using MeterVault.Core.Domain;

namespace MeterVault.Core.Tests;

/// <summary>
/// The event menu on a meter page is driven by these rules, so they pin which events each mode can
/// actually use — an event the normalizer ignores must never be offered as if it fixed something.
/// </summary>
public sealed class MeterEventRulesTests
{
    [Theory]
    [InlineData(MeterMode.CumulativeCounter)]
    [InlineData(MeterMode.GenerationCounter)]
    [InlineData(MeterMode.RuntimeCounter)]
    public void Registers_offer_swap_and_reset(MeterMode mode)
    {
        Assert.Equal([MeterEventType.MeterSwap, MeterEventType.CounterReset, MeterEventType.Note], MeterEventRules.RecordableFor(mode));
        Assert.True(MeterEventRules.IsMonotonic(mode));
        Assert.True(MeterEventRules.TakesReadings(mode));
    }

    [Fact]
    public void A_tank_offers_level_and_delivery_and_takes_no_readings()
    {
        Assert.Equal([MeterEventType.TankLevel, MeterEventType.Delivery, MeterEventType.Note],
            MeterEventRules.RecordableFor(MeterMode.ConsumableBalance));
        Assert.False(MeterEventRules.TakesReadings(MeterMode.ConsumableBalance));
        Assert.False(MeterEventRules.CanRecord(MeterMode.ConsumableBalance, MeterEventType.MeterSwap));
    }

    [Theory]
    [InlineData(MeterMode.DirectDelta)]
    [InlineData(MeterMode.InstantRate)]
    [InlineData(MeterMode.Virtual)]
    public void Modes_without_a_register_only_take_notes(MeterMode mode) =>
        Assert.Equal([MeterEventType.Note], MeterEventRules.RecordableFor(mode));

    [Fact]
    public void Correction_is_never_offered_because_nothing_reads_it()
    {
        foreach (var mode in Enum.GetValues<MeterMode>())
        {
            Assert.DoesNotContain(MeterEventType.Correction, MeterEventRules.RecordableFor(mode));
        }
    }
}