/*
 *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "webrtc/base/win32filesystem.h"

#include "webrtc/base/win32.h"
#include <shellapi.h>
#include <shlobj.h>
#include <tchar.h>

#include "webrtc/base/arraysize.h"
#include "webrtc/base/fileutils.h"
#include "webrtc/base/pathutils.h"
#include "webrtc/base/scoped_ptr.h"
#include "webrtc/base/stream.h"
#include "webrtc/base/stringutils.h"

// In several places in this file, we test the integrity level of the process
// before calling GetLongPathName. We do this because calling GetLongPathName
// when running under protected mode IE (a low integrity process) can result in
// a virtualized path being returned, which is wrong if you only plan to read.
// TODO: Waiting to hear back from IE team on whether this is the
// best approach; IEIsProtectedModeProcess is another possible solution.

namespace rtc {

bool Win32Filesystem::CreateFolder(const Pathname &pathname) {
  if (pathname.pathname().empty() || !pathname.filename().empty())
    return false;

  std::wstring path16;
  if (!Utf8ToWindowsFilename(pathname.pathname(), &path16))
    return false;

  DWORD res = ::GetFileAttributes(path16.c_str());
  if (res != INVALID_FILE_ATTRIBUTES) {
    // Something exists at this location, check if it is a directory
    return ((res & FILE_ATTRIBUTE_DIRECTORY) != 0);
  } else if ((GetLastError() != ERROR_FILE_NOT_FOUND)
              && (GetLastError() != ERROR_PATH_NOT_FOUND)) {
    // Unexpected error
    return false;
  }

  // Directory doesn't exist, look up one directory level
  if (!pathname.parent_folder().empty()) {
    Pathname parent(pathname);
    parent.SetFolder(pathname.parent_folder());
    if (!CreateFolder(parent)) {
      return false;
    }
  }

  return (::CreateDirectory(path16.c_str(), NULL) != 0);
}

FileStream *Win32Filesystem::OpenFile(const Pathname &filename,
                                      const std::string &mode) {
  FileStream *fs = new FileStream();
  if (fs && !fs->Open(filename.pathname().c_str(), mode.c_str(), NULL)) {
    delete fs;
    fs = NULL;
  }
  return fs;
}

bool Win32Filesystem::CreatePrivateFile(const Pathname &filename) {
  // To make the file private to the current user, we first must construct a
  // SECURITY_DESCRIPTOR specifying an ACL. This code is mostly based upon
  // http://msdn.microsoft.com/en-us/library/ms707085%28VS.85%29.aspx

  // Get the current process token.
  HANDLE process_token = INVALID_HANDLE_VALUE;
  if (!::OpenProcessToken(::GetCurrentProcess(),
                          TOKEN_QUERY,
                          &process_token)) {
    LOG_ERR(LS_ERROR) << "OpenProcessToken() failed";
    return false;
  }

  // Get the size of its TOKEN_USER structure. Return value is not checked
  // because we expect it to fail.
  DWORD token_user_size = 0;
  (void)::GetTokenInformation(process_token,
                              TokenUser,
                              NULL,
                              0,
                              &token_user_size);

  // Get the TOKEN_USER structure.
  scoped_ptr<char[]> token_user_bytes(new char[token_user_size]);
  PTOKEN_USER token_user = reinterpret_cast<PTOKEN_USER>(
      token_user_bytes.get());
  memset(token_user, 0, token_user_size);
  BOOL success = ::GetTokenInformation(process_token,
                                       TokenUser,
                                       token_user,
                                       token_user_size,
                                       &token_user_size);
  // We're now done with this.
  ::CloseHandle(process_token);
  if (!success) {
    LOG_ERR(LS_ERROR) << "GetTokenInformation() failed";
    return false;
  }

  if (!IsValidSid(token_user->User.Sid)) {
    LOG_ERR(LS_ERROR) << "Current process has invalid user SID";
    return false;
  }

  // Compute size needed for an ACL that allows access to just this user.
  int acl_size = sizeof(ACL) + sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD) +
      GetLengthSid(token_user->User.Sid);

  // Allocate it.
  scoped_ptr<char[]> acl_bytes(new char[acl_size]);
  PACL acl = reinterpret_cast<PACL>(acl_bytes.get());
  memset(acl, 0, acl_size);
  if (!::InitializeAcl(acl, acl_size, ACL_REVISION)) {
    LOG_ERR(LS_ERROR) << "InitializeAcl() failed";
    return false;
  }

