MeterVault/tests/Integration.Tests/Overview/OverviewLogicTests.cs

using MeterVault.App;
using MeterVault.App.Analysis;
using MeterVault.App.Components.Pages.Overview;
using MeterVault.App.Localization;
using MeterVault.Core.Analysis;
using MeterVault.Core.Analysis.Costing;
using MeterVault.Core.Analysis.Quantities;
using MeterVault.Core.Analysis.Totals;
using MeterVault.Core.Analysis.Virtual;
using MeterVault.Core.Domain;
using MeterVault.Infrastructure.Analysis;
using MeterVault.Infrastructure.Costing;
using MeterVault.Infrastructure.Dashboard;
using static MeterVault.Integration.Tests.Analysis.AnalysisUiTestData;

namespace MeterVault.Integration.Tests.Overview;

/// <summary>
/// The Overview's rules without a database (brief §7.1): a cost change is stated over what both periods cover
/// completely (D-07) — the whole totals when both are complete, else the paired buckets both have, else not at all; a
/// projection only for a complete month or year to date after enough days (D-09); the words and links of its rows; and
/// the specific wording of invalid calculations, totals conflicts and overlap hints in attention items (D-53).
/// </summary>
public sealed class OverviewLogicTests
{
    private static readonly AttentionNames Names = new(
        new Dictionary<int, string> { [1] = "Haus", [2] = "Netz", [4] = "Solar 1", [5] = "Solar 2", [9] = "Summe Solar" },
        new Dictionary<int, string> { [1] = "Strom" });

    [Fact]
    public void Complete_totals_are_compared_as_a_whole()
    {
        var buckets = Buckets(D(2025, 1, 1), D(2025, 3, 31));
        var pairs = Pairs(buckets);
        var now = Priced(buckets, 100, 0.30);
        var before = Priced(buckets, 80, 0.30);

        var change = OverviewComparison.Between(now.Totals, now.Total, before.Totals, before.Total, pairs);

        Assert.Equal(CostChangeBasis.WholePeriod, change.Basis);
        Assert.False(change.IsPartial);
        Assert.Equal(90, change.Current!.Value, 6);
        Assert.Equal(72, change.Previous!.Value, 6);
        Assert.Equal(18, change.Change.Absolute!.Value, 6);
        Assert.Equal(25, change.Change.Percent!.Value, 6);
        Assert.True(change.Matched.IsContiguous);
        Assert.Equal((D(2025, 1, 1), D(2025, 3, 31)), (change.Matched.Current!.FirstDay, change.Matched.Current.LastDay));
        Assert.Equal((D(2024, 1, 1), D(2024, 3, 31)), (change.Matched.Comparison!.FirstDay, change.Matched.Comparison.LastDay));
    }

    [Fact]
    public void A_partial_period_is_compared_over_the_buckets_both_have_complete()
    {
        // January and March are complete on both sides; February is only partly covered now: it is left out of the
        // change, which is then stated over two separate stretches.
        var buckets = Buckets(D(2025, 1, 1), D(2025, 3, 31));
        var now = Figures(buckets, (100, BucketStatus.Available), (50, BucketStatus.Partial), (100, BucketStatus.Available));
        var before = Figures(buckets, (80, BucketStatus.Available), (80, BucketStatus.Available), (120, BucketStatus.Available));

        var change = OverviewComparison.Between(now.Totals, now.Total, before.Totals, before.Total, Pairs(buckets));

        Assert.Equal(CostChangeBasis.MatchedBuckets, change.Basis);
        Assert.True(change.IsPartial);
        Assert.Equal(60, change.Current!.Value, 6);
        Assert.Equal(60, change.Previous!.Value, 6);
        Assert.Equal(0, change.Change.Direction);
        Assert.Equal(2, change.Matched.Pieces.Count);
        Assert.False(change.Matched.IsContiguous);
        Assert.Equal(D(2025, 3, 31), change.Matched.Current!.LastDay);
    }

    [Fact]
    public void Nothing_complete_on_both_sides_is_not_comparable_and_no_comparison_is_nothing_at_all()
    {
        var buckets = Buckets(D(2025, 1, 1), D(2025, 2, 28));
        var now = Figures(buckets, (100, BucketStatus.Partial), (100, BucketStatus.Available));
        var before = Figures(buckets, (100, BucketStatus.Available), (100, BucketStatus.Missing));

        var change = OverviewComparison.Between(now.Totals, now.Total, before.Totals, before.Total, Pairs(buckets));
        Assert.Equal(CostChangeBasis.NotComparable, change.Basis);
        Assert.False(change.Change.IsAvailable);
        Assert.False(change.Matched.IsComparable);

        var none = OverviewComparison.Between(now.Totals, now.Total, null, null, []);
        Assert.Equal(CostChangeBasis.NoComparison, none.Basis);
    }

