#include "kernel/param.h"
#include "kernel/stat.h"
#include "kernel/types.h"
#include "user/user.h"

int main(int argc, char *argv[]) {
  if (argc < 2) {
    fprintf(2, "Usage: xargs command\n");
    exit(1);
  }

  char *cmd[argc + 1];
  int index = 0, data = 0;
  for (int i = 1; i < argc; ++i) {
    cmd[index++] = argv[i];
  }

  char buffer[MAXARG];
  char line[MAXARG] = {0};
  int line_pos = 0;

  while ((data = read(0, buffer, MAXARG)) > 0) {
    for (int i = 0; i < data; ++i) {
      if (buffer[i] == '\n' || buffer[i] == ' ') {
        line[line_pos] = 0;
        if (line_pos > 0) {
          char *arg = malloc(line_pos + 1);
          strcpy(arg, line);
          cmd[index++] = arg;
        }
        line_pos = 0;

        if (buffer[i] == '\n') {
          cmd[index] = 0;
          if (fork() == 0) {
            exec(cmd[0], cmd);
            exit(1);
          }
          wait(0);
          index = argc - 1;
        }
      } else {
        line[line_pos++] = buffer[i];
      }
    }
  }

  // bug fixed
  if (line_pos > 0) {
    line[line_pos] = 0;
    cmd[index++] = line;
    cmd[index] = 0;
    if (fork() == 0) {
      exec(cmd[0], cmd);
    }
    wait(0);
  }
  exit(0);
}