//#include "fuse.h" add this when layer3
#define FUSE_USE_VERSION 31

#include "files.h"
#include <cassert>
#include <sstream>
#include <string.h>

struct DirectoryEntry {
  u_int64_t inode_number;
  char file_name[256];
  void serialize(char *buffer) {
    u_int64_t t = inode_number;
    for (int j = 0; j < 8; j++) {
      buffer[j] = t & (((u_int64_t)1 << (8)) - 1);
      t >>= 8;
    }
    strcpy(buffer + 8, file_name);
  }
  void deserialize(char *buffer) {
    inode_number = 0;
    for (int j = 0; j < 8; j++)
      inode_number =
          inode_number | (((u_int64_t)(unsigned char)buffer[j]) << (8 * j));
    strcpy(file_name, buffer + 8);
  }
};

void FilesOperation::printbuffer(const char *buff, int len) {
  for (int i = 0; i < len; i++) {
    printf("%x ", buff[i]);
  }
  printf("\n");
}

FilesOperation::FilesOperation(RawDisk &disk_, Fs *fs) : disk(disk_) {
  this->fs = fs;
}

void FilesOperation::create_dot_dotdot(INode_Data *inode,
                                       u_int64_t parent_inode_number) {
  char buffer[IO_BLOCK_SIZE] = {0};
  DirectoryEntry dot;
  dot.inode_number = inode->inode_num;
  strcpy(dot.file_name, ".");
  dot.serialize(buffer);
  DirectoryEntry dotdot;
  dotdot.inode_number = parent_inode_number;
  strcpy(dotdot.file_name, "..");
  dotdot.serialize(buffer + 264);
  int ret = fs->write(inode, buffer, IO_BLOCK_SIZE, 0);
  // printf("in create_dot_dotdot: fs->write returned %d\n",ret);
}

void FilesOperation::initialize_rootinode() {
  // this method must be called explicitly right after initializion
  INode_Data *root_inode = new INode_Data();
  fs->inode_manager->new_inode(0, 0, S_IFDIR, root_inode);
  u_int64_t root_inode_number = root_inode->inode_num;
  create_dot_dotdot(root_inode, root_inode_number);
  root_node = fischl_init_entry(root_inode_number, "/", root_inode);
  assert(root_node->self_info != NULL);
  fs->inode_manager->save_inode(root_inode);
}

void FilesOperation::printDirectory(u_int64_t inode_number) {
  INode_Data inode;
  inode.inode_num = inode_number;
  fs->inode_manager->load_inode(&inode);
  char buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
    fs->read(&inode, buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(buffer + i);
      if (ent.inode_number)
        printf("%s\t%llu;\t", ent.file_name, ent.inode_number);
    }
  }
  printf("\n");
}

INode_Data *FilesOperation::create_new_inode(u_int64_t parent_inode_number,
                                             const char *name, mode_t mode) {
  // trys to create a file under parent directory
  if (strlen(name) >= 256) {
    perror("Name too long, cannot create file or directory");
    return NULL;
  }
  INode_Data inode;
  inode.inode_num = parent_inode_number;
  fs->inode_manager->load_inode(&inode);
  if ((inode.metadata.permissions & S_IFMT) != S_IFDIR) {
    fprintf(stderr, "[%s ,%d] please create under directory\n", __func__,
            __LINE__);
    return NULL;
  }

  // Check if file or directory already exists
  char r_buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
    fs->read(&inode, r_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(r_buffer + i);
      if (strcmp(ent.file_name, name) == 0 && ent.inode_number != 0) {
        if ((mode & S_IFMT) == S_IFDIR) {
          fprintf(stderr, "[%s ,%d] %s/ already exists\n", __func__, __LINE__,
                  name);
        } else {
          fprintf(stderr, "[%s ,%d] %s already exists\n", __func__, __LINE__,
                  name);
        }
        return NULL;
      }
    }
  }

