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

import 'package:camera_linux/camera_linux.dart';
import 'package:camera_macos/camera_macos_arguments.dart';
import 'package:camera_macos/camera_macos_device.dart';
import 'package:camera_macos/camera_macos_platform_interface.dart';
import 'package:camera_platform_interface/camera_platform_interface.dart';
import 'package:camera_windows/camera_windows.dart';
import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:image/image.dart' as img;
import 'package:zxing2/qrcode.dart';

import '../../notifications/show_flush_bar.dart';
import '../../utilities/assets.dart';
import '../../utilities/logger.dart';
import '../../utilities/text_styles.dart';
import 'desktop_dialog.dart';
import 'desktop_dialog_close_button.dart';
import 'primary_button.dart';
import 'secondary_button.dart';

class QrCodeScannerDialog extends StatefulWidget {
  final Function(String) onQrCodeDetected;

  QrCodeScannerDialog({
    required this.onQrCodeDetected,
  });

  @override
  _QrCodeScannerDialogState createState() => _QrCodeScannerDialogState();
}

class _QrCodeScannerDialogState extends State<QrCodeScannerDialog> {
  final CameraLinux? _cameraLinuxPlugin =
      Platform.isLinux ? CameraLinux() : null;
  final CameraWindows? _cameraWindowsPlugin =
      Platform.isWindows ? CameraWindows() : null;
  bool _isCameraOpen = false;
  Image? _image;
  bool _isScanning = false;
  int _cameraId = -1;
  String? _macOSDeviceId;
  final int _imageDelayInMs = 250;

  @override
  void initState() {
    super.initState();
    _isCameraOpen = false;
    _isScanning = false;
    _initializeCamera();
  }

  @override
  void dispose() {
    _stopCamera();
    super.dispose();
  }

  Future<void> _initializeCamera() async {
    try {
      setState(() {
        _isScanning = true; // Show the progress indicator
      });

      if (Platform.isLinux && _cameraLinuxPlugin != null) {
        await _cameraLinuxPlugin!.initializeCamera();
        Logging.instance.log("Linux Camera initialized", level: LogLevel.Info);
      } else if (Platform.isWindows && _cameraWindowsPlugin != null) {
        final List<CameraDescription> cameras =
            await _cameraWindowsPlugin!.availableCameras();
        if (cameras.isEmpty) {
          throw CameraException('No cameras available', 'No cameras found.');
        }
        final CameraDescription camera = cameras[0]; // Could be user-selected.
        _cameraId = await _cameraWindowsPlugin!.createCameraWithSettings(
          camera,
          const MediaSettings(
            resolutionPreset: ResolutionPreset.low,
            fps: 4,
            videoBitrate: 200000,
            enableAudio: false,
          ),
        );
        await _cameraWindowsPlugin!.initializeCamera(_cameraId);
        // await _cameraWindowsPlugin!.onCameraInitialized(_cameraId).first;
        // TODO [prio=low]: Make this work. ^^^
        Logging.instance.log("Windows Camera initialized with ID: $_cameraId",
            level: LogLevel.Info);
      } else if (Platform.isMacOS) {
        final List<CameraMacOSDevice> videoDevices = await CameraMacOS.instance
            .listDevices(deviceType: CameraMacOSDeviceType.video);
        if (videoDevices.isEmpty) {
          throw Exception('No cameras available');
        }
        _macOSDeviceId = videoDevices.first.deviceId;
        await CameraMacOS.instance
            .initialize(cameraMacOSMode: CameraMacOSMode.photo);

        setState(() {
          _isCameraOpen = true;
        });

        Logging.instance.log(
            "macOS Camera initialized with ID: $_macOSDeviceId",
            level: LogLevel.Info);
      }
      if (mounted) {
        setState(() {
          _isCameraOpen = true;
          _isScanning = true;
        });
      }
      unawaited(_captureAndScanImage()); // Could be awaited.
    } catch (e, s) {
      Logging.instance
          .log("Failed to initialize camera: $e\n$s", level: LogLevel.Error);
      if (mounted) {
        // widget.onSnackbar("Failed to initialize camera. Please try again.");
        setState(() {
          _isScanning = false;
        });
      }
    }
  }

