using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Aiwaz.Contracts;
using Aiwaz.Core;

namespace Aiwaz.Resources
{
    public abstract class RenderTarget : CommandUser, IRenderTargetBase, IDisposable
    {
        public RenderTarget()
            : base()
        {
            Commands.Add(new Command(this, CommandFlags.EndChain | CommandFlags.FlushChain, setRenderTargetCommandType, 0, 0));

            this.ClearDepth = 1.0f;
        }

        ~RenderTarget()
        {
            if (Engine.Initialized)
                this.Dispose();
        }

        #region IRenderTargetBase Members
        
        internal static SlimDX.Direct3D10.ShaderResourceView[] emptyShaderResView = new SlimDX.Direct3D10.ShaderResourceView[128];

        private SlimDX.Direct3D10.RenderTargetView[] renderTargetViews;
        private List<IRenderTargetBase> additionalRenderTargets = new List<IRenderTargetBase>();
        private SlimDX.Direct3D10.Viewport[] viewports;

        protected int multiSampleCount = 1;
        protected int multiSampleQuality = 0;
        private BindFlags lastBindFlags = BindFlags.Default;

        public float ClearDepth                 { get; set; }
        public byte ClearStencil                { get; set; }
        public SlimDX.Color4 ClearColor         { get; set; }

        private ViewPort viewPort;
        public ViewPort ViewPort 
        {
            get { return viewPort; }
            set
            {
                viewPort = value;
                this.KillViewPortAndRenderTargetData();
                this.BuildViewPortAndRenderTargetData();
            }
        }

        public abstract int RenderTargetWidth                  { get; }
        public abstract int RenderTargetHeight                 { get; }
        public abstract SlimDX.DXGI.Format RenderTargetFormat  { get; }

        private bool hasDepthStencilBuffer;
        public bool HasDepthStencilBuffer
        {
            get { return hasDepthStencilBuffer; }
            set
            {
                hasDepthStencilBuffer = value;

                Engine.Device.ClearState();

	            if (DX10DepthStencilView != null)
		            DX10DepthStencilView.Dispose();
	            DX10DepthStencilView = null;

                if (DX10DepthStencilTexture != null)
		            DX10DepthStencilTexture.Dispose();
                DX10DepthStencilTexture = null;

	            if (!hasDepthStencilBuffer)
		            return; // no further effort needed here

	            var depthTextureDesc = new SlimDX.Direct3D10.Texture2DDescription()
                {
                    Width = this.RenderTargetWidth,
	                Height = this.RenderTargetHeight,
	                MipLevels = 1,
	                ArraySize = 1,
	                Format = SlimDX.DXGI.Format.D24_UNorm_S8_UInt,
                    SampleDescription = new SlimDX.DXGI.SampleDescription(multiSampleCount == 0 ? 1 : multiSampleCount, multiSampleQuality),
	                Usage = SlimDX.Direct3D10.ResourceUsage.Default,
	                BindFlags = SlimDX.Direct3D10.BindFlags.DepthStencil,
                    CpuAccessFlags  = SlimDX.Direct3D10.CpuAccessFlags.None,
                    OptionFlags = SlimDX.Direct3D10.ResourceOptionFlags.None
                };

                DX10DepthStencilTexture = new SlimDX.Direct3D10.Texture2D(Engine.Device, depthTextureDesc);
                if (DX10DepthStencilTexture == null)
                    throw new Aiwaz.Core.ActionFailedException("RenderTarget: Unable to create depth stencil texture.");

	            var depthStencilViewDesc = new SlimDX.Direct3D10.DepthStencilViewDescription()
                {
                    Format = depthTextureDesc.Format,
                    Dimension = multiSampleCount >= 1 ? SlimDX.Direct3D10.DepthStencilViewDimension.Texture2DMultisampled : SlimDX.Direct3D10.DepthStencilViewDimension.Texture2D,
	                MipSlice = 0
                };