  bool allocated = false;
  INode_Data *new_inode = new INode_Data();
  fs->inode_manager->new_inode(0, 0, mode, new_inode);
  if ((mode & S_IFMT) == S_IFDIR) {
    create_dot_dotdot(new_inode, parent_inode_number);
    fs->inode_manager->save_inode(new_inode);
  }

  char rw_buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
    fs->read(&inode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(rw_buffer + i);
      if (ent.inode_number == 0) {
        allocated = true;
        ent.inode_number = new_inode->inode_num;
        strcpy(ent.file_name, name);
        ent.serialize(rw_buffer + i);
        break;
      }
    }
    if (allocated) {
      fs->write(&inode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
      break;
    }
  }

  if (!allocated) {
    char write_buffer[IO_BLOCK_SIZE] = {0};
    DirectoryEntry ent;
    ent.inode_number = new_inode->inode_num;
    strcpy(ent.file_name, name);
    ent.serialize(write_buffer);
    fs->write(&inode, write_buffer, IO_BLOCK_SIZE,
              (inode.metadata.size / IO_BLOCK_SIZE) * IO_BLOCK_SIZE);
    fs->inode_manager->save_inode(&inode);
  }

  return new_inode;
}

u_int64_t FilesOperation::disk_namei(const char *path) {
  // returns the inode number corresponding to path
  u_int64_t current_inode = root_node->self_info->inode_number;
  std::string current_dirname;
  std::istringstream pathStream(path);
  std::string new_name;
  std::getline(pathStream, new_name, '/');
  if (!new_name.empty()) {
    printf("disk_namei: path should start with /\n");
    return -1;
  }
  while (std::getline(pathStream, new_name, '/')) {
    INode_Data inode;
    inode.inode_num = current_inode;
    fs->inode_manager->load_inode(&inode);
    if ((inode.metadata.permissions & S_IFMT) != S_IFDIR ||
        inode.metadata.size == 0) {
      printf("disk_namei: %s is not a non-empty directory\n",
             current_dirname.c_str());
      return -1;
    }
    u_int64_t new_inode_number = 0;

    char buffer[IO_BLOCK_SIZE] = {0};
    for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
      fs->read(&inode, buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
      DirectoryEntry ent;
      for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
        ent.deserialize(buffer + i);
        if (strcmp(ent.file_name, new_name.c_str()) == 0) {
          new_inode_number = ent.inode_number;
          break;
        }
      }
      if (new_inode_number)
        break;
    }
    if (!new_inode_number) {
      printf("disk_namei: no name matching %s under directory %s\n",
             new_name.c_str(), current_dirname.c_str());
      return -1;
    }
    current_inode = new_inode_number;
    current_dirname = new_name;
  }
  return current_inode;
  // path = "/" should return root_inode_number
  // (root_node->self_info->inode_number) path = "/foo.txt" should return inode
  // for foo.txt path = "/mydir" should return inode for mydir path =
  // "/nonemptydir/foo" should return inode for foo path = "/notnonemptydir/foo"
  // should raise error
}

u_int64_t FilesOperation::namei(const char *path) {
  FileNode *filenode = fischl_find_entry(root_node, path);
  if (filenode)
    return filenode->inode_number;
  else
    return -1;
}

int FilesOperation::fischl_mkdir(const char *path, mode_t mode) {
  // check path
  char *pathdup = strdup(path);
  char *lastSlash = strrchr(pathdup, '/');
  *lastSlash = '\0'; // Split the string into parent path and new directory
                     // name; <parent path>\0<direcotry name>
  char *newDirname =
      lastSlash + 1;          //\0<direcotry name>, get from <direcotry name>
  char *ParentPath = pathdup; // pathdup are separated by pathdup, so it take
                              // <parent path> only

