using System;
using System.IO;
using System.Runtime.InteropServices;
using Wabbajack.DTOs.Texture;

namespace Compression.BSA;
/*
 * Copied from https://raw.githubusercontent.com/AlexxEG/BSA_Browser/master/Sharp.BSA.BA2/BA2Util/DDS.cs
 * which is also GPL3 code. Modified slightly for Wabbajack
 * 
 */

/* 
 * Copied from dds.h. Includes (almost) only stuff I need in this project.
 * 
 * Link: https://github.com/digitalutopia1/BA2Lib/blob/master/BA2Lib/dds.h
 * 
 */

public class DDS
{
    public const int DDS_MAGIC = 0x20534444; // "DDS "

    public const int DDS_FOURCC = 0x00000004; // DDPF_FOURCC
    public const int DDS_RGB = 0x00000040; // DDPF_RGB
    public const int DDS_RGBA = 0x00000041; // DDPF_RGB | DDPF_ALPHAPIXELS

    public const int
        DDS_HEADER_FLAGS_TEXTURE = 0x00001007; // DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH | DDSD_PIXELFORMAT

    public const int DDS_HEADER_FLAGS_MIPMAP = 0x00020000; // DDSD_MIPMAPCOUNT
    public const int DDS_HEADER_FLAGS_LINEARSIZE = 0x00080000; // DDSD_LINEARSIZE

    public const int DDS_SURFACE_FLAGS_TEXTURE = 0x00001000; // DDSCAPS_TEXTURE
    public const int DDS_SURFACE_FLAGS_MIPMAP = 0x00400008; // DDSCAPS_COMPLEX | DDSCAPS_MIPMAP

    public const int DDS_ALPHA_MODE_UNKNOWN = 0x0;

    public static uint HeaderSizeForFormat(DXGI_FORMAT fmt)
    {
        switch (fmt)
        {
            case DXGI_FORMAT.BC1_UNORM_SRGB:
            case DXGI_FORMAT.BC3_UNORM_SRGB:
            case DXGI_FORMAT.BC4_UNORM:
            case DXGI_FORMAT.BC5_SNORM:
            case DXGI_FORMAT.BC6H_UF16:
            case DXGI_FORMAT.BC7_UNORM:
            case DXGI_FORMAT.BC7_UNORM_SRGB:
                return DDS_HEADER_DXT10.Size + DDS_HEADER.Size;
            default:
                return DDS_HEADER.Size;
        }
    }

    public static uint MAKEFOURCC(char ch0, char ch1, char ch2, char ch3)
    {
        // This is alien to me...
        return (byte) ch0 | ((uint) (byte) ch1 << 8) | ((uint) (byte) ch2 << 16) | ((uint) (byte) ch3 << 24);
    }
}

public enum DXT10_RESOURCE_DIMENSION
{
    DIMENSION_TEXTURE1D = 2,
    DIMENSION_TEXTURE2D = 3,
    DIMENSION_TEXTURE3D = 4
}

[Flags]
public enum DDSCAPS2 : uint
{
    CUBEMAP = 0x200,
    CUBEMAP_POSITIVEX = 0x400,
    CUBEMAP_NEGATIVEX = 0x800,
    CUBEMAP_POSITIVEY = 0x1000,
    CUBEMAP_NEGATIVEY = 0x2000,
    CUBEMAP_POSITIVEZ = 0x4000,
    CUBEMAP_NEGATIVEZ = 0x8000,
    CUBEMAP_ALLFACES = 0xFC00
}

[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct DDS_HEADER
{
    public uint dwSize;
    public uint dwHeaderFlags;
    public uint dwHeight;
    public uint dwWidth;
    public uint dwPitchOrLinearSize;
    public uint dwDepth; // only if DDS_HEADER_FLAGS_VOLUME is set in dwHeaderFlags
    public uint dwMipMapCount;
    public uint dwReserved1; // [11]
    public DDS_PIXELFORMAT PixelFormat; // ddspf
    public uint dwSurfaceFlags;
    public uint dwCubemapFlags;
    public uint dwReserved2; // [3]

    public uint GetSize()
    {
        // 9 uint + DDS_PIXELFORMAT uints + 2 uint arrays with 14 uints total
        // each uint 4 bytes each
        return 9 * 4 + PixelFormat.GetSize() + 14 * 4;
    }


    public void Write(BinaryWriter bw)
    {
        bw.Write(dwSize);
        bw.Write(dwHeaderFlags);
        bw.Write(dwHeight);
        bw.Write(dwWidth);
        bw.Write(dwPitchOrLinearSize);
        bw.Write(dwDepth);
        bw.Write(dwMipMapCount);

        // Just write it multiple times, since it's never assigned a value anyway
        for (var i = 0; i < 11; i++)
            bw.Write(dwReserved1);

        // DDS_PIXELFORMAT
        bw.Write(PixelFormat.dwSize);
        bw.Write(PixelFormat.dwFlags);
        bw.Write(PixelFormat.dwFourCC);
        bw.Write(PixelFormat.dwRGBBitCount);
        bw.Write(PixelFormat.dwRBitMask);
        bw.Write(PixelFormat.dwGBitMask);
        bw.Write(PixelFormat.dwBBitMask);
        bw.Write(PixelFormat.dwABitMask);

        bw.Write(dwSurfaceFlags);
        bw.Write(dwCubemapFlags);

        // Just write it multiple times, since it's never assigned a value anyway
        for (var i = 0; i < 3; i++)
            bw.Write(dwReserved2);
    }

    public static uint Size
    {
        get
        {
            unsafe
            {
                return (uint) (sizeof(DDS_HEADER) + sizeof(int) * 10 + sizeof(int) * 2);
            }

            ;
        }
    }
}

[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct DDS_HEADER_DXT10
{
    public uint dxgiFormat;
    public uint resourceDimension;
    public uint miscFlag;
    public uint arraySize;
    public uint miscFlags2;

    public void Write(BinaryWriter bw)
    {
        bw.Write(dxgiFormat);
        bw.Write(resourceDimension);
        bw.Write(miscFlag);
        bw.Write(arraySize);
        bw.Write(miscFlags2);
    }

    public static uint Size
    {
        get
        {
            unsafe
            {
                return (uint) sizeof(DDS_HEADER_DXT10);
            }

            ;
        }
    }
}

[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct DDS_PIXELFORMAT
{
    public uint dwSize;
    public uint dwFlags;
    public uint dwFourCC;
    public uint dwRGBBitCount;
    public uint dwRBitMask;
    public uint dwGBitMask;
    public uint dwBBitMask;
    public uint dwABitMask;

    public DDS_PIXELFORMAT(uint size, uint flags, uint fourCC, uint rgbBitCount, uint rBitMask, uint gBitMask,
        uint bBitMask, uint aBitMask)
    {
        dwSize = size;
        dwFlags = flags;
        dwFourCC = fourCC;
        dwRGBBitCount = rgbBitCount;
        dwRBitMask = rBitMask;
        dwGBitMask = gBitMask;
        dwBBitMask = bBitMask;
        dwABitMask = aBitMask;
    }

    public uint GetSize()
    {
        // 8 uints, each 4 bytes each
        return 8 * 4;
    }
}