/*
 *  Copyright (C) 2005-2018 Team Kodi
 *  This file is part of Kodi - https://kodi.tv
 *
 *  SPDX-License-Identifier: GPL-2.0-or-later
 *  See LICENSES/README.md for more information.
 */

/*
* know bugs:
* - when opening a server for the first time with ip address and the second time
*   with server name, access to the server is denied.
* - when browsing entire network, user can't go back one step
*   share = smb://, user selects a workgroup, user selects a server.
*   doing ".." will go back to smb:// (entire network) and not to workgroup list.
*
* debugging is set to a max of 10 for release builds (see local.h)
*/

#include "SMBDirectory.h"

#include "FileItem.h"
#include "PasswordManager.h"
#include "ServiceBroker.h"
#include "guilib/LocalizeStrings.h"
#include "settings/AdvancedSettings.h"
#include "settings/Settings.h"
#include "settings/SettingsComponent.h"
#include "utils/StringUtils.h"
#include "utils/URIUtils.h"
#include "utils/XTimeUtils.h"
#include "utils/log.h"

#include "platform/posix/filesystem/SMBWSDiscovery.h"

#include <mutex>

#include <libsmbclient.h>

struct CachedDirEntry
{
  unsigned int type;
  std::string name;
};

using namespace XFILE;

CSMBDirectory::CSMBDirectory(void)
{
  smb.AddActiveConnection();
}

CSMBDirectory::~CSMBDirectory(void)
{
  smb.AddIdleConnection();
}

bool CSMBDirectory::GetDirectory(const CURL& url, CFileItemList &items)
{
  // We accept smb://[[[domain;]user[:password@]]server[/share[/path[/file]]]]

  /* samba isn't thread safe with old interface, always lock */
  std::unique_lock<CCriticalSection> lock(smb);

  smb.Init();

  //Separate roots for the authentication and the containing items to allow browsing to work correctly
  std::string strRoot = url.Get();
  std::string strAuth;

  lock.unlock(); // OpenDir is locked

  // if url provided does not having anything except smb protocol
  // Do a WS-Discovery search to find possible smb servers to mimic smbv1 behaviour
  if (strRoot == "smb://")
  {
    auto settingsComponent = CServiceBroker::GetSettingsComponent();
    if (!settingsComponent)
      return false;

    auto settings = CServiceBroker::GetSettingsComponent()->GetSettings();
    if (!settings)
      return false;

    // Check WS-Discovery daemon enabled, if not return as smb:// cant be handled further
    if (settings->GetBool(CSettings::SETTING_SERVICES_WSDISCOVERY))
    {
      WSDiscovery::CWSDiscoveryPosix& WSInstance =
          dynamic_cast<WSDiscovery::CWSDiscoveryPosix&>(CServiceBroker::GetWSDiscovery());
      return WSInstance.GetServerList(items);
    }
    else
    {
      return false;
    }
  }

  int fd = OpenDir(url, strAuth);
  if (fd < 0)
    return false;

  URIUtils::AddSlashAtEnd(strRoot);
  URIUtils::AddSlashAtEnd(strAuth);

  std::string strFile;

  // need to keep the samba lock for as short as possible.
  // so we first cache all directory entries and then go over them again asking for stat
  // "stat" is locked each time. that way the lock is freed between stat requests
  std::vector<CachedDirEntry> vecEntries;
  struct smbc_dirent* dirEnt;

  lock.lock();
  if (!smb.IsSmbValid())
    return false;
  while ((dirEnt = smbc_readdir(fd)))
  {
    CachedDirEntry aDir;
    aDir.type = dirEnt->smbc_type;
    aDir.name = dirEnt->name;
    vecEntries.push_back(aDir);
  }
  smbc_closedir(fd);
  lock.unlock();

  for (size_t i=0; i<vecEntries.size(); i++)
  {
    CachedDirEntry aDir = vecEntries[i];