  FileNode *parent_filenode = strlen(ParentPath)
                                  ? fischl_find_entry(root_node, ParentPath)
                                  : root_node->self_info;
  if (parent_filenode == NULL) {
    fprintf(stderr, "[%s ,%d] ParentPath:{%s} not found\n", __func__, __LINE__,
            ParentPath);
    free(pathdup);
    return -ENOENT; // parentpath directory does not exist
  }
  u_int64_t parent_inode_number = parent_filenode->inode_number;
  // printf("%s, %llu, %s\n", parent_filenode->name, parent_inode_number,
  // newDirname); make new inode
  INode_Data *ret =
      create_new_inode(parent_inode_number, newDirname,
                       mode | S_IFDIR); // specify S_IFDIR as directory
  if (ret == NULL)
    return -1; // ENOSPC but create_new_inode handle ENAMETOOLONG EEXIST
  fischl_add_entry(parent_filenode->subdirectory, ret->inode_num, newDirname,
                   ret);
  free(pathdup);
  return 0; // SUCCESS
}
/*
    special file
*/
int FilesOperation::fischl_mknod(const char *path, mode_t mode, dev_t dev) {
  // check path
  char *pathdup = strdup(path);
  char *lastSlash = strrchr(pathdup, '/');
  *lastSlash = '\0'; // Split the string into parent path and new directory
                     // name; <parent path>\0<direcotry name>
  char *newFilename =
      lastSlash + 1;          //\0<direcotry name>, get from <direcotry name>
  char *ParentPath = pathdup; // pathdup are separated by pathdup, so it take
                              // <parent path> only
  // fprintf(stderr,"[%s ,%d] ParentPath:%s, strlen=%d\n",__func__,__LINE__,
  // ParentPath, strlen(ParentPath));
  FileNode *parent_filenode = strlen(ParentPath)
                                  ? fischl_find_entry(root_node, ParentPath)
                                  : root_node->self_info;
  if (parent_filenode == NULL) {
    fprintf(stderr, "[%s ,%d] ParentPath:{%s} not found\n", __func__, __LINE__,
            ParentPath);
    free(pathdup);
    return -1;
  }
  u_int64_t parent_inode_number = parent_filenode->inode_number;
  // make new inode
  INode_Data *ret = create_new_inode(parent_inode_number, newFilename, mode);
  if (ret == NULL)
    return -1; // ENOSPC but create_new_inode handle ENAMETOOLONG EEXIST
  // make new node
  fischl_add_entry(parent_filenode->subdirectory, ret->inode_num, newFilename,
                   ret);
  free(pathdup);
  return 0; // SUCESS
}
/*
    regular file
*/
int FilesOperation::fischl_create(const char *path, mode_t mode,
                                  struct fuse_file_info *fi) {
  // check path
  char *pathdup = strdup(path);
  char *lastSlash = strrchr(pathdup, '/');
  *lastSlash = '\0'; // Split the string into parent path and new directory
                     // name; <parent path>\0<direcotry name>
  char *newFilename =
      lastSlash + 1;          //\0<direcotry name>, get from <direcotry name>
  char *ParentPath = pathdup; // pathdup are separated by pathdup, so it take
                              // <parent path> only
  // fprintf(stderr,"[%s ,%d] ParentPath:%s, strlen=%d\n",__func__,__LINE__,
  // ParentPath, strlen(ParentPath));
  FileNode *parent_filenode = strlen(ParentPath)
                                  ? fischl_find_entry(root_node, ParentPath)
                                  : root_node->self_info;
  if (parent_filenode == NULL) {
    fprintf(stderr, "[%s ,%d] ParentPath:{%s} not found\n", __func__, __LINE__,
            ParentPath);
    free(pathdup);
    return -1;
  }
  u_int64_t parent_inode_number = parent_filenode->inode_number;
  // make new inode
  INode_Data *ret = create_new_inode(parent_inode_number, newFilename, mode);
  if (ret == NULL)
    return -1; // ENOSPC but create_new_inode handle ENAMETOOLONG EEXIST
  // make new node in RAM
  fischl_add_entry(parent_filenode->subdirectory, ret->inode_num, newFilename,
                   ret);
  // directly give inode number rather than create file descriptor table
  fi->fh =
      ret->inode_num; // assign file descriptor as inode number to fuse system
  free(pathdup);
  return 0; // SUCESS
}

int FilesOperation::fischl_getattr(const char *path, struct stat *stbuf,
                                   struct fuse_file_info *fi) {

