using System;
using System.Diagnostics;
using System.Drawing;
using Switch_Toolbox.Library;
using System.Runtime.InteropServices;

namespace Switch_Toolbox.Library
{
    public class DDSCompressor
    {
        //Huge thanks to gdkchan and AbooodXD for the method of decomp BC5/BC4.

        //Todo. Add these to DDS code and add in methods to compress and decode more formats
        //BC7 also needs to be decompressed properly since OpenTK can't decompress those

        //BC4 actually breaks a bit with artifacts so i'll need to go back and fix

        private static byte[] BCnDecodeTile(byte[] Input, int Offset, bool IsBC1)
        {
            Color[] CLUT = new Color[4];

            int c0 = Get16(Input, Offset + 0);
            int c1 = Get16(Input, Offset + 2);

            CLUT[0] = DecodeRGB565(c0);
            CLUT[1] = DecodeRGB565(c1);
            CLUT[2] = CalculateCLUT2(CLUT[0], CLUT[1], c0, c1, IsBC1);
            CLUT[3] = CalculateCLUT3(CLUT[0], CLUT[1], c0, c1, IsBC1);

            int Indices = Get32(Input, Offset + 4);

            int IdxShift = 0;

            byte[] Output = new byte[4 * 4 * 4];

            int OOffset = 0;

            for (int TY = 0; TY < 4; TY++)
            {
                for (int TX = 0; TX < 4; TX++)
                {
                    int Idx = (Indices >> IdxShift) & 3;

                    IdxShift += 2;

                    Color Pixel = CLUT[Idx];

                    Output[OOffset + 0] = Pixel.B;
                    Output[OOffset + 1] = Pixel.G;
                    Output[OOffset + 2] = Pixel.R;
                    Output[OOffset + 3] = Pixel.A;

                    OOffset += 4;
                }
            }
            return Output;
        }
        private static Color DecodeRGB565(int Value)
        {
            int B = ((Value >> 0) & 0x1f) << 3;
            int G = ((Value >> 5) & 0x3f) << 2;
            int R = ((Value >> 11) & 0x1f) << 3;

            return Color.FromArgb(
                R | (R >> 5),
                G | (G >> 6),
                B | (B >> 5));
        }
        private static Color CalculateCLUT2(Color C0, Color C1, int c0, int c1, bool IsBC1)
        {
            if (c0 > c1 || !IsBC1)
            {
                return Color.FromArgb(
                    (2 * C0.R + C1.R) / 3,
                    (2 * C0.G + C1.G) / 3,
                    (2 * C0.B + C1.B) / 3);
            }
            else
            {
                return Color.FromArgb(
                    (C0.R + C1.R) / 2,
                    (C0.G + C1.G) / 2,
                    (C0.B + C1.B) / 2);
            }
        }
        private static Color CalculateCLUT3(Color C0, Color C1, int c0, int c1, bool IsBC1)
        {
            if (c0 > c1 || !IsBC1)
            {
                return
                    Color.FromArgb(
                        (2 * C1.R + C0.R) / 3,
                        (2 * C1.G + C0.G) / 3,
                        (2 * C1.B + C0.B) / 3);
            }

            return Color.Transparent;
        }
        public static Bitmap DecompressBC1(Byte[] data, int width, int height, bool IsSRGB)
        {
            int W = (width + 3) / 4;
            int H = (height + 3) / 4;

            byte[] Output = new byte[W * H * 64];

            for (int Y = 0; Y < H; Y++)
            {
                for (int X = 0; X < W; X++)
                {
                    int IOffs = (Y * W + X) * 8;

                    byte[] Tile = BCnDecodeTile(data, IOffs, true);

                    int TOffset = 0;

                    for (int TY = 0; TY < 4; TY++)
                    {
                        for (int TX = 0; TX < 4; TX++)
                        {
                            int OOffset = (X * 4 + TX + (Y * 4 + TY) * W * 4) * 4;

                            Output[OOffset + 0] = Tile[TOffset + 0];
                            Output[OOffset + 1] = Tile[TOffset + 1];
                            Output[OOffset + 2] = Tile[TOffset + 2];
                            Output[OOffset + 3] = Tile[TOffset + 3];

