/**
 * Copies a BMP piece by piece, just because.
 */

#include <stdio.h>
#include <stdlib.h>
#include <cs50.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <math.h>


#include "bmp.h"

int main(int argc, char *argv[])
{


    bool testFloat = true;
    float scaleFactor;
    // ensure proper usage
    if (argc != 4)
    {
        fprintf(stderr, "Usage: ./resize float infile outfile\n");
        return 1;
    }



    while (testFloat)
    {
        // get line of text, returning FLT_MAX on failure
        string line = argv[1];

        if (line == NULL)
        {
            fprintf(stderr, "Float is NULL %f\n", FLT_MAX);
            return 1;
        }

        // return a float if only a float was provided
        if (strlen(line) > 0 && !isspace(line[0]))
        {
            char *tail;1b.bmp
            errno = 0;
            float f = strtof(line, &tail);
            if (errno == 0 && *tail == '\0' && isfinite(f) != 0 && f < FLT_MAX)
            {
                // disallow hexadecimal and exponents
                if (strcspn(line, "XxEePp") == strlen(line))
                {
                    scaleFactor = f;
                    if (scaleFactor <= 0){
                        fprintf(stderr, "Float less then 0 %f\n", scaleFactor);
                        return 1;
                    }

                    testFloat = false;
                }
            }
        }

        if (testFloat){
        fprintf(stderr, "Float not entered %s\n", line);
        return 1;
        }
    }



    // remember filenames
    char *infile = argv[2];
    char *outfile = argv[3];

    // 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, oldbi;
    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;
    }

    oldbi.biWidth  = bi.biWidth;
    oldbi.biHeight = bi.biHeight;

    int oldpadding =  (4 - (oldbi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;

    bi.biWidth  *= scaleFactor;
    bi.biHeight *= scaleFactor;

    // determine padding for scanlines
    int padding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;

    bi.biSizeImage = bi.biWidth * abs(bi.biHeight) * sizeof(RGBTRIPLE) + padding;
    bf.bfSize = bi.biSizeImage + sizeof(BITMAPFILEHEADER) +  sizeof(BITMAPINFOHEADER);


    // write outfile's BITMAPFILEHEADER
    fwrite(&bf, sizeof(BITMAPFILEHEADER), 1, outptr);

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

    float hsum,vsum;
    int jsum,isum,rewindfile;

    vsum = scaleFactor;
    isum = 0;


    // iterate over infile's scanlines
    for (int i = 0, biHeight = abs(oldbi.biHeight); i < biHeight; i++)
    {

       while((int)vsum > isum){

          hsum = scaleFactor;
          jsum = 0;

          // iterate over pixels in scanline
          for (int j = 0; j < oldbi.biWidth; j++)
          {
              // temporary storage
              RGBTRIPLE triple;

              // read RGB triple from infile
              fread(&triple, sizeof(RGBTRIPLE), 1, inptr);

              while((int)hsum > jsum){
                 // write RGB triple to outfile
                 fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
                 jsum++;
              }
              hsum += scaleFactor;

          }

          // skip over padding, if any
          fseek(inptr, oldpadding, SEEK_CUR);

          // then add it back (to demonstrate how)
          for (int k = 0; k < padding; k++)
          {
              fputc(0x00, outptr);
          }

          isum++;
       //   printf("%lu %d %d\n",sizeof(RGBTRIPLE), oldbi.biWidth, oldpadding);

         rewindfile = ((int)sizeof(RGBTRIPLE) * oldbi.biWidth + oldpadding) * (-1);
         fseek(inptr,rewindfile,SEEK_CUR);
       }
       vsum+= scaleFactor;
       fseek(inptr,-rewindfile,SEEK_CUR);

    }


    // close infile
    fclose(inptr);

    // close outfile
    fclose(outptr);

    // success
    return 0;
}