/**
 *  @file maildir-updateflags.cc
 *  @brief  Implementation of the Maildir class.
 *  @author Andreas Aardal Hanssen
 *  @date 2002-2005
 */

#include "iodevice.h"
#include "iofactory.h"
#include "maildir.h"

#include <errno.h>

#include <dirent.h>
#include <unistd.h>

using std::string;

void Binc::Maildir::updateFlags(void)
{
  // don't update a read-only mailbox.
  if (readOnly) return;

  // open the cur/ directory
  string curpath = path + "/cur/";
  DIR *pdir = opendir(curpath.c_str());
  if (pdir == nullptr) {
    bincError << "failed to open " << curpath << ": " << strerror(errno) << std::endl;
    return;
  }

  // read all entries in the directory
  std::vector<string> entries;
  struct dirent *pdirent;
  while ((pdirent = readdir(pdir)) != nullptr) {
    string filename = pdirent->d_name;
    if (filename[0] == '.') continue;
    entries.push_back(filename);
  }
  closedir(pdir);

  bool customFlagsChanged = false;

  // loop through all messages in cur/, and update the flags that have changed.
  for (const auto &filename : entries) {
    // separate the unique name from the flags. accept messages that do not
    // contain the flags section.
    string uniquename;
    string::size_type pos;
    if ((pos = filename.find(":2,")) != string::npos)
      uniquename = filename.substr(0, pos);
    else
      uniquename = filename;

    // only update flags for messages that are known.
    MaildirMessage *message = get(uniquename);
    if (!message) continue;

    // check if custom flags have changed; if so, we need to regenerate the
    // cache file.
    if (message->internalFlags & MaildirMessage::CustomFlagsChanged) customFlagsChanged = true;

    // generate the flag string.
    string flags;
    int mflags = message->getStdFlags();
    if (mflags & Message::F_DRAFT) flags += "D";
    if (mflags & Message::F_FLAGGED) flags += "F";
    if (mflags & Message::F_PASSED) flags += "P";
    if (mflags & Message::F_ANSWERED) flags += "R";
    if (mflags & Message::F_SEEN) flags += "S";
    if (mflags & Message::F_DELETED) flags += "T";

    // prepare the old and new message name. if equal, skip to the next
    // message.
    string srcname = curpath + filename;
    string destname = curpath + uniquename + ":2," + flags;
    if (srcname == destname) continue;

    // rename the file
    if (rename(srcname.c_str(), destname.c_str()) != 0) {
      if (errno == ENOENT) {
        closedir(pdir);
        if ((pdir = opendir(curpath.c_str())) == nullptr) {
          bincError << "failed to open " << curpath << ": " << strerror(errno) << std::endl;
          return;
        }

        // restart scan. this catches the race condition where concurrent
        // clients may have set a flag or removed the message.
        continue;
      }

      bincError << "failed to rename  " << srcname << " to " << destname << ": "
                << strerror(errno) << std::endl;
    } else {
      index.insert(uniquename, 0, uniquename + ":2," + flags);
    }
  }

  // finally, regenerate the cache file if the custom flags have changed.
  if (customFlagsChanged) {
    Lock lock(path);
    writeCache();
  }
}