/* -*-mode: C; fill-column: 78; c-basic-offset: 4; -*- */

/* 
 * Copyright 2005-2009 by Eric House (xwords@eehouse.org).  All rights
 * reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>

#include "crefmgr.h"
#include "cref.h"
#include "mlock.h"
#include "configs.h"
#include "timermgr.h"

class SocketStuff {
 public:
    SocketStuff( CookieRef* cref )
        : m_cref(cref)
        {        
            pthread_mutex_init( &m_writeMutex, NULL );
        }
    ~SocketStuff() { pthread_mutex_destroy( &m_writeMutex ); }
    CookieRef* m_cref;
    pthread_mutex_t m_writeMutex; /* so only one thread writes at a time */
};

static CRefMgr* s_instance = NULL;

/* static */ CRefMgr*
CRefMgr::Get() 
{
    if ( s_instance == NULL ) {
        s_instance = new CRefMgr();
    }
    return s_instance;
} /* Get */

CRefMgr::CRefMgr()
    : m_nextCID(0)
    , m_nRoomsFilled(0)
    , m_startTime(time(NULL))
{
    /* should be using pthread_once() here */
    pthread_mutex_init( &m_SocketStuffMutex, NULL );
    pthread_mutex_init( &m_nextCIDMutex, NULL );
    pthread_mutex_init( &m_roomsFilledMutex, NULL );
    pthread_mutex_init( &m_freeList_mutex, NULL );
    pthread_rwlock_init( &m_cookieMapRWLock, NULL );
    m_db = DBMgr::Get();
}

CRefMgr::~CRefMgr()
{
    assert( this == s_instance );

    delete m_db;

    pthread_mutex_destroy( &m_freeList_mutex );
    pthread_rwlock_destroy( &m_cookieMapRWLock );

    SocketMap::iterator iter;
    for ( iter = m_SocketStuff.begin(); iter != m_SocketStuff.end(); ++iter ) {
        SocketStuff* stuff = iter->second;
        delete stuff;
    }

    s_instance = NULL;
}

void
CRefMgr::CloseAll()
{
    /* Get every cref instance, shut it down */

    for ( ; ; ) {
        CookieRef* cref = NULL;
        {
            RWWriteLock rwl( &m_cookieMapRWLock );
            CookieMap::iterator iter = m_cookieMap.begin();
            if ( iter == m_cookieMap.end() ) {
                break;
            }
            cref = iter->second; 
            {
                SafeCref scr( cref ); /* cref */
                scr.Shutdown();
            }
        }
    }
} /* CloseAll */

CookieID
CRefMgr::nextCID( const char* connName )
{
    /* Later may want to guarantee that wrap-around doesn't cause an overlap.
       But that's really only a theoretical possibility. */
    MutexLock ml(&m_nextCIDMutex);
    return ++m_nextCID;
} /* nextCID */

void 
CRefMgr::IncrementFullCount( void )
{
    MutexLock ml( &m_roomsFilledMutex );
    ++m_nRoomsFilled;
}

int 
CRefMgr::GetNumRoomsFilled( void )
{
    MutexLock ml(&m_roomsFilledMutex);
    return m_nRoomsFilled;
}

int 
CRefMgr::GetSize( void )
{
    return m_cookieMap.size();
}

void
CRefMgr::GetStats( CrefMgrInfo& mgrInfo )
{
    mgrInfo.m_nRoomsFilled = GetNumRoomsFilled();
    mgrInfo.m_startTimeSpawn = m_startTime;

    if ( 0 == m_ports.length() ) {
        RelayConfigs* cfg = RelayConfigs::GetConfigs();
        vector<int> ints;
        if ( cfg->GetValueFor( "GAME_PORTS", ints ) ) {
            vector<int>::const_iterator iter;
            for ( iter = ints.begin(); ; ) {
                char buf[8];
                snprintf( buf, sizeof(buf), "%d", *iter );
                m_ports += buf;
                ++iter;
                if ( iter == ints.end() ) {
                    break;
                }
                m_ports += ",";
            }
        }
    }
    mgrInfo.m_ports = m_ports.c_str();

