MCCAD/MCCAD/ViewModels/DrawingViewModel.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text.Json;
using System.Windows.Input;
using MCCAD.Models;
using ReactiveUI;

namespace MCCAD.ViewModels;

public class DrawingViewModel : ViewModelBase, IRoutableViewModel
{
    private OvalView _ov;
    private PolygonView _pv;
    private LineView _lv;
    private Drawing _inner;

    private static readonly List<IFigureDeserializer> _deserializers =
        [new LineView.Deserializer(), new PolygonView.Deserializer(), new OvalView.Deserializer()];

    public DrawingViewModel(IScreen hostScreen, Drawing drawing)
    {
        HostScreen = hostScreen;
        _inner = drawing;
        LoadFigures();
    }

    private void LoadFigures()
    {
        foreach (var figure in JsonSerializer.Deserialize<List<string>>(_inner.Data))
        foreach (var deserializer in _deserializers)
        {
            if (deserializer.TryDeserialize(figure, out var view))
            {
                Figures.Add(view);
                break;
            }
        }
    }

    public OvalView Ov
    {
        get => _ov;
        set => this.RaiseAndSetIfChanged(ref _ov, value);
    }

    public PolygonView Pv
    {
        get => _pv;
        set => this.RaiseAndSetIfChanged(ref _pv, value);
    }

    public LineView Lv
    {
        get => _lv;
        set => this.RaiseAndSetIfChanged(ref _lv, value);
    }

    public ObservableCollection<IFigureView> Figures { get; set; } = [];
    public string? UrlPathSegment { get; } = Guid.NewGuid().ToString();
    public IScreen HostScreen { get; }

    public ICommand OnSave => ReactiveCommand.Create(() =>
    {
        _inner.Data = JsonSerializer.Serialize(Figures.Select(i => i.Save()));
        _inner.LastChange = DateTime.Now.ToUniversalTime();
        CadDBContext.Instance.SaveChanges();
    });

    public ICommand Back => ReactiveCommand.Create(() => { HostScreen.Router.NavigateBack.Execute(); }
    );
}