using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using LehrerApp.Core.Interfaces;
using LehrerApp.Core.Models;
using LehrerApp.Core.Services;
using LehrerApp.Data;
using LehrerApp.Desktop.Services;
using LehrerApp.Desktop.ViewModels.Planning;
using LehrerApp.Sync;
using LehrerApp.Sync.Crypto;
using System.Collections.ObjectModel;
using System.Globalization;
using System.Security.Cryptography;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace LehrerApp.Desktop.ViewModels.Settings;

public partial class SettingsViewModel
{
    // ── Fächer ────────────────────────────────────────────────────────────────

    [ObservableProperty] private string _newName          = "";
    [ObservableProperty] private string _newShort         = "";
    [ObservableProperty] private string _newNameError     = "";

    public ObservableCollection<SubjectListItem> Subjects { get; } = [];

    // ── Fächer: Laden / Hinzufügen / Löschen ─────────────────────────────────

    public void LoadSubjects()
    {
        Subjects.Clear();
        foreach (var s in _subjects.GetAll())
            Subjects.Add(new SubjectListItem(s));
    }

    [RelayCommand]
    private void AddSubject()
    {
        if (string.IsNullOrWhiteSpace(NewName)) { NewNameError = "Name erforderlich."; return; }
        try
        {
            _subjects.Save(new Subject { Name = NewName.Trim(), ShortName = NewShort.Trim() });
        }
        catch (InvalidOperationException ex)
        {
            NewNameError = ex.Message;
            return;
        }
        NewName = ""; NewShort = ""; NewNameError = "";
        LoadSubjects();
    }

    [RelayCommand]
    private void DeleteSubject(SubjectListItem? item)
    {
        if (item is null) return;
        try
        {
            _subjects.Delete(item.Id);
        }
        catch (InvalidOperationException ex)
        {
            NewNameError = ex.Message;
            return;
        }
        NewNameError = "";
        if (CatalogSubject?.Id == item.Id) CatalogSubject = null;
        LoadSubjects();
    }
}

public class SubjectListItem(Subject s)
{
    public Guid   Id        { get; } = s.Id;
    public string Name      { get; } = s.Name;
    public string ShortName { get; } = s.ShortName;
}