  (void)fi;
  int res = 0;
  u_int64_t fh = namei(path);

  if (fh == -1) {
    return -ENOENT;
  }

  INode_Data inode;
  inode.inode_num = fh;
  fs->inode_manager->load_inode(&inode);

  memset(stbuf, 0, sizeof(struct stat));
  if ((inode.metadata.permissions & S_IFMT) == S_IFDIR) {
    stbuf->st_mode = S_IFDIR | 0755;
    stbuf->st_nlink = inode.metadata.reference_count;
    stbuf->st_uid = inode.metadata.uid;
    stbuf->st_gid = inode.metadata.gid;
  } else {
    stbuf->st_mode = S_IFREG | 0444;
    stbuf->st_nlink = inode.metadata.reference_count;
    stbuf->st_uid = inode.metadata.uid;
    stbuf->st_gid = inode.metadata.gid;
    stbuf->st_size = inode.metadata.size;
  }
  perror(std::to_string(inode.metadata.size).c_str());
  return res;
}

int FilesOperation::fischl_readdir(const char *path, void *buf,
                                   fuse_fill_dir_t filler, off_t ft,
                                   struct fuse_file_info *fi,
                                   enum fuse_readdir_flags flg) {
  // check path
  u_int64_t fh = namei(path);

  if (fh == -1) {
    return -1;
  }

  INode_Data inode;
  inode.inode_num = fh;
  fs->inode_manager->load_inode(&inode);
  char buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
    fs->read(&inode, buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(buffer + i);
      if (ent.inode_number) {
        filler(buf, ent.file_name, NULL, 0, FUSE_FILL_DIR_PLUS);
        // printf("%s\t%llu;\t", ent.file_name, ent.inode_number);
      }
    }
  }

  return 0;
}

int FilesOperation::fischl_releasedir(const char *path,
                                      struct fuse_file_info *fi) {
  if (fischl_find_entry(root_node, path) == NULL)
    return -ENOENT;
  // do with file descriptor that cannot be used
  fi->fh = -1;
  return 0; // SUCESS
}

void FilesOperation::unlink_inode(u_int64_t inode_number) {
  INode_Data inode;
  inode.inode_num = inode_number;
  fs->inode_manager->load_inode(&inode);
  if ((inode.metadata.permissions & S_IFMT) == S_IFDIR) {
    char buffer[IO_BLOCK_SIZE] = {0};
    for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
      fs->read(&inode, buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
      DirectoryEntry ent;
      for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
        if (ent.inode_number && strcmp(ent.file_name, ".") &&
            strcmp(ent.file_name, "..")) {
          unlink_inode(ent.inode_number);
        }
      }
    }
  }
  // TODO: error handling
  int res = fs->truncate(&inode, 0);
  fs->inode_manager->free_inode(&inode);
}

int FilesOperation::fischl_rmdir(const char *path) {
  char *pathdup = strdup(path);
  char *lastSlash = strrchr(pathdup, '/');
  *lastSlash = '\0';
  char *dirname = lastSlash + 1;
  char *ParentPath = pathdup;
  if (!strcmp(dirname, ".") || !strcmp(dirname, "..")) {
    printf("refusing to remove . or ..\n");
    return -1;
  }
  FileNode *parent_filenode = fischl_find_entry(root_node, ParentPath);
  if (parent_filenode == NULL) {
    printf("parent %s not found by fischl_find_entry\n", ParentPath);
    free(pathdup);
    return -1;
  }
  u_int64_t parent_inode_number = parent_filenode->inode_number;
  u_int64_t target_inode = 0;

  // remove its record from parent
  INode_Data parent_INode;
  parent_INode.inode_num = parent_inode_number;
  fs->inode_manager->load_inode(&parent_INode);
  char rw_buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < parent_INode.metadata.size / IO_BLOCK_SIZE;
       idx++) {
    fs->read(&parent_INode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(rw_buffer + i);
      if (strcmp(ent.file_name, dirname) == 0) {
        target_inode = ent.inode_number;
        ent.inode_number = 0;
        memset(ent.file_name, 0, sizeof(ent.file_name));
        ent.serialize(rw_buffer + i);
        break;
      }
    }
    if (target_inode) {
      fs->write(&parent_INode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
      break;
    }
  }