    RWReadLock rwl( &m_cookieMapRWLock );
    mgrInfo.m_nCrefsCurrent = m_cookieMap.size();

    CookieMap::iterator iter;
    for ( iter = m_cookieMap.begin(); iter != m_cookieMap.end(); ++iter ) {
        CookieRef* cref = iter->second;

        CrefInfo info;
        info.m_cookie = cref->Cookie();
        info.m_connName = cref->ConnName();
        info.m_cookieID = cref->GetCookieID();
        info.m_curState = cref->CurState();
        info.m_nPlayersSought = cref->GetPlayersSought();
        info.m_nPlayersHere = cref->GetPlayersHere();
        info.m_startTime = cref->GetStarttime();
        info.m_langCode = cref->GetLangCode();
        
        SafeCref sc(cref);
        sc.GetHostsConnected( &info.m_hostsIds, &info.m_hostSeeds, &info.m_hostIps );
        
        mgrInfo.m_crefInfo.push_back( info );
    }
}

CookieID
CRefMgr::cookieIDForConnName( const char* connName )
{
    CookieID cid = 0;
    /* for now, just walk the existing data structure and see if the thing's
       in use.  If it isn't, return a new id. */

    RWReadLock rwl( &m_cookieMapRWLock );

    CookieMap::iterator iter = m_cookieMap.begin();
    while ( iter != m_cookieMap.end() ) {
        CookieRef* cref = iter->second;
        if ( 0 == strcmp( cref->ConnName(), connName ) ) {
            cid = iter->first;
            break;
        }
        ++iter;
    }

    return cid;
} /* cookieIDForConnName */

void
CRefMgr::addToFreeList( CookieRef* cref )
{
    MutexLock ml( &m_freeList_mutex );
    m_freeList.push_back( cref );
}

CookieRef*
CRefMgr::getFromFreeList( void )
{
    CookieRef* cref = NULL;
    MutexLock ml( &m_freeList_mutex );
    if ( m_freeList.size() > 0 ) {
        cref = m_freeList.front();
        m_freeList.pop_front();
    }
    return cref;
}

/* connect case */
CookieRef*
CRefMgr::getMakeCookieRef( const char* cookie, HostID hid, int socket, 
                           int nPlayersH, int nPlayersT, int langCode, 
                           int gameSeed, bool wantsPublic, 
                           bool makePublic )
{
    CookieRef* cref;

    /* We have a cookie from a new connection or from a reconnect.  This may
       be the first time it's been seen, or there may be a game currently in
       the XW_ST_CONNECTING state, or it may be a dupe of a connect packet.
       If there's a game, cool.  Otherwise add a new one.  Pass the connName
       which will be used if set, but if not set we'll be generating another
       later when the game is complete.
    */

    char connNameBuf[MAX_CONNNAME_LEN+1] = {0};
    int alreadyHere = 0;
    CookieID cid = m_db->FindOpen( cookie, langCode, nPlayersT, nPlayersH,
                                   wantsPublic, 
                                   connNameBuf, sizeof(connNameBuf), 
                                   &alreadyHere );
    if ( cid > 0 ) {
        cref = getCookieRef_impl( cid ); 
    } else {
        cid = nextCID( NULL );
        cref = AddNew( cookie, connNameBuf, cid, langCode, 
                       nPlayersT, alreadyHere );
        if ( !connNameBuf[0] ) { /* didn't exist in DB */
            m_db->AddNew( cookie, cref->ConnName(), cid, langCode, nPlayersT, 
                          wantsPublic || makePublic );
        } else {
            m_db->AddCID( connNameBuf, cid );
        }
    }

    return cref;
} /* getMakeCookieRef */

/* reconnect case */
CookieRef* 
CRefMgr::getMakeCookieRef( const char* connName, const char* cookie,
                           HostID hid, int socket, int nPlayersH, 
                           int nPlayersS, int seed, int langCode, 
                           bool isPublic, bool* isDead )
{
    CookieRef* cref = NULL;