    [Fact]
    public void A_zero_baseline_has_a_change_but_no_percentage()
    {
        var buckets = Buckets(D(2025, 1, 1), D(2025, 1, 31));
        var now = Priced(buckets, 100, 0.30);
        var before = Priced(buckets, 0, 0.30);

        var change = OverviewComparison.Between(now.Totals, now.Total, before.Totals, before.Total, Pairs(buckets));

        Assert.Equal(30, change.Change.Absolute!.Value, 6);
        Assert.False(change.Change.PercentApplicable);
        Assert.Equal("percentage not applicable", In("en", () => Format.ChangePercent(change.Change)));
    }

    [Fact]
    public void A_month_to_date_is_projected_only_from_a_complete_figure_after_a_week()
    {
        // 1 – 19 September 14:37: 18.6 days elapsed of 30. 10 kWh a day at 0.30 € and 3 € a month standing charge, plus a
        // one-off manual cost of 50 € that is not drawn on.
        var period = PeriodResolver.Resolve(PeriodPreset.MonthToDate, null, null, Now, Berlin);
        var elapsed = (period.Now - period.From).TotalDays;
        var total = MonthFigure(period, usagePerDay: 10, elapsed, standingPerMonth: 3, manual: 50);

        var projection = OverviewProjection.For(period, total);

        Assert.NotNull(projection);
        Assert.Equal(18, projection!.Days);
        var running = total.Usage!.Value + total.StandingCharge!.Value;
        Assert.Equal((running / elapsed * 30) + 50, projection.Value, 6);

        // Not after only a few days, not from a partial figure, never for a complete or a custom period.
        var early = PeriodResolver.Resolve(PeriodPreset.MonthToDate, null, null, new DateTimeOffset(2026, 9, 5, 12, 0, 0, TimeSpan.FromHours(2)), Berlin);
        Assert.Null(OverviewProjection.For(early, MonthFigure(early, 10, (early.Now - early.From).TotalDays, 3, 0)));
        Assert.Null(OverviewProjection.For(period, MonthFigure(period, 10, elapsed, 3, 0, BucketStatus.Partial)));
        Assert.Null(OverviewProjection.For(PeriodResolver.Resolve(PeriodPreset.PreviousYear, null, null, Now, Berlin), total));
        Assert.Null(OverviewProjection.For(PeriodResolver.Resolve(PeriodPreset.Last12Months, null, null, Now, Berlin), total));
    }

    [Fact]
    public void Rows_are_named_in_the_readers_language_and_link_to_their_scope_with_the_same_dates() => In("de", () =>
    {
        var query = AnalysisQuery.Default(AnalysisDefaults.Overview).WithPeriod(PeriodPreset.PreviousYear);
        var none = CostChange.NoComparison;

        var category = new OverviewChangeRow(OverviewRowKind.Category, "Strom", null, null, none) { CategoryId = 4 };
        Assert.Equal("Strom", OverviewText.NameOf(category));
        Assert.Equal("/trends?scope=category&id=4&metric=cost&period=prev-year", OverviewText.HrefOf(category, query));

        var uncategorized = new OverviewChangeRow(OverviewRowKind.Uncategorized, string.Empty, null, null, none);
        Assert.Equal("Ohne Kategorie", OverviewText.NameOf(uncategorized));
        Assert.Null(OverviewText.HrefOf(uncategorized, query));

        var typeCharge = new OverviewChangeRow(OverviewRowKind.StandingCharge, "Strom", null, null, none)
        {
            StandingCharge = new StandingChargeKey(TariffScope.EnergyType, 1),
            EnergyTypeId = 1,
        };
        Assert.Equal("Grundpreis — Strom", OverviewText.NameOf(typeCharge));
        Assert.Equal("/energy/1?period=prev-year", OverviewText.HrefOf(typeCharge, query));

        var global = new OverviewChangeRow(OverviewRowKind.StandingCharge, string.Empty, null, null, none) { StandingCharge = new StandingChargeKey(TariffScope.Global, null) };
        Assert.Equal("Grundpreis — global", OverviewText.NameOf(global));

        var credit = new OverviewChangeRow(OverviewRowKind.Line, "Netz", null, null, none) { MeterId = 2, LineKind = BillLineKind.FeedIn };
        Assert.Equal("Einspeisevergütung", OverviewText.DetailOf(credit));
        Assert.Equal("/meters/2?tab=analysis&period=prev-year", OverviewText.HrefOf(credit, query));

        var manual = new OverviewChangeRow(OverviewRowKind.ManualCosts, string.Empty, null, null, none);
        Assert.Equal("Manuelle Kosten", OverviewText.NameOf(manual));
    });

