using SharpDX.Direct3D;
using SharpDX.Direct3D11;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using TerraFX.Interop.DirectX;
using TerraFX.Interop.Windows;

namespace CustomResolution.Shaders;

public class ExampleShader : MiniShader
{
    public ExampleShader() : base("Example")
    {
        Constants = new(this);
    }

    public MiniShaderConstants<TConstants> Constants { get; private set; } 

    public override void Dispose()
    {
        Constants.Dispose();
        base.Dispose();
    }

    public void Draw()
    {
        using MiniShaderState state = new();

        state.SetShader(Ctx.VertexShader, VS);
        state.SetShader(Ctx.PixelShader, PS);
        state.SetShader(Ctx.GeometryShader, null);

        state.Set(Ctx.InputAssembler, nameof(Ctx.InputAssembler.PrimitiveTopology), PrimitiveTopology.TriangleList);

        state.SetConstantBuffer(Ctx.PixelShader, 0, Constants.Buffer);

        Ctx.PixelShader.SetConstantBuffer(0, Constants.Buffer);

        var blendDesc = Ctx.OutputMerger.BlendState.Description;
        blendDesc.RenderTarget[0].IsBlendEnabled = true;
        blendDesc.RenderTarget[0].SourceBlend = BlendOption.SourceAlpha;
        blendDesc.RenderTarget[0].DestinationBlend = BlendOption.InverseSourceAlpha;
        blendDesc.RenderTarget[0].BlendOperation = BlendOperation.Add;
        blendDesc.RenderTarget[0].SourceAlphaBlend = BlendOption.SourceAlpha;
        blendDesc.RenderTarget[0].DestinationAlphaBlend = BlendOption.InverseSourceAlpha;
        blendDesc.RenderTarget[0].AlphaBlendOperation = BlendOperation.Maximum;
        blendDesc.RenderTarget[0].RenderTargetWriteMask = ColorWriteMaskFlags.All;

        using var blendState = new BlendState(Device, blendDesc);
        state.Set(Ctx.OutputMerger, nameof(Ctx.OutputMerger.BlendState), blendState);

        Ctx.Draw(3, 0);
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct TConstants
    {
        public float Time;
    }
}