using MeterVault.Core.Domain;
using MeterVault.Core.Normalization;
using static MeterVault.Core.Tests.TestData;

namespace MeterVault.Core.Tests;

/// <summary>
/// The water meter register swaps mid-series (…861 → 2 → 15). The swap month's consumption (12)
/// cannot be derived from the two visible registers alone — an explicit swap event carries the
/// boundary, and continuity is preserved across it (SDD §2.3, §7.1).
/// </summary>
public sealed class WaterSwapTests
{
    private readonly INormalizationEngine _engine = NormalizationEngine.CreateDefault();

    private static NormalizationContext WaterContext(MeterEvent swap) => new()
    {
        Meter = new MeterConfig
        {
            MeterId = 10,
            Mode = MeterMode.CumulativeCounter,
            Unit = "m3",
            InitialBaseline = 820, // Nov 2022 register, so Dez books 14.
        },
        Readings =
        [
            Reading(10, Month(2022, 12), 834),
            Reading(10, Month(2023, 1), 848),
            Reading(10, Month(2023, 2), 861),
            Reading(10, Month(2023, 3), 2),   // new meter
            Reading(10, Month(2023, 4), 15),
        ],
        Events = [swap],
    };

    [Fact]
    public void Swap_with_boundary_registers_reconciles_to_twelve()
    {
        // Old meter ran 861 → 873 before removal; new meter installed reading 2.
        var swap = Swap(10, Month(2023, 3), prevValue: 873, newValue: 2);

        var result = _engine.Normalize(WaterContext(swap));

        Assert.Equal([14d, 14d, 13d, 12d, 13d], result.Select(c => c.Amount));
    }

    [Fact]
    public void Swap_with_explicit_amount_override_reconciles_to_twelve()
    {
        // The importer can seed the sheet's own März consumption (12) as an override.
        var swap = Swap(10, Month(2023, 3), amount: 12);

        var result = _engine.Normalize(WaterContext(swap));

        Assert.Equal([14d, 14d, 13d, 12d, 13d], result.Select(c => c.Amount));
    }
}