#include <graphics.h>
#include <iostream>
using namespace std;

struct FileHeader {
    WORD bfType;
    DWORD bfSize;
    WORD bfReserved1;
    WORD bfReserved2;
    DWORD bfOffbits;
} file_header;

struct MAPINFO {
    DWORD Size;
    DWORD Width;
    DWORD Height;
    WORD Planes;
    WORD BitCount;
    DWORD Compression;
    DWORD SizeImage;
    long XPelsPerMeter;
    long YPelsPerMeter;
    DWORD ClrUsed;
    DWORD ClrImportant;
} map_info;

struct RGBquad {
    byte rgbRed;
    byte rgbGreen;
    byte rgbBlue;
    byte rgbReserved;
};

int main() {
    FILE *f1 = fopen("pigvin256.bmp", "rb");

    fread(&file_header, sizeof(file_header), 1, f1);

    cout << "-----FILE HEADER" << endl;
    cout << "bfType - " << file_header.bfType << endl;
    cout << "bfSize - " << file_header.bfSize << endl;
    cout << "bfReserved1 - " << file_header.bfReserved1 << endl;
    cout << "bfReserved2 - " << file_header.bfReserved2 << endl;
    cout << "bfOffBits - " << file_header.bfOffbits << endl;

    fread(&map_info, sizeof(map_info), 1, f1);

    cout << "-----MAP INFO" << endl;
    cout << "Size - " << map_info.Size << endl;
    cout << "Width - " << map_info.Width << endl;
    cout << "Height - " << map_info.Height << endl;
    cout << "Planes - " << map_info.Planes << endl;
    cout << "BitCount - " << map_info.BitCount << endl;
    cout << "Compression - " << map_info.Compression << endl;
    cout << "SizeImage - " << map_info.SizeImage << endl;
    cout << "XPelsPerMeter - " << map_info.XPelsPerMeter << endl;
    cout << "YPelsPerMeter - " << map_info.YPelsPerMeter << endl;
    cout << "ClrUsed - " << map_info.ClrUsed << endl;
    cout << "ClrImportant - " << map_info.ClrImportant << endl;

    if(map_info.BitCount == 8) {
        FILE *f2 = fopen("pigvin256q.bmp", "wb");

        fwrite(&file_header, sizeof(file_header), 1, f2);
        fwrite(&map_info, sizeof(map_info), 1, f2);

        int N = map_info.ClrUsed;
        RGBquad BmiColors[N];

        fread(BmiColors, sizeof(RGBquad), N, f1);

        byte r, g, b, v;
        for(int i = 0; i < N; i++) {
            r = BmiColors[i].rgbRed;
            g = BmiColors[i].rgbGreen;
            b = BmiColors[i].rgbBlue;
            v = (r + g + b) / 3;
            BmiColors[i].rgbRed = v;
            BmiColors[i].rgbGreen = v;
            BmiColors[i].rgbBlue = v;
        }
        fwrite(BmiColors, sizeof(RGBquad), N, f2);

        byte *buffer = new byte[map_info.Width];
        int n;
        do {
            n = fread(buffer, sizeof(byte), map_info.Width, f1);
            fwrite(buffer, sizeof(byte), n, f2);
        }while(n == map_info.Width);

        delete [] buffer;
        fclose(f2);
    }else
        cout << "Unsupported image color type" << endl;

    fclose(f1);
    return 0;
}