@using MeterVault.App.Energy
@using MeterVault.Core.Analysis
@using MeterVault.Infrastructure.Analysis
@inject NavigationManager Nav

@* The energy type's History (brief §7.3): the shared chart and table for the chosen metric, over the page's period and
   interval, compared with the chosen period (a calendar year for a year). "Total" charts the type's measures — never a
   breakdown on top of its parent or a calculated view on top of its sources (D-22); "Individual meters" charts the
   meters side by side and says how each one counts, so their bars are not read as adding up. Signed values stay signed.
   A bucket opens its finer detail (D-51). *@

<div class="mv-energy-history">
    <div class="mv-energy-history__views">
        <MudToggleGroup T="string" Value="@View" ValueChanged="OnViewChangedAsync" SelectionMode="SelectionMode.SingleSelection"
                        Outlined="true" Color="Color.Primary" Size="Size.Small" aria-label="@S.EnergyView_ViewLabel"
                        Class="mv-energy-history__toggle">
            <MudToggleItem T="string" Value="@EnergyPageKeys.ViewTotal" Text="@S.EnergyView_ViewTotal" />
            <MudToggleItem T="string" Value="@EnergyPageKeys.ViewMeters" Text="@S.EnergyView_ViewMeters" />
        </MudToggleGroup>
        <MudText Typo="Typo.caption" Class="mv-muted">
            @(_view?.IsIndividual == true ? S.EnergyView_ViewMetersHelp : S.EnergyView_ViewTotalHelp)
        </MudText>
    </div>

    @if (_view is null || _quantities is null)
    {
        @* Nothing read yet: the page shows its own loading state. *@
    }
    else if (_view.IsEmpty)
    {
        <MudAlert Severity="Severity.Info" Dense="true">@EmptyText()</MudAlert>
    }
    else if (_view.Main is { IsPending: true })
    {
        <PendingState OnRefresh="OnRefresh" />
    }
    else if (_quantities.NotYetOccurred || NoData())
    {
        <EmptyPeriodState NotYetOccurred="_quantities.NotYetOccurred" Availability="Availability()" LatestHref="@LatestHref()" />
    }
    else
    {
        <ComparisonSummary Period="Analysis.Period" Resolution="ComparisonResolution()" Matched="_view.Main?.Comparison?.Matched" Class="mb-3" />
        <AnalysisChart Buckets="_buckets" Series="_view.Chart" ComparisonPairs="_pairs" Title="@_title" OnBucketClick="_onBucketClick"
                       Resolution="_view.Coarsest" OnUseBucket="UseBucket" />

        @if (_view.IsIndividual)
        {
            @if (_view.Hidden > 0)
            {
                <MudText Typo="Typo.body2" Class="mv-muted mt-2">
                    @Loc.F(S.EnergyView_MoreMeters, _view.Shown.Count, _view.Shown.Count + _view.Hidden)
                    <MudLink Href="@AnalysisLinks.Analysis(QueryScope.ForEnergyType(Analysis.EnergyTypeId), _view.Metric, Query)" Typo="Typo.body2">@S.Nav_Analysis</MudLink>
                </MudText>
            }
            @if (_view.Memberships.Count > 0)
            {
                <section class="mv-energy-history__counts" aria-labelledby="@_countsId">
                    <MudText Typo="Typo.subtitle2" id="@_countsId">@S.EnergyView_HowCounted</MudText>
                    <ul>
                        @foreach (var (series, membership) in _view.Memberships)
                        {
                            <li>
                                <MudIcon Icon="@MeterListRows.MembershipIcon(membership)" Size="Size.Small" aria-hidden="true" Class="mv-muted" />
                                <span>
                                    <MudLink Href="@MeterLinks.Analysis(series.MeterId!.Value, Query)" Typo="Typo.body2">@series.Name</MudLink>:
                                    @membership.Label@(string.IsNullOrEmpty(membership.Detail) ? null : " — " + membership.Detail)
                                </span>
                            </li>
                        }
                    </ul>
                </section>
            }
        }
        else if (_view.Metric == AnalysisMetric.Cost && Analysis.Cost is { } cost)
        {
            <AttentionList CostAttention="cost.Attention" Problems="cost.QuantityProblems" Names="Analysis.Names" Query="Query"
                           MaxItems="3" Class="mt-3" />
        }

        <div class="mt-4">
            <AnalysisTable Buckets="_buckets" Series="_view.Table" ComparisonPairs="_pairs" Caption="@_title" DrillHref="_drillHref" />
        </div>
    }
</div>

@code {
    /// <summary>The page's committed value.</summary>
    [Parameter, EditorRequired]
    public EnergyAnalysis Analysis { get; set; } = null!;

    /// <summary>The page's analysis state.</summary>
    [Parameter, EditorRequired]
    public AnalysisQuery Query { get; set; } = null!;

    /// <summary>The page's defaults (drill-downs and "latest data" keep the page's other keys).</summary>
    [Parameter, EditorRequired]
    public AnalysisDefaults Defaults { get; set; } = null!;