    /* fetch these from DB */
    char curCookie[MAX_INVITE_LEN+1];
    int curLangCode;
    int nPlayersT = 0;
    int nAlreadyHere = 0;

    CookieID cid = m_db->FindGame( connName, curCookie, sizeof(curCookie),
                                   &curLangCode, &nPlayersT, &nAlreadyHere,
                                   isDead );
    if ( 0 != cid ) {           /* already open */
        cref = getCookieRef_impl( cid );
    } else {
        /* The entry may not even be in the DB, e.g. if it got deleted.
           Deal with that possibility by taking the caller's word for it. */
        CookieID cid = nextCID( NULL );

        if ( nPlayersT == 0 ) { /* wasn't in the DB */
            m_db->AddNew( cookie, connName, cid, langCode, nPlayersS, isPublic );
            curLangCode = langCode;
            nPlayersT = nPlayersS;
        } else {
            cookie = curCookie;
        }

        cref = AddNew( cookie, connName, cid, curLangCode, nPlayersT, 
                       nAlreadyHere );
        m_db->AddCID( connName, cid );
    }
    return cref;
} /* getMakeCookieRef */

CookieRef* 
CRefMgr::getMakeCookieRef( const char* const connName, bool* isDead )
{
    CookieRef* cref = NULL;
    char curCookie[MAX_INVITE_LEN+1];
    int curLangCode;
    int nPlayersT = 0;
    int nAlreadyHere = 0;

    CookieID cid = m_db->FindGame( connName, curCookie, sizeof(curCookie),
                                   &curLangCode, &nPlayersT, &nAlreadyHere,
                                   isDead );
    if ( 0 != cid ) {           /* already open */
        cref = getCookieRef_impl( cid );
    } else {
        if ( nPlayersT == 0 ) { /* wasn't in the DB */
            /* do nothing; insufficient info to fake it */
        } else {
            CookieID cid = nextCID( NULL );
            cref = AddNew( curCookie, connName, cid, curLangCode, nPlayersT, 
                           nAlreadyHere );
            m_db->AddCID( connName, cid );
        }
    }
    return cref;
}

bool
CRefMgr::Associate( int socket, CookieRef* cref )
{
    MutexLock ml( &m_SocketStuffMutex );
    return Associate_locked( socket, cref );
}

bool
CRefMgr::Associate_locked( int socket, CookieRef* cref )
{
    bool isNew = false;
    SocketMap::iterator iter = m_SocketStuff.find( socket );
    /* This isn't enough.  Must provide a way to reuse sockets should a
       genuinely different connection appear.  Now maybe we already remove
       this reference when a socket is closed.  Test this!  Or assert
       something here.  Bottom line: need to swallow repeated/duplicate
       connect messages from same host. */
    if ( iter == m_SocketStuff.end() ) {
        SocketStuff* stuff = new SocketStuff( cref );
        m_SocketStuff.insert( pair< int, SocketStuff* >( socket, stuff ) );
        isNew = true;
    } else {
        logf( XW_LOGERROR, "Already have cref/threadID pair for socket %d; "
              "error???", socket );
    }
    return isNew;
}

void 
CRefMgr::Disassociate_locked( int socket, CookieRef* cref )
{
    SocketMap::iterator iter = m_SocketStuff.find( socket );
    if ( iter == m_SocketStuff.end() ) {
        logf( XW_LOGERROR, "can't find SocketStuff for socket %d", socket );
    } else {
        SocketStuff* stuff = iter->second;
        assert( cref == NULL || stuff->m_cref == cref );
        delete stuff;
        m_SocketStuff.erase( iter );
    }
}

void 
CRefMgr::Disassociate( int socket, CookieRef* cref )
{
    MutexLock ml( &m_SocketStuffMutex );
    Disassociate_locked( socket, cref );
}

void
CRefMgr::MoveSockets( vector<int> sockets, CookieRef* cref )
{
    MutexLock ml( &m_SocketStuffMutex );
    vector<int>::iterator iter;
    for ( iter = sockets.begin(); iter != sockets.end(); ++iter ) {
        Disassociate_locked( *iter, NULL );
        Associate_locked( *iter, cref );
    }
}