  // remove inode itself
  if (target_inode) {
    unlink_inode(target_inode);
    // remove node itself and from parent hash
    fischl_rm_entry(parent_filenode->subdirectory, dirname);
    free(pathdup);
    return 0;
  } else {
    printf("cannot find %s in %s", dirname, ParentPath);
    free(pathdup);
    return -1;
  }
}

int FilesOperation::fischl_chmod(const char *path, mode_t mode,
                                 struct fuse_file_info *fi) {
  (void)fi;
  int res = 0;
  u_int64_t fh = namei(path);

  if (fh == -1) {
    return -ENOENT;
  }

  INode_Data inode;
  inode.inode_num = fh;
  fs->inode_manager->load_inode(&inode);
  inode.metadata.permissions = mode;
  fs->inode_manager->save_inode(&inode);
  return 0;
}

int FilesOperation::fischl_chown(const char *path, uid_t uid, gid_t gid,
                                 struct fuse_file_info *fi) {
  (void)fi;
  int res = 0;
  u_int64_t fh = namei(path);

  if (fh == -1) {
    return -ENOENT;
  }

  INode_Data inode;
  inode.inode_num = fh;
  fs->inode_manager->load_inode(&inode);
  inode.metadata.uid = uid;
  inode.metadata.gid = gid;
  fs->inode_manager->save_inode(&inode);
  return 0;
}

int FilesOperation::fischl_unlink(const char *path) {
  char *pathdup = strdup(path);
  char *lastSlash = strrchr(pathdup, '/');
  *lastSlash = '\0';
  char *filename = lastSlash + 1;
  char *ParentPath = pathdup;
  if (!strcmp(filename, ".") || !strcmp(filename, "..")) {
    printf("refusing to remove . or ..\n");
    return -1;
  }
  FileNode *parent_filenode = fischl_find_entry(root_node, ParentPath);
  if (parent_filenode == NULL) {
    printf("parent %s not found by fischl_find_entry\n", ParentPath);
    free(pathdup);
    return -1;
  }
  u_int64_t parent_inode_number = parent_filenode->inode_number;
  u_int64_t target_inode = 0;

  // remove its record from parent
  INode_Data parent_INode;
  parent_INode.inode_num = parent_inode_number;
  fs->inode_manager->load_inode(&parent_INode);
  char rw_buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < parent_INode.metadata.size / IO_BLOCK_SIZE;
       idx++) {
    fs->read(&parent_INode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(rw_buffer + i);
      if (strcmp(ent.file_name, filename) == 0) {
        target_inode = ent.inode_number;
        ent.inode_number = 0;
        memset(ent.file_name, 0, sizeof(ent.file_name));
        ent.serialize(rw_buffer + i);
        break;
      }
    }
    if (target_inode) {
      fs->write(&parent_INode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
      break;
    }
  }

  // remove inode itself
  if (target_inode) {
    unlink_inode(target_inode);
    // remove node itself and from parent hash
    fischl_rm_entry(parent_filenode->subdirectory, filename);
    free(pathdup);
    return 0;
  } else {
    printf("cannot find %s in %s", filename, ParentPath);
    free(pathdup);
    return -1;
  }
}

int FilesOperation::fischl_open(const char *path, struct fuse_file_info *fi) {
  /*Creation (O_CREAT, O_EXCL, O_NOCTTY) flags will be filtered out / handled by
   the kernel. if no files will use create function
  */
  FileNode *get_file;
  if ((get_file = fischl_find_entry(root_node, path)) == NULL)
    return -ENOENT;
  // if need to do with flag fi->flags ((fi->flags & O_ACCMODE)). Initial
  // setting ALL access create function will handle file descriptor fi->fh
  fi->fh = get_file->inode_number;
  return 0; // SUCESS
}

