#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "bmp.h"

int main(int argc, char* argv[])
{
    if (argc != 4)
    {
        printf("Usage: ./resize f infile outfile \n");
        return 1;
    }
     // remember filenames
    char *infile = argv[2];
    char *outfile = argv[3];
    float key = atof(argv[1]);

    // open input file
    FILE *inptr = fopen(infile, "r");
    if (inptr == NULL)
    {
        fprintf(stderr, "Could not open %s.\n", infile);
        return 1;
    }

    // open output file
    FILE *outptr = fopen(outfile, "w");
    if (outptr == NULL)
    {
        fclose(inptr);
        fprintf(stderr, "Could not create %s.\n", outfile);
        return 1;
    }

    // read infile's BITMAPFILEHEADER
    BITMAPFILEHEADER bf;
    fread(&bf, sizeof(BITMAPFILEHEADER), 1, inptr);

    // read infile's BITMAPINFOHEADER
    BITMAPINFOHEADER bi;
    fread(&bi, sizeof(BITMAPINFOHEADER), 1, inptr);

    // ensure infile is (likely) a 24-bit uncompressed BMP 4.0
    if (bf.bfType != 0x4d42 || bf.bfOffBits != 54 || bi.biSize != 40 ||
        bi.biBitCount != 24 || bi.biCompression != 0)
    {
        fclose(outptr);
        fclose(inptr);
        fprintf(stderr, "Unsupported file format.\n");
        return 4;
    }
    int hH = abs(bi.biHeight), hW = bi.biWidth;
    bi.biHeight *= round(key);
    bi.biWidth *= round(key);
    int padding = (bi.biWidth * sizeof(RGBTRIPLE)) % 4;
    bf.bfSize = 54 +   abs(bi.biHeight)* sizeof(RGBTRIPLE) *(bi.biWidth +  padding);
    //printf("size: %i | width: %i height: %i | padding: %i\n", bf.bfSize, bi.biWidth, bi.biHeight, padding);
    // write outfile's BITMAPFILEHEADER
    fwrite(&bf, sizeof(BITMAPFILEHEADER), 1, outptr);

    // write outfile's BITMAPINFOHEADER
    fwrite(&bi, sizeof(BITMAPINFOHEADER), 1, outptr);

    // iterate over infile's scanlines

    for (int i = 0, ptr_pos = 54, size_pad = (hW * sizeof(RGBTRIPLE)) % 4, rkey = round(key), biH = abs(bi.biHeight), igl = 0  ; i < hH; i++)
    {

        for (int j = 0; j < hW; j++)
        {

            RGBTRIPLE triple;

            fread(&triple, sizeof(RGBTRIPLE), 1, inptr);
            for (int z = 0; z < rkey; z++)
            {
                for (int y = 0; y < rkey; y++)
                {
                     //printf("out: %ld  in: %ld pixel: %i%i%i ||  ", ftell(outptr), ftell(inptr), (int)triple.rgbtRed,(int)triple.rgbtGreen,(int)triple.rgbtBlue);
                     fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
                }
                //printf("\n");
                fseek(outptr,(sizeof(RGBTRIPLE)* bi.biWidth) - (key) * sizeof(RGBTRIPLE), SEEK_CUR);
            }
            fseek(outptr, sizeof(RGBTRIPLE)* (key - bi.biWidth* key)  , SEEK_CUR);
       // printf("nline : %f pos: %ld\n", sizeof(RGBTRIPLE)* (key - bi.biWidth* key), ftell(outptr));
        }
        fseek(outptr,sizeof(RGBTRIPLE), SEEK_CUR);
        // then add it back (to demonstrate how)
        for (int k = 0; k < padding; k++)
        {
             RGBTRIPLE triple;


             printf("out: %ld || in: %ld \n", ftell(outptr), ftell(inptr));
             fread(&triple, sizeof(RGBTRIPLE), 1, inptr);
             fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
        }
        fseek(outptr, 54 + sizeof(RGBTRIPLE)* ( bi.biWidth* key) * (i + 1) , SEEK_SET);
    }

    // close infile
    fclose(inptr);

    // close outfile
    fclose(outptr);

    // success
    return 0;
}