// #include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#define MAX_PATH_LENGTH 100
#define MAX_DIR_DEPTH 4

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

  if (mkdir("/SOME", 0777) == -1) {
    perror("Failed to create directory under /some");
    return 1;
  }

  // Create a directory under /SOME/RAMFS
  if (mkdir("/SOME/RAMFS", 0777) == -1) {
    perror("Failed to create directory under /SOME/RAMFS");
    return 1;
  }

  // Mount the first ramfs at /SOME/RAMFS
  if (mount("", "/SOME/RAMFS", "ramfs", 0, NULL) == -1) {
    perror("Failed to mount ramfs at /SOME/RAMFS");
    return 1;
  }

  if (mkdir("/SOME/RAMFS/some", 0777) == -1) {
    perror("Failed to create directory under /SOME/RAMFS/some");
    return 1;
  }

  puts("Success mkdir /SOME/RAMFS/some");

  // Create a directory under /SOME/RAMFS/some/another
  if (mkdir("/SOME/RAMFS/some/another", 0777) == -1) {
    perror("Failed to create directory under /SOME/RAMFS/some/another");
    return 1;
  }

  puts("Success mkdir /SOME/RAMFS/some/another");

  if (mount("", "/SOME/RAMFS/some/another", "ramfs", 0, NULL) == -1) {
    perror("Failed to mount ramfs at /SOME/RAMFS/some/another");
    return 1;
  }

  puts("Success mount on /SOME/RAMFS/some/another");

  if (mkdir("/SOME/RAMFS/some/another/just_another", 0777) == -1) {
    perror("Failed to create directory under /SOME/RAMFS/some/another");
    return 1;
  }

  puts("Success mkdir /SOME/RAMFS/some/another/just_another");

  if (mount("", "/SOME/RAMFS/some/another/just_another", "ramfs", 0, NULL) ==
      -1) {
    perror("Failed to mount ramfs at /SOME/RAMFS/some/another");
    return 1;
  }

  puts("Success mount on /SOME/RAMFS/some/another/just_another");

  // Write files under /SOME/RAMFS and /SOME/RAMFS/some/another
  FILE *file1 = fopen("/SOME/RAMFS/file1.txt", "w");
  if (file1 == NULL) {
    perror("Failed to open /SOME/RAMFS/file1.txt");
    return 1;
  }
  fprintf(file1, "This is file1.txt\n");
  fclose(file1);

  FILE *file2 = fopen("/SOME/RAMFS/some/another/file2.txt", "w");
  if (file2 == NULL) {
    perror("Failed to open /SOME/RAMFS/some/another/file2.txt");
    return 1;
  }
  fprintf(file2, "This is file2.txt\n");
  fclose(file2);

  FILE *file3 = fopen("/SOME/RAMFS/some/another/just_another/file3.txt", "w+");
  if (file3 == NULL) {
    perror("Failed to open /SOME/RAMFS/some/another/just_another/file3.txt");
    return 1;
  }
  fprintf(file3, "Multi mount behave well.\n");
  // print file3.txt
  char buffer[100];
  fseek(file3, 0, SEEK_SET);
  fread(buffer, 1, 100, file3);
  printf("file3.txt content: %s\n", buffer);
  fclose(file3);

  // test umount with flags ( use umount2 )
  if (umount("/SOME/RAMFS/some/another/just_another") == -1) {
    perror("Failed to umount ramfs at /SOME/RAMFS/some/another/just_another");
    return 1;
  }

  puts("Successful umount /SOME/RAMFS/some/another/just_another");

  // delete just_another
  if (rmdir("/SOME/RAMFS/some/another/just_another") == -1) {
    perror("Failed to delete /SOME/RAMFS/some/another/just_another");
    return 1;
  }

  return 0;
}