#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <getopt.h>
#include <time.h>

int main(int argc, char *argv[]) {
  int max_lines = -1; // -1 means unlimited
  int verbose = 0;

  // Parse arguments (-n max_lines, -v verbose)
  char opt;
  while ((opt = getopt(argc, argv, "n:v")) != -1) {
    switch (opt) {
    case 'n':
      max_lines = atoi(optarg); break;
    case 'v':
      verbose = 1; break;
    default:
      printf("Usage: %s [-n max_lines] [-v]\n", argv[0]);
      return 1;
    }
  }

  // Read from stdin line by line
  // Count lines and characters
  // If verbose, echo lines to stdout
  char buffer[256];
  int lines = 0;
  int chars = 0;
  while (fgets(buffer, sizeof(buffer), stdin) != NULL) {
    int size = strlen(buffer);
    if (verbose)
      fwrite(buffer, sizeof(char), size, stdout);
    chars += size;
    if (size > 0 && buffer[size - 1] == '\n')
      lines++;
    if (lines == max_lines)
      break;
  }

  // Print statistics to stderr
  fprintf(stderr, "Lines: %d\n", lines);

  return 0;
}
