import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'dart:async';
import 'media_preview_screen.dart';

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

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

enum FlashModeType { off, autoCapture, alwaysCapture, torch }

class _CameraScreenState extends State<CameraScreen> {
  CameraController? _controller;
  List<CameraDescription> _cameras = [];

  int _cameraIndex = 0;
  bool _isRecording = false;

  FlashModeType _flashMode = FlashModeType.off;
  double _minZoom = 1.0;
  double _maxZoom = 1.0;
  double _currentZoom = 1.0;

  bool _showZoomSlider = false;

  Future<void>? _initFuture;

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

  Future<void> _init() async {
    _cameras = await availableCameras();
    await _initCamera();
  }

  Future<void> _initCamera() async {
    final camera = _cameras[_cameraIndex];

    final controller = CameraController(
      camera,
      ResolutionPreset.high,
      enableAudio: true,
    );

    await controller.initialize();
    _minZoom = await controller.getMinZoomLevel();
    _maxZoom = await controller.getMaxZoomLevel();
    _currentZoom = _minZoom;
    if (!mounted) return;

    setState(() {
      _controller = controller;
    });
  }

  Future<void> _switchCamera() async {
    if (_cameras.length < 2) return;

    await _controller?.dispose();

    _cameraIndex = (_cameraIndex + 1) % _cameras.length;

    setState(() => _controller = null);
    await _initCamera();
  }

  Future<void> _cycleFlashMode() async {
    if (_controller == null) return;

    switch (_flashMode) {
      case FlashModeType.off:
        _flashMode = FlashModeType.autoCapture;
        await _controller!.setFlashMode(FlashMode.off);
        break;

      case FlashModeType.autoCapture:
        _flashMode = FlashModeType.alwaysCapture;
        await _controller!.setFlashMode(FlashMode.off);
        break;

      case FlashModeType.alwaysCapture:
        _flashMode = FlashModeType.torch;
        await _controller!.setFlashMode(FlashMode.torch);
        break;

      case FlashModeType.torch:
        _flashMode = FlashModeType.off;
        await _controller!.setFlashMode(FlashMode.off);
        break;
    }

    setState(() {});
  }

  Future<void> _takePhoto() async {
    if (_controller == null) return;

    bool usedTorch = false;

    if (_flashMode == FlashModeType.alwaysCapture) {
      await _controller!.setFlashMode(FlashMode.torch);
      usedTorch = true;
      await Future.delayed(const Duration(milliseconds: 120));
    }

    if (_flashMode == FlashModeType.autoCapture) {
      await _controller!.setFlashMode(FlashMode.torch);
      usedTorch = true;
      await Future.delayed(const Duration(milliseconds: 120));
    }

    final file = await _controller!.takePicture();

    if (usedTorch) {
      await _controller!.setFlashMode(FlashMode.off);
    }
    WidgetsBinding.instance.addPostFrameCallback((_) async {
      final result = await Navigator.push(
        context,
        MaterialPageRoute(
          builder: (_) => MediaPreviewScreen(path: file.path, isVideo: false),
        ),
      );

      if (result == true && mounted) {
        Navigator.pop(context, (file, 'image'));
      }
    });
  }

  bool usedTorch = false;
  Future<void> _startVideo() async {
    if (_controller == null || _isRecording) return;
    if (_flashMode == FlashModeType.alwaysCapture) {
      await _controller!.setFlashMode(FlashMode.torch);
      usedTorch = true;
      await Future.delayed(const Duration(milliseconds: 120));
    }

    if (_flashMode == FlashModeType.autoCapture) {
      await _controller!.setFlashMode(FlashMode.torch);
      usedTorch = true;
      await Future.delayed(const Duration(milliseconds: 120));
    }

    await _controller!.startVideoRecording();

    setState(() => _isRecording = true);
  }

  Future<void> _stopVideo() async {
    if (_controller == null || !_isRecording) return;
    if (usedTorch) {
      await _controller!.setFlashMode(FlashMode.off);
    }

    final file = await _controller!.stopVideoRecording();

    setState(() => _isRecording = false);

    final result = await Navigator.push(
      context,
      MaterialPageRoute(
        builder: (_) => MediaPreviewScreen(path: file.path, isVideo: true),
      ),
    );

    if (result == true && mounted) {
      Navigator.pop(context, (file, 'video'));
    }
  }

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

    final clamped = zoom.clamp(_minZoom, _maxZoom);

    await _controller!.setZoomLevel(clamped);

    setState(() {
      _currentZoom = clamped;
    });
  }

  @override
  void dispose() {
    _controller?.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      body: FutureBuilder(
        future: _initFuture,
        builder: (context, snapshot) {
          if (_controller == null || !_controller!.value.isInitialized) {
            return const Center(child: CircularProgressIndicator());
          }

          return Stack(
            children: [
              // 📷 Camera preview (full screen, Telegram style crop)
              Positioned.fill(
                child: FittedBox(
                  fit: BoxFit.cover,
                  child: SizedBox(
                    width: _controller!.value.previewSize!.height,
                    height: _controller!.value.previewSize!.width,
                    child: GestureDetector(
                      onScaleStart: (_) {
                        setState(() {
                          _showZoomSlider = true;
                        });
                      },

                      onScaleUpdate: (details) {
                        final zoom = (_currentZoom * details.scale).clamp(
                          _minZoom,
                          _maxZoom,
                        );

