using foodmarket.Application.Inventory;
using Xunit;

namespace foodmarket.UnitTests;

/// <summary>Логика разбивки результата инвентаризации на Оприходование/Списание
/// (модель МойСклада). diff==0 не участвует; суммы = кол-во × себестоимость.</summary>
public class InventoryResultTests
{
    private static (Guid, decimal, decimal) L(decimal diff, decimal cost) => (Guid.NewGuid(), diff, cost);

    [Fact]
    public void Surplus_goes_to_enter_shortage_to_loss()
    {
        var p1 = Guid.NewGuid(); var p2 = Guid.NewGuid();
        var split = InventoryResult.Build(new[]
        {
            (p1, 3m, 100m),   // излишек +3
            (p2, -2m, 50m),   // недостача -2
        });

        Assert.Single(split.Surplus);
        Assert.Single(split.Shortage);
        Assert.Equal(p1, split.Surplus[0].ProductId);
        Assert.Equal(3m, split.Surplus[0].Quantity);
        Assert.Equal(p2, split.Shortage[0].ProductId);
        Assert.Equal(2m, split.Shortage[0].Quantity);   // |-2|
    }

    [Fact]
    public void Zero_diff_lines_are_ignored()
    {
        var split = InventoryResult.Build(new[]
        {
            L(0m, 100m),   // совпало — не трогаем
            L(0m, 999m),
            L(1m, 10m),    // только эта
        });
        Assert.Single(split.Surplus);
        Assert.Empty(split.Shortage);
        Assert.Equal(1m, split.Surplus[0].Quantity);
    }

    [Fact]
    public void Sums_are_quantity_times_cost()
    {
        var split = InventoryResult.Build(new[]
        {
            L(2m, 150m),    // +2 × 150 = 300
            L(5m, 20m),     // +5 × 20  = 100
            L(-3m, 40m),    // 3  × 40  = 120 (недостача)
        });
        Assert.Equal(400m, split.SurplusTotal);
        Assert.Equal(120m, split.ShortageTotal);
        Assert.True(split.HasSurplus);
        Assert.True(split.HasShortage);
    }

    [Fact]
    public void Line_total_rounds_to_two_decimals()
    {
        var split = InventoryResult.Build(new[] { L(3m, 548.6441m) });
        // 3 × 548.6441 = 1645.9323 → округление до 2 знаков
        Assert.Equal(1645.93m, split.Surplus[0].LineTotal);
    }

    [Fact]
    public void No_diffs_gives_empty_split()
    {
        var split = InventoryResult.Build(new[] { L(0m, 10m), L(0m, 20m) });
        Assert.False(split.HasSurplus);
        Assert.False(split.HasShortage);
        Assert.Equal(0m, split.SurplusTotal);
        Assert.Equal(0m, split.ShortageTotal);
    }
}