#include "TimerThread.hpp"

#include "Common.hpp"
#include "ScopedLock.hpp"

#include <errno.h> // ETIMEDOUT
#include <pthread.h> // pthread_attr_t, sched_param



TimerThread::TimerThread()
  : Thread(true)
  , m_mutex()
  , m_condVar(m_mutex)
  , m_users()
{
  TRACE;
}


TimerThread::~TimerThread()
{
  TRACE;
}


void TimerThread::addTimerUser(TimerUser* user,
                               const time_t expiration,
                               const time_t periodTime)
{
  TRACE;
  ScopedLock sl( m_mutex );
  if ( not m_isRunning ) return;
  timespec expirationTS = { expiration, 0 };
  timespec periodTimeTS = { periodTime, 0 };

  UserEntry userEntry = { periodTimeTS, user };
  m_users.insert( std::pair<timespec, UserEntry>( expirationTS, userEntry ) );

  std::string s;
  s = std::string("adding user: ") + stringify(user);
  LOG(Logger::FINEST, s.c_str());

  m_condVar.signal();
}


void TimerThread::addTimerUser( TimerUser* user,
                               const timespec expiration,
                               const timespec periodTime )
{
  TRACE;
  ScopedLock sl( m_mutex );
  if ( not m_isRunning ) return;
  UserEntry userEntry = { periodTime, user };
  m_users.insert( std::pair<timespec, UserEntry>( expiration, userEntry ) );

  std::string s;
  s = std::string("adding user: ") + stringify(user);
  LOG(Logger::FINEST, s.c_str());

  m_condVar.signal();
}


bool TimerThread::removeTimerUser ( void* timerUser )
{
  TRACE;
  ScopedLock sl( m_mutex );
  if ( not m_isRunning ) return false;
  std::multimap<timespec, UserEntry>::iterator it, tmp;
  bool found(false);
  for ( it = m_users.begin(); it != m_users.end(); ) {

    std::string s;
    s = stringify(it->second.user) + " = ? = " + stringify(timerUser);
    LOG(Logger::FINEST, "Checking user to delete...does it match? ");
    LOG(Logger::FINEST, s.c_str());

    /// @todo solve the abstract pointer problem
    if ( (it->second.user) == timerUser ) {
      tmp = it++;
      LOG(Logger::FINEST, "Removing a user.");
      m_users.erase(tmp);
      m_condVar.signal();
      found = true;  // one user can be registered multiple times
    } else {
      it++;
    }
  }
  return found;
}

// override to signal as well
void TimerThread::stop()
{
  TRACE;
  ScopedLock sl( m_mutex );
  m_isRunning = false;
  m_condVar.broadcast();
}


void* TimerThread::run( void )
{
  TRACE;
  timespec nextExpiration;

  std::multimap<timespec, UserEntry, timespec_cmp> tmp;
  std::multimap<timespec, UserEntry>::iterator it;
  std::pair<std::multimap<timespec, UserEntry>::iterator,
            std::multimap<timespec, UserEntry>::iterator> ret;

  while( m_isRunning ) {

    m_mutex.lock();
    while ( m_users.empty() and m_isRunning ) {
      LOG(Logger::FINEST, "Waiting for a user, since the map is empty.");
      m_condVar.wait();
    }
    m_mutex.unlock();

    if ( not m_isRunning) return 0;
    nextExpiration = m_users.begin()->first;

    m_mutex.lock();
    // timer deleted / added, get nextExpiration again
    if ( m_condVar.wait( nextExpiration.tv_sec,
                         nextExpiration.tv_nsec ) != ETIMEDOUT ) {
      LOG(Logger::FINEST, "Abort sleep: user has been added/removed.");
      m_mutex.unlock();
      continue;
    }
    m_mutex.unlock();

    // notify & remove
    m_mutex.lock();
    ret = m_users.equal_range( nextExpiration );

    /// @todo modify key values in multimap, must be a better way
    tmp.clear();
    for ( it = ret.first; it != ret.second; it++ ) {
      LOG(Logger::FINEST, "Notifying one user.");
      it->second.user->timerExpired();
      if ( it->second.periodTime.tv_sec != 0 or it->second.periodTime.tv_nsec != 0) {
        LOG(Logger::FINEST, "Periodic, re-adding.");
        tmp.insert(std::pair<timespec, UserEntry>(
                  it->second.periodTime, it->second ) );
      }
    }
    m_users.erase( nextExpiration );
    m_users.insert( tmp.begin(), tmp.end() );
    m_mutex.unlock();

  }

  if ( not m_users.empty() ) {
    for ( it = m_users.begin(); it != m_users.end(); it++ ) {
      LOG(Logger::FINEST, "Calling timerDestroyed on one user.");
      it->second.user->timerDestroyed();
    }
  }
  return 0;
}