int FilesOperation::fischl_release(const char *path,
                                   struct fuse_file_info *fi) {
  /*Creation (O_CREAT, O_EXCL, O_NOCTTY) flags will be filtered out / handled by
   the kernel. if no files will use create function
  */
  FileNode *get_file;
  if ((get_file = fischl_find_entry(root_node, path)) == NULL)
    return -ENOENT;
  // do with file descriptor that cannot be used
  fi->fh = -1;
  return 0; // SUCESS
}

int FilesOperation::fischl_write(const char *path, const char *buf, size_t size,
                                 off_t offset, struct fuse_file_info *fi) {
  /** Write data to an open file
   *
   * Write should return exactly the number of bytes requested
   * except on error.	 An exception to this is when the 'direct_io'
   * mount option is specified (see read operation).
   *
   * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is
   * expected to reset the setuid and setgid bits.
   */
  // use path for debug, filedescriptor is enough
  // FileNode *get_file;
  // if((get_file = fischl_find_entry(root_node, path)) == NULL)
  //     return -ENOENT;
  // Caution! this based on content in file are multiple of IO_BLOCK_SIZE, not
  // the exact write size. based on current write_datablock API implement, when
  // write_datablock pass with actual size not index this function should be
  // fixed

  INode_Data inode;
  // Assuming inode is correctly initialized here based on 'path'
  inode.inode_num = fi->fh;
  fs->inode_manager->load_inode(&inode);
  // size_t len = (inode.metadata.size/IO_BLOCK_SIZE) * IO_BLOCK_SIZE;  //
  // Assuming each block is 4096 bytes
  // Determine the length of the buffer
  // Allocate memory for the new buffer
  char *buffer = (char *)malloc(size);
  memcpy(buffer, buf, size);
  size_t bytes_write = fs->write(&inode, buffer, size, offset);
  /*size_t block_index = offset / IO_BLOCK_SIZE;  // Starting block index
  size_t block_offset = offset % IO_BLOCK_SIZE; // Offset within the first block
  while (bytes_write < size) {
      char block_buffer[IO_BLOCK_SIZE];  // Temporary buffer for each block
      size_t copy_size = std::min(size - bytes_write, IO_BLOCK_SIZE -
  block_offset); memcpy(block_buffer + block_offset, buf + bytes_write,
  copy_size); fs->write(&inode, block_buffer, IO_BLOCK_SIZE,
  block_index*IO_BLOCK_SIZE);
      // fprintf(stderr,"[%s ,%d] inode.size %d, block_index %d, block_buffer
  %s\n",__func__,__LINE__, inode.size, block_index, block_buffer); bytes_write
  += copy_size; block_index++; block_offset = 0;  // Only the first block might
  have a non-zero offset
  }*/
  fs->inode_manager->save_inode(&inode);
  free(buffer);
  return bytes_write; // Return the actual number of bytes read
}

int FilesOperation::insert_inode_to(u_int64_t parent_inode_number,
                                    const char *name, INode_Data *new_inode) {
  // trys to create a file under parent directory
  if (strlen(name) >= 256) {
    perror("Name too long, cannot create file or directory");
    return -1;
  }
  INode_Data inode;
  inode.inode_num = parent_inode_number;
  fs->inode_manager->load_inode(&inode);
  if ((inode.metadata.permissions & S_IFMT) != S_IFDIR) {
    fprintf(stderr, "[%s ,%d] please create under directory\n", __func__,
            __LINE__);
    return -1;
  }

  // Check if file or directory already exists
  char r_buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
    fs->read(&inode, r_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(r_buffer + i);
      if (strcmp(ent.file_name, name) == 0 && ent.inode_number != 0) {
        if ((new_inode->metadata.permissions & S_IFMT) == S_IFDIR) {
          fprintf(stderr, "[%s ,%d] %s/ already exists\n", __func__, __LINE__,
                  name);
        } else {
          fprintf(stderr, "[%s ,%d] %s already exists\n", __func__, __LINE__,
                  name);
        }
        return -1;
      }
    }
  }

  bool allocated = false;

