using System.Numerics;
using AcDream.App.World;

namespace AcDream.App.Tests.World;

public sealed class LiveWorldOriginStateTests
{
    [Fact]
    public void Placeholder_IsNotAuthoritativeUntilFirstInitialization()
    {
        var state = new LiveWorldOriginState();

        state.SetPlaceholder(42, 43);

        Assert.Equal(42, state.CenterX);
        Assert.Equal(43, state.CenterY);
        Assert.False(state.IsKnown);
        Assert.True(state.TryInitialize(10, 11));
        Assert.Equal(10, state.CenterX);
        Assert.Equal(11, state.CenterY);
        Assert.True(state.IsKnown);
        Assert.False(state.TryInitialize(20, 21));
        Assert.Equal(10, state.CenterX);
        Assert.Equal(11, state.CenterY);
    }

    [Fact]
    public void Recenter_ReplacesKnownOriginAndResetRetainsItAsPlaceholder()
    {
        var state = new LiveWorldOriginState();
        Assert.True(state.TryInitialize(1, 2));

        state.Recenter(3, 4);
        state.Reset();

        Assert.Equal(3, state.CenterX);
        Assert.Equal(4, state.CenterY);
        Assert.False(state.IsKnown);
        Assert.True(state.TryInitialize(5, 6));
    }

    [Fact]
    public void RecenterBeforeInitialization_PreservesUnknownAndResetIsIdempotent()
    {
        var state = new LiveWorldOriginState();
        state.SetPlaceholder(20, 21);

        state.Recenter(30, 31);
        state.Reset();
        state.Reset();

        Assert.Equal(30, state.CenterX);
        Assert.Equal(31, state.CenterY);
        Assert.False(state.IsKnown);

        Assert.True(state.TryInitialize(40, 41));
        state.Recenter(50, 51);

        Assert.True(state.IsKnown);
        Assert.Equal(50, state.CenterX);
        Assert.Equal(51, state.CenterY);
    }

    [Fact]
    public void CellLocalForSeed_UsesTheCurrentLandblockOrigin()
    {
        var state = new LiveWorldOriginState();
        state.SetPlaceholder(0x30, 0x32);

        Vector3 local = state.CellLocalForSeed(
            new Vector3(200f, -300f, 5f),
            0x3130_0001u);

        Assert.Equal(new Vector3(8f, 84f, 5f), local);
    }
}