// Bitmaps are curently stored two ways in this program, which I'm calling
// "packed" and "unpacked." Both are 0xAAGGBBRR little endian. Unpacked bitmaps
// use the typical method of storage, rows of X that you increment by
// Width*BytesPerPixel to look up the Y coordinate. "Packed" bitmaps encode
// pixels as 4x4 chunks. To illustrate this clearly with an 8x4 bitmap:

//  A1 A2 A3 A4 E1 E2 E3 E4
//  B1 B2 B3 B4 F1 F2 F3 F4
//  C1 C2 C3 C4 G1 G2 G3 G4
//  D1 D2 D3 D4 H1 H2 H3 H4

// Unpacked would be stored in memory order as A1 A2 A3 A4 E1 E2 E3 E4...
// while packed would be stored as A1 A2 A3 A4 B1 B2 B3 B4...

// In cases where the bitmap is a non-divisible-by-four size, we simply treat
// the bitmap as if it's the right size and add the extra pixels in the allocation.

// This wasn't an optimization I necessarily _needed_ to make this early on--I
// never even did any measuring to see if there was any speedup-- but I
// couldn't resist it. I like doing the software rendering stuff.

// TODO(fox): I could write an AVX version of this function, but it may not be
// that much faster since we have to do a bit of uninterleaving.

// 0 - store in 4x4 chunks
// 1 - unpack to 1xwidth
void Bitmap_ConvertPacking(void *Buffer, void *DestBuffer, uint16 Width, uint16 Height, uint16 BytesPerPixel, uint16 Which)
{
    uint8 *Src = (uint8 *)Buffer;
    uint8 *Temp = (uint8 *)DestBuffer;
    uint32 RemainderPixels = Width % 4;
    for (uint32 Y = 0; Y < Height; Y++) {
        uint32 X = 0;
        while (X < Width - RemainderPixels) {
            uint16 WidthP, HeightP;
            Bitmap_CalcPackedDimensions(Width, Height, &WidthP, &HeightP);
            uint32 XLookup = (X >> 2)*16 + (X % 4);
            uint32 YLookup = (Y >> 2)*(WidthP*4) + (Y % 4)*4;
            uint32 PixelToSeek = XLookup + YLookup;
            if (Y == 48 && X == 0)
                uint8 war = 0;
            // if (YLookup == 2500 && XLookup == 1)
            uint8 *DPixel, *Pixel;
            if (Which == 0) {
                DPixel = Temp + PixelToSeek*BytesPerPixel;
                Pixel  = Src  + Y*Width*4 + X*BytesPerPixel;
            } else {
                Pixel  = Src  + PixelToSeek*BytesPerPixel;
                DPixel = Temp + Y*Width*4 + X*BytesPerPixel;
            }

#if ARM
            if (InstructionMode == instruction_mode_neon) {
                uint32x2x2_t Row = vld2_u32((uint32 *)Pixel);
                vst2_u32((uint32 *)DPixel, Row);
                X += 4;
#else
            if (InstructionMode == instruction_mode_sse || InstructionMode == instruction_mode_avx) {
                __m128i Row = _mm_loadu_si128((__m128i *)Pixel);
                _mm_storeu_si128((__m128i *)DPixel, Row);
                X+=4;
#endif
            } else {
                *(uint32 *)DPixel = *(uint32 *)Pixel;
                X++;
            }
        }
        while (X < Width) {
            uint16 WidthP, HeightP;
            Bitmap_CalcPackedDimensions(Width, Height, &WidthP, &HeightP);
            uint32 XLookup = (X >> 2)*16 + (X % 4);
            uint32 YLookup = (Y >> 2)*(WidthP*4) + (Y % 4)*4;
            uint32 PixelToSeek = XLookup + YLookup;
            uint8 *DPixel, *Pixel;
            if (Which == 0) {
                DPixel = Temp + PixelToSeek*BytesPerPixel;
                Pixel  = Src  + Y*Width*4 + X*BytesPerPixel;
            } else {
                Pixel  = Src  + PixelToSeek*BytesPerPixel;
                DPixel = Temp + Y*Width*4 + X*BytesPerPixel;
            }

            *(uint32 *)DPixel = *(uint32 *)Pixel;
            X++;
        }
    }
}

// TODO(fox): Replace this in the future.
#if 0
static void *
MoveImportToBitmap(memory *Memory, pixel_buffer *Raster, void *Input)
{
    uint8 *Row = ((uint8 *)Input);
    // void *Output = AllocateMemory(Memory, Bitmap_CalcTotalBytes(Raster->Width, Raster->Height, Raster->BytesPerPixel), B_Layers);
    uint8 *Row2 = ((uint8 *)Output);

    uint64 bytes = 0;
    uint16 ByteOffset = Bitmap_CalculateByteOffset(BytesPerPixel);
    uint64 TotalBytes = Bitmap_CalculateTotalBytes(Width, Height, BytesPerPixel);
    uint64 RemainderBytes = TotalBytes % ByteOffset;

