using PnvPanel.Domain.Pricing;
using Xunit;

namespace PnvPanel.Domain.Tests.Pricing;

public class PricingDiscountTests
{
    private static PricingDiscountTier Tier(int minConfigs, int percent) =>
        PricingDiscountTier.Create(Guid.NewGuid(), minConfigs, percent);

    [Fact]
    public void ResolvePercent_WhenNoTiers_ReturnsZero()
    {
        var percent = PricingDiscount.ResolvePercent([], maxConfigs: 10);

        Assert.Equal(0, percent);
    }

    [Fact]
    public void ResolvePercent_WhenBelowAllThresholds_ReturnsZero()
    {
        var tiers = new[] { Tier(3, 5), Tier(6, 10) };

        var percent = PricingDiscount.ResolvePercent(tiers, maxConfigs: 2);

        Assert.Equal(0, percent);
    }

    [Fact]
    public void ResolvePercent_PicksHighestApplicableTier_NotCumulative()
    {
        var tiers = new[] { Tier(3, 5), Tier(6, 10), Tier(12, 15) };

        var percent = PricingDiscount.ResolvePercent(tiers, maxConfigs: 8);

        Assert.Equal(10, percent);
    }

    [Fact]
    public void ResolvePercent_ExactlyOnThreshold_Applies()
    {
        var tiers = new[] { Tier(3, 5) };

        var percent = PricingDiscount.ResolvePercent(tiers, maxConfigs: 3);

        Assert.Equal(5, percent);
    }

    [Fact]
    public void Apply_WithZeroPercent_ReturnsAmountUnchanged()
    {
        var amount = PricingDiscount.Apply(1000, 0);

        Assert.Equal(1000, amount);
    }

    [Fact]
    public void Apply_WithPercent_RoundsToNearestInteger()
    {
        var amount = PricingDiscount.Apply(999, 10);

        Assert.Equal(899, amount);
    }
}