/******************************************************************************
 * $Id$
 *
 * Copyright (c) 2005-2008 Transmission authors and contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *****************************************************************************/

#include <assert.h>
#include <stdlib.h>
#include <string.h> /* memcpy */

#include <signal.h>
#include <sys/types.h> /* stat */
#include <sys/stat.h> /* stat */
#include <unistd.h> /* stat */
#include <dirent.h> /* opendir */

#include "transmission.h"
#include "blocklist.h"
#include "fdlimit.h"
#include "list.h"
#include "metainfo.h" /* tr_metainfoFree */
#include "net.h"
#include "peer-mgr.h"
#include "platform.h" /* tr_lock */
#include "port-forwarding.h"
#include "ratecontrol.h"
#include "rpc-server.h"
#include "stats.h"
#include "torrent.h"
#include "tracker.h"
#include "trevent.h"
#include "utils.h"
#include "web.h"

/* Generate a peer id : "-TRxyzb-" + 12 random alphanumeric
   characters, where x is the major version number, y is the
   minor version number, z is the maintenance number, and b
   designates beta (Azureus-style) */
uint8_t*
tr_peerIdNew( void )
{
    int i;
    int val;
    int total = 0;
    uint8_t * buf = tr_new( uint8_t, 21 );
    const char * pool = "0123456789abcdefghijklmnopqrstuvwxyz";
    const int base = 36;

    memcpy( buf, PEERID_PREFIX, 8 );

    for( i=8; i<19; ++i ) {
        val = tr_rand( base );
        total += val;
        buf[i] = pool[val];
    }

    val = total % base ? base - (total % base) : 0;
    total += val;
    buf[19] = pool[val];
    buf[20] = '\0';

    return buf;
}

const uint8_t*
tr_getPeerId( void )
{
    static uint8_t * id = NULL;
    if( id == NULL )
        id = tr_peerIdNew( );
    return id;
}

/***
****
***/

tr_encryption_mode
tr_sessionGetEncryption( tr_session * session )
{
    assert( session != NULL );

    return session->encryptionMode;
}

void
tr_sessionSetEncryption( tr_session * session, tr_encryption_mode mode )
{
    assert( session != NULL );
    assert( mode==TR_ENCRYPTION_PREFERRED
         || mode==TR_ENCRYPTION_REQUIRED
         || mode==TR_PLAINTEXT_PREFERRED );

    session->encryptionMode = mode;
}

/***
****
***/

static void metainfoLookupRescan( tr_handle * h );

tr_handle *
tr_sessionInitFull( const char * configDir,
                    const char * downloadDir,
                    const char * tag,
                    int          isPexEnabled,
                    int          isPortForwardingEnabled,
                    int          publicPort,
                    int          encryptionMode,
                    int          isUploadLimitEnabled,
                    int          uploadLimit,
                    int          isDownloadLimitEnabled,
                    int          downloadLimit,
                    int          globalPeerLimit,
                    int          messageLevel,
                    int          isMessageQueueingEnabled,
                    int          isBlocklistEnabled,
                    int          peerSocketTOS,
                    int          rpcIsEnabled,
                    int          rpcPort,
                    const char * rpcACL )
{
    tr_handle * h;
    char filename[MAX_PATH_LENGTH];

#ifndef WIN32
    /* Don't exit when writing on a broken socket */
    signal( SIGPIPE, SIG_IGN );
#endif

    if( configDir == NULL )
        configDir = tr_getDefaultConfigDir( );

    tr_msgInit( );
    tr_setMessageLevel( messageLevel );
    tr_setMessageQueuing( isMessageQueueingEnabled );

    h = tr_new0( tr_handle, 1 );
    h->lock = tr_lockNew( );
    h->isPexEnabled = isPexEnabled ? 1 : 0;
    h->encryptionMode = encryptionMode;
    h->peerSocketTOS = peerSocketTOS;
    h->downloadDir = tr_strdup( downloadDir );

    tr_setConfigDir( h, configDir );

    tr_netInit(); /* must go before tr_eventInit */

    tr_eventInit( h );
    while( !h->events )
        tr_wait( 50 );

    h->tag = tr_strdup( tag );
    h->peerMgr = tr_peerMgrNew( h );