#if 0
pthread_mutex_t* 
CRefMgr::GetWriteMutexForSocket( int socket )
{
    pthread_mutex_t* mutex = NULL;
    MutexLock ml( &m_SocketStuffMutex );
    SocketMap::iterator iter = m_SocketStuff.find( socket );
    if ( iter != m_SocketStuff.end() ) {
        SocketStuff* stuff = iter->second;
        /* this is dangerous!  What if we want to nuke SocketStuff while this
           is locked?  And shouldn't it be the case that only one thread at a
           time can be trying to write to one of a given cref's sockets since
           only one thread at a time is handling a cref? */
        mutex = &stuff->m_writeMutex;
    }
    logf( XW_LOGERROR, "GetWriteMutexForSocket: not found" );
    return mutex;
} /* GetWriteMutexForSocket */
#endif

void 
CRefMgr::RemoveSocketRefs( int socket )
{
    {    
        SafeCref scr( socket );
        scr.Remove( socket );
    }

    Disassociate( socket, NULL );
}

void
CRefMgr::PrintSocketInfo( int socket, string& out )
{
    SafeCref scr( socket );
    const char* name = scr.Cookie();
    if ( name != NULL && name[0] != '\0' ) {
        char buf[64];

        snprintf( buf, sizeof(buf), "* socket: %d\n", socket );
        out += buf;

        snprintf( buf, sizeof(buf), "  in cookie: %s\n", name );
        out += buf;
    }
}

/* static */ SocketsIterator 
CRefMgr::MakeSocketsIterator()
{
    pthread_mutex_lock( &m_SocketStuffMutex );
    SocketsIterator iter( m_SocketStuff.begin(), m_SocketStuff.end(), 
                          &m_SocketStuffMutex );
    return iter;
}

CookieRef* 
CRefMgr::getCookieRef( CookieID cookieID )
{
    return getCookieRef_impl( cookieID );
} /* getCookieRef */

CookieRef* 
CRefMgr::getCookieRef( int socket )
{
    CookieRef* cref = NULL;
    MutexLock ml( &m_SocketStuffMutex );
    SocketMap::iterator iter = m_SocketStuff.find( socket );
    if ( iter != m_SocketStuff.end() ) {
        SocketStuff* stuff = iter->second;
        cref = stuff->m_cref;
    }

    return cref;
} /* getCookieRef */

#ifdef RELAY_HEARTBEAT
/* static */ void
CRefMgr::heartbeatProc( void* closure )
{
    CRefMgr* self = (CRefMgr*)closure;
    self->checkHeartbeats( ::uptime() );
} /* heartbeatProc */
#endif

CookieRef*
CRefMgr::AddNew( const char* cookie, const char* connName, CookieID id,
                 int langCode, int nPlayers, int nAlreadyHere )
{
    if ( 0 == connName[0] ) {
        connName = NULL;
    }
    /* PENDING: should this return a locked cref? */
    logf( XW_LOGINFO, "%s( cookie=%s, connName=%s, cid=%d)", __func__,
          cookie, connName, id );

    CookieRef* ref = getFromFreeList();

    RWWriteLock rwl( &m_cookieMapRWLock );
    logf( XW_LOGINFO, "making new cref: %d", id );
    
    if ( !!ref ) {
        ref->ReInit( cookie, connName, id, langCode, nPlayers, nAlreadyHere );
    } else {
        ref = new CookieRef( cookie, connName, id, langCode, nPlayers, 
                             nAlreadyHere );
    }

    ref->assignConnName();

    m_cookieMap.insert( pair<CookieID, CookieRef*>(ref->GetCookieID(), ref ) );
    logf( XW_LOGINFO, "%s: paired cookie %s/connName %s with cid %d", __func__, 
          (cookie?cookie:"NULL"), connName, ref->GetCookieID() );