  char rw_buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
    fs->read(&inode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(rw_buffer + i);
      if (ent.inode_number == 0) {
        allocated = true;
        ent.inode_number = new_inode->inode_num;
        strcpy(ent.file_name, name);
        ent.serialize(rw_buffer + i);
        break;
      }
    }
    if (allocated) {
      fs->write(&inode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
      break;
    }
  }

  if (!allocated) {
    char write_buffer[IO_BLOCK_SIZE] = {0};
    DirectoryEntry ent;
    ent.inode_number = new_inode->inode_num;
    strcpy(ent.file_name, name);
    ent.serialize(write_buffer);
    fs->write(&inode, write_buffer, IO_BLOCK_SIZE,
              (inode.metadata.size / IO_BLOCK_SIZE) * IO_BLOCK_SIZE);
    fs->inode_manager->save_inode(&inode);
  }

  return 0;
}

// TODO: rename dir and rename fail
int FilesOperation::fischl_rename(const char *path, const char *new_name,
                                  unsigned int flags) {
  char *pathdup = strdup(path);
  char *lastSlash = strrchr(pathdup, '/');
  *lastSlash = '\0';
  char *filename = lastSlash + 1;
  char *ParentPath = pathdup;
  if (!strcmp(filename, ".") || !strcmp(filename, "..")) {
    printf("refusing to remove . or ..\n");
    return -1;
  }
  FileNode *parent_filenode = fischl_find_entry(root_node, ParentPath);
  if (parent_filenode == NULL) {
    printf("parent %s not found by fischl_find_entry\n", ParentPath);
    free(pathdup);
    return -1;
  }
  u_int64_t parent_inode_number = parent_filenode->inode_number;
  u_int64_t target_inode = 0;

  // remove its record from parent
  INode_Data parent_INode;
  parent_INode.inode_num = parent_inode_number;
  fs->inode_manager->load_inode(&parent_INode);
  char rw_buffer[IO_BLOCK_SIZE] = {0};
  for (u_int64_t idx = 0; idx < parent_INode.metadata.size / IO_BLOCK_SIZE;
       idx++) {
    fs->read(&parent_INode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
    DirectoryEntry ent;
    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
      ent.deserialize(rw_buffer + i);
      if (strcmp(ent.file_name, filename) == 0) {
        target_inode = ent.inode_number;
        break;
      }
    }
    if (target_inode) {
      break;
    }
  }

  // remove inode itself
  if (target_inode) {
    INode_Data ret;
    ret.inode_num = target_inode;
    fs->inode_manager->load_inode(&ret);

    if (flags == RENAME_EXCHANGE) {
      printf("RENAME_EXCHANGE ");
    } else if (flags == RENAME_NOREPLACE) {
      printf("RENAME_NOREPLACE ");
    } else
      printf("ELSE ");

    printf("FOUND INODE AT %llu %s\n", target_inode, new_name);
    char *pathdup2 = strdup(new_name);
    char *lastSlash2 = strrchr(pathdup2, '/');
    *lastSlash2 = '\0'; // Split the string into parent path and new directory
                        // name; <parent path>\0<direcotry name>
    char *newDirname2 =
        lastSlash2 + 1; //\0<direcotry name>, get from <direcotry name>
    char *ParentPath2 = pathdup2; // pathdup are separated by pathdup, so it
                                  // take <parent path> only

    FileNode *parent_filenode2 = strlen(ParentPath)
                                     ? fischl_find_entry(root_node, ParentPath2)
                                     : root_node->self_info;
    if (parent_filenode2 == NULL) {
      fprintf(stderr, "[%s ,%d] ParentPath:{%s} not found\n", __func__,
              __LINE__, ParentPath2);
      free(pathdup2);
      return -ENOENT; // parentpath directory does not exist
    }
    u_int64_t parent_inode_number2 = parent_filenode2->inode_number;
    // printf("%s, %llu, %s\n", parent_filenode->name, parent_inode_number,
    // newDirname); make new inode
    if (insert_inode_to(parent_inode_number2, newDirname2, &ret) < 0) {
      return -1;
    }