    [Fact]
    public void An_invalid_calculation_says_what_is_wrong_and_about_which_meters() => In("en", () =>
    {
        var unknown = new AnalysisProblem(AnalysisProblemKind.InvalidDefinition, 9)
        {
            Virtual = new VirtualProblem(VirtualProblemKind.UnknownMeter, [12], []),
        };
        var item = AttentionItems.ForProblem(unknown, Names);
        Assert.Equal(
            "Summe Solar: the calculation is invalid, so no values can be shown. The formula refers to a meter that does not exist (Meter #12).",
            item.Text);
        Assert.Equal("Edit calculation", item.ActionText);

        var cycle = AttentionItems.ForProblem(
            new AnalysisProblem(AnalysisProblemKind.InvalidDefinition, 9) { Virtual = new VirtualProblem(VirtualProblemKind.DependencyCycle, [9, 4, 9], []) },
            Names);
        Assert.EndsWith("(Summe Solar → Solar 1 → Summe Solar).", cycle.Text, StringComparison.Ordinal);

        var units = AttentionItems.ForProblem(
            new AnalysisProblem(AnalysisProblemKind.InvalidDefinition, 9) { Virtual = new VirtualProblem(VirtualProblemKind.UnitMismatch, [4, 5], ["kWh", "m³"]) },
            Names);
        Assert.EndsWith("The formula adds or subtracts meters in different units (kWh, m³).", units.Text, StringComparison.Ordinal);

        var kinds = AttentionItems.ForProblem(
            new AnalysisProblem(AnalysisProblemKind.InvalidDefinition, 9) { Virtual = new VirtualProblem(VirtualProblemKind.KindMismatch, [4, 1], ["Generation", "Consumption"]) },
            Names);
        Assert.EndsWith("(Generation, Consumption).", kinds.Text, StringComparison.Ordinal);

        // Without the validator's finding the item stays general.
        Assert.Equal(
            "Summe Solar: the calculation is invalid, so no values can be shown.",
            AttentionItems.ForProblem(new AnalysisProblem(AnalysisProblemKind.InvalidDefinition, 9), Names).Text);
    });

    [Fact]
    public void Calculation_findings_are_worded_in_german() => In("de", () =>
    {
        var item = AttentionItems.ForProblem(
            new AnalysisProblem(AnalysisProblemKind.InvalidDefinition, 9) { Virtual = new VirtualProblem(VirtualProblemKind.SelfReference, [9], []) },
            Names);
        Assert.Equal(
            "Summe Solar: Die Berechnung ist ungültig, daher können keine Werte angezeigt werden. Die Formel verweist auf den Zähler selbst (Summe Solar).",
            item.Text);
    });

    [Fact]
    public void A_totals_conflict_and_a_billing_workaround_say_what_contradicts_itself() => In("en", () =>
    {
        var duplicate = AttentionItems.ForProblem(
            new AnalysisProblem(AnalysisProblemKind.TotalsProblem, 2) { Totals = new TotalsProblem(TotalsProblemKind.DuplicateRole, 2, 1, MeterRole.GridImport) },
            Names);
        Assert.Equal(
            "Netz and Haus: the totals configuration contradicts itself. Two meters hold the same role at the same time; the one created first keeps it (Grid import).",
            duplicate.Text);

        var loop = AttentionItems.ForProblem(
            new AnalysisProblem(AnalysisProblemKind.TotalsProblem, 1) { Totals = new TotalsProblem(TotalsProblemKind.ContainmentCycle, 1) },
            Names);
        Assert.Equal("Haus: the totals configuration contradicts itself. The meter links form a loop.", loop.Text);

        var billing = AttentionItems.ForCost(
            new CostAttention(CostAttentionKind.BillingConfiguration, 5) { Totals = new TotalsProblem(TotalsProblemKind.SeparateBillingUnitMismatch, 5, 1) },
            Names);
        Assert.StartsWith("Solar 2: the billing setup does not fit and was worked around. The meter has its own price, but its unit", billing.Text, StringComparison.Ordinal);
        Assert.EndsWith("(Haus).", billing.Text, StringComparison.Ordinal);
    });

