gpw_next/GPW.CORE.Smart10/Components/Pages/Weather.razor

@page "/weather"
@rendermode InteractiveServer
@attribute [StreamRendering]

<PageTitle>Weather</PageTitle>

<h1>Weather</h1>

<p>This component demonstrates showing data.</p>
@if (isLoading)
{
    <p><em>pre-loading...</em></p>
}
else
{
    <p role="status">Current count: @currentCount</p>
    <button class="btn btn-primary" @onclick="IncrementCount">Click me</button>
    <ExecutionContextTest></ExecutionContextTest>

    @if (forecasts == null)
    {
        <p><em>Loading...</em></p>
    }
    else
    {
        <table class="table">
            <thead>
                <tr>
                    <th>Date</th>
                    <th aria-label="Temperature in Celsius">Temp. (C)</th>
                    <th aria-label="Temperature in Fahrenheit">Temp. (F)</th>
                    <th>Summary</th>
                </tr>
            </thead>
            <tbody>
                @foreach (var forecast in forecasts)
                {
                    <tr>
                        <td>@forecast.Date.ToShortDateString()</td>
                        <td>@forecast.TemperatureC</td>
                        <td>@forecast.TemperatureF</td>
                        <td>@forecast.Summary</td>
                    </tr>
                }
            </tbody>
        </table>
    }
}


@code {
    private bool isLoading = false;
    private int currentCount = 0;

    private void IncrementCount()
    {
        currentCount++;
        Console.WriteLine($"Curr: {currentCount}");
    }

    private WeatherForecast[]? forecasts;

    [Inject]
    private IJSRuntime JS { get; set; } = null!;

    // protected override async Task OnInitializedAsync()
    // {
    //     // Simulate asynchronous loading to demonstrate streaming rendering
    //     isLoading = true;
    //     await InvokeAsync(StateHasChanged);
    //     await Task.Delay(400);
    //     isLoading = false;
    //     await InvokeAsync(StateHasChanged);
    //     await Task.Delay(600);
    //     LoadForecasts();
    // }

    private bool _interactiveStarted;
    private bool _loadingStarted;

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (!firstRender) return;

        // Prova una semplice chiamata JS: se fallisce siamo in prerender
        try
        {
            await JS.InvokeVoidAsync("console.debug", "client active check");
            _interactiveStarted = true;
        }
        catch
        {
            _interactiveStarted = false;
        }

        if (_interactiveStarted && !_loadingStarted)
        {
            _loadingStarted = true;
            await StartLoadingAsync(); // avvia il lavoro "pesante" solo qui
        }
    }
    private async Task StartLoadingAsync()
    {
        // esempio: simulazione caricamento
        isLoading = true;
        StateHasChanged();
        await Task.Delay(400);
        isLoading = false;
        StateHasChanged();
        await Task.Delay(600);
        // carica i dati veri
        LoadForecasts();
        StateHasChanged();
    }

    private void LoadForecasts()
    {
        var startDate = DateOnly.FromDateTime(DateTime.Now);
        var summaries = new[] { "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching" };
        forecasts = Enumerable.Range(1, 5).Select(index => new WeatherForecast
        {
            Date = startDate.AddDays(index),
            TemperatureC = Random.Shared.Next(-20, 55),
            Summary = summaries[Random.Shared.Next(summaries.Length)]
        }).ToArray();
    }

    private class WeatherForecast
    {
        public DateOnly Date { get; set; }
        public int TemperatureC { get; set; }
        public string? Summary { get; set; }
        public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
    }
}