/*
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "tdbInt.h"

int tdbGnrtFileID(const char *fname, uint8_t *fileid, bool unique) {
  struct stat statbuf;

  if (stat(fname, &statbuf) < 0) {
    return -1;
  }

  memset(fileid, 0, TDB_FILE_ID_LEN);

  ((uint64_t *)fileid)[0] = (uint64_t)statbuf.st_ino;
  ((uint64_t *)fileid)[1] = (uint64_t)statbuf.st_dev;
  if (unique) {
    ((uint64_t *)fileid)[2] = rand();
  }

  return 0;
}

int tdbCheckFileAccess(const char *pathname, int mode) {
  int flags = 0;

  if (mode & TDB_F_OK) {
    flags |= F_OK;
  }

  if (mode & TDB_R_OK) {
    flags |= R_OK;
  }

  if (mode & TDB_W_OK) {
    flags |= W_OK;
  }

  return access(pathname, flags);
}

int tdbGetFileSize(const char *fname, int pgSize, SPgno *pSize) {
  struct stat st;
  int         ret;

  ret = stat(fname, &st);
  if (ret != 0) {
    return -1;
  }

  ASSERT(st.st_size % pgSize == 0);

  *pSize = st.st_size / pgSize;
  return 0;
}

int tdbPRead(int fd, void *pData, int count, i64 offset) {
  void *pBuf;
  int   nbytes;
  i64   ioffset;
  int   iread;

  pBuf = pData;
  nbytes = count;
  ioffset = offset;
  while (nbytes > 0) {
    iread = pread(fd, pBuf, nbytes, ioffset);
    if (iread < 0) {
      /* TODO */
    } else if (iread == 0) {
      return (count - iread);
    }

    nbytes = nbytes - iread;
    pBuf = (void *)((u8 *)pBuf + iread);
    ioffset += iread;
  }

  return count;
}