  // Allow access to only the current user.
  if (!::AddAccessAllowedAce(acl,
                             ACL_REVISION,
                             GENERIC_READ | GENERIC_WRITE | STANDARD_RIGHTS_ALL,
                             token_user->User.Sid)) {
    LOG_ERR(LS_ERROR) << "AddAccessAllowedAce() failed";
    return false;
  }

  // Now make the security descriptor.
  SECURITY_DESCRIPTOR security_descriptor;
  if (!::InitializeSecurityDescriptor(&security_descriptor,
                                      SECURITY_DESCRIPTOR_REVISION)) {
    LOG_ERR(LS_ERROR) << "InitializeSecurityDescriptor() failed";
    return false;
  }

  // Put the ACL in it.
  if (!::SetSecurityDescriptorDacl(&security_descriptor,
                                   TRUE,
                                   acl,
                                   FALSE)) {
    LOG_ERR(LS_ERROR) << "SetSecurityDescriptorDacl() failed";
    return false;
  }

  // Finally create the file.
  SECURITY_ATTRIBUTES security_attributes;
  security_attributes.nLength = sizeof(security_attributes);
  security_attributes.lpSecurityDescriptor = &security_descriptor;
  security_attributes.bInheritHandle = FALSE;
  HANDLE handle = ::CreateFile(
      ToUtf16(filename.pathname()).c_str(),
      GENERIC_READ | GENERIC_WRITE,
      FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
      &security_attributes,
      CREATE_NEW,
      0,
      NULL);
  if (INVALID_HANDLE_VALUE == handle) {
    LOG_ERR(LS_ERROR) << "CreateFile() failed";
    return false;
  }
  if (!::CloseHandle(handle)) {
    LOG_ERR(LS_ERROR) << "CloseFile() failed";
    // Continue.
  }
  return true;
}

bool Win32Filesystem::DeleteFile(const Pathname &filename) {
  LOG(LS_INFO) << "Deleting file " << filename.pathname();
  if (!IsFile(filename)) {
    ASSERT(IsFile(filename));
    return false;
  }
  return ::DeleteFile(ToUtf16(filename.pathname()).c_str()) != 0;
}

bool Win32Filesystem::DeleteEmptyFolder(const Pathname &folder) {
  LOG(LS_INFO) << "Deleting folder " << folder.pathname();

  std::string no_slash(folder.pathname(), 0, folder.pathname().length()-1);
  return ::RemoveDirectory(ToUtf16(no_slash).c_str()) != 0;
}

bool Win32Filesystem::GetTemporaryFolder(Pathname &pathname, bool create,
                                         const std::string *append) {
  wchar_t buffer[MAX_PATH + 1];
  if (!::GetTempPath(arraysize(buffer), buffer))
    return false;
  if (!IsCurrentProcessLowIntegrity() &&
      !::GetLongPathName(buffer, buffer, arraysize(buffer)))
    return false;
  size_t len = strlen(buffer);
  if ((len > 0) && (buffer[len-1] != '\\')) {
    len += strcpyn(buffer + len, arraysize(buffer) - len, L"\\");
  }
  if (len >= arraysize(buffer) - 1)
    return false;
  pathname.clear();
  pathname.SetFolder(ToUtf8(buffer));
  if (append != NULL) {
    ASSERT(!append->empty());
    pathname.AppendFolder(*append);
  }
  return !create || CreateFolder(pathname);
}

std::string Win32Filesystem::TempFilename(const Pathname &dir,
                                          const std::string &prefix) {
  wchar_t filename[MAX_PATH];
  if (::GetTempFileName(ToUtf16(dir.pathname()).c_str(),
                        ToUtf16(prefix).c_str(), 0, filename) != 0)
    return ToUtf8(filename);
  ASSERT(false);
  return "";
}

bool Win32Filesystem::MoveFile(const Pathname &old_path,
                               const Pathname &new_path) {
  if (!IsFile(old_path)) {
    ASSERT(IsFile(old_path));
    return false;
  }
  LOG(LS_INFO) << "Moving " << old_path.pathname()
               << " to " << new_path.pathname();
  return ::MoveFile(ToUtf16(old_path.pathname()).c_str(),
                    ToUtf16(new_path.pathname()).c_str()) != 0;
}

