@page "/solar"
@using MeterVault.App.Components.Pages.Specialized
@using MeterVault.Core.Analysis
@implements IDisposable
@inject NavigationManager Nav
@inject InstanceClock Clock
@inject SolarService SolarSvc
@inject ILogger<Solar> Logger

@* The Solar view (brief §7.5, D-54): the shared header, toolbar and missing-data semantics around the specialised
   measures — generation, self-consumption, feed-in, autarky and what the generation is worth — one section per energy
   type with generation. Each figure carries its status and says how it was obtained; a role the figures need and
   nobody holds gets a setup card with a scoped path into the meter editor. *@

<PageHeader Title="@S.Nav_Solar" Description="@S.Solar_Description">
    <Breadcrumbs>
        <AnalysisBreadcrumbs Query="_query" Current="@S.Nav_Solar" />
    </Breadcrumbs>
</PageHeader>

@if (_query is not null)
{
    <PeriodToolbar Query="_query" Period="_state.Value?.Analysis.Period" Plan="_state.Value?.Analysis.Plan" Defaults="Defaults"
                   QueryChanged="OnQueryChanged" Class="mb-4" />
}

<LoadPanel State="_state" OnRetry="RetryAsync" Context="view">
    @if (view.Analysis.Sites.Count == 0)
    {
        <div class="mv-empty" role="status">
            <MudIcon Icon="@Icons.Material.Outlined.SolarPower" Class="mv-empty__icon" aria-hidden="true" />
            <div class="mv-empty__body">
                <MudText Typo="Typo.subtitle1">@S.Solar_NoGenerationTitle</MudText>
                <MudText Typo="Typo.body2" Class="mv-muted">@Loc.F(S.Solar_NoGenerationHelp, MeterMode.GenerationCounter.Display())</MudText>
                <div class="d-flex flex-wrap mt-2" style="gap:.5rem">
                    <MudButton Variant="Variant.Outlined" Color="Color.Primary" Size="Size.Small" Href="/meters">@S.Nav_Meters</MudButton>
                    <MudButton Variant="Variant.Text" Color="Color.Primary" Size="Size.Small" Href="/import">@S.Nav_Import</MudButton>
                </div>
            </div>
        </div>
    }
    else if (!view.Analysis.IsRefused)
    {
        @foreach (var site in view.Sites)
        {
            <SolarSiteSection @key="site.Site.EnergyTypeId" View="site" Query="view.Query" Currency="@view.Analysis.Currency"
                              ShowHeading="@(view.Sites.Count > 1)" OnRefresh="RetryAsync" />
        }
    }
</LoadPanel>

@code {
    private static readonly AnalysisDefaults Defaults = AnalysisDefaults.History;

    private readonly LoadSequencer _loads = new();
    private readonly LoadState<SolarPageView> _state = new();
    private AnalysisQuery? _query;

    /// <summary>One committed result: the query it answers, the read model and every section's series.</summary>
    private sealed record SolarPageView(AnalysisQuery Query, SolarAnalysis Analysis, IReadOnlyList<SolarSiteView> Sites);

    protected override void OnInitialized() => Nav.LocationChanged += OnLocationChanged;

    protected override Task OnParametersSetAsync() => ReloadIfChangedAsync();

    private void OnLocationChanged(object? sender, LocationChangedEventArgs e) => _ = InvokeAsync(ReloadIfChangedAsync);

    private async Task ReloadIfChangedAsync()
    {
        var query = AnalysisQuery.Parse(Nav.Uri, Defaults);
        if (query == _query)
        {
            return;
        }

        _query = query;
        await LoadAsync(query);
        StateHasChanged();
    }

    private Task RetryAsync() => _query is null ? Task.CompletedTask : LoadAsync(_query);

    private Task LoadAsync(AnalysisQuery query) => _loads.RunAsync(_state, async token =>
    {
        // "Now" is read once per load (D-01); "all" spans what the energy types with generation have data for (D-19).
        var now = Clock.Now;
        var availability = query.Period == PeriodPreset.AllHistory ? await SolarSvc.GetAvailabilityAsync(now, token) : null;
        var period = query.Resolve(now, SolarSvc.Zone, availability);
        var analysis = await SolarSvc.GetAsync(new SolarRequest(period) { Bucket = query.Bucket, Comparison = query.Comparison }, token);
        return new SolarPageView(query, analysis, [.. analysis.Sites.Select(s => SolarSiteView.Build(s, query, analysis.Currency))]);
    }, Logger);

    private void OnQueryChanged(AnalysisQuery query) => AnalysisNavigation.Replace(Nav, query, Defaults);

    public void Dispose()
    {
        Nav.LocationChanged -= OnLocationChanged;
        _loads.Dispose();
    }
}