    while (bytes <= TotalBytes - RemainderBytes) {
        uint8 *Pixel = (uint8 *)Row + bytes;
        uint8 *Pixel2 = (uint8 *)Row2 + bytes;
        if (InstructionMode == instruction_mode_sse || InstructionMode == instruction_mode_avx) {
            __m128i OutputPixel = _mm_loadu_si128((__m128i *)Pixel);
            _mm_storeu_si128((__m128i *)Pixel2, OutputPixel);
            bytes += 4*Raster->BytesPerPixel;
        } else {
            *(uint32 *)Pixel2 = *(uint32 *)Pixel;
            bytes += Raster->BytesPerPixel;
        }
    }
    while (bytes <= TotalBytes) {
        uint8 *Pixel = (uint8 *)Row + bytes;
        uint8 *Pixel2 = (uint8 *)Row2 + bytes;
        *(uint32 *)Pixel2 = *(uint32 *)Pixel;
        bytes += Raster->BytesPerPixel;
    }
    return Output;
}
#endif

static void
Bitmap_Clear(void *Buffer, uint16 Width, uint16 Height, uint16 BytesPerPixel)
{
    uint8 *Row = (uint8 *)Buffer;
#if ARM
    uint32 Zero[4] = {0};
    uint32x2x4_t Zero8 = vld4_dup_u32(Zero);
#else
    __m256i Zero8 = _mm256_setzero_si256();
    __m128i Zero = _mm_setzero_si128();
#endif
    uint64 bytes = 0;

    uint16 ByteOffset = Bitmap_CalcByteOffset(BytesPerPixel);
    uint64 TotalBytes = Bitmap_CalcTotalBytes(Width, Height, BytesPerPixel);

    while (bytes < TotalBytes) {
        uint8 *Pixel = Row + bytes;
#if ARM
        if (InstructionMode == instruction_mode_neon) {
            vst4_u32((uint32 *)Pixel, Zero8);
#else
        if (InstructionMode == instruction_mode_avx) {
            _mm256_storeu_si256((__m256i *)Pixel, Zero8);
        } else if (InstructionMode == instruction_mode_sse) {
            _mm_storeu_si128((__m128i *)Pixel, Zero);
#endif
        } else {
            *(uint32 *)Pixel = 0x00000000;
        }
        bytes += ByteOffset;
    }
}

static void
Bitmap_CalcPackedDimensions(uint16 Width, uint16 Height, uint16 *WidthP, uint16 *HeightP) {
    uint16 ExtraWidth = 4 - (Width % 4);
    if (ExtraWidth == 4)
        ExtraWidth = 0;
    uint16 ExtraHeight = 4 - (Height % 4);
    if (ExtraHeight == 4)
        ExtraHeight = 0;
    *WidthP = Width + ExtraWidth;
    *HeightP = Height + ExtraHeight;
}

static uint16
Bitmap_CalcByteOffset(uint16 BytesPerPixel) {
    uint16 ByteOffset = BytesPerPixel;
#if ARM
    if (InstructionMode == instruction_mode_neon)
        ByteOffset = 8*BytesPerPixel;
#else
    if (InstructionMode == instruction_mode_avx)
        ByteOffset = 8*BytesPerPixel;
    if (InstructionMode == instruction_mode_sse)
        ByteOffset = 4*BytesPerPixel;
#endif
    return ByteOffset;
}

static uint64
Bitmap_CalcUnpackedBytes(uint16 Width, uint16 Height, uint16 BytesPerPixel) {
    uint64 TotalBytes = (uint64)Width*Height*BytesPerPixel;
    return TotalBytes;
}

static uint64
Bitmap_CalcTotalBytes(uint16 Width, uint16 Height, uint16 BytesPerPixel) {
    uint16 WidthP, HeightP;
    Bitmap_CalcPackedDimensions(Width, Height, &WidthP, &HeightP);
    uint64 TotalBytes = (uint64)WidthP*HeightP*BytesPerPixel;
    return TotalBytes;
}

// TODO(fox): Maybe turn this into a generic memory copy; we don't need to care
// about pixels for any particular reason here.
static void
Bitmap_CopyToPointer(void *Input, void *Output, uint16 BytesPerPixel, uint64 TotalBytes)
{
    uint8 *Row = (uint8 *)Input;
    uint8 *Row2 = (uint8 *)Output;

    uint64 bytes = 0;
    uint16 ByteOffset = Bitmap_CalcByteOffset(BytesPerPixel);
    uint64 RemainderBytes = TotalBytes % ByteOffset;

