#include <sys/stat.h>
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <string.h>

char src_file[] = "/home/averhuls/twain/quotes";

main(argc, argv)
int argc;
char **argv;
{
  int i, j, len, num_entries, index, blank_lines;
  struct stat stat_buf;
  char *buffer;
  char line[128];
  int entry_index_array[200];
  time_t tloc;
  FILE *fp;

  /*
   * Open the file containing the quotes.
   */
  if ((fp = fopen(src_file, "r")) == (FILE *) 0)
  {
    char buf[40];
    sprintf(buf, "can't open %s\n", src_file);
    perror(buf);
    exit(1);
  }

  /*
   * Get the size of the quotes file and allocate space for it.
   */
  if (stat(src_file, &stat_buf) == -1)
  {
    perror("fstat");
    exit(1);
  }

  buffer = (char *) malloc(stat_buf.st_size);

  /*
   * Find number of entries in src_file and build the 
   * entry_index_array.
   */
  i = 0;
  num_entries = 1;
  while (fgets(line, 128,fp))
  {
    len = strlen(line);
    strncpy(&buffer[i], line, len);
    i += len;
    buffer[i-1] = 0;  // terminate the line
    if (line[0] == '\n')
    {
      num_entries++;
      entry_index_array[num_entries] = i;
    }
  }
  fclose(fp);

  /*
   * If an output file name is specified, open it.
   */
  if (argc > 1)
  {
    if ((fp = fopen(argv[1], "w+")) == (FILE *)0)
    {
      printf("can't open %s\n", argv[1]);
      perror("");
      exit(1);
    }

    if (strcmp(argv[1], "/etc/motd") == 0)
    {
      blank_lines = 9;
    }
    else
    {
      blank_lines = 1;
    }
  }
  else
  {
    fp = stdout;
    blank_lines = 1;
  }

  /*
   * Find entry to generate.
   */
  time(&tloc);
  srand(tloc);
  index = rand() % num_entries;
	
  /*
   * Index into buffer for the chosen (pseudo random) quote
   */
  i = entry_index_array[index];

  /*
   * Write output.
   */
  for (j = 0; j < blank_lines; j++)
  {
    fputs("\n", fp);
  }

  /* write until we get to a blank line */
  while (buffer[i] != '\0')
  {
    fputs(&buffer[i], fp); 
    fputs("\n", fp); 
    i += strlen(&buffer[i]) + 1; // skip past line terminator
  }

  fputs("\nMark Twain\n", fp);
	
  for (j = 0; j < blank_lines; j++)
  {
    fputs("\n", fp);
  }
	
  free(buffer);
  fclose(fp);
}