using System.Collections.ObjectModel;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using LehrerApp.Desktop.Services;

namespace LehrerApp.Desktop.ViewModels.Groups;

public partial class WebUntisClassSelectionViewModel(WebUntisIntegrationService untis) : ObservableObject
{
    public ObservableCollection<UntisSchoolYearDto> SchoolYears { get; } = [];
    public ObservableCollection<UntisClassDto> Classes { get; } = [];
    [ObservableProperty] private UntisSchoolYearDto? _selectedSchoolYear;
    [ObservableProperty] private UntisClassDto? _selectedClass;
    [ObservableProperty] private string _status = "";
    [ObservableProperty] private bool _busy;
    public bool CanConfirm => SelectedClass is not null && !Busy;

    partial void OnSelectedClassChanged(UntisClassDto? value) => OnPropertyChanged(nameof(CanConfirm));
    partial void OnBusyChanged(bool value) => OnPropertyChanged(nameof(CanConfirm));

    public async Task InitializeAsync()
    {
        Busy = true;
        try
        {
            foreach (var year in (await untis.GetSchoolYearsAsync()).OrderByDescending(x => x.StartDate))
                SchoolYears.Add(year);
            SelectedSchoolYear = SchoolYears.FirstOrDefault(x => x.StartDate <= Today() && x.EndDate >= Today())
                                 ?? SchoolYears.FirstOrDefault();
            await LoadClasses();
        }
        catch (WebUntisIntegrationException ex) { Status = ex.Message; }
        finally { Busy = false; }
    }

    [RelayCommand]
    private async Task LoadClasses()
    {
        if (SelectedSchoolYear is null) return;
        Busy = true; Classes.Clear(); SelectedClass = null;
        try
        {
            foreach (var entry in (await untis.GetClassesAsync(SelectedSchoolYear.UntisId)).OrderBy(x => x.Name))
                Classes.Add(entry);
            Status = Classes.Count == 0 ? "Keine Klassen gefunden." : $"{Classes.Count} Klassen gefunden.";
        }
        catch (WebUntisIntegrationException ex) { Status = ex.Message; }
        finally { Busy = false; }
    }

    private static int Today()
    {
        var date = DateOnly.FromDateTime(DateTime.Today);
        return date.Year * 10000 + date.Month * 100 + date.Day;
    }
}