                            TOffset += 4;
                        }
                    }
                }
            }
            return BitmapExtension.GetBitmap(Output, W * 4, H * 4);
        }
        public static Bitmap DecompressBC3(Byte[] data, int width, int height, bool IsSRGB)
        {
            int W = (width + 3) / 4;
            int H = (height + 3) / 4;

            byte[] Output = new byte[W * H * 64];

            for (int Y = 0; Y < H; Y++)
            {
                for (int X = 0; X < W; X++)
                {
                    int IOffs = (Y * W + X) * 16;

                    byte[] Tile = BCnDecodeTile(data, IOffs + 8, false);

                    byte[] Alpha = new byte[8];

                    Alpha[0] = data[IOffs + 0];
                    Alpha[1] = data[IOffs + 1];

                    CalculateBC3Alpha(Alpha);

                    int AlphaLow = Get32(data, IOffs + 2);
                    int AlphaHigh = Get16(data, IOffs + 6);

                    ulong AlphaCh = (uint)AlphaLow | (ulong)AlphaHigh << 32;

                    int TOffset = 0;

                    for (int TY = 0; TY < 4; TY++)
                    {
                        for (int TX = 0; TX < 4; TX++)
                        {
                            int OOffset = (X * 4 + TX + (Y * 4 + TY) * W * 4) * 4;

                            byte AlphaPx = Alpha[(AlphaCh >> (TY * 12 + TX * 3)) & 7];

                            Output[OOffset + 0] = Tile[TOffset + 0];
                            Output[OOffset + 1] = Tile[TOffset + 1];
                            Output[OOffset + 2] = Tile[TOffset + 2];
                            Output[OOffset + 3] = AlphaPx;

                            TOffset += 4;
                        }
                    }
                }
            }

            return BitmapExtension.GetBitmap(Output, W * 4, H * 4);
        }
        public static Bitmap DecompressBC4(Byte[] data, int width, int height, bool IsSNORM)
          {
              int W = (width + 3) / 4;
              int H = (height + 3) / 4;

              byte[] Output = new byte[W * H * 64];

              for (int Y = 0; Y < H; Y++)
              {
                  for (int X = 0; X < W; X++)
                  {
                      int IOffs = (Y * W + X) * 8;

                      byte[] Red = new byte[8];

                      Red[0] = data[IOffs + 0];
                      Red[1] = data[IOffs + 1];

                      CalculateBC3Alpha(Red);

                      int RedLow = Get32(data, IOffs + 2);
                      int RedHigh = Get16(data, IOffs + 6);

                      ulong RedCh = (uint)RedLow | (ulong)RedHigh << 32;

                      int TOffset = 0;
                      int TW = Math.Min(width - X * 4, 4);
                      int TH = Math.Min(height - Y * 4, 4);

                      for (int TY = 0; TY < 4; TY++)
                      {
                          for (int TX = 0; TX < 4; TX++)
                          {
                              int OOffset = (X * 4 + TX + (Y * 4 + TY) * W * 4) * 4;

                              byte RedPx = Red[(RedCh >> (TY * 12 + TX * 3)) & 7];

                              Output[OOffset + 0] = RedPx;
                              Output[OOffset + 1] = RedPx;
                              Output[OOffset + 2] = RedPx;
                              Output[OOffset + 3] = 255;

                              TOffset += 4;
                          }
                      }
                  }
              }

              return BitmapExtension.GetBitmap(Output, W * 4, H * 4);
          }
        public static byte[] DecompressBC5(Byte[] data, int width, int height, bool IsSNORM, bool IsByteArray)
        {
            int W = (width + 3) / 4;
            int H = (height + 3) / 4;


            byte[] Output = new byte[W * H * 64];

            for (int Y = 0; Y < H; Y++)
            {
                for (int X = 0; X < W; X++)

                {
                    int IOffs = (Y * W + X) * 16;
                    byte[] Red = new byte[8];
                    byte[] Green = new byte[8];

