////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
////////////////////////////////////////////////////////////////////////////////

#include "FileUtils.h"

#ifdef TRI_HAVE_DIRENT_H
#include <dirent.h>
#endif

#ifdef TRI_HAVE_DIRECT_H
#include <direct.h>
#endif

#include "Basics/Exceptions.h"
#include "Basics/StringBuffer.h"
#include "Basics/files.h"
#include "Basics/Logger.h"
#include "Basics/tri-strings.h"

#if defined(_WIN32) && defined(_MSC_VER)

#define TRI_DIR_FN(item) item.name

#else

#define TRI_DIR_FN(item) item->d_name

#endif

namespace arangodb {
namespace basics {
namespace FileUtils {

////////////////////////////////////////////////////////////////////////////////
/// @brief removes trailing path separators from path
///
/// path will be modified in-place
////////////////////////////////////////////////////////////////////////////////

std::string removeTrailingSeparator(std::string const& name) {
  size_t endpos = name.find_last_not_of(TRI_DIR_SEPARATOR_CHAR);
  if (endpos != std::string::npos) {
    return name.substr(0, endpos + 1);
  }

  return name;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief normalizes path
///
/// path will be modified in-place
////////////////////////////////////////////////////////////////////////////////

void normalizePath(std::string& name) {
  std::replace(name.begin(), name.end(), '/', TRI_DIR_SEPARATOR_CHAR);
}

////////////////////////////////////////////////////////////////////////////////
/// @brief creates a filename
////////////////////////////////////////////////////////////////////////////////

std::string buildFilename(char const* path, char const* name) {
  std::string result(path);

  if (! result.empty()) {
    result = removeTrailingSeparator(result) + TRI_DIR_SEPARATOR_CHAR;
  }
  
  result.append(name); 
  normalizePath(result); // in place

  return result;
}

std::string buildFilename(std::string const& path, std::string const& name) {
  std::string result(path);

  if (! result.empty()) {
    result = removeTrailingSeparator(result) + TRI_DIR_SEPARATOR_CHAR;
  }
  
  result.append(name); 
  normalizePath(result); // in place

  return result;
}

void throwFileReadError(int fd, std::string const& filename) {
  TRI_set_errno(TRI_ERROR_SYS_ERROR);
  int res = TRI_errno();

  if (fd >= 0) {
    TRI_CLOSE(fd);
  }

  std::string message("read failed for file '" + filename + "': " +
                      strerror(res));
  LOG(TRACE) << "" << message;

  THROW_ARANGO_EXCEPTION(TRI_ERROR_SYS_ERROR);
}

void throwFileWriteError(int fd, std::string const& filename) {
  TRI_set_errno(TRI_ERROR_SYS_ERROR);
  int res = TRI_errno();

  if (fd >= 0) {
    TRI_CLOSE(fd);
  }

  std::string message("write failed for file '" + filename + "': " +
                      strerror(res));
  LOG(TRACE) << "" << message;

  THROW_ARANGO_EXCEPTION(TRI_ERROR_SYS_ERROR);
}

std::string slurp(std::string const& filename) {
  int fd = TRI_OPEN(filename.c_str(), O_RDONLY | TRI_O_CLOEXEC);

  if (fd == -1) {
    throwFileReadError(fd, filename);
  }

  char buffer[10240];
  StringBuffer result(TRI_CORE_MEM_ZONE);

  while (true) {
    ssize_t n = TRI_READ(fd, buffer, sizeof(buffer));

    if (n == 0) {
      break;
    }

    if (n < 0) {
      throwFileReadError(fd, filename);
    }

    result.appendText(buffer, n);
  }

  TRI_CLOSE(fd);

  std::string r(result.c_str(), result.length());

  return r;
}

void slurp(std::string const& filename, StringBuffer& result) {
  int fd = TRI_OPEN(filename.c_str(), O_RDONLY | TRI_O_CLOEXEC);

  if (fd == -1) {
    throwFileReadError(fd, filename);
  }

  // reserve space in the output buffer
  off_t fileSize = size(filename);
  if (fileSize > 0) {
    result.reserve((size_t)fileSize);
  }

  char buffer[10240];

  while (true) {
    ssize_t n = TRI_READ(fd, buffer, sizeof(buffer));

    if (n == 0) {
      break;
    }

    if (n < 0) {
      throwFileReadError(fd, filename);
    }

    result.appendText(buffer, n);
  }

  TRI_CLOSE(fd);
}

void spit(std::string const& filename, char const* ptr, size_t len) {
  int fd =
      TRI_CREATE(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC | TRI_O_CLOEXEC,
                 S_IRUSR | S_IWUSR | S_IRGRP);

  if (fd == -1) {
    throwFileWriteError(fd, filename);
  }

  while (0 < len) {
    ssize_t n = TRI_WRITE(fd, ptr, (TRI_write_t)len);