                DX10DepthStencilView = new SlimDX.Direct3D10.DepthStencilView(Engine.Device, DX10DepthStencilTexture, depthStencilViewDesc);
                if (DX10DepthStencilView == null)
                    throw new Aiwaz.Core.ActionFailedException("RenderTarget: Unable to create depth stencil view.");
            }
        }

        public SlimDX.Direct3D10.RenderTargetView DX10RenderTargetView      { get; protected set; }
        public SlimDX.Direct3D10.DepthStencilView DX10DepthStencilView      { get; protected set; }
        public SlimDX.Direct3D10.Texture2D DX10DepthStencilTexture          { get; protected set; }

        public void AddAdditionalRenderTarget(IRenderTargetBase target)
        {
            this.RemoveAdditionalRenderTarget(target);
	        //if (AdditionalRenderTargets.Count + 1 == D3D10_SIMULTANEOUS_RENDER_TARGET_COUNT)
            //    throw new Aiwaz.Core.ActionFailedException("RenderTarget: Unable to add an additional rendering target, list is full.");

            additionalRenderTargets.Add(target);
	        this.KillViewPortAndRenderTargetData();
	        this.BuildViewPortAndRenderTargetData();
        }

        public void RemoveAdditionalRenderTarget(IRenderTargetBase target)
        {
            if (additionalRenderTargets.Remove(target))
            {
                this.KillViewPortAndRenderTargetData();
                this.BuildViewPortAndRenderTargetData();
            }
        }

        public void Bind(BindFlags bindFlags)
        {
            if ((bindFlags & ~ BindFlags.ClearAll) != (lastBindFlags & ~ BindFlags.ClearAll))
	        {
                lastBindFlags = bindFlags;
		        this.KillViewPortAndRenderTargetData();
		        this.BuildViewPortAndRenderTargetData();
	        }
            else
                lastBindFlags = bindFlags;

            this.Clear(bindFlags);

            Engine.Device.PixelShader.SetShaderResources(emptyShaderResView, 0, 128);
            Engine.Device.OutputMerger.SetTargets(DX10DepthStencilView, renderTargetViews);
            Engine.Device.Rasterizer.SetViewports(viewports);

            Engine.EngineStates.LastRenderTarget = this;
        }

        public void UnbindAllRenderTargets()
        {
            if (Engine.EngineStates.LastRenderTarget == this)
            {
                Engine.Device.OutputMerger.SetTargets(new SlimDX.Direct3D10.RenderTargetView[0]);
                Engine.Device.Rasterizer.SetViewports(new SlimDX.Direct3D10.Viewport[0]);
                Engine.EngineStates.LastRenderTarget = null;
            }
        }

        protected void BuildViewPortAndRenderTargetData()
        {
	        // Rebuild render targets
	        if (renderTargetViews == null && viewports == null)
	        {
		        if ((lastBindFlags & BindFlags.BindAllTextures) == BindFlags.BindAllTextures)
		        {
			        renderTargetViews   = new SlimDX.Direct3D10.RenderTargetView[additionalRenderTargets.Count + 1];
                    viewports           = new SlimDX.Direct3D10.Viewport[additionalRenderTargets.Count + 1];

                    renderTargetViews[0] = this.DX10RenderTargetView;
                    viewports[0] = this.ViewPort;
                    for (int i = 0; i < additionalRenderTargets.Count; ++i)
                    {
                        renderTargetViews[i + 1] = additionalRenderTargets[i].DX10RenderTargetView;
                        viewports[i + 1] = additionalRenderTargets[i].ViewPort;
                    }
		        }
		        else if ((lastBindFlags & BindFlags.BindAllTextures) != BindFlags.None)
		        {
			        var activeRenderTargetCount = 0;
                    if ((lastBindFlags & BindFlags.BindBaseTexture)         != BindFlags.None) ++activeRenderTargetCount;
                    if ((lastBindFlags & BindFlags.BindAdditionalTexture0)  != BindFlags.None) ++activeRenderTargetCount;
                    if ((lastBindFlags & BindFlags.BindAdditionalTexture1)  != BindFlags.None) ++activeRenderTargetCount;
                    if ((lastBindFlags & BindFlags.BindAdditionalTexture2)  != BindFlags.None) ++activeRenderTargetCount;
                    if ((lastBindFlags & BindFlags.BindAdditionalTexture3)  != BindFlags.None) ++activeRenderTargetCount;

