using MoonWorks;
using MoonWorks.Math.Float;
using MoonWorks.Graphics;

namespace MoonWorks.Test
{
	class MSAAGame : Game
	{
		private GraphicsPipeline[] msaaPipelines = new GraphicsPipeline[4];
		private GraphicsPipeline blitPipeline;

		private Texture[] renderTargets = new Texture[4];
		private Sampler rtSampler;
		private GpuBuffer quadVertexBuffer;
		private GpuBuffer quadIndexBuffer;

		private SampleCount currentSampleCount = SampleCount.Four;

		public MSAAGame() : base(TestUtils.GetStandardWindowCreateInfo(), TestUtils.GetStandardFrameLimiterSettings(), TestUtils.DefaultBackend, 60, true)
		{
			Logger.LogInfo("Press Left and Right to cycle between sample counts");
			Logger.LogInfo("Setting sample count to: " + currentSampleCount);

			// Create the MSAA pipelines
			ShaderModule triangleVertShaderModule = new ShaderModule(GraphicsDevice, TestUtils.GetShaderPath("RawTriangle.vert"));
			ShaderModule triangleFragShaderModule = new ShaderModule(GraphicsDevice, TestUtils.GetShaderPath("SolidColor.frag"));

			GraphicsPipelineCreateInfo pipelineCreateInfo = TestUtils.GetStandardGraphicsPipelineCreateInfo(
				TextureFormat.R8G8B8A8,
				triangleVertShaderModule,
				triangleFragShaderModule
			);
			for (int i = 0; i < msaaPipelines.Length; i += 1)
			{
				pipelineCreateInfo.MultisampleState.MultisampleCount = (SampleCount) i;
				msaaPipelines[i] = new GraphicsPipeline(GraphicsDevice, pipelineCreateInfo);
			}

			// Create the blit pipeline
			ShaderModule blitVertShaderModule = new ShaderModule(GraphicsDevice, TestUtils.GetShaderPath("TexturedQuad.vert"));
			ShaderModule blitFragShaderModule = new ShaderModule(GraphicsDevice, TestUtils.GetShaderPath("TexturedQuad.frag"));

			pipelineCreateInfo = TestUtils.GetStandardGraphicsPipelineCreateInfo(
				MainWindow.SwapchainFormat,
				blitVertShaderModule,
				blitFragShaderModule
			);
			pipelineCreateInfo.VertexInputState = VertexInputState.CreateSingleBinding<PositionTextureVertex>();
			pipelineCreateInfo.FragmentShaderInfo.SamplerBindingCount = 1;
			blitPipeline = new GraphicsPipeline(GraphicsDevice, pipelineCreateInfo);

			// Create the MSAA render textures
			for (int i = 0; i < renderTargets.Length; i += 1)
			{
				renderTargets[i] = Texture.CreateTexture2D(
					GraphicsDevice,
					MainWindow.Width,
					MainWindow.Height,
					TextureFormat.R8G8B8A8,
					TextureUsageFlags.ColorTarget | TextureUsageFlags.Sampler,
					1,
					(SampleCount) i
				);
			}

			// Create the sampler
			rtSampler = new Sampler(GraphicsDevice, SamplerCreateInfo.PointClamp);

			// Create and populate the vertex and index buffers
			var resourceUploader = new ResourceUploader(GraphicsDevice);

			quadVertexBuffer = resourceUploader.CreateBuffer(
				[
					new PositionTextureVertex(new Vector3(-1, -1, 0), new Vector2(0, 0)),
					new PositionTextureVertex(new Vector3(1, -1, 0), new Vector2(1, 0)),
					new PositionTextureVertex(new Vector3(1, 1, 0), new Vector2(1, 1)),
					new PositionTextureVertex(new Vector3(-1, 1, 0), new Vector2(0, 1))
				],
				BufferUsageFlags.Vertex
			);

			quadIndexBuffer = resourceUploader.CreateBuffer<ushort>(
				[
					0, 1, 2,
					0, 2, 3
				],
				BufferUsageFlags.Index
			);

			resourceUploader.Upload();
			resourceUploader.Dispose();
		}

		protected override void Update(System.TimeSpan delta)
		{
			SampleCount prevSampleCount = currentSampleCount;

			if (TestUtils.CheckButtonPressed(Inputs, TestUtils.ButtonType.Left))
			{
				currentSampleCount -= 1;
				if (currentSampleCount < 0)
				{
					currentSampleCount = SampleCount.Eight;
				}
			}
			if (TestUtils.CheckButtonPressed(Inputs, TestUtils.ButtonType.Right))
			{
				currentSampleCount += 1;
				if (currentSampleCount > SampleCount.Eight)
				{
					currentSampleCount = SampleCount.One;
				}
			}

			if (prevSampleCount != currentSampleCount)
			{
				Logger.LogInfo("Setting sample count to: " + currentSampleCount);
			}
		}

		protected override void Draw(double alpha)
		{
			CommandBuffer cmdbuf = GraphicsDevice.AcquireCommandBuffer();
			Texture? backbuffer = cmdbuf.AcquireSwapchainTexture(MainWindow);
			if (backbuffer != null)
			{
				Texture rt = renderTargets[(int) currentSampleCount];

				cmdbuf.BeginRenderPass(new ColorAttachmentInfo(rt, WriteOptions.SafeDiscard, Color.Black));
				cmdbuf.BindGraphicsPipeline(msaaPipelines[(int) currentSampleCount]);
				cmdbuf.DrawPrimitives(0, 1);
				cmdbuf.EndRenderPass();

				cmdbuf.BeginRenderPass(new ColorAttachmentInfo(backbuffer, WriteOptions.SafeDiscard, LoadOp.DontCare));
				cmdbuf.BindGraphicsPipeline(blitPipeline);
				cmdbuf.BindFragmentSamplers(new TextureSamplerBinding(rt, rtSampler));
				cmdbuf.BindVertexBuffers(quadVertexBuffer);
				cmdbuf.BindIndexBuffer(quadIndexBuffer, IndexElementSize.Sixteen);
				cmdbuf.DrawIndexedPrimitives(0, 0, 2);
				cmdbuf.EndRenderPass();
			}
			GraphicsDevice.Submit(cmdbuf);
		}

		public static void Main(string[] args)
		{
			MSAAGame game = new MSAAGame();
			game.Run();
		}
	}
}