  Future<void> _stopCamera() async {
    try {
      if (Platform.isLinux && _cameraLinuxPlugin != null) {
        _cameraLinuxPlugin!.stopCamera();
        Logging.instance.log("Linux Camera stopped", level: LogLevel.Info);
      } else if (Platform.isWindows && _cameraWindowsPlugin != null) {
        // if (_cameraId >= 0) {
        await _cameraWindowsPlugin!.dispose(_cameraId);
        Logging.instance.log("Windows Camera stopped with ID: $_cameraId",
            level: LogLevel.Info);
        // } else {
        //   Logging.instance.log("Windows Camera ID is null. Cannot dispose.",
        //       level: LogLevel.Error);
        // }
      } else if (Platform.isMacOS) {
        // if (_macOSDeviceId != null) {
        await CameraMacOS.instance.stopImageStream();
        Logging.instance.log("macOS Camera stopped with ID: $_macOSDeviceId",
            level: LogLevel.Info);
        // } else {
        //   Logging.instance.log("macOS Camera ID is null. Cannot stop.",
        //       level: LogLevel.Error);
        // }
      }
    } catch (e, s) {
      Logging.instance
          .log("Failed to stop camera: $e\n$s", level: LogLevel.Error);
    } finally {
      if (mounted) {
        setState(() {
          _isScanning = false;
          _isCameraOpen = false;
        });
      }
    }
  }

  Future<void> _captureAndScanImage() async {
    while (_isCameraOpen && _isScanning) {
      try {
        String? base64Image;
        if (Platform.isLinux && _cameraLinuxPlugin != null) {
          base64Image = await _cameraLinuxPlugin!.captureImage();
        } else if (Platform.isWindows) {
          final XFile xfile =
              await _cameraWindowsPlugin!.takePicture(_cameraId);
          final bytes = await xfile.readAsBytes();
          base64Image = base64Encode(bytes);
          // We could use a Uint8List to optimize for Windows and macOS.
        } else if (Platform.isMacOS) {
          final macOSimg = await CameraMacOS.instance.takePicture();
          if (macOSimg == null) {
            Logging.instance
                .log("Failed to capture image", level: LogLevel.Error);
            await Future.delayed(Duration(milliseconds: _imageDelayInMs));
            continue;
          }
          final img.Image? image = img.decodeImage(macOSimg.bytes!);
          if (image == null) {
            Logging.instance
                .log("Failed to capture image", level: LogLevel.Error);
            await Future.delayed(Duration(milliseconds: _imageDelayInMs));
            continue;
          }
          base64Image = base64Encode(img.encodePng(image));
        }
        if (base64Image == null || base64Image.isEmpty) {
          // Logging.instance
          //     .log("Failed to capture image", level: LogLevel.Error);
          // Spammy.
          await Future.delayed(Duration(milliseconds: _imageDelayInMs));
          continue;
        }
        final img.Image? image = img.decodeImage(base64Decode(base64Image));
        // TODO [prio=low]: Optimize this process. Docs say:
        // > WARNING Since this will check the image data against all known
        // > decoders, it is much slower than using an explicit decoder
        if (image == null) {
          Logging.instance.log("Failed to decode image", level: LogLevel.Error);
          await Future.delayed(Duration(milliseconds: _imageDelayInMs));
          continue;
        }

        if (mounted) {
          setState(() {
            _image = Image.memory(
              base64Decode(base64Image!),
              fit: BoxFit.cover,
            );
          });
        }

        final String? scanResult = await _scanImage(image);
        if (scanResult != null && scanResult.isNotEmpty) {
          widget.onQrCodeDetected(scanResult);
          if (mounted) {
            Navigator.of(context).pop();
          }
          break;
        } else {
          // Logging.instance.log("No QR code found in the image", level: LogLevel.Info);
          // if (mounted) {
          //   widget.onSnackbar("No QR code found in the image.");
          // }
          // Spammy.
        }

        await Future.delayed(Duration(milliseconds: _imageDelayInMs));
      } catch (e, s) {
        // Logging.instance.log("Failed to capture and scan image: $e\n$s", level: LogLevel.Error);
        // Spammy.