    // We use UTF-8 internally, as does SMB
    strFile = aDir.name;

    if (!strFile.empty() && strFile != "." && strFile != ".."
      && strFile != "lost+found"
      && aDir.type != SMBC_PRINTER_SHARE && aDir.type != SMBC_IPC_SHARE)
    {
      int64_t iSize = 0;
      bool bIsDir = true;
      bool hidden = false;
      struct stat info = {};

      if(StringUtils::EndsWith(strFile, "$") && aDir.type == SMBC_FILE_SHARE )
        continue;

      if (StringUtils::StartsWith(strFile, "."))
        hidden = true;

      // only stat files that can give proper responses
      if ( aDir.type == SMBC_FILE ||
           aDir.type == SMBC_DIR )
      {
        // set this here to if the stat should fail
        bIsDir = (aDir.type == SMBC_DIR);

        if ((m_flags & DIR_FLAG_NO_FILE_INFO)==0 && CServiceBroker::GetSettingsComponent()->GetAdvancedSettings()->m_sambastatfiles)
        {
          // make sure we use the authenticated path which contains any default username
          const std::string strFullName = strAuth + smb.URLEncode(strFile);

          lock.lock();
          if (!smb.IsSmbValid())
          {
            items.ClearItems();
            return false;
          }

          if( smbc_stat(strFullName.c_str(), &info) == 0 )
          {

            char value[20];
            // We poll for extended attributes which symbolizes bits but split up into a string. Where 0x02 is hidden and 0x12 is hidden directory.
            // According to the libsmbclient.h it returns 0 on success and -1 on error.
            // But before Samba 4.17.5 it seems to return the length of the returned value
            // (which is 4), see https://bugzilla.samba.org/show_bug.cgi?id=14808.
            // Checking for >= 0 should work both for the old erroneous and the correct behaviour.
            if (smbc_getxattr(strFullName.c_str(), "system.dos_attr.mode", value, sizeof(value)) >= 0)
            {
              long longvalue = strtol(value, NULL, 16);
              if (longvalue & SMBC_DOS_MODE_HIDDEN)
                hidden = true;
            }
            else
              CLog::Log(
                  LOGERROR,
                  "Getting extended attributes for the share: '{}'\nunix_err:'{:x}' error: '{}'",
                  CURL::GetRedacted(strFullName), errno, strerror(errno));

            bIsDir = S_ISDIR(info.st_mode);
            iSize = info.st_size;
          }
          else
            CLog::Log(LOGERROR, "{} - Failed to stat file {}", __FUNCTION__,
                      CURL::GetRedacted(strFullName));

          lock.unlock();
        }
      }

      if (bIsDir)
      {
        CFileItemPtr pItem(new CFileItem(strFile));
        std::string path(strRoot);

        // needed for network / workgroup browsing
        // skip if root if we are given a server
        if (aDir.type == SMBC_SERVER)
        {
          /* create url with same options, user, pass.. but no filename or host*/
          CURL rooturl(strRoot);
          rooturl.SetFileName("");
          rooturl.SetHostName("");
          path = smb.URLEncode(rooturl);
        }
        path = URIUtils::AddFileToFolder(path,aDir.name);
        URIUtils::AddSlashAtEnd(path);
        pItem->SetPath(path);
        pItem->m_bIsFolder = true;
        pItem->m_dateTime = info.st_mtime != 0 ? info.st_mtime : info.st_ctime;
        if (hidden)
          pItem->SetProperty("file:hidden", true);
        items.Add(pItem);
      }
      else
      {
        CFileItemPtr pItem(new CFileItem(strFile));
        pItem->SetPath(strRoot + aDir.name);
        pItem->m_bIsFolder = false;
        pItem->m_dwSize = iSize;
        pItem->m_dateTime = info.st_mtime != 0 ? info.st_mtime : info.st_ctime;
        if (hidden)
          pItem->SetProperty("file:hidden", true);
        items.Add(pItem);
      }
    }
  }

  return true;
}

int CSMBDirectory::Open(const CURL &url)
{
  smb.Init();
  std::string strAuth;
  return OpenDir(url, strAuth);
}