                    Red[0] = data[IOffs + 0];
                    Red[1] = data[IOffs + 1];

                    Green[0] = data[IOffs + 8];
                    Green[1] = data[IOffs + 9];

                    if (IsSNORM == true)
                    {
                        CalculateBC3AlphaS(Red);
                        CalculateBC3AlphaS(Green);
                    }
                    else
                    {
                        CalculateBC3Alpha(Red);
                        CalculateBC3Alpha(Green);
                    }

                    int RedLow = Get32(data, IOffs + 2);
                    int RedHigh = Get16(data, IOffs + 6);

                    int GreenLow = Get32(data, IOffs + 10);
                    int GreenHigh = Get16(data, IOffs + 14);

                    ulong RedCh = (uint)RedLow | (ulong)RedHigh << 32;
                    ulong GreenCh = (uint)GreenLow | (ulong)GreenHigh << 32;

                    int TW = Math.Min(width - X * 4, 4);
                    int TH = Math.Min(height - Y * 4, 4);


                    if (IsSNORM == true)
                    {
                        for (int TY = 0; TY < TH; TY++)
                        {
                            for (int TX = 0; TX < TW; TX++)
                            {

                                int Shift = TY * 12 + TX * 3;
                                int OOffset = ((Y * 4 + TY) * width + (X * 4 + TX)) * 4;

                                byte RedPx = Red[(RedCh >> Shift) & 7];
                                byte GreenPx = Green[(GreenCh >> Shift) & 7];

                                if (IsSNORM == true)
                                {
                                    RedPx += 0x80;
                                    GreenPx += 0x80;
                                }

                                float NX = (RedPx / 255f) * 2 - 1;
                                float NY = (GreenPx / 255f) * 2 - 1;
                                float NZ = (float)Math.Sqrt(1 - (NX * NX + NY * NY));

                                Output[OOffset + 0] = Clamp((NX + 1) * 0.5f);
                                Output[OOffset + 1] = Clamp((NY + 1) * 0.5f);
                                Output[OOffset + 2] = Clamp((NZ + 1) * 0.5f);
                                Output[OOffset + 3] = 0xff;
                            }
                        }
                    }
                    else
                    {
                        for (int TY = 0; TY < TH; TY++)
                        {
                            for (int TX = 0; TX < TW; TX++)
                            {

                                int Shift = TY * 12 + TX * 3;
                                int OOffset = ((Y * 4 + TY) * width + (X * 4 + TX)) * 4;

                                byte RedPx = Red[(RedCh >> Shift) & 7];
                                byte GreenPx = Green[(GreenCh >> Shift) & 7];

                                Output[OOffset + 0] = RedPx;
                                Output[OOffset + 1] = GreenPx;
                                Output[OOffset + 2] = 255;
                                Output[OOffset + 3] = 255;

                            }
                        }
                    }
                }
            }
            return Output;
        }
        public static Bitmap DecompressBC5(Byte[] data, int width, int height, bool IsSNORM)
        {
            int W = (width + 3) / 4;
            int H = (height + 3) / 4;


            byte[] Output = new byte[W * H * 64];

            for (int Y = 0; Y < H; Y++)
            {
                for (int X = 0; X < W; X++)

                {
                    int IOffs = (Y * W + X) * 16;
                    byte[] Red = new byte[8];
                    byte[] Green = new byte[8];

                    Red[0] = data[IOffs + 0];
                    Red[1] = data[IOffs + 1];

                    Green[0] = data[IOffs + 8];
                    Green[1] = data[IOffs + 9];

                    if (IsSNORM == true)
                    {
                        CalculateBC3AlphaS(Red);
                        CalculateBC3AlphaS(Green);
                    }
                    else
                    {
                        CalculateBC3Alpha(Red);
                        CalculateBC3Alpha(Green);
                    }

                    int RedLow = Get32(data, IOffs + 2);
                    int RedHigh = Get16(data, IOffs + 6);

                    int GreenLow = Get32(data, IOffs + 10);
                    int GreenHigh = Get16(data, IOffs + 14);

                    ulong RedCh = (uint)RedLow | (ulong)RedHigh << 32;
                    ulong GreenCh = (uint)GreenLow | (ulong)GreenHigh << 32;

                    int TW = Math.Min(width - X * 4, 4);
                    int TH = Math.Min(height - Y * 4, 4);


                    if (IsSNORM == true)
                    {
                        for (int TY = 0; TY < TH; TY++)
                        {
                            for (int TX = 0; TX < TW; TX++)
                            {

