#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
const n=100;
#pragma pack(push, 1)

#define DEBUG 1
#if DEBUG
#define LOG(fmt, ...) fprintf(stderr, fmt "\n", __VA_ARGS__)
#else
#define LOG(...)
#endif

typedef struct BmpHeader {
    uint16_t signature;
    uint32_t file_zize, reserved, offset;
} BmpHeader;

typedef struct BmpInfoHeader {
    BmpHeader bh;
    uint32_t size, width, height;
    uint16_t planes,bpp;
    uint32_t compression, image_size, unused[2], colors, important;
} BmpInfoHeader;

typedef  struct rgb {
    union {
        struct {
            uint8_t b, g, r;
        };
        uint8_t  start;
    };
} rgb;

#pragma pack(pop)



int main(int argc, char *argv[]) {
    if (argc < 3) {
        printf("%s <bmp in> <bmp out>\n", argv[0]);
        exit(1);
    }

    //char *tmpEnd;
    //int brighten = strtol(argv[1], &tmpEnd, 10);
    //LOG("____________________________________\nPercentage: %d", brighten);
    FILE *bmf = fopen(argv[1], "rb");
    //FILE *bmpout = fopen(argv[3], "wb");
    //LOG("Input file name: %s\nOutput file name: %s\n", argv[2], argv[3]);

    BmpInfoHeader bih;
    fread(&bih, sizeof bih, 1, bmf);
    BmpHeader bh = bih.bh;


    if (bih.size != 40 || bih.planes != 1 || bh.reserved != 0 || bih.compression > 2) {
        printf("BMP file corrupted");
        exit(2);
    }
    if (bih.bpp != 24) {
        printf("bpp %hd not supported\n", bih.bpp);
        exit(3);
    }

    LOG("size  %d, offset  0x%x\n", bih.bh.file_zize, bih.bh.offset);
    LOG("bpp  %hd, compression  %ld, colors  %d\n", bih.bpp,bih.compression, bih.colors);
    fseek(bmf, bih.bh.offset, SEEK_SET);



  FILE *temp=fopen(argv[1],"rb");

        unsigned char info[54];
        fread(info, sizeof(unsigned char), 54, temp); // read the 54-byte header

        // extract image height and width from header
        int width = *(int*)&info[18];
        int height = *(int*)&info[22];

        int size = 3 * width * height;
        unsigned char data [size]; // allocate 3 bytes per pixel
        fread(data, sizeof(unsigned char), size, temp); // read the rest of the data at once

        FILE *bmout=fopen(argv[2],"wb");
        //fwrite(&bih, sizeof bih, 1, bmout);
        for(int i = 0; i < size; i += 3)
        {
            unsigned char tmp = data[i];
            data[i] = data[i+2];
            data[i+2] = tmp;
        }


   /*
    FILE *bmout=fopen(argv[2],"wb");
    fwrite(&bih, sizeof bih, 1, bmout);
    for (int i=0;i<bih.width*bih.height;i++)
    {
        rgb pixel;
        fread(&pixel,sizeof pixel, 1, bmf);//1 15 57
        if(pixel.g+n<bih.width)
            pixel.r = pixel.g + n;
        else
            pixel.r=bih.width;
        for(int j=0;j<3;j++)
        {
            uint8_t *subpix=&pixel.start+j;


        }
        fwrite(&pixel,sizeof pixel,1,bmout);

    }
    fclose(bmout);*/
    fclose(bmf);
    return 0;
}