/// \brief Checks authentication against SAMBA share and prompts for username and password if needed
/// \param strAuth The SMB style path
/// \return SMB file descriptor
int CSMBDirectory::OpenDir(const CURL& url, std::string& strAuth)
{
  int fd = -1;

  /* make a writeable copy */
  CURL urlIn = CSMB::GetResolvedUrl(url);

  CPasswordManager::GetInstance().AuthenticateURL(urlIn);
  strAuth = smb.URLEncode(urlIn);

  // remove the / or \ at the end. the samba library does not strip them off
  // don't do this for smb:// !!
  std::string s = strAuth;
  int len = s.length();
  if (len > 1 && s.at(len - 2) != '/' &&
      (s.at(len - 1) == '/' || s.at(len - 1) == '\\'))
  {
    s.erase(len - 1, 1);
  }

  CLog::LogFC(LOGDEBUG, LOGSAMBA, "Using authentication url {}", CURL::GetRedacted(s));

  {
    std::unique_lock<CCriticalSection> lock(smb);
    if (!smb.IsSmbValid())
      return -1;
    fd = smbc_opendir(s.c_str());
  }

  while (fd < 0) /* only to avoid goto in following code */
  {
    std::string cError;

    if (errno == EACCES)
    {
      if (m_flags & DIR_FLAG_ALLOW_PROMPT)
        RequireAuthentication(urlIn);
      break;
    }

    if (errno == ENODEV || errno == ENOENT)
      cError = StringUtils::Format(g_localizeStrings.Get(770), errno);
    else
      cError = strerror(errno);

    if (m_flags & DIR_FLAG_ALLOW_PROMPT)
      SetErrorDialog(257, cError.c_str());
    break;
  }

  if (fd < 0)
  {
    // write error to logfile
    CLog::Log(
        LOGERROR,
        "SMBDirectory->GetDirectory: Unable to open directory : '{}'\nunix_err:'{:x}' error : '{}'",
        CURL::GetRedacted(strAuth), errno, strerror(errno));
  }

  return fd;
}

bool CSMBDirectory::Create(const CURL& url2)
{
  std::unique_lock<CCriticalSection> lock(smb);
  smb.Init();

  CURL url = CSMB::GetResolvedUrl(url2);
  CPasswordManager::GetInstance().AuthenticateURL(url);
  std::string strFileName = smb.URLEncode(url);

  int result = smbc_mkdir(strFileName.c_str(), 0);
  bool success = (result == 0 || EEXIST == errno);
  if(!success)
    CLog::Log(LOGERROR, "{} - Error( {} )", __FUNCTION__, strerror(errno));

  return success;
}

bool CSMBDirectory::Remove(const CURL& url2)
{
  std::unique_lock<CCriticalSection> lock(smb);
  smb.Init();

  CURL url = CSMB::GetResolvedUrl(url2);
  CPasswordManager::GetInstance().AuthenticateURL(url);
  std::string strFileName = smb.URLEncode(url);

  int result = smbc_rmdir(strFileName.c_str());

  if(result != 0 && errno != ENOENT)
  {
    CLog::Log(LOGERROR, "{} - Error( {} )", __FUNCTION__, strerror(errno));
    return false;
  }

  return true;
}

bool CSMBDirectory::Exists(const CURL& url2)
{
  std::unique_lock<CCriticalSection> lock(smb);
  smb.Init();

  CURL url = CSMB::GetResolvedUrl(url2);
  CPasswordManager::GetInstance().AuthenticateURL(url);
  std::string strFileName = smb.URLEncode(url);

  struct stat info;
  if (smbc_stat(strFileName.c_str(), &info) != 0)
    return false;

  return S_ISDIR(info.st_mode);
}