using Emgu.CV;
using System.Collections.ObjectModel;
using System.IO;
using System.Windows.Media.Imaging;
using Res = XP.Camera.Calibration.Resources.CalibrationResources;

namespace XP.Camera.Calibration.ViewModels;

public class ChessboardCalibrationViewModel : BindableBase
{
    private readonly ICalibrationDialogService _dialogService;
    private readonly ChessboardCalibrator _calibrator = new();
    private readonly ObservableCollection<string> _imagePaths = new();

    private BitmapSource? _imageSource;
    private string _statusText = Res.ChessboardStatusReady;
    private int _chessboardWidth = 11;
    private int _chessboardHeight = 8;
    private float _squareSize = 15;
    private int _selectedImageIndex = -1;
    private bool _isCalibrating = false;
    private double _progressValue = 0;
    private string _progressText = "";

    public ChessboardCalibrationViewModel(ICalibrationDialogService dialogService)
    {
        _dialogService = dialogService;
        ImageFileNames = new ObservableCollection<string>();

        AddImagesCommand = new DelegateCommand(AddImages);
        ClearImagesCommand = new DelegateCommand(ClearImages, CanClearImages)
            .ObservesProperty(() => ImageFileNames.Count);
        CalibrateCommand = new DelegateCommand(async () => await CalibrateAsync(), CanCalibrate)
            .ObservesProperty(() => ImageFileNames.Count)
            .ObservesProperty(() => IsCalibrating);
        SaveCalibrationCommand = new DelegateCommand(SaveCalibration);
        LoadCalibrationCommand = new DelegateCommand(LoadCalibration);
        UndistortImageCommand = new DelegateCommand(UndistortImage);

        _calibrator.ProgressChanged += OnCalibrationProgressChanged;
    }

    public ObservableCollection<string> ImageFileNames { get; }
    public BitmapSource? ImageSource { get => _imageSource; set => SetProperty(ref _imageSource, value); }
    public string StatusText { get => _statusText; set => SetProperty(ref _statusText, value); }
    public int ChessboardWidth { get => _chessboardWidth; set => SetProperty(ref _chessboardWidth, value); }
    public int ChessboardHeight { get => _chessboardHeight; set => SetProperty(ref _chessboardHeight, value); }
    public float SquareSize { get => _squareSize; set => SetProperty(ref _squareSize, value); }

    public int SelectedImageIndex
    {
        get => _selectedImageIndex;
        set { if (SetProperty(ref _selectedImageIndex, value) && value >= 0) LoadSelectedImage(value); }
    }

    public bool IsCalibrating { get => _isCalibrating; set => SetProperty(ref _isCalibrating, value); }
    public double ProgressValue { get => _progressValue; set => SetProperty(ref _progressValue, value); }
    public string ProgressText { get => _progressText; set => SetProperty(ref _progressText, value); }

    public DelegateCommand AddImagesCommand { get; }
    public DelegateCommand ClearImagesCommand { get; }
    public DelegateCommand CalibrateCommand { get; }
    public DelegateCommand SaveCalibrationCommand { get; }
    public DelegateCommand LoadCalibrationCommand { get; }
    public DelegateCommand UndistortImageCommand { get; }

    private void AddImages()
    {
        var fileNames = _dialogService.ShowOpenMultipleFilesDialog("图像文件|*.jpg;*.png;*.bmp;*.tif");
        if (fileNames == null) return;
        foreach (var file in fileNames)
        {
            _imagePaths.Add(file);
            ImageFileNames.Add(Path.GetFileName(file));
        }
        StatusText = string.Format(Res.ChessboardStatusAdded, _imagePaths.Count);
    }

    private bool CanClearImages() => ImageFileNames.Count > 0;

    private void ClearImages()
    {
        _imagePaths.Clear();
        ImageFileNames.Clear();
        ImageSource = null;
        StatusText = Res.ChessboardStatusCleared;
        RaiseEvent(ImageClearedRequested);
    }

    private bool CanCalibrate() => ImageFileNames.Count >= 3 && !IsCalibrating;

    private void OnCalibrationProgressChanged(int current, int total, string message)
    {
        System.Windows.Application.Current.Dispatcher.Invoke(() =>
        {
            ProgressValue = (double)current / total * 100;
            if (message.Contains("检测角点"))
            {
                var match = System.Text.RegularExpressions.Regex.Match(message, @"\((\d+)/(\d+)\)");
                ProgressText = match.Success
                    ? string.Format(Res.ChessboardProgressDetecting, match.Groups[1].Value, match.Groups[2].Value)
                    : message;
            }
            else if (message.Contains("执行相机标定"))
                ProgressText = Res.ChessboardProgressCalibrating;
            else if (message.Contains("计算重投影误差"))
            {
                var match = System.Text.RegularExpressions.Regex.Match(message, @"\((\d+)/(\d+)\)");
                ProgressText = match.Success
                    ? string.Format(Res.ChessboardProgressCalculating, match.Groups[1].Value, match.Groups[2].Value)
                    : message;
            }
            else if (message.Contains("标定完成"))
                ProgressText = Res.ChessboardProgressComplete;
            else if (message.Contains("标定失败"))
                ProgressText = Res.ChessboardProgressFailed;
            else
                ProgressText = message;
        });
    }

    private async System.Threading.Tasks.Task CalibrateAsync()
    {
        if (_imagePaths.Count < 3)
        {
            _dialogService.ShowError(Res.ChessboardErrorMinImages, Res.ChessboardCalibrationComplete);
            return;
        }

