using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;


namespace PlanetTutorial
{

    public class RenderTargetState
    {
        public RenderTarget2D RenderTarget;
        //public DepthStencilBuffer DepthBuffer;
        GraphicsDevice GraphicsDevice;
        RenderTargetState oldState;

        bool CreatedBuffers;

        int renderTargetWidth, renderTargetHeight;
        int depthBufferWidth, depthBufferHeight;

        public RenderTargetState(GraphicsDevice GraphicsDevice,
                                 int renderTargetIndex)
        {
            this.GraphicsDevice = GraphicsDevice;
            RenderTarget =
                (RenderTarget2D)GraphicsDevice.GetRenderTarget(renderTargetIndex);
            //DepthBuffer = GraphicsDevice.DepthStencilBuffer;
            CreatedBuffers = false;
        }

        public RenderTargetState(GraphicsDevice GraphicsDevice)
            :
                    this(GraphicsDevice, 0)
        {

        }

        public RenderTargetState(GraphicsDevice GraphicsDevice,
                                 int renderTargetWidth,
                                 int renderTargetHeight)
            : this(GraphicsDevice,
                   renderTargetWidth,
                   renderTargetHeight,
                   renderTargetWidth,
                   renderTargetHeight)
        {
        }

        public RenderTargetState(GraphicsDevice GraphicsDevice,
                                 int renderTargetWidth,
                                 int renderTargetHeight,
                                 int depthBufferWidth,
                                 int depthBufferHeight)
        {
            this.GraphicsDevice = GraphicsDevice;

            this.renderTargetWidth = renderTargetWidth;
            this.renderTargetHeight = renderTargetHeight;
            this.depthBufferWidth = depthBufferWidth;
            this.depthBufferHeight = depthBufferHeight;

            CreateBuffers();

            CreatedBuffers = true;

            GraphicsDevice.DeviceReset +=
                new EventHandler(GraphicsDevice_DeviceReset);

            GraphicsDevice.DeviceResetting +=
                new EventHandler(GraphicsDevice_DeviceResetting);
        }

        private void CreateBuffers()
        {
            RenderTarget =
                new RenderTarget2D(
                    GraphicsDevice,
                    renderTargetWidth,
                    renderTargetHeight,
                    1,
                    RenderTargetHelper.SelectRenderTargetMode(false));

            //DepthBuffer =
                //new DepthStencilBuffer(
                //    GraphicsDevice,
                //    depthBufferWidth,
                //    depthBufferHeight,
                //    GraphicsDevice.DepthStencilBuffer.Format);
        }

        void GraphicsDevice_DeviceReset(object sender, EventArgs e)
        {
            if (CreatedBuffers)
                CreateBuffers();
        }

        void GraphicsDevice_DeviceResetting(object sender, EventArgs e)
        {
            DestroyBuffers();
        }

        public RenderTargetState SetToDevice()
        {
            return SetToDevice(0);
        }

        public RenderTargetState SetToDevice(int renderTargetIndex)
        {
            oldState = new RenderTargetState(GraphicsDevice,
                                             renderTargetIndex);

            GraphicsDevice.SetRenderTarget(//renderTargetIndex,
                                           RenderTarget);
            //GraphicsDevice.DepthStencilBuffer = DepthBuffer;

            return oldState;
        }

        public void DestroyBuffers()
        {
            oldState = null;

            if (CreatedBuffers)
            {
                if (RenderTarget != null)
                {
                    RenderTarget.Dispose();
                    RenderTarget = null;
                }
                //if (DepthBuffer != null)
                //{
                //    DepthBuffer.Dispose();
                //    DepthBuffer = null;
                //}
            }
        }

        public RenderTargetState BeginRenderToTexture()
        {
            oldState = SetToDevice();

            return oldState;
        }

        public RenderTargetState BeginRenderToTexture(int renderTargetIndex)
        {
            oldState = SetToDevice(renderTargetIndex);

            return oldState;
        }

        public RenderTargetState EndRenderToTexture()
        {
            return EndRenderToTexture(0);
        }

        public RenderTargetState EndRenderToTexture(int renderTargetIndex)
        {
            RenderTargetState renderBuffer =
                    oldState.SetToDevice(renderTargetIndex);

            oldState = null;

            return renderBuffer;
        }

        public Texture2D EndRenderGetTexture()
        {
            return EndRenderGetTexture(0);
        }

        public Texture2D EndRenderGetTexture(int renderTargetIndex)
        {
            RenderTargetState renderBuffer =
                    oldState.SetToDevice(renderTargetIndex);

            oldState = null;

            return renderBuffer.RenderTarget;
        }
    }

    public class RenderTargetHelper
    {
        public static DepthFormat SelectStencilMode(
                                        SurfaceFormat renderTargetFormat)
        {
            // Check stencil formats
            GraphicsAdapter adapter = GraphicsAdapter.DefaultAdapter;
            SurfaceFormat format = adapter.CurrentDisplayMode.Format;