    for (u_int64_t idx = 0; idx < parent_INode.metadata.size / IO_BLOCK_SIZE;
         idx++) {
      fs->read(&parent_INode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
      DirectoryEntry ent;
      for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
        ent.deserialize(rw_buffer + i);
        if (strcmp(ent.file_name, filename) == 0) {
          target_inode = ent.inode_number;
          ent.inode_number = 0;
          memset(ent.file_name, 0, sizeof(ent.file_name));
          ent.serialize(rw_buffer + i);
          break;
        }
      }
      if (target_inode) {
        fs->write(&parent_INode, rw_buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
        break;
      }
    }

    fischl_rm_entry(parent_filenode->subdirectory, filename);
    fischl_add_entry(parent_filenode2->subdirectory, ret.inode_num, newDirname2,
                     &ret);
    free(pathdup);
    // remove node itself and from parent hash
    free(pathdup2);
    return 0;
  } else {
    printf("cannot find %s in %s", filename, ParentPath);
    free(pathdup);
    return -1;
  }
}

int FilesOperation::fischl_truncate(const char *path, off_t offset,
                                    struct fuse_file_info *fi) {
  (void)fi;
  int res = 0;
  u_int64_t fh = namei(path);

  if (fh == -1) {
    return -ENOENT;
  }

  INode_Data inode;
  inode.inode_num = fh;
  fs->inode_manager->load_inode(&inode);
  res = fs->truncate(&inode, offset);
  fs->inode_manager->save_inode(&inode);
  return res;
}

int FilesOperation::fischl_read(const char *path, char *buf, size_t size,
                                off_t offset, struct fuse_file_info *fi) {
  /** Read data from an open file
   *
   * Read should return exactly the number of bytes requested except
   * on EOF or error, otherwise the rest of the data will be
   * substituted with zeroes.	 An exception to this is when the
   * 'direct_io' mount option is specified, in which case the return
   * value of the read system call will reflect the return value of
   * this operation.
   */
  // Caution! this based on content in file are multiple of IO_BLOCK_SIZE, not
  // the exact write size. based on current read_datablock API implement, when
  // read_datablock pass with actual size not index this function should be
  // fixed
  INode_Data inode;
  // Assuming inode is correctly initialized here based on 'path'
  inode.inode_num = fi->fh;
  fs->inode_manager->load_inode(&inode);
  size_t bytes_read = fs->read(&inode, buf, size, offset);
  /*size_t len = (inode.metadata.size/IO_BLOCK_SIZE) * IO_BLOCK_SIZE;  //
  Assuming each block is 4096 bytes

  if (offset >= len) return 0;  // Offset is beyond the end of the file
  if (offset + size > len) size = len - offset;  // Adjust size if it goes
  beyond EOF

  size_t bytes_read = 0;
  size_t block_index = offset / IO_BLOCK_SIZE;  // Starting block index
  size_t block_offset = offset % IO_BLOCK_SIZE; // Offset within the first block
  // fprintf(stderr,"[%s ,%d] inode.metadata.size %d\n",__func__,__LINE__,
  inode.metadata.size); while (bytes_read < size && block_index <
  inode.metadata.size/IO_BLOCK_SIZE) { char block_buffer[IO_BLOCK_SIZE];  //
  Temporary buffer for each block fs->read(&inode, block_buffer, IO_BLOCK_SIZE,
  block_index*IO_BLOCK_SIZE);
      // fprintf(stderr,"[%s ,%d] block_index %d\n",__func__,__LINE__,
  block_index); size_t copy_size = std::min(size - bytes_read, IO_BLOCK_SIZE -
  block_offset); memcpy(buf + bytes_read, block_buffer + block_offset,
  copy_size);
      // fprintf(stderr,"[%s ,%d] buf %s, block_buffer %s\n",__func__,__LINE__,
  buf, block_buffer); bytes_read += copy_size; block_index++; block_offset = 0;
  // Only the first block might have a non-zero offset
  }*/

  return bytes_read; // Return the actual number of bytes read
}