: _toggleFlash,
            icon: Icon(_flashOn ? Icons.flash_on : Icons.flash_off),
            iconSize: 28,
          ),
        ],
      ),
    );
  }
}