#ifdef RELAY_HEARTBEAT
    if ( m_cookieMap.size() == 1 ) {
        RelayConfigs* cfg = RelayConfigs::GetConfigs();
        int heartbeat;
        cfg->GetValueFor( "HEARTBEAT", &heartbeat );
        TimerMgr::GetTimerMgr()->SetTimer( heartbeat, heartbeatProc, this,
                                           heartbeat );
    }
#endif

    logf( XW_LOGINFO, "%s=>%p", __func__, ref );
    return ref;
} /* AddNew */

void
CRefMgr::Recycle_locked( CookieRef* cref )
{
    logf( XW_LOGINFO, "%s(cref=%p,cookie=%s)", __func__, cref, cref->Cookie() );
    CookieID id = cref->GetCookieID();
    DBMgr::Get()->ClearCID( cref->ConnName() );
    cref->Clear();
    addToFreeList( cref );

    cref->Unlock();

    /* don't grab this lock until after releasing cref's lock; otherwise
       deadlock happens. */
    RWWriteLock rwl( &m_cookieMapRWLock );

    CookieMap::iterator iter = m_cookieMap.begin();
    while ( iter != m_cookieMap.end() ) {
        CookieRef* ref = iter->second;
        if ( ref == cref ) {
            logf( XW_LOGINFO, "%s: erasing cref cid %d", __func__, id );
            m_cookieMap.erase( iter );
            break;
        }
        ++iter;
    }
    assert( iter != m_cookieMap.end() ); /* we found something */

#ifdef RELAY_HEARTBEAT
    if ( m_cookieMap.size() == 0 ) {
        TimerMgr::GetTimerMgr()->ClearTimer( heartbeatProc, this );
    }
#endif
} /* CRefMgr::Recycle */

void
CRefMgr::Recycle( CookieID id )
{
    CookieRef* cref = getCookieRef( id );
    if ( cref != NULL ) {
        cref->Lock();
        Recycle_locked( cref );
    }
} /* Delete */

void
CRefMgr::Recycle( const char* connName )
{
    CookieID id = cookieIDForConnName( connName );
    Recycle( id );
} /* Delete */

CookieRef* 
CRefMgr::getCookieRef_impl( CookieID cookieID )
{
    CookieRef* ref = NULL;
    RWReadLock rwl( &m_cookieMapRWLock );

    CookieMap::iterator iter = m_cookieMap.find( cookieID );
    while ( iter != m_cookieMap.end() ) {
        CookieRef* second = iter->second;
        if ( second->GetCookieID() == cookieID ) {
            ref = second;
            break;
        }
        ++iter;
    }
    return ref;
}

#ifdef RELAY_HEARTBEAT
void
CRefMgr::checkHeartbeats( time_t now )
{
    vector<CookieRef*> crefs;

    {
        RWReadLock rwl( &m_cookieMapRWLock );
        CookieMap::iterator iter = m_cookieMap.begin();
        while ( iter != m_cookieMap.end() ) {
            crefs.push_back(iter->second);
            ++iter;
        }
    }

    unsigned int ii;
    for ( ii = 0; ii < crefs.size(); ++ii ) {
        SafeCref scr( crefs[ii] );
        scr.CheckHeartbeats( now );
    }
} /* checkHeartbeats */
#endif

time_t
CRefMgr::uptime( void )
{
    return time(NULL) - m_startTime;
}

/* static */ CookieMapIterator
CRefMgr::GetCookieIterator()
{
    CookieMapIterator iter(&m_cookieMapRWLock);
    return iter;
}