                                int Shift = TY * 12 + TX * 3;
                                int OOffset = ((Y * 4 + TY) * width + (X * 4 + TX)) * 4;

                                byte RedPx = Red[(RedCh >> Shift) & 7];
                                byte GreenPx = Green[(GreenCh >> Shift) & 7];

                                if (IsSNORM == true)
                                {
                                    RedPx += 0x80;
                                    GreenPx += 0x80;
                                }

                                float NX = (RedPx / 255f) * 2 - 1;
                                float NY = (GreenPx / 255f) * 2 - 1;
                                float NZ = (float)Math.Sqrt(1 - (NX * NX + NY * NY));

                                Output[OOffset + 0] = Clamp((NZ + 1) * 0.5f);
                                Output[OOffset + 1] = Clamp((NY + 1) * 0.5f);
                                Output[OOffset + 2] = Clamp((NX + 1) * 0.5f);
                                Output[OOffset + 3] = 0xff;
                            }
                        }
                    }
                    else
                    {
                        for (int TY = 0; TY < TH; TY++)
                        {
                            for (int TX = 0; TX < TW; TX++)
                            {

                                int Shift = TY * 12 + TX * 3;
                                int OOffset = ((Y * 4 + TY) * width + (X * 4 + TX)) * 4;

                                byte RedPx = Red[(RedCh >> Shift) & 7];
                                byte GreenPx = Green[(GreenCh >> Shift) & 7];

                                Output[OOffset + 0] = 255;
                                Output[OOffset + 1] = GreenPx;
                                Output[OOffset + 2] = RedPx;
                                Output[OOffset + 3] = 255;

                            }
                        }
                    }
                }
            }
            return BitmapExtension.GetBitmap(Output, W * 4, H * 4);
        }

        /*   public static unsafe byte[] CreateImage(Byte[] data, int width, int height, DDS.DXGI_FORMAT format)
           {
               long inputRowPitch;
               long inputSlicePitch;
               TexHelper.Instance.ComputePitch((DXGI_FORMAT)format, width, height, out inputRowPitch, out inputSlicePitch, CP_FLAGS.NONE);

               if (data.Length == inputSlicePitch)
               {
                   byte* buf;
                   buf = (byte*)Marshal.AllocHGlobal((int)inputSlicePitch);
                   Marshal.Copy(data, 0, (IntPtr)buf, (int)inputSlicePitch);

                   DirectXTexNet.Image inputImage = new DirectXTexNet.Image(width, height, (DXGI_FORMAT)format, inputRowPitch, inputSlicePitch, (IntPtr)buf, null);
                   ScratchImage scratchImage = TexHelper.Instance.Initialize2D((DXGI_FORMAT)format, width, height, 1, 1, CP_FLAGS.NONE);

                   using (var comp = scratchImage.Compress(DXGI_FORMAT.BC1_UNORM, TEX_COMPRESS_FLAGS.PARALLEL, 0.5f))
                   {
                       long outRowPitch;
                       long outSlicePitch;
                       TexHelper.Instance.ComputePitch((DXGI_FORMAT)format, width, height, out outRowPitch, out outSlicePitch, CP_FLAGS.NONE);

                       byte[] result = new byte[outSlicePitch];
                       Marshal.Copy(result, 0, scratchImage.GetPixels(), (int)outSlicePitch);

                       return result;
                   }
               }
               return null;
           }*/
        public unsafe byte* PointerData(byte* data, int length)
        {
            byte[] safe = new byte[length];
            for (int i = 0; i < length; i++)
                safe[i] = data[i];

            fixed (byte* converted = safe)
            {
                // This will update the safe and converted arrays.
                for (int i = 0; i < length; i++)
                    converted[i]++;