bool Win32Filesystem::MoveFolder(const Pathname &old_path,
                                 const Pathname &new_path) {
  if (!IsFolder(old_path)) {
    ASSERT(IsFolder(old_path));
    return false;
  }
  LOG(LS_INFO) << "Moving " << old_path.pathname()
               << " to " << new_path.pathname();
  if (::MoveFile(ToUtf16(old_path.pathname()).c_str(),
               ToUtf16(new_path.pathname()).c_str()) == 0) {
    if (::GetLastError() != ERROR_NOT_SAME_DEVICE) {
      LOG_GLE(LS_ERROR) << "Failed to move file";
      return false;
    }
    if (!CopyFolder(old_path, new_path))
      return false;
    if (!DeleteFolderAndContents(old_path))
      return false;
  }
  return true;
}

bool Win32Filesystem::IsFolder(const Pathname &path) {
  WIN32_FILE_ATTRIBUTE_DATA data = {0};
  if (0 == ::GetFileAttributesEx(ToUtf16(path.pathname()).c_str(),
                                 GetFileExInfoStandard, &data))
    return false;
  return (data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ==
      FILE_ATTRIBUTE_DIRECTORY;
}

bool Win32Filesystem::IsFile(const Pathname &path) {
  WIN32_FILE_ATTRIBUTE_DATA data = {0};
  if (0 == ::GetFileAttributesEx(ToUtf16(path.pathname()).c_str(),
                                 GetFileExInfoStandard, &data))
    return false;
  return (data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0;
}

bool Win32Filesystem::IsAbsent(const Pathname& path) {
  WIN32_FILE_ATTRIBUTE_DATA data = {0};
  if (0 != ::GetFileAttributesEx(ToUtf16(path.pathname()).c_str(),
                                 GetFileExInfoStandard, &data))
    return false;
  DWORD err = ::GetLastError();
  return (ERROR_FILE_NOT_FOUND == err || ERROR_PATH_NOT_FOUND == err);
}

bool Win32Filesystem::CopyFile(const Pathname &old_path,
                               const Pathname &new_path) {
  return ::CopyFile(ToUtf16(old_path.pathname()).c_str(),
                    ToUtf16(new_path.pathname()).c_str(), TRUE) != 0;
}

bool Win32Filesystem::IsTemporaryPath(const Pathname& pathname) {
  TCHAR buffer[MAX_PATH + 1];
  if (!::GetTempPath(arraysize(buffer), buffer))
    return false;
  if (!IsCurrentProcessLowIntegrity() &&
      !::GetLongPathName(buffer, buffer, arraysize(buffer)))
    return false;
  return (::strnicmp(ToUtf16(pathname.pathname()).c_str(),
                     buffer, strlen(buffer)) == 0);
}

bool Win32Filesystem::GetFileSize(const Pathname &pathname, size_t *size) {
  WIN32_FILE_ATTRIBUTE_DATA data = {0};
  if (::GetFileAttributesEx(ToUtf16(pathname.pathname()).c_str(),
                            GetFileExInfoStandard, &data) == 0)
  return false;
  *size = data.nFileSizeLow;
  return true;
}

bool Win32Filesystem::GetFileTime(const Pathname& path, FileTimeType which,
                                  time_t* time) {
  WIN32_FILE_ATTRIBUTE_DATA data = {0};
  if (::GetFileAttributesEx(ToUtf16(path.pathname()).c_str(),
                            GetFileExInfoStandard, &data) == 0)
    return false;
  switch (which) {
  case FTT_CREATED:
    FileTimeToUnixTime(data.ftCreationTime, time);
    break;
  case FTT_MODIFIED:
    FileTimeToUnixTime(data.ftLastWriteTime, time);
    break;
  case FTT_ACCESSED:
    FileTimeToUnixTime(data.ftLastAccessTime, time);
    break;
  default:
    return false;
  }
  return true;
}

bool Win32Filesystem::GetAppPathname(Pathname* path) {
  TCHAR buffer[MAX_PATH + 1];
  if (0 == ::GetModuleFileName(NULL, buffer, arraysize(buffer)))
    return false;
  path->SetPathname(ToUtf8(buffer));
  return true;
}