    /* Initialize rate and file descripts controls */

    h->upload = tr_rcInit();
    tr_rcSetLimit( h->upload, uploadLimit );
    h->useUploadLimit = isUploadLimitEnabled;

    h->download = tr_rcInit();
    tr_rcSetLimit( h->download, downloadLimit );
    h->useDownloadLimit = isDownloadLimitEnabled;

    tr_fdInit( globalPeerLimit );
    h->shared = tr_sharedInit( h, isPortForwardingEnabled, publicPort );
    h->isPortSet = publicPort >= 0;

    /* first %s is the application name
       second %s is the version number */
    tr_inf( _( "%s %s started" ), TR_NAME, LONG_VERSION_STRING );

    /* initialize the blocklist */
    tr_buildPath( filename, sizeof( filename ), h->configDir, "blocklists", NULL );
    tr_mkdirp( filename, 0777 );
    tr_buildPath( filename, sizeof( filename ), h->configDir, "blocklists", "level1.bin", NULL );
    h->blocklist = _tr_blocklistNew( filename, isBlocklistEnabled );

    tr_statsInit( h );

    h->web = tr_webInit( h );
    h->rpcServer = tr_rpcInit( h, rpcIsEnabled, rpcPort, rpcACL );

    metainfoLookupRescan( h );

    return h;
}

tr_handle *
tr_sessionInit( const char * configDir,
                const char * downloadDir,
                const char * tag )
{
    return tr_sessionInitFull( configDir,
                               downloadDir,
                               tag,
                               TR_DEFAULT_PEX_ENABLED,
                               TR_DEFAULT_PORT_FORWARDING_ENABLED,
                               -1, /* public port */
                               TR_ENCRYPTION_PREFERRED, /* encryption mode */
                               FALSE, /* use upload speed limit? */ 
                               -1, /* upload speed limit */
                               FALSE, /* use download speed limit? */
                               -1, /* download speed limit */
                               TR_DEFAULT_GLOBAL_PEER_LIMIT,
                               TR_MSG_INF, /* message level */
                               FALSE, /* is message queueing enabled? */
                               FALSE, /* is the blocklist enabled? */
                               TR_DEFAULT_PEER_SOCKET_TOS,
                               TR_DEFAULT_RPC_ENABLED,
                               TR_DEFAULT_RPC_PORT,
                               TR_DEFAULT_RPC_ACL );
}

/***
****
***/

void
tr_sessionSetDownloadDir( tr_handle * handle, const char * dir )
{
    if( handle->downloadDir != dir )
    {
        tr_free( handle->downloadDir );
        handle->downloadDir = tr_strdup( dir );
    }
}

const char *
tr_sessionGetDownloadDir( const tr_handle * handle )
{
    return handle->downloadDir;
}

/***
****
***/

void
tr_globalLock( struct tr_handle * handle )
{
    tr_lockLock( handle->lock );
}

void
tr_globalUnlock( struct tr_handle * handle )
{
    tr_lockUnlock( handle->lock );
}

int
tr_globalIsLocked( const struct tr_handle * handle )
{
    return handle && tr_lockHave( handle->lock );
}

/***********************************************************************
 * tr_setBindPort
 ***********************************************************************
 * 
 **********************************************************************/

struct bind_port_data
{
    tr_handle * handle;
    int port;
};

static void
tr_setBindPortImpl( void * vdata )
{
    struct bind_port_data * data = vdata;
    tr_handle * handle = data->handle;
    const int port = data->port;

    handle->isPortSet = 1;
    tr_sharedSetPort( handle->shared, port );

    tr_free( data );
}

void
tr_sessionSetPublicPort( tr_handle * handle, int port )
{
    struct bind_port_data * data = tr_new( struct bind_port_data, 1 );
    data->handle = handle;
    data->port = port;
    tr_runInEventThread( handle, tr_setBindPortImpl, data );
}

int
tr_sessionGetPublicPort( const tr_handle * h )
{
    assert( h != NULL );
    return tr_sharedGetPublicPort( h->shared );
}

tr_port_forwarding
tr_sessionGetPortForwarding( const tr_handle * h )
{
    return tr_sharedTraversalStatus( h->shared );
}

