using MeterVault.Core.Analysis;
using MeterVault.Core.Analysis.Virtual;
using static MeterVault.Core.Tests.Analysis.VirtualFixtures;

namespace MeterVault.Core.Tests;

/// <summary>
/// The electricity derived columns are data-driven virtual expressions, not hardcoded formulas
/// (SDD §2.2, §7.4): Netz Einsparung = Haus − Netz, Anlage Eigenverbrauch = Erzeugung − Einsparung. Ported from
/// the removed VirtualNormalizer to the evaluator that runs on read (D-29), over month buckets.
/// </summary>
public sealed class VirtualMeterTests
{
    private const int Haus = 1;
    private const int Netz = 2;
    private const int Solar = 50;
    private const int NetzEinsparung = 100;
    private const int Eigenverbrauch = 101;

    [Fact]
    public void Netz_einsparung_is_haus_minus_netz()
    {
        var haus = Source(Haus, Monthly((2022, 10, 411), (2022, 11, 742)));   // Haus Verbrauch
        var netz = Source(Netz, Monthly((2022, 10, 416), (2022, 11, 832)));   // Netz Verbrauch

        var result = VirtualEvaluator.Evaluate(
            NetzEinsparung, Formula.Parse("m1 - m2"), QuantityKind.Consumption, Months(2022, 10, 2), [haus, netz]);

        Assert.Equal([-5d, -90d], result.Values.Select(v => v.Value!.Value));
    }

    [Fact]
    public void Eigenverbrauch_is_erzeugung_minus_einsparung()
    {
        var october = Months(2022, 10, 1);
        var einsparung = VirtualEvaluator.Evaluate(
            NetzEinsparung,
            Formula.Parse("m1 - m2"),
            QuantityKind.Consumption,
            october,
            [Source(Haus, Monthly((2022, 10, 411))), Source(Netz, Monthly((2022, 10, 416)))]);
        var solar = Source(Solar, Monthly((2022, 10, 76)));                   // Solar Erzeugung

        var result = VirtualEvaluator.Evaluate(
            Eigenverbrauch, Formula.Parse("m50 - m100"), QuantityKind.Net, october, [solar, VirtualSource.FromEvaluation(einsparung)]);

        // 76 − (−5) = 81 (Anlage Eigenverbrauch Okt 2022), through the nested Netz Einsparung meter.
        Assert.Equal([81d], result.Values.Select(v => v.Value!.Value));
    }
}