CookieMapIterator::CookieMapIterator(pthread_rwlock_t* rwlock)
    : m_rwl( rwlock )
    ,_iter( CRefMgr::Get()->m_cookieMap.begin() )
{
}

CookieID
CookieMapIterator::Next()
{
    CookieID id = 0;
    if ( _iter != CRefMgr::Get()->m_cookieMap.end() ) {
        CookieRef* cref = _iter->second;
        id = cref->GetCookieID();
        ++_iter;
    }
    return id;
}

//////////////////////////////////////////////////////////////////////////////
// SafeCref
//////////////////////////////////////////////////////////////////////////////

/* connect case */
SafeCref::SafeCref( const char* cookie, int socket, int nPlayersH, int nPlayersS, 
                    unsigned short gameSeed, int langCode, bool wantsPublic, 
                    bool makePublic )
    : m_cref( NULL )
    , m_mgr( CRefMgr::Get() )
    , m_isValid( false )
{
    CookieRef* cref;

    cref = m_mgr->getMakeCookieRef( cookie, 0, socket,
                                    nPlayersH, nPlayersS, langCode,
                                    gameSeed, wantsPublic, makePublic );
    if ( cref != NULL ) {
        m_locked = cref->Lock();
        m_cref = cref;
        m_isValid = true;
    }
}

/* REconnect case */
SafeCref::SafeCref( const char* connName, const char* cookie, HostID hid, 
                    int socket, int nPlayersH, int nPlayersS, 
                    unsigned short gameSeed, int langCode, 
                    bool wantsPublic, bool makePublic )
    : m_cref( NULL )
    , m_mgr( CRefMgr::Get() )
    , m_isValid( false )
{
    CookieRef* cref;
    assert( hid <= 4 );         /* no more than 4 hosts */

    bool isDead = false;
    cref = m_mgr->getMakeCookieRef( connName, cookie, hid, socket, nPlayersH, 
                                    nPlayersS, gameSeed, langCode,
                                    wantsPublic || makePublic, &isDead );
    if ( cref != NULL ) {
        m_locked = cref->Lock();
        m_cref = cref;
        m_isValid = true;
        m_dead = isDead;
    }
}

/* ConnName case -- must exist */
SafeCref::SafeCref( const char* const connName )
    : m_cref( NULL )
    , m_mgr( CRefMgr::Get() )
    , m_isValid( false )
{
    bool isDead = false;
    CookieRef* cref = m_mgr->getMakeCookieRef( connName, &isDead );
    if ( cref != NULL ) {
        m_locked = cref->Lock();
        m_cref = cref;
        m_isValid = true;
        m_dead = isDead;
    }
}

SafeCref::SafeCref( CookieID connID, bool failOk )
    : m_cref( NULL )
    , m_mgr( CRefMgr::Get() )
    , m_isValid( false )
{
    CookieRef* cref = m_mgr->getCookieRef( connID );
    if ( cref != NULL ) {       /* known cookie? */
        m_locked = cref->Lock();
        m_isValid = m_locked && connID == cref->GetCookieID();
        m_cref = cref;
    }
}

SafeCref::SafeCref( int socket )
    : m_cref( NULL )
    , m_mgr( CRefMgr::Get() )
    , m_isValid( false )
{
    CookieRef* cref = m_mgr->getCookieRef( socket );
    if ( cref != NULL ) {       /* known socket? */
        m_locked = cref->Lock();
        m_isValid = m_locked && cref->HasSocket_locked( socket );
        m_cref = cref;
    }
}

SafeCref::SafeCref( CookieRef* cref )
    : m_cref( NULL )
    , m_mgr( CRefMgr::Get() )
    , m_isValid( false )
{
    m_locked = cref->Lock();
    m_isValid = m_locked;
    m_cref = cref;
}

SafeCref::~SafeCref()
{
    if ( m_cref != NULL && m_locked ) {
        if ( m_cref->ShouldDie() ) {
            m_mgr->Recycle_locked( m_cref );
        } else {
            m_cref->Unlock();
        }
    }
}