                return converted;
            }
        }
        public static byte[] DecompressBlock(Byte[] data, int width, int height, DDS.DXGI_FORMAT format)
        {
            return DirectXTex.ImageCompressor.Decompress(data, width, height, (int)format);
        }
        public static byte[] CompressBlock(Byte[] data, int width, int height, DDS.DXGI_FORMAT format)
        {
            return DirectXTex.ImageCompressor.Compress(data, width, height, (int)format);
        }
        public static byte[] EncodePixelBlock(Byte[] data, int width, int height, DDS.DXGI_FORMAT format)
        {
            if (format == DDS.DXGI_FORMAT.DXGI_FORMAT_R8G8B8A8_UNORM || format == DDS.DXGI_FORMAT.DXGI_FORMAT_R8G8B8A8_UNORM_SRGB)
                return data;

            return DirectXTex.ImageConverter.Convert(data, width, height,(int)DDS.DXGI_FORMAT.DXGI_FORMAT_R8G8B8A8_UNORM, (int)format);
        }
        public static byte[] DecodePixelBlock(Byte[] data, int width, int height, DDS.DXGI_FORMAT format)
        {
            if (format == DDS.DXGI_FORMAT.DXGI_FORMAT_R8G8B8A8_UNORM || format == DDS.DXGI_FORMAT.DXGI_FORMAT_R8G8B8A8_UNORM_SRGB)
                return data;

            return DirectXTex.ImageConverter.Convert(data, width, height, (int)format, (int)DDS.DXGI_FORMAT.DXGI_FORMAT_R8G8B8A8_UNORM);
        }

        public static Bitmap DecompressBlock(Byte[] data, int width, int height, DDS.DXGI_FORMAT format, bool GetBitmap)
        {
            return BitmapExtension.GetBitmap(DirectXTex.ImageCompressor.Decompress(data, width, height, (int)format), width, height);
        }

        public static int Get16(byte[] Data, int Address)
        {
            return
                Data[Address + 0] << 0 |
                Data[Address + 1] << 8;
        }

        public static int Get32(byte[] Data, int Address)
        {
            return
                Data[Address + 0] << 0 |
                Data[Address + 1] << 8 |
                Data[Address + 2] << 16 |
                Data[Address + 3] << 24;
        }

        private static byte Clamp(float Value)
        {
            if (Value > 1)
            {
                return 0xff;
            }
            else if (Value < 0)
            {
                return 0;
            }
            else
            {
                return (byte)(Value * 0xff);
            }
        }

        private static void CalculateBC3Alpha(byte[] Alpha)
        {
            for (int i = 2; i < 8; i++)
            {
                if (Alpha[0] > Alpha[1])
                {
                    Alpha[i] = (byte)(((8 - i) * Alpha[0] + (i - 1) * Alpha[1]) / 7);
                }
                else if (i < 6)
                {
                    Alpha[i] = (byte)(((6 - i) * Alpha[0] + (i - 1) * Alpha[1]) / 7);
                }
                else if (i == 6)
                {
                    Alpha[i] = 0;
                }
                else /* i == 7 */
                {
                    Alpha[i] = 0xff;
                }
            }
        }
        private static void CalculateBC3AlphaS(byte[] Alpha)
        {
            for (int i = 2; i < 8; i++)
            {
                if ((sbyte)Alpha[0] > (sbyte)Alpha[1])
                {
                    Alpha[i] = (byte)(((8 - i) * (sbyte)Alpha[0] + (i - 1) * (sbyte)Alpha[1]) / 7);
                }
                else if (i < 6)
                {
                    Alpha[i] = (byte)(((6 - i) * (sbyte)Alpha[0] + (i - 1) * (sbyte)Alpha[1]) / 7);
                }
                else if (i == 6)
                {
                    Alpha[i] = 0x80;
                }
                else /* i == 7 */
                {
                    Alpha[i] = 0x7f;
                }
            }
        }

        public static byte[] DecodeBC7(int X, int Y, int block)
        {
            byte[] result = null;

            //Alright so BC7 decompression as multple modes

            return result;
        }
    }
}