app/APP/Main.cs

using System.Diagnostics;
using APP.DTO;
using APP.Utility;

namespace APP;

public partial class Main : Form
{
    private Auth? _auth;
    private bool _authSucc;
    private ImageList _imageListSeason;
    private List<Anime>? _seasonAnime;
    private User? _user;

    public Main()
    {
        InitializeComponent();
        _imageListSeason = new ImageList();
        Load += OnLoadEv;
    }

    private async void OnLoadEv(object? sender, EventArgs e)
    {
        _auth = await SaveBoy.ReadAuth();
        if (_auth != null)
        {
            // check if we exist
            var users = await BackendComms.GetUser();
            if (users == null || users.All(u => u.Username != _auth.Username))
            {
                // We dont exist
                SaveBoy.DeleteAuth();
                _auth = null;
            }
            else
            {
                // try auth
                if (await BackendComms.Auth(_auth.Username, _auth.Secret))
                {
                    // Login successful
                    loginToolStripMenuItem.Visible = false;
                    _authSucc = true;
                    await UpdateUser();
                }
                else
                {
                    _authSucc = false;
                }
            }
        }

        await UpdateSeason();
    }

    private async Task UpdateSeason()
    {
        _seasonAnime = await BackendComms.GetSeason();
        if (_seasonAnime == null)
        {
            ShowError("Fehler beim Season abrufen");
        }
        else
        {
            foreach (var anime in _seasonAnime)
            {
                //_imageListSeason.Images.Add("", new )
                listViewSeason.Items.Add(new ListViewItem
                {
                    Text = anime.Title
                });
            }
        }
    }

    private async Task UpdateUser()
    {
        _user = await BackendComms.GetUser(_auth?.Username);
        if (_user == null)
        {
            ShowError("Fehler beim User abrufen");
        }
        else
        {
            tabUser.Text = _user.Username;
            userLabel.Text = _user.Username;
            userLabel.Visible = true;
            userLinkLabel.Text = _user.Url;
            userLinkLabel.Visible = true;
            userLabelInfo.Text = StringAssemble.UserInfo(_user);
            userLabelInfo.Visible = true;
            userLabelInfoData.Text = StringAssemble.UserData(_user);
            userLabelInfoData.Visible = true;
            if (!string.IsNullOrWhiteSpace(_user.ImageUrl))
            {
                userImage.LoadAsync(_user.ImageUrl);
            }
        }
    }

    private static void ShowError(string text)
    {
        MessageBox.Show(text, @"FEHLER", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }

    private async void loginToolStripMenuItem_Click(object sender, EventArgs e)
    {
        if (_authSucc) return;
        var users = await BackendComms.GetUser();
        if (DoRegister(users))
        {
            await UpdateUser();
        }
    }

    private bool DoRegister(List<User>? users)
    {
        // Register promt
        var regWin = new RegisterWin(_auth, users);
        regWin.ShowDialog();
        if (regWin.Cancelled)
        {
            regWin.Dispose();
            return false;
        }

        _auth = new Auth
        {
            Username = regWin.Auth.Username,
            Secret = regWin.Auth.Secret
        };
        loginToolStripMenuItem.Visible = false;
        regWin.Dispose();
        return true;
    }

    private async void userLinkLabel_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
    {
        if (string.IsNullOrWhiteSpace(_user?.Url)) return;
        try
        {
            var url = new Uri(_user.Url).ToString();
            var sInfo = new ProcessStartInfo(url)
            {
                UseShellExecute = true
            };
            Process.Start(sInfo);
        }
        catch (Exception ex)
        {
            await Console.Error.WriteLineAsync(ex.Message);
        }
    }

    private void logToolStripMenuItem_Click(object sender, EventArgs e)
    {
        var logWin = new LogWin(LogBoy.GetLog());
        logWin.ShowDialog();
        logWin.Dispose();
    }
}