    while (bytes <= TotalBytes - RemainderBytes) {
        if (bytes > 2496*4)
            int pp = 0;
        uint8 *Pixel = (uint8 *)Row + bytes;
        uint8 *Pixel2 = (uint8 *)Row2 + bytes;
#if ARM
        if (InstructionMode == instruction_mode_neon) {
            uint32x2x4_t OutputPixel = vld4_u32((uint32 *)Pixel);
            vst4_u32((uint32 *)Pixel2, OutputPixel);
#else
        if (InstructionMode == instruction_mode_avx) {
            __m256i OutputPixel = _mm256_loadu_si256((__m256i *)Pixel);
            _mm256_storeu_si256((__m256i *)Pixel2, OutputPixel);
        } else if (InstructionMode == instruction_mode_sse) {
            __m128i OutputPixel = _mm_loadu_si128((__m128i *)Pixel);
            _mm_storeu_si128((__m128i *)Pixel2, OutputPixel);
#endif
        } else {
            *(uint32 *)Pixel2 = *(uint32 *)Pixel;
        }
        bytes += ByteOffset;
    }
    while (bytes <= TotalBytes) {
        uint8 *Pixel = (uint8 *)Row + bytes;
        uint8 *Pixel2 = (uint8 *)Row2 + bytes;
        *(uint32 *)Pixel2 = *(uint32 *)Pixel;
        bytes += BytesPerPixel;
    }
}

// This would be an easy SIMD if only AVX had a scatter call...
// NOTE(fox): Only works with unpacked bitmaps for now.
static void
Bitmap_CalcHistogram(void *Data, void *Input, uint16 BytesPerPixel, uint64 TotalBytes)
{
    uint32 *Slot = (uint32 *)Data;
    uint8 *Row = (uint8 *)Input;
    uint64 bytes = 0;
    uint16 ByteOffset = Bitmap_CalcByteOffset(BytesPerPixel);
    uint64 RemainderBytes = TotalBytes % ByteOffset;

    for (int i = 0; i < 256*5; i++) {
        *(real32 *)((uint8 *)Slot + i*sizeof(real32)) = 0;
    }

    while (bytes <= TotalBytes) {
        uint8 *Pixel = (uint8 *)Row + bytes;

        uint8 A = (*(uint32 *)Pixel >> 24);
        uint8 R = (*(uint32 *)Pixel >> 16);
        uint8 G = (*(uint32 *)Pixel >> 8);
        uint8 B = (*(uint32 *)Pixel >> 0);

        uint8 Avg = (uint8)((real32)(R + G + B) / 3.0f);

        *(real32 *)((uint8 *)Slot +         Avg*sizeof(real32)) += 1;
        *(real32 *)((uint8 *)Slot + (256   + R)*sizeof(real32)) += 1;
        *(real32 *)((uint8 *)Slot + (256*2 + G)*sizeof(real32)) += 1;
        *(real32 *)((uint8 *)Slot + (256*3 + B)*sizeof(real32)) += 1;
        *(real32 *)((uint8 *)Slot + (256*4 + A)*sizeof(real32)) += 1;

        bytes += BytesPerPixel;
    }
}

#if 0
static void
BitmapPackRGB(pixel_buffer *Buffer) {
    Assert(Buffer->Pitch);
    Convert4x4Chunk(Buffer, 0);
    CopyToBuffer(Buffer, 1);
    ClearBuffer(Buffer, Buffer->EffectBuffer);
}

static void
DebugFillSolid(pixel_buffer *Raster, v4 Color)
{
    uint32 ColS = ColToUint32(Color);
    __m256i Col8 = _mm256_set1_epi32(ColS);
    __m128i Col = _mm_set1_epi32(ColS);
    uint8 *Row = (uint8 *)Raster->OriginalBuffer;

    uint64 bytes = 0;
    uint16 ByteOffset = Raster->BytesPerPixel;
    if (InstructionMode == instruction_mode_avx)
        ByteOffset = 8*Raster->BytesPerPixel;
    else if (InstructionMode == instruction_mode_sse)
        ByteOffset = 4*Raster->BytesPerPixel;

    uint64 TotalBytes = Raster->FullHeight*Raster->FullWidth*Raster->BytesPerPixel;

    while (bytes < TotalBytes) {
        uint8 *Pixel = Row + bytes;
        if (InstructionMode == instruction_mode_avx) {
            _mm256_storeu_si256((__m256i *)Pixel, Col8);
        } else if (InstructionMode == instruction_mode_sse) {
            _mm_storeu_si128((__m128i *)Pixel, Col);
        } else {
            *(uint32 *)Pixel = ColS;
        }
        bytes += ByteOffset;
    }
}

static void
DebugBitmap(pixel_buffer *Raster)
{
    uint8 asda = 0x0;
    uint8 *Row = ((uint8 *)Raster->OriginalBuffer);
    real32 XInc = 255.0f / Raster->Width;
    real32 YInc = 255.0f / Raster->Height;
    for (uint8 Y = 0; Y < Raster->Height; Y++) {
        for (uint8 X = 0; X < Raster->Width; X++) {
            uint8 *Pixel = (uint8 *)Row + Raster->FullWidth*Y*4 + X*4;
            // *(uint32 *)Pixel = 0xffffffff;
            if (Y > 3) { asda = 0xff; }
            *(uint32 *)Pixel = ((0xff << 24) |
                                (asda << 16) |
                                (RoundReal32ToInt32((YInc * Y)) << 8) |
                                (RoundReal32ToInt32((XInc * X))) );
        }
    }
}
#endif