/*
    Copyright (c) 2007 Till Adam <adam@kde.org>
    Copyright (C) 2008 Omat Holding B.V. <info@omat.nl>
    Copyright (C) 2009 Kevin Ottens <ervin@kde.org>

    Copyright (c) 2010 Klarälvdalens Datakonsult AB,
                       a KDAB Group company <info@kdab.com>
    Author: Kevin Ottens <kevin@kdab.com>

    This library is free software; you can redistribute it and/or modify it
    under the terms of the GNU Library General Public License as published by
    the Free Software Foundation; either version 2 of the License, or (at your
    option) any later version.

    This library is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
    License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to the
    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301, USA.
*/

#include "imapidlemanager.h"

#include <KDE/KDebug>

#include <kimap/idlejob.h>
#include <kimap/selectjob.h>
#include <kimap/session.h>

#include <QtCore/QTimer>

#include "imapresource.h"
#include "sessionpool.h"

ImapIdleManager::ImapIdleManager( ResourceStateInterface::Ptr state,
                                  SessionPool *pool, ImapResourceBase *parent )
  : QObject( parent ), m_sessionRequestId( 0 ), m_pool( pool ), m_session( 0 ),
    m_idle( 0 ), m_resource( parent ), m_state( state ),
    m_lastMessageCount( -1 ), m_lastRecentCount( -1 )
{
  connect( pool, SIGNAL(sessionRequestDone(qint64,KIMAP::Session*,int,QString)),
           this, SLOT(onSessionRequestDone(qint64,KIMAP::Session*,int,QString)) );
  m_sessionRequestId = m_pool->requestSession();
}

ImapIdleManager::~ImapIdleManager()
{
  stop();
  if ( m_pool ) {
    if ( m_sessionRequestId ) {
      m_pool->cancelSessionRequest( m_sessionRequestId );
    }
    if ( m_session ) {
      m_pool->releaseSession( m_session );
    }
  }
}

void ImapIdleManager::stop()
{
  if ( m_idle ) {
    m_idle->stop();
    disconnect(m_idle, 0, this, 0);
    m_idle = 0;
  }
  if ( m_pool ) {
    disconnect(m_pool, 0, this, 0);
  }
}

KIMAP::Session *ImapIdleManager::session() const
{
  return m_session;
}

void ImapIdleManager::reconnect()
{
  kDebug() << "attempting to reconnect IDLE session";
  if ( m_session == 0 && m_pool->isConnected() && m_sessionRequestId == 0 )
    m_sessionRequestId = m_pool->requestSession();
}

void ImapIdleManager::onSessionRequestDone( qint64 requestId, KIMAP::Session *session,
                                            int errorCode, const QString &/*errorString*/ )
{
  if ( requestId!=m_sessionRequestId || session==0 || errorCode!=SessionPool::NoError ) {
    return;
  }

  m_session = session;
  m_sessionRequestId = 0;

  connect( m_pool, SIGNAL(connectionLost(KIMAP::Session*)),
           this, SLOT(onConnectionLost(KIMAP::Session*)) );
  connect( m_pool, SIGNAL(disconnectDone()),
           this, SLOT(onPoolDisconnect()) );


  KIMAP::SelectJob *select = new KIMAP::SelectJob( m_session );
  select->setMailBox( m_state->mailBoxForCollection( m_state->collection() ) );
  connect( select, SIGNAL(result(KJob*)),
           this, SLOT(onSelectDone(KJob*)) );
  select->start();

  m_idle = new KIMAP::IdleJob( m_session );
  connect( m_idle, SIGNAL(mailBoxStats(KIMAP::IdleJob*,QString,int,int)),
           this, SLOT(onStatsReceived(KIMAP::IdleJob*,QString,int,int)) );
  connect( m_idle, SIGNAL(mailBoxMessageFlagsChanged(KIMAP::IdleJob*,qint64)),
           this, SLOT(onFlagsChanged(KIMAP::IdleJob*)) );
  connect( m_idle, SIGNAL(result(KJob*)),
           this, SLOT(onIdleStopped()) );
  m_idle->start();
}

void ImapIdleManager::onConnectionLost( KIMAP::Session *session )
{
  if ( session == m_session ) {
    // Our session becomes invalid, so get ride of
    // the pointer, we don't need to release it once the
    // task is done
    m_session = 0;
    QMetaObject::invokeMethod( this, "reconnect", Qt::QueuedConnection );
  }
}

void ImapIdleManager::onPoolDisconnect()
{
  // All the sessions in the pool we used changed,
  // so get ride of the pointer, we don't need to
  // release our session anymore
  m_pool = 0;
}

void ImapIdleManager::onSelectDone( KJob *job )
{
  KIMAP::SelectJob *select = static_cast<KIMAP::SelectJob*>( job );

  m_lastMessageCount = select->messageCount();
  m_lastRecentCount = select->recentCount();
}

void ImapIdleManager::onIdleStopped()
{
  kDebug( 5327 ) << "IDLE dropped maybe we should reconnect?";
  m_idle = 0;
  if ( m_session ) {
    kDebug( 5327 ) << "Restarting the IDLE session!";
    m_idle = new KIMAP::IdleJob( m_session );
    connect( m_idle, SIGNAL(mailBoxStats(KIMAP::IdleJob*,QString,int,int)),
             this, SLOT(onStatsReceived(KIMAP::IdleJob*,QString,int,int)) );
    connect( m_idle, SIGNAL(result(KJob*)),
             this, SLOT(onIdleStopped()) );
    m_idle->start();
  }
}

void ImapIdleManager::onStatsReceived(KIMAP::IdleJob *job, const QString &mailBox,
                                      int messageCount, int recentCount)
{
  kDebug( 5327 ) << "IDLE stats received:" << job << mailBox << messageCount << recentCount;
  kDebug( 5327 ) << "Cached information:" << m_state->collection().remoteId() << m_state->collection().id()
                 << m_lastMessageCount << m_lastRecentCount;

  // It seems we're not in sync with the cache, resync is needed
  if ( messageCount!=m_lastMessageCount || recentCount!=m_lastRecentCount ) {
    m_lastMessageCount = messageCount;
    m_lastRecentCount = recentCount;

    kDebug( 5327 ) << "Resync needed for" << mailBox << m_state->collection().id();
    m_resource->synchronizeCollection( m_state->collection().id() );
  }
}

void ImapIdleManager::onFlagsChanged( KIMAP::IdleJob *job )
{
  kDebug( 5327 ) << "IDLE flags changed in" << m_session->selectedMailBox();
  m_resource->synchronizeCollection( m_state->collection().id() );
}