        IsCalibrating = true;
        ProgressValue = 0;
        ProgressText = Res.ChessboardProgressPreparing;
        StatusText = Res.ChessboardStatusCalibrating;

        try
        {
            await System.Threading.Tasks.Task.Run(() =>
            {
                if (_calibrator.CalibrateFromImages(new List<string>(_imagePaths), ChessboardWidth, ChessboardHeight, SquareSize, out string error))
                {
                    System.Windows.Application.Current.Dispatcher.Invoke(() =>
                    {
                        var imageErrors = new System.Text.StringBuilder();
                        for (int i = 0; i < _calibrator.PerImageErrors.Count; i++)
                            imageErrors.AppendLine(string.Format(Res.ChessboardImageError, i + 1, _calibrator.PerImageErrors[i]));
                        StatusText = string.Format(Res.ChessboardStatusSuccess, _calibrator.ReprojectionError, imageErrors.ToString());
                        _dialogService.ShowInfo(Res.ChessboardCalibrationComplete, Res.ChessboardSaveSuccess);
                    });
                }
                else
                {
                    System.Windows.Application.Current.Dispatcher.Invoke(() =>
                    {
                        StatusText = string.Format(Res.ChessboardStatusFailed, error);
                        _dialogService.ShowError(error, Res.ChessboardCalibrationComplete);
                    });
                }
            });
        }
        finally
        {
            IsCalibrating = false;
            ProgressValue = 0;
        }
    }

    private void SaveCalibration()
    {
        var fileName = _dialogService.ShowSaveFileDialog("标定文件|*.json", "camera_calibration.json");
        if (fileName == null) return;
        try
        {
            _calibrator.SaveCalibration(fileName);
            StatusText = string.Format(Res.ChessboardStatusSaved, fileName);
            _dialogService.ShowInfo(Res.ChessboardSaveSuccess, Res.ChessboardCalibrationComplete);
        }
        catch (Exception ex)
        {
            _dialogService.ShowError($"保存失败: {ex.Message}", Res.ChessboardCalibrationComplete);
        }
    }

    private void LoadCalibration()
    {
        var fileName = _dialogService.ShowOpenFileDialog("标定文件|*.json");
        if (fileName == null) return;
        if (_calibrator.LoadCalibration(fileName))
        {
            StatusText = string.Format(Res.ChessboardStatusLoaded, fileName);
            _dialogService.ShowInfo(Res.ChessboardLoadSuccess, Res.ChessboardCalibrationComplete);
        }
        else
        {
            _dialogService.ShowError(Res.CalibrationLoadFailed, Res.ChessboardCalibrationComplete);
        }
    }

    private void UndistortImage()
    {
        var fileName = _dialogService.ShowOpenFileDialog("图像文件|*.jpg;*.png;*.bmp;*.tif");
        if (fileName == null) return;
        using var image = CvInvoke.Imread(fileName);
        var undistorted = _calibrator.UndistortImage(image);
        ImageSource = MatToBitmapSource(undistorted);
        StatusText = string.Format(Res.ChessboardStatusUndistorted, Path.GetFileName(fileName));
        RaiseEvent(ImageLoadedRequested);
    }

    private void LoadSelectedImage(int index)
    {
        if (index < 0 || index >= _imagePaths.Count) return;
        var img = _calibrator.DrawChessboardCorners(_imagePaths[index], ChessboardWidth, ChessboardHeight);
        if (img != null)
        {
            ImageSource = MatToBitmapSource(img);
            RaiseEvent(ImageLoadedRequested);
        }
        if (_calibrator.PerImageErrors.Count > index)
            StatusText = string.Format(Res.ChessboardStatusImageError, index + 1, _calibrator.PerImageErrors[index]);
    }

    public event EventHandler? ImageLoadedRequested;
    public event EventHandler? ImageClearedRequested;

    private void RaiseEvent(EventHandler? handler) => handler?.Invoke(this, EventArgs.Empty);

    private static BitmapSource MatToBitmapSource(Mat mat)
    {
        using var bitmap = mat.ToBitmap();
        var hBitmap = bitmap.GetHbitmap();
        try
        {
            return System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                hBitmap, IntPtr.Zero, System.Windows.Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
        }
        finally
        {
            DeleteObject(hBitmap);
        }
    }

    [System.Runtime.InteropServices.DllImport("gdi32.dll")]
    private static extern bool DeleteObject(IntPtr hObject);
}