bool Win32Filesystem::GetAppDataFolder(Pathname* path, bool per_user) {
  ASSERT(!organization_name_.empty());
  ASSERT(!application_name_.empty());
  TCHAR buffer[MAX_PATH + 1];
  int csidl = per_user ? CSIDL_LOCAL_APPDATA : CSIDL_COMMON_APPDATA;
  if (!::SHGetSpecialFolderPath(NULL, buffer, csidl, TRUE))
    return false;
  if (!IsCurrentProcessLowIntegrity() &&
      !::GetLongPathName(buffer, buffer, arraysize(buffer)))
    return false;
  size_t len = strcatn(buffer, arraysize(buffer), __T("\\"));
  len += strcpyn(buffer + len, arraysize(buffer) - len,
                 ToUtf16(organization_name_).c_str());
  if ((len > 0) && (buffer[len-1] != __T('\\'))) {
    len += strcpyn(buffer + len, arraysize(buffer) - len, __T("\\"));
  }
  len += strcpyn(buffer + len, arraysize(buffer) - len,
                 ToUtf16(application_name_).c_str());
  if ((len > 0) && (buffer[len-1] != __T('\\'))) {
    len += strcpyn(buffer + len, arraysize(buffer) - len, __T("\\"));
  }
  if (len >= arraysize(buffer) - 1)
    return false;
  path->clear();
  path->SetFolder(ToUtf8(buffer));
  return CreateFolder(*path);
}

bool Win32Filesystem::GetAppTempFolder(Pathname* path) {
  if (!GetAppPathname(path))
    return false;
  std::string filename(path->filename());
  return GetTemporaryFolder(*path, true, &filename);
}

bool Win32Filesystem::GetDiskFreeSpace(const Pathname& path,
                                       int64_t* free_bytes) {
  if (!free_bytes) {
    return false;
  }
  char drive[4];
  std::wstring drive16;
  const wchar_t* target_drive = NULL;
  if (path.GetDrive(drive, sizeof(drive))) {
    drive16 = ToUtf16(drive);
    target_drive = drive16.c_str();
  } else if (path.folder().substr(0, 2) == "\\\\") {
    // UNC path, fail.
    // TODO: Handle UNC paths.
    return false;
  } else {
    // The path is probably relative.  GetDriveType and GetDiskFreeSpaceEx
    // use the current drive if NULL is passed as the drive name.
    // TODO: Add method to Pathname to determine if the path is relative.
    // TODO: Add method to Pathname to convert a path to absolute.
  }
  UINT drive_type = ::GetDriveType(target_drive);
  if ((drive_type == DRIVE_REMOTE) || (drive_type == DRIVE_UNKNOWN)) {
    LOG(LS_VERBOSE) << "Remote or unknown drive: " << drive;
    return false;
  }

  int64_t total_number_of_bytes;       // receives the number of bytes on disk
  int64_t total_number_of_free_bytes;  // receives the free bytes on disk
  // make sure things won't change in 64 bit machine
  // TODO replace with compile time assert
  ASSERT(sizeof(ULARGE_INTEGER) == sizeof(uint64_t));  // NOLINT
  if (::GetDiskFreeSpaceEx(target_drive,
                           (PULARGE_INTEGER)free_bytes,
                           (PULARGE_INTEGER)&total_number_of_bytes,
                           (PULARGE_INTEGER)&total_number_of_free_bytes)) {
    return true;
  } else {
    LOG(LS_VERBOSE) << "GetDiskFreeSpaceEx returns error.";
    return false;
  }
}

Pathname Win32Filesystem::GetCurrentDirectory() {
  Pathname cwd;
  int path_len = 0;
  scoped_ptr<wchar_t[]> path;
  do {
    int needed = ::GetCurrentDirectory(path_len, path.get());
    if (needed == 0) {
      // Error.
      LOG_GLE(LS_ERROR) << "::GetCurrentDirectory() failed";
      return cwd;  // returns empty pathname
    }
    if (needed <= path_len) {
      // It wrote successfully.
      break;
    }
    // Else need to re-alloc for "needed".
    path.reset(new wchar_t[needed]);
    path_len = needed;
  } while (true);
  cwd.SetFolder(ToUtf8(path.get()));
  return cwd;
}

// TODO: Consider overriding DeleteFolderAndContents for speed and potentially
// better OS integration (recycle bin?)
/*
  std::wstring temp_path16 = ToUtf16(temp_path.pathname());
  temp_path16.append(1, '*');
  temp_path16.append(1, '\0');

  SHFILEOPSTRUCT file_op = { 0 };
  file_op.wFunc = FO_DELETE;
  file_op.pFrom = temp_path16.c_str();
  file_op.fFlags = FOF_NOCONFIRMATION | FOF_NOERRORUI | FOF_SILENT;
  return (0 == SHFileOperation(&file_op));
*/

}  // namespace rtc