Nexus.Reader/src/NexusReader.UI.Shared/Pages/Home.razor

@page "/"
@attribute [Authorize]
@using NexusReader.UI.Shared.Services
@implements IAsyncDisposable
@inject IQuizStateService QuizState
@inject IFocusModeService FocusMode
@inject IJSRuntime JS
<PageTitle>Nexus E-Reader</PageTitle>

<div class="home-reader-container">
    <ReaderCanvas @ref="readerCanvas" />
</div>


@code {
    private ReaderCanvas? readerCanvas;
    private string? _activeQuizBlockId;
    
    private IJSObjectReference? _interopModule;
    private IJSObjectReference? _keydownHandler;
    private DotNetObjectReference<Home>? _dotNetRef;

    protected override async Task OnInitializedAsync()
    {
        QuizState.OnQuizRequested += HandleQuizRequestedAsync;
        FocusMode.OnFocusModeChanged += HandleUpdate;
        await FocusMode.InitializeAsync();
    }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            try {
                _interopModule = await JS.InvokeAsync<IJSObjectReference>("import", "./_content/NexusReader.UI.Shared/js/focusInterop.js");
                _dotNetRef = DotNetObjectReference.Create(this);
                _keydownHandler = await _interopModule.InvokeAsync<IJSObjectReference>("attachKeyboardListener", _dotNetRef);
            } catch { } /* ignored dynamically */
        }
    }

    [JSInvokable]
    public async Task OnFocusKeypressed()
    {
        await FocusMode.ToggleAsync();
        StateHasChanged();
    }

    private async Task HandleNodeSelected(string nodeId)
    {
        if (readerCanvas != null)
        {
            await readerCanvas.ScrollToNodeAsync(nodeId);
        }
    }

    private async Task HandleQuizRequestedAsync(string blockId)
    {
        _activeQuizBlockId = blockId;
        await InvokeAsync(StateHasChanged);
    }

    private Task HandleUpdate() => InvokeAsync(StateHasChanged);

    public async ValueTask DisposeAsync()
    {
        QuizState.OnQuizRequested -= HandleQuizRequestedAsync;
        FocusMode.OnFocusModeChanged -= HandleUpdate;
        
        if (_interopModule != null && _keydownHandler != null)
        {
            try {
                await _interopModule.InvokeVoidAsync("detachKeyboardListener", _keydownHandler);
                await _interopModule.DisposeAsync();
                await _keydownHandler.DisposeAsync();
            } catch { } // Circuit disconnected catch explicitly
        }
        
        _dotNetRef?.Dispose();
    }
}