MeterVault/tests/Integration.Tests/Costing/CostReconciliationTests.cs

using MeterVault.Core.Domain;
using MeterVault.Core.Normalization;
using MeterVault.Infrastructure.Costing;
using MeterVault.Infrastructure.Import;
using MeterVault.Infrastructure.Normalization;
using MeterVault.Infrastructure.Persistence;
using Microsoft.EntityFrameworkCore;
using static MeterVault.Integration.Tests.Reconciliation.ReconciliationSupport;

namespace MeterVault.Integration.Tests.Costing;

/// <summary>
/// Reconciles the cost engine against the Wasser sheet's Kosten column (consumption × €/m³) and
/// checks category rollups and the monthly consumption rollups that replaced the continuous
/// aggregates (SDD §7.5, D-17).
/// </summary>
[Collection("Timescale")]
public sealed class CostReconciliationTests(TimescaleFixture fx)
{
    private static readonly DateTimeOffset From = new(2022, 11, 1, 0, 0, 0, TimeSpan.Zero);
    private static readonly DateTimeOffset To = new(2024, 1, 1, 0, 0, 0, TimeSpan.Zero);

    [Fact]
    public async Task Water_cost_matches_the_sheet()
    {
        await using var db = fx.CreateContext();
        var meterId = await ImportWaterAsync(db);

        db.Tariffs.Add(new Tariff
        {
            ScopeType = TariffScope.Meter,
            ScopeId = meterId,
            Component = TariffComponent.UnitPrice,
            Value = 5.00,
            Unit = "EUR/m3",
            ValidFrom = new DateOnly(2022, 11, 1),
        });
        await db.SaveChangesAsync();

        var costs = await new CostService(fx).GetMeterCostsAsync(meterId, From, To);
        var computed = costs.ToDictionary(c => c.Period, c => c.Cost);
        var oracle = OracleByMonth(ReadRows(Water), dateColumn: 0, valueColumn: 4, firstDataRow: 1); // Kosten

        AssertReconciles(computed, oracle, tolerance: 0.02, "water cost", minMatches: 10);

        await CleanupAsync(db, meterId);
    }

    [Fact]
    public async Task Category_rollup_includes_meter_costs()
    {
        await using var db = fx.CreateContext();
        var meterId = await ImportWaterAsync(db);
        var wasserCategory = await db.CostCategories.FirstAsync(c => c.Name == "Wasser");

        db.Tariffs.Add(new Tariff
        {
            ScopeType = TariffScope.Meter,
            ScopeId = meterId,
            Component = TariffComponent.UnitPrice,
            Value = 5.00,
            Unit = "EUR/m3",
            ValidFrom = new DateOnly(2022, 11, 1),
        });
        db.CostCategoryMembers.Add(new CostCategoryMember { CategoryId = wasserCategory.Id, MeterId = meterId });
        await db.SaveChangesAsync();

        var rollup = await new CostService(fx).GetCategoryCostsAsync(wasserCategory.Id, From, To);
        var dec2022 = rollup.Single(r => r.Period == new DateOnly(2022, 12, 1));

        Assert.Equal(70d, dec2022.Cost, 2); // Dez 2022: 14 m³ × 5,00 €

        await db.CostCategoryMembers.Where(m => m.MeterId == meterId).ExecuteDeleteAsync();
        await CleanupAsync(db, meterId);
    }

    [Fact]
    public async Task Monthly_rollup_equals_the_consumption_it_sums()
    {
        // D-17: the rollup written with the import, in the normalizer's zone (UTC here), is what month and year
        // reads use — no refresh step, no lag, and the same total the consumption rows add up to.
        await using var db = fx.CreateContext();
        var meterId = await ImportWaterAsync(db);

        var months = await db.ConsumptionRollupMonths.AsNoTracking()
            .Where(r => r.MeterId == meterId)
            .ToDictionaryAsync(r => r.Month, r => r.Amount);
        var rows = await db.Consumption.AsNoTracking().Where(c => c.MeterId == meterId).ToListAsync();
        var byMonth = rows
            .GroupBy(c => new DateOnly(c.Time.UtcDateTime.Year, c.Time.UtcDateTime.Month, 1))
            .ToDictionary(g => g.Key, g => g.Sum(c => c.Amount));

        Assert.Equal(14d, months[new DateOnly(2022, 12, 1)], 6); // Dez 2022 consumption
        Assert.Equal(byMonth.Keys.Order(), months.Keys.Order());
        Assert.All(byMonth, m => Assert.Equal(m.Value, months[m.Key], 9));

        // The day table holds the same December, on the day the month row is filed.
        var decemberDays = await db.ConsumptionRollups.AsNoTracking()
            .Where(r => r.MeterId == meterId && r.Day >= new DateOnly(2022, 12, 1) && r.Day < new DateOnly(2023, 1, 1))
            .SumAsync(r => r.Amount);
        Assert.Equal(14d, decemberDays, 6);

        await CleanupAsync(db, meterId);
    }

    private static async Task<int> ImportWaterAsync(MeterVaultDbContext db)
    {
        await DatabaseSeeder.SeedAsync(db);
        var waterType = await db.EnergyTypes.FirstAsync(t => t.Key == "water");
        var meter = new Meter
        {
            Name = $"cost-water-{Guid.NewGuid():N}",
            EnergyTypeId = waterType.Id,
            Mode = MeterMode.CumulativeCounter,
            Unit = "m3",
            InitialBaseline = 820,
        };
        db.Meters.Add(meter);
        await db.SaveChangesAsync();

        var profile = new MappingProfile
        {
            Name = "cost-water",
            DateColumn = 0,
            DateKind = DateKind.MonthName,
            FirstDataRowIndex = 1,
            DetectCumulativeSwaps = true,
            Columns =
            [
                new ColumnMapping
                {
                    Index = 1, Role = MappingRole.Reading, MeterId = meter.Id, Unit = "m3", SwapConsumptionColumn = 2,
                },
            ],
        };

        StagedImport staged;
        using (var reader = new StreamReader(FixturePath(Water)))
        {
            staged = new CsvImporter().Stage(profile, reader);
        }

        var service = new ImportService(db, new NormalizationService(db, NormalizationEngine.CreateDefault()));
        await service.CommitAsync(staged, "Wasser.csv", null);
        return meter.Id;
    }

    private static async Task CleanupAsync(MeterVaultDbContext db, int meterId)
    {
        await db.Consumption.Where(c => c.MeterId == meterId).ExecuteDeleteAsync();
        await db.Readings.Where(r => r.MeterId == meterId).ExecuteDeleteAsync();
        await db.MeterEvents.Where(e => e.MeterId == meterId).ExecuteDeleteAsync();
        await db.Tariffs.Where(t => t.ScopeId == meterId && t.ScopeType == TariffScope.Meter).ExecuteDeleteAsync();
        await db.Meters.Where(m => m.Id == meterId).ExecuteDeleteAsync();
    }
}