@inject IJSRuntime JS
@implements IAsyncDisposable

<div class="signature-container">
    <canvas id="@_canvasId" width="600" height="200" class="signature-canvas"></canvas>
    <div class="signature-actions">
        <button type="button" class="btn-clear-sig" @onclick="CancellaFirma">
            <i class="ri-delete-bin-line"></i>
            Cancella firma
        </button>
    </div>
</div>

@code {
    [Parameter] public EventCallback<string> OnFirmaCambiata { get; set; }

    readonly string _canvasId = $"sig-{Guid.NewGuid():N}";
    DotNetObjectReference<SignaturePad>? _dotNetRef;

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            _dotNetRef = DotNetObjectReference.Create(this);
            await JS.InvokeVoidAsync("signaturePad.init", _canvasId, _dotNetRef);
        }
    }

    [JSInvokable]
    public Task OnSignatureChanged(string dataUrl) => OnFirmaCambiata.InvokeAsync(dataUrl);

    async Task CancellaFirma()
    {
        await JS.InvokeVoidAsync("signaturePad.clear", _canvasId);
        await OnFirmaCambiata.InvokeAsync(string.Empty);
    }

    public async ValueTask DisposeAsync()
    {
        _dotNetRef?.Dispose();
        await ValueTask.CompletedTask;
    }
}