    [Fact]
    public void An_overlap_hint_of_a_kind_the_page_does_not_know_still_says_what_it_is() => In("de", () =>
    {
        Assert.Equal(
            "Der Zähler ist nicht verknüpft und wird als Teil des Gesamtverbrauchs gezählt",
            OverlapHintKind.NotLinkedBelowTotalLoad.Display());

        var hint = AttentionItems.ForProblem(
            new AnalysisProblem(AnalysisProblemKind.PossibleOverlap, 2) { Hint = new OverlapHint((OverlapHintKind)99, 1, 2, 1) },
            Names);
        Assert.Equal("Netz: 99", hint.Text);
        Assert.Equal("/energy/1?tab=meters", hint.ActionHref);
    });

    [Fact]
    public void The_chart_selection_is_read_from_the_address()
    {
        Assert.Null(OverviewView.ChartKeyOf("http://localhost/"));
        Assert.Null(OverviewView.ChartKeyOf("http://localhost/?period=ytd"));
        Assert.Equal("t1:use:kWh", OverviewView.ChartKeyOf("http://localhost/?period=ytd&chart=t1%3Ause%3AkWh#top"));
        Assert.Equal("#0af", OverviewDonutSlice.SafeColor("#0af"));
        Assert.Null(OverviewDonutSlice.SafeColor("red; background:url(x)"));
        Assert.Equal("var(--mud-palette-info)", OverviewDonutSlice.PaletteVariable(2));
    }

    private static IReadOnlyList<BucketPair> Pairs(IReadOnlyList<AnalysisBucket> buckets)
    {
        var period = Range(buckets[0].FirstDay, buckets[^1].EndDay.AddDays(-1));
        var resolution = ComparisonResolver.Resolve(period, new ComparisonRequest(ComparisonKind.PreviousYear));
        return ComparisonResolver.PairBuckets(period, resolution.Period!, buckets);
    }

    /// <summary>One line at 0.30 €/kWh whose monthly quantity and availability are given per bucket.</summary>
    private static CostResult Figures(IReadOnlyList<AnalysisBucket> buckets, params (double Amount, BucketStatus Availability)[] months)
    {
        var parts = CostCalculator.Parts(buckets);
        var quantities = parts.Select(p => months[p.BucketIndex].Availability == BucketStatus.Missing
            ? CostQuantity.Unknown(p)
            : CostQuantity.Known(p, months[p.BucketIndex].Amount, months[p.BucketIndex].Availability)).ToList();
        return CostCalculator.Calculate(new CostRequest(
            buckets, D(2039, 12, 31), TariffBook.Create([Price(TariffComponent.UnitPrice, 0.30, "EUR/kWh")], "EUR"),
            [new CostLine(10, 1, BillLineKind.UnitPrice, "kWh", quantities)]));
    }

    /// <summary>A month to date: <paramref name="usagePerDay"/> kWh a day at 0.30 €, a monthly standing charge and a manual cost.</summary>
    private static CostAmount MonthFigure(
        ResolvedPeriod period, double usagePerDay, double elapsed, double standingPerMonth, double manual, BucketStatus availability = BucketStatus.Available)
    {
        var plan = BucketPlanner.Plan(period, BucketSize.Month);
        var parts = CostCalculator.Parts(plan.Buckets);
        var quantities = parts.Select(p => CostQuantity.Known(p, usagePerDay * elapsed, availability)).ToList();
        var today = PeriodResolver.LocalDate(period.Now, period.Zone);
        ManualCost[] manualCosts = manual > 0 ? [new ManualCost { Id = 1, PeriodStart = period.FirstDay.AddDays(2), PeriodEnd = period.FirstDay.AddDays(2), Amount = manual }] : [];
        var result = CostCalculator.Calculate(new CostRequest(
            plan.Buckets,
            today,
            TariffBook.Create([Price(TariffComponent.UnitPrice, 0.30, "EUR/kWh"), Price(TariffComponent.BasePrice, standingPerMonth, "EUR/month", id: 2)], "EUR"),
            [new CostLine(10, 1, BillLineKind.UnitPrice, "kWh", quantities)],
            [StandingChargeScope.ForEnergyType(1, new ServicePeriod(D(2020, 1, 1)))],
            manualCosts));
        return result.Total;
    }

    private static Tariff Price(TariffComponent component, double value, string unit, int id = 1) => new()
    {
        Id = id,
        ScopeType = TariffScope.EnergyType,
        ScopeId = 1,
        Component = component,
        Value = value,
        Unit = unit,
        ValidFrom = D(2000, 1, 1),
    };
}