                    renderTargetViews = new SlimDX.Direct3D10.RenderTargetView[activeRenderTargetCount];
                    viewports = new SlimDX.Direct3D10.Viewport[activeRenderTargetCount];

			        int bufferIndex = 0;
                    if ((lastBindFlags & BindFlags.BindBaseTexture)         != BindFlags.None)
                    {
                        renderTargetViews[bufferIndex] = this.DX10RenderTargetView;
                        viewports[bufferIndex++] = this.ViewPort;
                    }
                    if ((lastBindFlags & BindFlags.BindAdditionalTexture0)  != BindFlags.None)
                    {
                        renderTargetViews[bufferIndex] = additionalRenderTargets[0].DX10RenderTargetView;
                        viewports[bufferIndex++] = additionalRenderTargets[0].ViewPort;
                    }
                    if ((lastBindFlags & BindFlags.BindAdditionalTexture1)  != BindFlags.None)
                    {
                        renderTargetViews[bufferIndex] = additionalRenderTargets[1].DX10RenderTargetView;
                        viewports[bufferIndex++] = additionalRenderTargets[1].ViewPort;
                    }
                    if ((lastBindFlags & BindFlags.BindAdditionalTexture2)  != BindFlags.None)
                    {
                        renderTargetViews[bufferIndex] = additionalRenderTargets[2].DX10RenderTargetView;
                        viewports[bufferIndex++] = additionalRenderTargets[2].ViewPort;
                    }
                    if ((lastBindFlags & BindFlags.BindAdditionalTexture3)  != BindFlags.None)
                    {
                        renderTargetViews[bufferIndex] = additionalRenderTargets[3].DX10RenderTargetView;
                        viewports[bufferIndex++] = additionalRenderTargets[3].ViewPort;
                    }
		        }
		        else
                    throw new ActionFailedException("No render target bindable.");
	        }
        }


        protected void KillViewPortAndRenderTargetData()
        {
            renderTargetViews = null;
            viewports = null;

            if (Engine.EngineStates.LastRenderTarget == this)
                Engine.EngineStates.LastRenderTarget = null;
        }

        #endregion

        #region IDisposable Members

        protected void DisposeInternal()
        {
            this.KillViewPortAndRenderTargetData();
            this.UnbindAllRenderTargets();

            if (DX10RenderTargetView != null)
                DX10RenderTargetView.Dispose();
            DX10RenderTargetView = null;

            if (DX10DepthStencilView != null)
                DX10DepthStencilView.Dispose();
            DX10DepthStencilView = null;

            if (DX10DepthStencilTexture != null)
                DX10DepthStencilTexture.Dispose();
            DX10DepthStencilTexture = null;
        }

        public override void Dispose()
        {
            this.DisposeInternal();
            base.Dispose();
        }

        #endregion

        #region CommandUser

        const byte setRenderTargetCommandType = 0;
        public override CommandExecuteResult ExecuteCommand(byte commandType, CommandBuffer currentBuffer, int currentPositon)
        {
            if (commandType == setRenderTargetCommandType)
	        {
		        if (Engine.EngineStates.LastRenderTarget != this)
		        {
			        this.UnbindAllRenderTargets();
			        this.Bind(BindFlags.Default);
		        }
		        else
			        this.Clear(BindFlags.Default);
	        }
	        return CommandExecuteResult.None;
        }


        protected void Clear(BindFlags bindFlags)
        {
	        if ((bindFlags & BindFlags.ClearColor) != BindFlags.None)
		        Engine.Device.ClearRenderTargetView(DX10RenderTargetView, ClearColor);

	        if ((bindFlags & BindFlags.ClearDepthStencil) != BindFlags.None && DX10DepthStencilView != null)
                Engine.Device.ClearDepthStencilView(DX10DepthStencilView, SlimDX.Direct3D10.DepthStencilClearFlags.Depth | SlimDX.Direct3D10.DepthStencilClearFlags.Stencil, ClearDepth, ClearStencil);
        }

        #endregion
    }
}