        // if (mounted) {
        //   widget.onSnackbar(
        //       "Error capturing or scanning the image. Please try again.");
        // }
      }
    }
  }

  Future<String?> _scanImage(img.Image image) async {
    try {
      final LuminanceSource source = RGBLuminanceSource(
        image.width,
        image.height,
        image
            .convert(numChannels: 4)
            .getBytes(order: img.ChannelOrder.abgr)
            .buffer
            .asInt32List(),
      );
      final BinaryBitmap bitmap =
          BinaryBitmap(GlobalHistogramBinarizer(source));

      final QRCodeReader reader = QRCodeReader();
      final qrDecode = reader.decode(bitmap);
      if (qrDecode.text.isEmpty) {
        return null;
      }
      return qrDecode.text;
    } catch (e, s) {
      // Logging.instance.log("Failed to decode QR code: $e\n$s", level: LogLevel.Error);
      // Spammy.
      return null;
    }
  }

  @override
  Widget build(BuildContext context) {
    return DesktopDialog(
      maxWidth: 696,
      maxHeight: 600,
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Padding(
                padding: const EdgeInsets.only(left: 32),
                child: Text(
                  "Scan QR code",
                  style: STextStyles.desktopH3(context),
                ),
              ),
              const DesktopDialogCloseButton(),
            ],
          ),
          Expanded(
            child: _isCameraOpen
                ? _image != null
                    ? _image!
                    : const Center(
                        child: CircularProgressIndicator(),
                      )
                : const Center(
                    child:
                        CircularProgressIndicator(), // Show progress indicator immediately
                  ),
          ),
          Padding(
            padding: const EdgeInsets.all(16),
            child: Row(
              children: [
                Expanded(child: Container()),
                // "Select file" button.
                SecondaryButton(
                  buttonHeight: ButtonHeight.l,
                  label: "Select file",
                  width: 200,
                  onPressed: () async {
                    final result = await FilePicker.platform.pickFiles(
                      type: FileType.custom,
                      allowedExtensions: ["png", "jpg", "jpeg"],
                    );

                    if (result == null || result.files.single.path == null) {
                      await showFloatingFlushBar(
                        type: FlushBarType.info,
                        message: "No file selected",
                        iconAsset: Assets.svg.file,
                        context: context,
                      );
                      return;
                    }

                    final filePath = result?.files.single.path!;
                    if (filePath == null) {
                      await showFloatingFlushBar(
                        type: FlushBarType.info,
                        message: "Error selecting file.",
                        iconAsset: Assets.svg.file,
                        context: context,
                      );
                      return;
                    }
                    try {
                      final img.Image? image =
                          img.decodeImage(File(filePath!).readAsBytesSync());
                      if (image == null) {
                        await showFloatingFlushBar(
                          type: FlushBarType.info,
                          message: "Failed to decode image.",
                          iconAsset: Assets.svg.file,
                          context: context,
                        );
                        return;
                      }

                      final String? scanResult = await _scanImage(image);
                      if (scanResult != null && scanResult.isNotEmpty) {
                        widget.onQrCodeDetected(scanResult);
                        Navigator.of(context).pop();
                      } else {
                        await showFloatingFlushBar(
                          type: FlushBarType.info,
                          message: "No QR code found in the image.",
                          iconAsset: Assets.svg.file,
                          context: context,
                        );
                      }
                    } catch (e, s) {
                      Logging.instance.log("Failed to decode image: $e\n$s",
                          level: LogLevel.Error);
                      await showFloatingFlushBar(
                        type: FlushBarType.info,
                        message:
                            "Error processing the image. Please try again.",
                        iconAsset: Assets.svg.file,
                        context: context,
                      );
                    }
                  },
                ),
                const SizedBox(width: 16),
                // Close button.
                PrimaryButton(
                  buttonHeight: ButtonHeight.l,
                  label: "Close",
                  width: 272.5,
                  onPressed: () {
                    _stopCamera();
                    Navigator.of(context).pop();
                  },
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}