DbFirst/DbFirst.BlazorWebApp/Components/Layout/MainLayout.razor

@inherits LayoutComponentBase
@implements IDisposable
@inject ThemeState ThemeState
@inject IJSRuntime JS
@inject AuthService AuthService
@inject IAuthApiClient AuthApiClient
@inject NavigationManager Navigation

<div class="page @(ThemeState.IsDarkMode ? "app-dark" : "app-light") @(ThemeState.IsNativeDarkTheme ? "native-dark" : "")">
    <div class="sidebar">
        <NavMenu />
    </div>

    <main>
        <div class="top-row px-4">
            <DxComboBox Data="@ThemeState.AvailableThemes"
                        Value="@ThemeState.CurrentThemeName"
                        ValueChanged="@((string t) => ThemeState.SetTheme(t))"
                        style="width: 130px;" />
            <span style="margin-left: 12px;">
                <DxButton Text="@(ThemeState.IsDarkMode ? "Dark Mode aus" : "Dark Mode an")"
                          Click="ToggleTheme" />
            </span>
            @if (AuthService.IsAuthenticated)
            {
                <span class="ms-auto d-flex align-items-center gap-2">
                    <span class="top-row-username">@AuthService.UserName</span>
                    <DxButton Text="Abmelden"
                              Click="LogoutAsync"
                              RenderStyle="ButtonRenderStyle.Secondary" />
                </span>
            }
            <a href="https://learn.microsoft.com/aspnet/core/" target="_blank">About</a>
        </div>

        <article class="content px-4">
            @if (_checkingAuth)
            {
                <div class="loading-container">
                    <span>Wird geladen…</span>
                </div>
            }
            else
            {
                @Body
            }
        </article>
    </main>
</div>

<div id="blazor-error-ui">
    An unhandled error has occurred.
    <a href="" class="reload">Reload</a>
    <a class="dismiss">🗙</a>
</div>

@code {
    private bool _isInteractive;
    private bool _checkingAuth = true;

    protected override void OnInitialized()
    {
        ThemeState.OnChange += OnThemeChanged;
        AuthService.OnChange += OnAuthChanged;
    }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            _isInteractive = true;

            if (!AuthService.IsAuthenticated)
            {
                try
                {
                    var username = await JS.InvokeAsync<string?>("authStorage.get", "auth_user");
                    var cookie = await JS.InvokeAsync<string?>("authStorage.get", "auth_cookie");

                    if (!string.IsNullOrEmpty(username) && !string.IsNullOrEmpty(cookie))
                    {
                        var restored = await AuthApiClient.RestoreAsync(username, cookie);
                        if (!restored)
                        {
                            await JS.InvokeVoidAsync("authStorage.clear");
                            Navigation.NavigateTo("/login", replace: true);
                            return;
                        }
                    }
                    else
                    {
                        Navigation.NavigateTo("/login", replace: true);
                        return;
                    }
                }
                catch
                {
                    Navigation.NavigateTo("/login", replace: true);
                    return;
                }
            }

            _checkingAuth = false;
            StateHasChanged();
        }

        await ApplyDxDarkOverrideAsync();
    }

    private async Task LogoutAsync()
    {
        try
        {
            await AuthApiClient.LogoutAsync();
            await JS.InvokeVoidAsync("authStorage.clear");
        }
        catch
        {
            // Fehler beim Abmelden ignorieren, trotzdem weiterleiten
        }

        Navigation.NavigateTo("/login", replace: true);
    }

    private void OnAuthChanged()
    {
        InvokeAsync(StateHasChanged);
    }

    private void OnThemeChanged()
    {
        InvokeAsync(async () =>
        {
            StateHasChanged();
            if (_isInteractive)
                await ApplyDxDarkOverrideAsync();
        });
    }

    private async Task ApplyDxDarkOverrideAsync()
    {
        if (!_isInteractive) return;
        try
        {
            bool needsOverride = ThemeState.IsDarkMode && !ThemeState.IsNativeDarkTheme;
            await JS.InvokeVoidAsync("setDxDarkOverride", needsOverride);
        }
        catch (JSException)
        {
            // JS-Funktion noch nicht verfügbar – kein Circuit-Crash
        }
    }

    private void ToggleTheme()
    {
        ThemeState.SetDarkMode(!ThemeState.IsDarkMode);
    }

    public void Dispose()
    {
        ThemeState.OnChange -= OnThemeChanged;
        AuthService.OnChange -= OnAuthChanged;
    }
}