/***
****
***/

void
tr_sessionSetSpeedLimitEnabled( tr_handle  * h,
                                int          up_or_down,
                                int          use_flag )
{
    if( up_or_down == TR_UP )
        h->useUploadLimit = use_flag ? 1 : 0;
    else
        h->useDownloadLimit = use_flag ? 1 : 0;
}

int
tr_sessionIsSpeedLimitEnabled( const tr_handle * h, int up_or_down )
{
       return up_or_down==TR_UP ? h->useUploadLimit : h->useDownloadLimit;
}

void
tr_sessionSetSpeedLimit( tr_handle  * h,
                         int          up_or_down,
                         int          KiB_sec )
{
    if( up_or_down == TR_DOWN )
        tr_rcSetLimit( h->download, KiB_sec );
    else
        tr_rcSetLimit( h->upload, KiB_sec );
}

int
tr_sessionGetSpeedLimit( const tr_handle * h, int up_or_down )
{
    return tr_rcGetLimit( up_or_down==TR_UP ? h->upload : h->download );
}

/***
****
***/

void
tr_sessionSetPeerLimit( tr_handle * handle UNUSED,
                        uint16_t    maxGlobalPeers )
{
    tr_fdSetPeerLimit( maxGlobalPeers );
}

uint16_t
tr_sessionGetPeerLimit( const tr_handle * handle UNUSED )
{
    return tr_fdGetPeerLimit( );
}

/***
****
***/

void
tr_torrentRates( tr_handle * h, float * toClient, float * toPeer )
{
    if( h )
    {
        tr_globalLock( h );

        if( toClient )
            *toClient = tr_rcRate( h->download );
        if( toPeer )
            *toPeer = tr_rcRate( h->upload );

        tr_globalUnlock( h );
    }
}

int
tr_torrentCount( const tr_handle * h )
{
    return h->torrentCount;
}

static void
tr_closeAllConnections( void * vh )
{
    tr_handle * h = vh;
    tr_torrent * tor;

    tr_sharedShuttingDown( h->shared );
    tr_trackerShuttingDown( h );
    tr_rpcClose( &h->rpcServer );

    while(( tor = tr_torrentNext( h, NULL )))
        tr_torrentFree( tor );

    tr_peerMgrFree( h->peerMgr );

    tr_rcClose( h->upload );
    tr_rcClose( h->download );
    
    h->isClosed = TRUE;
}

static int
deadlineReached( const uint64_t deadline )
{
    return tr_date( ) >= deadline;
}

#define SHUTDOWN_MAX_SECONDS 30

void
tr_sessionClose( tr_handle * h )
{
    int i;
    const int maxwait_msec = SHUTDOWN_MAX_SECONDS * 1000;
    const uint64_t deadline = tr_date( ) + maxwait_msec;

    tr_deepLog( __FILE__, __LINE__, NULL, "shutting down transmission session %p", h );
    tr_statsClose( h );

    tr_runInEventThread( h, tr_closeAllConnections, h );
    while( !h->isClosed && !deadlineReached( deadline ) )
        tr_wait( 100 );

    _tr_blocklistFree( h->blocklist );
    h->blocklist = NULL;
    tr_webClose( &h->web );

    tr_eventClose( h );
    while( h->events && !deadlineReached( deadline ) )
        tr_wait( 100 );

    tr_fdClose( );
    tr_lockFree( h->lock );
    for( i=0; i<h->metainfoLookupCount; ++i )
        tr_free( h->metainfoLookup[i].filename );
    tr_free( h->metainfoLookup );
    tr_free( h->tag );
    tr_free( h->configDir );
    tr_free( h->resumeDir );
    tr_free( h->torrentDir );
    tr_free( h->downloadDir );
    free( h );
}

