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

namespace XP.Camera.Calibration.ViewModels;

public class CalibrationViewModel : BindableBase
{
    private readonly ICalibrationDialogService _dialogService;
    private readonly CalibrationProcessor _calibrator = new();
    private Image<Bgr, byte>? _currentImage;
    private static readonly ILogger _logger = Log.ForContext<CalibrationViewModel>();
    private BitmapSource? _imageSource;
    private string _statusText = Res.CalibrationStatusReady;
    private bool _showWorldCoordinates;

    public CalibrationViewModel(ICalibrationDialogService dialogService)
    {
        _dialogService = dialogService;
        CalibrationPoints = new ObservableCollection<CalibrationProcessor.CalibrationPoint>();

        LoadImageCommand = new DelegateCommand(LoadImage);
        LoadCsvCommand = new DelegateCommand(LoadCsv);
        CalibrateCommand = new DelegateCommand(Calibrate, CanCalibrate)
            .ObservesProperty(() => CalibrationPoints.Count);
        SaveCalibrationCommand = new DelegateCommand(SaveCalibration);
        LoadCalibrationCommand = new DelegateCommand(LoadCalibration);
    }

    public ObservableCollection<CalibrationProcessor.CalibrationPoint> CalibrationPoints { get; }

    public BitmapSource? ImageSource
    {
        get => _imageSource;
        set => SetProperty(ref _imageSource, value);
    }

    public string StatusText
    {
        get => _statusText;
        set => SetProperty(ref _statusText, value);
    }

    public bool ShowWorldCoordinates
    {
        get => _showWorldCoordinates;
        set => SetProperty(ref _showWorldCoordinates, value);
    }

    public DelegateCommand LoadImageCommand { get; }
    public DelegateCommand LoadCsvCommand { get; }
    public DelegateCommand CalibrateCommand { get; }
    public DelegateCommand SaveCalibrationCommand { get; }
    public DelegateCommand LoadCalibrationCommand { get; }

    private void LoadImage()
    {
        _logger.Information("Loading image file");
        var fileName = _dialogService.ShowOpenFileDialog("图像文件|*.jpg;*.png;*.bmp;*.tif");
        if (fileName == null) return;

        _currentImage = new Image<Bgr, byte>(fileName);
        ImageSource = MatToBitmapSource(_currentImage.Mat);
        StatusText = string.Format(Res.CalibrationStatusImageLoaded, fileName);
        RaiseEvent(ImageLoadedRequested);
    }

    private void LoadCsv()
    {
        var fileName = _dialogService.ShowOpenFileDialog("CSV文件|*.csv|所有文件|*.*");
        if (fileName == null) return;

        var points = _calibrator.LoadPointsFromCsv(fileName);
        CalibrationPoints.Clear();
        foreach (var pt in points)
            CalibrationPoints.Add(pt);

        StatusText = string.Format(Res.CalibrationStatusCsvLoaded, CalibrationPoints.Count, fileName);
    }

    private bool CanCalibrate() => CalibrationPoints.Count >= 4;

    private void Calibrate()
    {
        if (CalibrationPoints.Count < 4)
        {
            _dialogService.ShowError(Res.CalibrationErrorMinPoints, Res.CalibrationSuccessTitle);
            return;
        }

        if (_calibrator.Calibrate(new List<CalibrationProcessor.CalibrationPoint>(CalibrationPoints)))
        {
            StatusText = string.Format(Res.CalibrationStatusSuccess, CalibrationPoints.Count);
            _dialogService.ShowInfo(Res.CalibrationSuccessMessage, Res.CalibrationSuccessTitle);
        }
        else
        {
            StatusText = Res.CalibrationStatusFailed;
            _dialogService.ShowError(Res.CalibrationStatusFailed, Res.CalibrationSuccessTitle);
        }
    }

    private void SaveCalibration()
    {
        var fileName = _dialogService.ShowSaveFileDialog("标定文件|*.json", "calibration.json");
        if (fileName == null) return;

        _calibrator.SaveCalibration(fileName, new List<CalibrationProcessor.CalibrationPoint>(CalibrationPoints));
        StatusText = string.Format(Res.CalibrationStatusSaved, fileName);
        _dialogService.ShowInfo(Res.CalibrationSaveSuccess, Res.CalibrationSuccessTitle);
    }

    private void LoadCalibration()
    {
        var fileName = _dialogService.ShowOpenFileDialog("标定文件|*.json");
        if (fileName == null) return;

        if (_calibrator.LoadCalibration(fileName))
        {
            StatusText = string.Format(Res.CalibrationStatusLoaded, fileName);
            _dialogService.ShowInfo(Res.CalibrationLoadSuccess, Res.CalibrationSuccessTitle);
        }
        else
        {
            _dialogService.ShowError(Res.CalibrationLoadFailed, Res.CalibrationSuccessTitle);
        }
    }

    public PointF ConvertPixelToWorld(PointF pixel) => _calibrator.PixelToWorld(pixel);

    public Image<Bgr, byte>? CurrentImage => _currentImage;

    public event EventHandler? ImageLoadedRequested;

    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);
}