using Friflo.Engine.ECS;
using Microsoft.Xna.Framework;
using MrGameEng.Core;
using MrGameEng.Graphics;
using Xunit;

namespace MrGameEng.Graphics.Tests;

public class SpriteAnimationTests
{
    private static Texture2DRegion Region(int x) => new(null!, new Rectangle(x, 0, 16, 16));

    private static SpriteAnimationClip Clip(bool loop, params int[] xs) =>
        new(Array.ConvertAll(xs, Region), framesPerSecond: 10f, loop);

    [Fact]
    public void FrameAt_LoopingClip_WrapsAround()
    {
        var clip = Clip(loop: true, 0, 1, 2);

        Assert.Equal(0, clip.FrameAt(0.00f).Bounds.X);
        Assert.Equal(1, clip.FrameAt(0.10f).Bounds.X);
        Assert.Equal(2, clip.FrameAt(0.25f).Bounds.X);
        Assert.Equal(0, clip.FrameAt(0.30f).Bounds.X); // wrapped
    }

    [Fact]
    public void FrameAt_NonLoopingClip_ClampsToLastFrame()
    {
        var clip = Clip(loop: false, 0, 1);

        Assert.Equal(1, clip.FrameAt(10f).Bounds.X);
    }

    private sealed class AnimScene : Scene
    {
        public Entity Animated;
        public SpriteAnimationClip Clip = SpriteAnimationTests.Clip(loop: false, 0, 1, 2);

        protected override void OnLoad()
        {
            this.UseSpriteAnimation();
            Animated = Store.CreateEntity(
                new Sprite { Color = Color.White },
                new SpriteAnimator(Clip));
        }
    }

    [Fact]
    public void AnimationSystem_AdvancesFrames_AndStopsAtEnd()
    {
        var context = new EngineContext();
        var scene = new AnimScene();
        context.Scenes.Switch(scene);

        context.Clock.Advance(0.15f); // 10 fps → frame 1
        context.Scenes.Update(context.Clock);
        Assert.Equal(1, scene.Animated.GetComponent<Sprite>().Region!.Bounds.X);

        context.Clock.Advance(1.0f); // far past the end of a non-looping clip
        context.Scenes.Update(context.Clock);
        Assert.Equal(2, scene.Animated.GetComponent<Sprite>().Region!.Bounds.X);
        Assert.False(scene.Animated.GetComponent<SpriteAnimator>().Playing);
    }
}