    if (n < 1) {
      throwFileWriteError(fd, filename);
    }

    ptr += n;
    len -= n;
  }

  TRI_CLOSE(fd);
}

void spit(std::string const& filename, std::string const& content) {
  int fd =
      TRI_CREATE(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC | TRI_O_CLOEXEC,
                 S_IRUSR | S_IWUSR | S_IRGRP);

  if (fd == -1) {
    throwFileWriteError(fd, filename);
  }

  char const* ptr = content.c_str();
  size_t len = content.size();

  while (0 < len) {
    ssize_t n = TRI_WRITE(fd, ptr, (TRI_write_t)len);

    if (n < 1) {
      throwFileWriteError(fd, filename);
    }

    ptr += n;
    len -= n;
  }

  TRI_CLOSE(fd);
}

void spit(std::string const& filename, StringBuffer const& content) {
  int fd =
      TRI_CREATE(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC | TRI_O_CLOEXEC,
                 S_IRUSR | S_IWUSR | S_IRGRP);

  if (fd == -1) {
    throwFileWriteError(fd, filename);
  }

  char const* ptr = content.c_str();
  size_t len = content.length();

  while (0 < len) {
    ssize_t n = TRI_WRITE(fd, ptr, (TRI_write_t)len);

    if (n < 1) {
      throwFileWriteError(fd, filename);
    }

    ptr += n;
    len -= n;
  }

  TRI_CLOSE(fd);
}

bool remove(std::string const& fileName, int* errorNumber) {
  if (errorNumber != nullptr) {
    *errorNumber = 0;
  }

  int result = std::remove(fileName.c_str());

  if (errorNumber != nullptr) {
    *errorNumber = errno;
  }

  return (result != 0) ? false : true;
}

bool rename(std::string const& oldName, std::string const& newName,
            int* errorNumber) {
  if (errorNumber != nullptr) {
    *errorNumber = 0;
  }

  int result = std::rename(oldName.c_str(), newName.c_str());

  if (errorNumber != nullptr) {
    *errorNumber = errno;
  }

  return (result != 0) ? false : true;
}

bool createDirectory(std::string const& name, int* errorNumber) {
  if (errorNumber != nullptr) {
    *errorNumber = 0;
  }

  return createDirectory(name, 0777, errorNumber);
}

bool createDirectory(std::string const& name, int mask, int* errorNumber) {
  if (errorNumber != nullptr) {
    *errorNumber = 0;
  }

  int result = TRI_MKDIR(name.c_str(), mask);

  int res = errno;
  if (result != 0 && res == EEXIST && isDirectory(name)) {
    result = 0;
  } else if (res != 0) {
    TRI_set_errno(TRI_ERROR_SYS_ERROR);
  }

  if (errorNumber != nullptr) {
    *errorNumber = res;
  }

  return (result != 0) ? false : true;
}

bool copyRecursive(std::string const& source, std::string const& target,
                   std::string& error) {
  if (isDirectory(source)) {
    return copyDirectoryRecursive(source, target, error);
  }

  return TRI_CopyFile(source, target, error);
}

bool copyDirectoryRecursive(std::string const& source,
                            std::string const& target, std::string& error) {
  bool rc = true;
#ifdef TRI_HAVE_WIN32_LIST_FILES
  auto isSubDirectory = [](struct _finddata_t item) -> bool {
    return ((item.attrib & _A_SUBDIR) != 0);
  };

  struct _finddata_t oneItem;
  intptr_t handle;

  std::string filter = source + "\\*";
  handle = _findfirst(filter.c_str(), &oneItem);

  if (handle == -1) {
    error = "directory " + source + "not found";
    return false;
  }

  do {
#else
  auto isSubDirectory = [](struct dirent* item) -> bool { return isDirectory(item->d_name); };

  struct dirent* d = (struct dirent*)TRI_Allocate(
      TRI_UNKNOWN_MEM_ZONE, (offsetof(struct dirent, d_name) + PATH_MAX + 1),
      false);

  if (d == nullptr) {
    error = "directory " + source + " OOM";
    return false;
  }

  DIR* filedir = opendir(source.c_str());

  if (filedir == nullptr) {
    TRI_Free(TRI_UNKNOWN_MEM_ZONE, d);
    error = "directory " + source + "not found";
    return false;
  }

  struct dirent* oneItem;
  while ((readdir_r(filedir, d, &oneItem) == 0) && (oneItem != nullptr)) {
#endif
    // Now iterate over the items.
    // check its not the pointer to the upper directory:
    if (!strcmp(TRI_DIR_FN(oneItem), ".") ||
        !strcmp(TRI_DIR_FN(oneItem), "..")) {
      continue;
    }

    std::string dst = target + TRI_DIR_SEPARATOR_STR + TRI_DIR_FN(oneItem);
    std::string src = source + TRI_DIR_SEPARATOR_STR + TRI_DIR_FN(oneItem);

