#include <stdio.h>
#include <stdlib.h>

#include <windows.h>

struct _pal {
    unsigned char r;
    unsigned char g;
    unsigned char b;
};
struct _pal pal[256];

BYTE* ConvertToBMP(BYTE* Buffer, int width, int height, long* newsize)
{
        if ((NULL == Buffer) || (width == 0) || (height == 0))
                return NULL;

        int padding = 0;
        int scanlinebytes = width * 3;
        while ((scanlinebytes + padding) % 4 != 0)
                padding++;
        int psw = scanlinebytes + padding;

        *newsize = height * psw;

        BYTE* newbuf = (unsigned char *) malloc(*newsize);

        memset (newbuf, 0, *newsize);

        long bufpos = height * width * 4;
        long newpos = 0;
        int y = 0, x = 0;
        for(y = 0; y < height; y++) {
                for (x = 0; x < 3 * width; x+=3) {
                        bufpos-=4;
                        newbuf[newpos++] = Buffer[bufpos + 2];
                        newbuf[newpos++] = Buffer[bufpos + 1];
                        newbuf[newpos++] = Buffer[bufpos];
                }
        }

        return newbuf;
}

int SaveBMP(BYTE* Buffer, int width, int height, long paddedsize, char* bmpfile)
{
        BITMAPFILEHEADER bmfh;
        BITMAPINFOHEADER info;

        memset (&bmfh, 0, sizeof(BITMAPFILEHEADER));
        memset (&info, 0, sizeof(BITMAPINFOHEADER));

        bmfh.bfType = 0x4d42;
        bmfh.bfReserved1 = 0;
        bmfh.bfReserved2 = 0;
        bmfh.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + paddedsize;
        bmfh.bfOffBits = 0x36;

        info.biSize = sizeof(BITMAPINFOHEADER);
        info.biWidth = width;
        info.biHeight = height;
        info.biPlanes = 1;
        info.biBitCount = 24;
        info.biCompression = BI_RGB;
        info.biSizeImage = 0;
        info.biXPelsPerMeter = 0x0ec4;
        info.biYPelsPerMeter = 0x0ec4;
        info.biClrUsed = 0;
        info.biClrImportant = 0;

        HANDLE file = CreateFile(bmpfile, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
        if (file == NULL) {
                CloseHandle(file);
                return 0;
        }

        unsigned long bwritten;
        if (WriteFile(file, &bmfh, sizeof(BITMAPFILEHEADER), &bwritten, NULL) == 0) {
                CloseHandle(file);
                return 0;
        }

        if (WriteFile(file, &info, sizeof(BITMAPINFOHEADER), &bwritten, NULL) == 0) {
                CloseHandle(file);
                return 0;
        }

        if (WriteFile(file, Buffer, paddedsize, &bwritten, NULL) == 0) {
                CloseHandle(file);
                return 0;
        }

        CloseHandle(file);

        return 1;
}

int main(int argc, char * argv[])
{
    int w, h;
    sscanf(argv[2], "%i", &w);
    sscanf(argv[3], "%i", &h);

    printf("File %s, size %ix%i\n", argv[1], w, h);

    FILE * fp = fopen(argv[1], "rb");
    fseek(fp, 0, SEEK_END);
    int size = ftell(fp);
    rewind(fp);
    unsigned char * buffer = (unsigned char*) malloc (sizeof(char) * size);
    fread(buffer, 1, size, fp);
    fclose(fp);

    int palcount = 0, offset = 0;
    while(palcount < 256) {
        unsigned short extr = (buffer[offset+1] << 8) | buffer[offset];
        pal[palcount].r = (extr & 0xF000) >> 8;
        pal[palcount].g = ((extr & 0x0F00)) >> 4;
        pal[palcount].b = ((extr & 0x00F0));
        printf("%i: %04x -> %i %i %i\n", palcount, extr, pal[palcount].r, pal[palcount].g, pal[palcount].b);
        palcount++;
        offset+=2;
    }

    unsigned char * imgbuffer = (unsigned char*) malloc (sizeof(char) * w * h * 4);

    int imgoffset = 0;
    while(offset < size) {
        unsigned char raw = buffer[offset];
        imgbuffer[imgoffset] = pal[raw].r;
        imgbuffer[imgoffset+1] = pal[raw].g;
        imgbuffer[imgoffset+2] = pal[raw].b;
        imgbuffer[imgoffset+3] = 0xFF;
        offset++;
        imgoffset+=4;
    }

    long bmpsize = 0;
    unsigned char * bmpbuffer = ConvertToBMP(imgbuffer, w, h, &bmpsize);
    SaveBMP(bmpbuffer, w, h, bmpsize, "image.bmp");

    free(buffer);
    free(imgbuffer);
    free(bmpbuffer);

    return 0;
}