using MeterVault.Core.Costing;
using MeterVault.Core.Domain;

namespace MeterVault.Core.Tests;

public sealed class TariffResolverTests
{
    private static Tariff Unit(double value, TariffScope scope, int? scopeId, DateOnly from, DateOnly? to = null) => new()
    {
        Component = TariffComponent.UnitPrice,
        Value = value,
        Unit = "EUR/kWh",
        ScopeType = scope,
        ScopeId = scopeId,
        ValidFrom = from,
        ValidTo = to,
    };

    [Fact]
    public void Picks_the_price_valid_for_the_date()
    {
        // Electricity price history from the Strom sheet.
        var tariffs = new[]
        {
            Unit(0.16, TariffScope.EnergyType, 1, new DateOnly(2022, 9, 1), new DateOnly(2022, 12, 31)),
            Unit(0.44, TariffScope.EnergyType, 1, new DateOnly(2023, 1, 1), new DateOnly(2023, 4, 30)),
            Unit(0.37, TariffScope.EnergyType, 1, new DateOnly(2023, 5, 1)),
        };

        Assert.Equal(0.16, TariffResolver.ResolveValue(tariffs, TariffComponent.UnitPrice, 5, 1, new DateOnly(2022, 10, 15)));
        Assert.Equal(0.44, TariffResolver.ResolveValue(tariffs, TariffComponent.UnitPrice, 5, 1, new DateOnly(2023, 2, 15)));
        Assert.Equal(0.37, TariffResolver.ResolveValue(tariffs, TariffComponent.UnitPrice, 5, 1, new DateOnly(2024, 6, 15)));
    }

    [Fact]
    public void Meter_scope_overrides_energy_type_and_global()
    {
        var tariffs = new[]
        {
            Unit(0.30, TariffScope.Global, null, new DateOnly(2023, 1, 1)),
            Unit(0.40, TariffScope.EnergyType, 1, new DateOnly(2023, 1, 1)),
            Unit(0.50, TariffScope.Meter, 7, new DateOnly(2023, 1, 1)),
        };

        Assert.Equal(0.50, TariffResolver.ResolveValue(tariffs, TariffComponent.UnitPrice, 7, 1, new DateOnly(2023, 6, 1)));
        Assert.Equal(0.40, TariffResolver.ResolveValue(tariffs, TariffComponent.UnitPrice, 8, 1, new DateOnly(2023, 6, 1)));
        Assert.Equal(0.30, TariffResolver.ResolveValue(tariffs, TariffComponent.UnitPrice, 8, 2, new DateOnly(2023, 6, 1)));
    }

    [Fact]
    public void Returns_zero_when_nothing_applies()
    {
        var tariffs = new[] { Unit(0.25, TariffScope.EnergyType, 1, new DateOnly(2024, 1, 1)) };

        Assert.Equal(0d, TariffResolver.ResolveValue(tariffs, TariffComponent.UnitPrice, 1, 1, new DateOnly(2023, 1, 1)));
    }
}