    // Handle subdirectories:
    if (isSubDirectory(oneItem)) {
      long systemError;
      int rc = TRI_CreateDirectory(dst.c_str(), systemError, error);
      if (rc != TRI_ERROR_NO_ERROR) {
        break;
      }
      if (!copyDirectoryRecursive(src, dst, error)) {
        break;
      }
      if (!TRI_CopyAttributes(src, dst, error)) {
        break;
      }
#ifndef _WIN32
    } else if (isSymbolicLink(oneItem->d_name)) {
      if (!TRI_CopySymlink(src, dst, error)) {
        break;
      }
#endif
    } else {
      if (!TRI_CopyFile(src, dst, error)) {
        break;
      }
    }
#ifdef TRI_HAVE_WIN32_LIST_FILES
  } while (_findnext(handle, &oneItem) != -1);

  _findclose(handle);

#else
  }
  TRI_Free(TRI_UNKNOWN_MEM_ZONE, d);
  closedir(filedir);

#endif
  return rc;
}

std::vector<std::string> listFiles(std::string const& directory) {
  std::vector<std::string> result;

#ifdef TRI_HAVE_WIN32_LIST_FILES

  struct _finddata_t fd;
  intptr_t handle;

  std::string filter = directory + "\\*";
  handle = _findfirst(filter.c_str(), &fd);

  if (handle == -1) {
    return result;
  }

  do {
    if (strcmp(fd.name, ".") != 0 && strcmp(fd.name, "..") != 0) {
      result.push_back(fd.name);
    }
  } while (_findnext(handle, &fd) != -1);

  _findclose(handle);

#else

  DIR* d = opendir(directory.c_str());

  if (d == nullptr) {
    return result;
  }

  dirent* de = readdir(d);

  while (de != nullptr) {
    if (strcmp(de->d_name, ".") != 0 && strcmp(de->d_name, "..") != 0) {
      result.push_back(de->d_name);
    }

    de = readdir(d);
  }

  closedir(d);

#endif

  return result;
}

bool isDirectory(std::string const& path) {
  TRI_stat_t stbuf;
  int res = TRI_STAT(path.c_str(), &stbuf);
#ifdef _WIN32
  return (res == 0) && ((stbuf.st_mode & S_IFMT) == S_IFDIR);
#else
  return (res == 0) && S_ISDIR(stbuf.st_mode);
#endif
}

bool isSymbolicLink(std::string const& path) {
#ifdef TRI_HAVE_WIN32_SYMBOLIC_LINK

  // .....................................................................
  // TODO: On the NTFS file system, there are the following file links:
  // hard links -
  // junctions -
  // symbolic links -
  // .....................................................................
  return false;

#else

  struct stat stbuf;
  int res = TRI_STAT(path.c_str(), &stbuf);

  return (res == 0) && S_ISLNK(stbuf.st_mode);

#endif
}

bool isRegularFile(std::string const& path) {
  TRI_stat_t stbuf;
  int res = TRI_STAT(path.c_str(), &stbuf);
  return (res == 0) && ((stbuf.st_mode & S_IFMT) == S_IFREG);
}

bool exists(std::string const& path) {
  TRI_stat_t stbuf;
  int res = TRI_STAT(path.c_str(), &stbuf);

  return res == 0;
}

off_t size(std::string const& path) {
  int64_t result = TRI_SizeFile(path.c_str());

  if (result < 0) {
    return (off_t)0;
  }

  return (off_t)result;
}

std::string stripExtension(std::string const& path,
                           std::string const& extension) {
  size_t pos = path.rfind(extension);
  if (pos == std::string::npos) {
    return path;
  }

  std::string last = path.substr(pos);
  if (last == extension) {
    return path.substr(0, pos);
  }

  return path;
}

bool changeDirectory(std::string const& path) {
  return TRI_CHDIR(path.c_str()) == 0;
}

std::string currentDirectory(int* errorNumber) {
  if (errorNumber != 0) {
    *errorNumber = 0;
  }

  size_t len = 1000;
  char* current = new char[len];

  while (TRI_GETCWD(current, (int)len) == nullptr) {
    if (errno == ERANGE) {
      len += 1000;
      delete[] current;
      current = new char[len];
    } else {
      delete[] current;

      if (errorNumber != 0) {
        *errorNumber = errno;
      }

      return ".";
    }
  }

  std::string result = current;

  delete[] current;

  return result;
}

std::string homeDirectory() {
  char* dir = TRI_HomeDirectory();
  std::string result = dir;
  TRI_FreeString(TRI_CORE_MEM_ZONE, dir);

  return result;
}
}
}
}