#include "int.h"
#include "sys.h"

#define print(str) write(STDOUT, str, (sizeof str) - 1)
void printhex(uint64_t num) {
  char msg[17] = {' '};
  msg[16] = '\n';
  for (int i = 0; i < 16; ++i) {
    char nibble = (num >> ((15 - i) * 4)) & 0xf;
    char c;
    if (nibble > 9) {
      c = nibble + '7';
    } else {
      c = nibble + '0';
    }
    msg[i] = c;
  }
  write(STDOUT, msg, 17);
}

int main(int argc, char* argv[]) {
  // Test the write syscall
  intptr_t n = write(STDOUT, "Hello\n", 6);
  if(n != 6) return n;

  // Test argc
  for(int i = 0; i < argc; ++i){
    int len = strlen(argv[i]);
    write(STDOUT, argv[i], len);
    write(STDOUT, "\n", 1);
  }

  // Test the fork syscall
  uint64_t pid = fork();
  // Print the pid in hex
  printhex(pid);
  // Child process
  if (pid == 0) {
    const char *progname = "/bin/sh";
    const char *argv[4] = {
        progname,
        "-c",
        "echo hi from sh",
        0,
    };
    const char **envp = {0};
    int32_t err = execve(progname, argv, envp);
    // return with error code if execve fails
    return err;
  } 
  int status; // Note: this is not JUST the exit code of the child
  waitpid(pid, &status, 0);
  print("Child wstatus: ");
  printhex((uint64_t)status);

  // Test the read syscall
  #define INPUT_BUFFER_LEN 4096
  char input_buffer[INPUT_BUFFER_LEN] = {0};
  int32_t fout = openc("outfile", O_RDWR | O_CREAT | O_TRUNC, 0664);

  print("Enter some text:");
  intptr_t n_read = read(STDIN, input_buffer, INPUT_BUFFER_LEN);
  write(STDOUT, input_buffer, n_read);
  if(fout > 0) {
    write(fout, input_buffer, n_read);
    fsync(fout);
    close(fout);
  }

  // Test the open syscall
  int32_t file = open("/proc/version", O_RDONLY);
  if (file > 0) {
    int i = read(file, input_buffer, INPUT_BUFFER_LEN);
    while(i > 0) {
      write(STDOUT, input_buffer, i);
      i = read(file, input_buffer, INPUT_BUFFER_LEN);
    }
  } else {
    print("Could not open /proc/version\n");
  }

  // Test sleep
  print("Sleeping for 5 secs\n");
  struct timespec sleeptime;
  sleeptime.tv_sec = 5;
  while (nanosleep(&sleeptime, &sleeptime) != 0) {}
  print("DONE\n");

  return 69;
}