/*
 * Copyright (c) 2014-2018 Cesanta Software Limited
 * All rights reserved
 *
 * Licensed under the Apache License, Version 2.0 (the ""License"");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an ""AS IS"" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef EXCLUDE_COMMON

#include "mg_mem.h"
#include "cs_dirent.h"

/*
 * This file contains POSIX opendir/closedir/readdir API implementation
 * for systems which do not natively support it (e.g. Windows).
 */

#ifdef _WIN32
struct win32_dir {
  DIR d;
  HANDLE handle;
  WIN32_FIND_DATAW info;
  struct dirent result;
};

DIR *opendir(const char *name) {
  struct win32_dir *dir = NULL;
  wchar_t wpath[MAX_PATH];
  DWORD attrs;

  if (name == NULL) {
    SetLastError(ERROR_BAD_ARGUMENTS);
  } else if ((dir = (struct win32_dir *) MG_MALLOC(sizeof(*dir))) == NULL) {
    SetLastError(ERROR_NOT_ENOUGH_MEMORY);
  } else {
    to_wchar(name, wpath, ARRAY_SIZE(wpath));
    attrs = GetFileAttributesW(wpath);
    if (attrs != 0xFFFFFFFF && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
      (void) wcscat(wpath, L"\\*");
      dir->handle = FindFirstFileW(wpath, &dir->info);
      dir->result.d_name[0] = '\0';
    } else {
      MG_FREE(dir);
      dir = NULL;
    }
  }

  return (DIR *) dir;
}

int closedir(DIR *d) {
  struct win32_dir *dir = (struct win32_dir *) d;
  int result = 0;

  if (dir != NULL) {
    if (dir->handle != INVALID_HANDLE_VALUE)
      result = FindClose(dir->handle) ? 0 : -1;
    MG_FREE(dir);
  } else {
    result = -1;
    SetLastError(ERROR_BAD_ARGUMENTS);
  }

  return result;
}

struct dirent *readdir(DIR *d) {
  struct win32_dir *dir = (struct win32_dir *) d;
  struct dirent *result = NULL;

  if (dir) {
    memset(&dir->result, 0, sizeof(dir->result));
    if (dir->handle != INVALID_HANDLE_VALUE) {
      result = &dir->result;
      (void) WideCharToMultiByte(CP_UTF8, 0, dir->info.cFileName, -1,
                                 result->d_name, sizeof(result->d_name), NULL,
                                 NULL);

      if (!FindNextFileW(dir->handle, &dir->info)) {
        (void) FindClose(dir->handle);
        dir->handle = INVALID_HANDLE_VALUE;
      }

    } else {
      SetLastError(ERROR_FILE_NOT_FOUND);
    }
  } else {
    SetLastError(ERROR_BAD_ARGUMENTS);
  }

  return result;
}
#endif

#endif /* EXCLUDE_COMMON */

/* ISO C requires a translation unit to contain at least one declaration */
typedef int cs_dirent_dummy;