    /// <summary>The metric shown (<see cref="EnergyMetrics.Effective"/>).</summary>
    [Parameter]
    public AnalysisMetric Metric { get; set; }

    /// <summary>The view key (<see cref="EnergyPageKeys.ViewTotal"/> or <see cref="EnergyPageKeys.ViewMeters"/>).</summary>
    [Parameter]
    public string View { get; set; } = EnergyPageKeys.ViewTotal;

    /// <summary>The view was switched; the page writes it into its address.</summary>
    [Parameter]
    public EventCallback<string> ViewChanged { get; set; }

    /// <summary>Loads again (analysis being prepared).</summary>
    [Parameter]
    public EventCallback OnRefresh { get; set; }

    private readonly string _countsId = "mv-counts-" + Guid.NewGuid().ToString("N")[..8];
    private object? _builtFrom;
    private EnergyHistoryView? _view;
    private AnalysisResult? _quantities;
    private IReadOnlyList<AnalysisBucket> _buckets = [];
    private IReadOnlyList<BucketPair>? _pairs;
    private string _title = string.Empty;
    private EventCallback<AnalysisBucket> _onBucketClick;
    private Func<AnalysisBucket, string?>? _drillHref;

    protected override void OnParametersSet()
    {
        // Rebuilt only for a new value, metric, view or comparison: the chart re-keys on a new list.
        var source = (Analysis, Metric, View, Query.Comparison);
        if (Equals(_builtFrom, source))
        {
            return;
        }

        _builtFrom = source;
        _quantities = Analysis.Quantities;
        _view = EnergyHistoryView.Build(Analysis, Metric, View == EnergyPageKeys.ViewMeters, Query.Comparison);
        if (_view.Metric == AnalysisMetric.Cost && Analysis.Cost is { } cost)
        {
            _buckets = cost.Plan.Buckets;
            _pairs = Analysis.CostComparison?.Pairs is { Count: > 0 } pairs ? pairs : null;
        }
        else
        {
            _buckets = _quantities?.Plan.Buckets ?? [];
            _pairs = _quantities?.Comparison?.Buckets;
        }

        var typeName = Analysis.Type?.Name ?? string.Empty;
        _title = Loc.F(S.EnergyView_ChartTitle, Metric.Display(), typeName);

        // Buckets are clickable, and the table has its drill column, only when some bucket leads somewhere (D-51): monthly
        // data has no days to open, and a click that does nothing is a dead end.
        var drills = _buckets.Any(b => DrillHref(b) is not null);
        _onBucketClick = drills ? EventCallback.Factory.Create<AnalysisBucket>(this, DrillAsync) : default;
        _drillHref = drills ? DrillHref : null;
    }

    /// <summary>The buckets are finer than the data: open the interval that shows it (replacing the address, D-46).</summary>
    private void UseBucket(BucketSize size) => AnalysisNavigation.Replace(Nav, Query.WithBucket(size), Defaults);

    private async Task OnViewChangedAsync(string? view) =>
        await ViewChanged.InvokeAsync(EnergyPageKeys.ResolveView(view));

    private string EmptyText()
    {
        if (_view!.Metric == AnalysisMetric.Cost)
        {
            return S.EnergyView_CostPerMeterNote;
        }

        return _view.IsIndividual
            ? Loc.F(S.EnergyView_NoMetersForMetric, _view.Metric.Display())
            : Loc.F(S.EnergyView_NoTotalForMetric, _view.Metric.Display());
    }

    private bool NoData()
    {
        if (_view!.Metric == AnalysisMetric.Cost)
        {
            return false;
        }

        var shown = _view.IsIndividual ? _view.Shown : EnergyMetrics.MeasuresOf(_quantities, _view.Metric);
        return _view.HasNoData(shown);
    }

    private MeterVault.Core.Analysis.Coverage.AvailableRange? Availability() =>
        _view?.Main?.Availability ?? _quantities?.Availability.Quantity;

    private ComparisonResolution? ComparisonResolution() =>
        _view?.Metric == AnalysisMetric.Cost ? Analysis.CostComparison?.Resolution : _quantities?.Comparison?.Resolution;

    private string? LatestHref() =>
        AnalysisNavigation.LatestData(Query, Availability()) is { } latest ? AnalysisNavigation.UriFor(Nav, latest, Defaults) : null;

    private string? DrillHref(AnalysisBucket bucket) =>
        AnalysisNavigation.DrillInto(Query, bucket, _view?.Coarsest) is { } next ? AnalysisNavigation.UriFor(Nav, next, Defaults) : null;

    /// <summary>A chart bucket opens its finer detail (D-51), pushing a history entry so Back returns here.</summary>
    private void DrillAsync(AnalysisBucket bucket)
    {
        if (DrillHref(bucket) is { } href)
        {
            Nav.NavigateTo(href);
        }
    }
}