                        _setZoom(zoom);
                      },
                      child: CameraPreview(_controller!),
                    ),
                  ),
                ),
              ),

              // 🌑 top gradient (Telegram feel)
              Positioned(
                top: 0,
                left: 0,
                right: 0,
                height: 120,
                child: Container(
                  decoration: const BoxDecoration(
                    gradient: LinearGradient(
                      begin: Alignment.topCenter,
                      end: Alignment.bottomCenter,
                      colors: [Colors.black87, Colors.transparent],
                    ),
                  ),
                ),
              ),

              // 🔘 top controls
              Positioned(
                top: 50,
                left: 20,
                right: 20,
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    // Flash (left)
                    IconButton(
                      onPressed: _cycleFlashMode,
                      icon: Icon(switch (_flashMode) {
                        FlashModeType.off => Icons.flash_off,
                        FlashModeType.autoCapture => Icons.flash_auto,
                        FlashModeType.alwaysCapture => Icons.flash_on,
                        FlashModeType.torch => Icons.highlight,
                      }, color: Colors.white),
                    ),

                    // Camera switch (right)
                    IconButton(
                      onPressed: _switchCamera,
                      icon: const Icon(Icons.cameraswitch, color: Colors.white),
                    ),
                  ],
                ),
              ),

              // 🔘 capture button (center bottom)
              Positioned(
                bottom: 90,
                left: 0,
                right: 0,
                child: Column(
                  children: [
                    GestureDetector(
                      onTap: _takePhoto,
                      onLongPressStart: (_) => _startVideo(),
                      onLongPressEnd: (_) => _stopVideo(),
                      child: AnimatedContainer(
                        duration: const Duration(milliseconds: 150),
                        width: _isRecording ? 80 : 72,
                        height: _isRecording ? 80 : 72,
                        decoration: BoxDecoration(
                          shape: BoxShape.circle,
                          color: _isRecording ? Colors.red : Colors.white,
                          border: Border.all(color: Colors.white, width: 4),
                        ),
                      ),
                    ),

                    const SizedBox(height: 16),

                    const Text(
                      "Нажмите для фото, удерживайте для съемки",
                      style: TextStyle(color: Colors.white70, fontSize: 13),
                    ),
                  ],
                ),
              ),

              // 🔴 recording indicator
              if (_isRecording)
                const Positioned(
                  top: 50,
                  left: 0,
                  right: 0,
                  child: Center(
                    child: Text(
                      "REC",
                      style: TextStyle(
                        color: Colors.red,
                        fontWeight: FontWeight.bold,
                        fontSize: 14,
                      ),
                    ),
                  ),
                ),
              if (_showZoomSlider)
                Positioned(
                  bottom: 200,
                  left: 20,
                  right: 20,
                  child: Center(
                    child: Container(
                      child: Row(
                        children: [
                          GestureDetector(
                            onTap: () {
                              final newZoom = (_currentZoom - 0.5).clamp(
                                _minZoom,
                                _maxZoom,
                              );
                              _setZoom(newZoom);
                            },
                            child: const Text(
                              '−',
                              style: TextStyle(
                                color: Colors.white,
                                fontSize: 18,
                              ),
                            ),
                          ),

                          const SizedBox(width: 8),

                          Expanded(
                            child: SliderTheme(
                              data: SliderTheme.of(context).copyWith(
                                trackHeight: 2,
                                activeTrackColor: Colors.white,
                                inactiveTrackColor: Colors.white24,
                                thumbColor: Colors.white,
                                overlayColor: Colors.white24,
                                thumbShape: const RoundSliderThumbShape(
                                  enabledThumbRadius: 6,
                                ),
                              ),
                              child: Slider(
                                value: _currentZoom,
                                min: _minZoom,
                                max: _maxZoom,
                                onChanged: (value) {
                                  _setZoom(value);
                                },
                              ),
                            ),
                          ),

                          const SizedBox(width: 8),
                          GestureDetector(
                            onTap: () {
                              final newZoom = (_currentZoom + 0.5).clamp(
                                _minZoom,
                                _maxZoom,
                              );
                              _setZoom(newZoom);
                            },
                            child: const Text(
                              '+',
                              style: TextStyle(
                                color: Colors.white,
                                fontSize: 18,
                              ),
                            ),
                          ),
                        ],
                      ),
                    ),
                  ),
                ),
            ],
          );
        },
      ),
    );
  }
}