            DepthFormat depthFormat = DepthFormat.Unknown;


            if (adapter.CheckDepthStencilMatch(
                        DeviceType.Hardware,
                        format,
                        renderTargetFormat,
                        DepthFormat.Depth24Stencil8))
            {
                depthFormat = DepthFormat.Depth24Stencil8;
            }
            else if (adapter.CheckDepthStencilMatch(
                        DeviceType.Hardware,
                        format,
                        renderTargetFormat,
                        DepthFormat.Depth24Stencil8Single))
            {
                depthFormat = DepthFormat.Depth24Stencil8Single;
            }
            else if (adapter.CheckDepthStencilMatch(
                        DeviceType.Hardware,
                        format,
                        renderTargetFormat,
                        DepthFormat.Depth24Stencil4))
            {
                depthFormat = DepthFormat.Depth24Stencil4;
            }
            else if (adapter.CheckDepthStencilMatch(
                        DeviceType.Hardware,
                        format,
                        renderTargetFormat,
                        DepthFormat.Depth15Stencil1))
            {
                depthFormat = DepthFormat.Depth15Stencil1;
            }
            else if (adapter.CheckDepthStencilMatch(
                        DeviceType.Reference,
                        format,
                        renderTargetFormat,
                        DepthFormat.Depth24Stencil8))
            {
                depthFormat = DepthFormat.Depth24Stencil8;
            }
            else if (adapter.CheckDepthStencilMatch(
                        DeviceType.Reference,
                        format,
                        renderTargetFormat,
                        DepthFormat.Depth24Stencil8Single))
            {
                depthFormat = DepthFormat.Depth24Stencil8Single;
            }
            else if (adapter.CheckDepthStencilMatch(
                        DeviceType.Reference,
                        format,
                        renderTargetFormat,
                        DepthFormat.Depth24Stencil4))
            {
                depthFormat = DepthFormat.Depth24Stencil4;
            }
            else if (adapter.CheckDepthStencilMatch(
                        DeviceType.Reference,
                        format,
                        renderTargetFormat,
                        DepthFormat.Depth15Stencil1))
            {
                depthFormat = DepthFormat.Depth15Stencil1;
            }

            return depthFormat;
        }


        public static SurfaceFormat SelectRenderTargetMode(bool preferFloat)
        {
            // Check stencil formats
            GraphicsAdapter adapter = GraphicsAdapter.DefaultAdapter;
            SurfaceFormat displayFormat = adapter.CurrentDisplayMode.Format;

            DepthFormat depthFormat = SelectStencilMode(displayFormat);

            SurfaceFormat surfaceFormat = SurfaceFormat.Color;

            if (preferFloat)
            {
                if (adapter.CheckDepthStencilMatch(
                            DeviceType.Hardware,
                            displayFormat,
                            SurfaceFormat.Single,
                            depthFormat))
                {
                    surfaceFormat = SurfaceFormat.Single;
                }
                else if (adapter.CheckDepthStencilMatch(
                            DeviceType.Hardware,
                            displayFormat,
                            SurfaceFormat.HalfSingle,
                            depthFormat))
                {
                    surfaceFormat = SurfaceFormat.HalfSingle;
                }
                else if (adapter.CheckDepthStencilMatch(
                            DeviceType.Hardware,
                            displayFormat,
                            SurfaceFormat.Color,
                            depthFormat))
                {
                    surfaceFormat = SurfaceFormat.Color;
                }
                else if (adapter.CheckDepthStencilMatch(
                            DeviceType.Reference,
                            displayFormat,
                            SurfaceFormat.Single,
                            depthFormat))
                {
                    surfaceFormat = SurfaceFormat.Single;
                }
                else if (adapter.CheckDepthStencilMatch(
                            DeviceType.Reference,
                            displayFormat,
                            SurfaceFormat.HalfSingle,
                            depthFormat))
                {
                    surfaceFormat = SurfaceFormat.HalfSingle;
                }
                else if (adapter.CheckDepthStencilMatch(
                            DeviceType.Reference,
                            displayFormat,
                            SurfaceFormat.Color,
                            depthFormat))
                {
                    surfaceFormat = SurfaceFormat.Color;
                }
                else
                {
                    surfaceFormat = SurfaceFormat.Unknown;
                }
            }

            return surfaceFormat;
        }
    }
}