presence_new/Presence.Desktop/ViewModels/PresenceViewModel.cs

using Avalonia.Data.Converters;
using presence.data.RemoteData.RemoteDataBase.DAO;
using presence.domain.Models;
using presence.domain.UseCase;
using Presence.Desktop.Models;
using Presence.Desktop.ViewModels;
using ReactiveUI;
using System;
using System.Collections.ObjectModel;
using System.Globalization;
using System.Reactive;

namespace Presence.Desktop.ViewModels
{
    public class PresenceViewModel : ViewModelBase, IRoutableViewModel
    {
        public string? UrlPathSegment { get; } = "Presence";
        public IScreen HostScreen { get; }

        private readonly GroupUseCase _groupUseCase;
        private readonly PresenceUseCase _presenceUseCase;

        public ObservableCollection<PresencePresenter> AttendanceRecords { get; set; } = new();
        public ObservableCollection<GroupPresenter> Groups { get; set; } = new();

        private GroupPresenter? _selectedGroup;
        public GroupPresenter? SelectedGroup
        {
            get => _selectedGroup;
            set
            {
                this.RaiseAndSetIfChanged(ref _selectedGroup, value);
                FilterAttendanceRecords();
            }
        }

        private DateTime? _selectedDate;
        public DateTime? SelectedDate
        {
            get => _selectedDate;
            set
            {
                this.RaiseAndSetIfChanged(ref _selectedDate, value);
                FilterAttendanceRecords();
            }
        }

        public ReactiveCommand<Unit, Unit> NavigateBackCommand { get; }

        public PresenceViewModel(GroupUseCase groupUseCase, PresenceUseCase presenceUseCase)
        {
            _groupUseCase = groupUseCase;

            _presenceUseCase = presenceUseCase;


            NavigateBackCommand = ReactiveCommand.Create(() => { });

            this.WhenAnyValue(vm => vm.SelectedGroup)
                .Subscribe(_ => 
                {
                    LoadGroups();
                });
        }

        private void LoadGroups()
        {
            Groups.Clear();
            var groups = _groupUseCase.GetAllGroups();

            foreach (var group in groups)
            {
                Groups.Add(new GroupPresenter
                {
                    Id = group.Id,
                    Name = group.Name
                });
            }
        }

        private void FilterAttendanceRecords()
        {
            if (SelectedGroup == null)
            {
                AttendanceRecords.Clear();
                return;
            }

            var records = _presenceUseCase.GetPresenceByGroupAndDate(
                SelectedGroup.Id,
                DateOnly.FromDateTime(SelectedDate.Value));

            AttendanceRecords.Clear();
            foreach (var record in records)
            {
                AttendanceRecords.Add(new PresencePresenter
                {
                    Id = record.Id, 
                    Date = record.Date,
                    ClassNumber = record.ClassNumber,
                    IsAttendence = record.IsAttendence,
                    User = new UserPresenter
                    {
                        Id = record.User.Id,
                        Name= record.User.FIO
                    }
                });
            }
        }

        
    }
}