tr_torrent **
tr_sessionLoadTorrents ( tr_handle   * h,
                         tr_ctor     * ctor,
                         int         * setmeCount )
{
    int i, n = 0;
    struct stat sb;
    DIR * odir = NULL;
    const char * dirname = tr_getTorrentDir( h );
    tr_torrent ** torrents;
    tr_list *l=NULL, *list=NULL;

    tr_ctorSetSave( ctor, FALSE ); /* since we already have them */

    if( !stat( dirname, &sb )
        && S_ISDIR( sb.st_mode )
        && (( odir = opendir ( dirname ) )) )
    {
        struct dirent *d;
        for (d = readdir( odir ); d!=NULL; d=readdir( odir ) )
        {
            if( d->d_name && d->d_name[0]!='.' ) /* skip dotfiles, ., and .. */
            {
                tr_torrent * tor;
                char filename[MAX_PATH_LENGTH];
                tr_buildPath( filename, sizeof(filename), dirname, d->d_name, NULL );
                tr_ctorSetMetainfoFromFile( ctor, filename );
                tor = tr_torrentNew( h, ctor, NULL );
                if( tor ) {
                    tr_list_append( &list, tor );
                    n++;
                }
            }
        }
        closedir( odir );
    }

    torrents = tr_new( tr_torrent*, n );
    for( i=0, l=list; l!=NULL; l=l->next )
        torrents[i++] = (tr_torrent*) l->data;
    assert( i==n );

    tr_list_free( &list, NULL );

    if( n )
        tr_inf( _( "Loaded %d torrents" ), n );

    if( setmeCount )
        *setmeCount = n;
    return torrents;
}

/***
****
***/

void
tr_sessionSetPexEnabled( tr_handle * handle, int isPexEnabled )
{
    handle->isPexEnabled = isPexEnabled ? 1 : 0;
}

int
tr_sessionIsPexEnabled( const tr_handle * handle )
{
    return handle->isPexEnabled;
}

/***
****
***/

void
tr_sessionSetPortForwardingEnabled( tr_handle * h, int enable )
{
    tr_globalLock( h );
    tr_sharedTraversalEnable( h->shared, enable );
    tr_globalUnlock( h );
}

int
tr_sessionIsPortForwardingEnabled( const tr_handle * h )
{
    return tr_sharedTraversalIsEnabled( h->shared );
}

/***
****
***/

int
tr_blocklistGetRuleCount( tr_handle * handle )
{
    return _tr_blocklistGetRuleCount( handle->blocklist );
}

int
tr_blocklistIsEnabled( const tr_handle * handle )
{
    return _tr_blocklistIsEnabled( handle->blocklist );
}

void
tr_blocklistSetEnabled( tr_handle * handle, int isEnabled )
{
    _tr_blocklistSetEnabled( handle->blocklist, isEnabled );
}

int
tr_blocklistExists( const tr_handle * handle )
{
    return _tr_blocklistExists( handle->blocklist );
}

int
tr_blocklistSetContent( tr_handle  * handle, const char * filename )
{
    return _tr_blocklistSetContent( handle->blocklist, filename );
}

int
tr_blocklistHasAddress( tr_handle * handle, const struct in_addr * addr )
{
    return _tr_blocklistHasAddress( handle->blocklist, addr );
}

/***
****
***/

static int
compareLookupEntries( const void * va, const void * vb )
{
    const struct tr_metainfo_lookup * a = va;
    const struct tr_metainfo_lookup * b = vb;
    return strcmp( a->hashString, b->hashString );
}

static void
metainfoLookupResort( tr_handle * h )
{
    qsort( h->metainfoLookup, 
           h->metainfoLookupCount,
           sizeof( struct tr_metainfo_lookup ),
           compareLookupEntries );
}

static int
compareHashStringToLookupEntry( const void * va, const void * vb )
{
    const char * a = va;
    const struct tr_metainfo_lookup * b = vb;
    return strcmp( a, b->hashString );
}

const char*
tr_sessionFindTorrentFile( const tr_handle  * h,
                           const char       * hashStr )
{
    struct tr_metainfo_lookup * l = bsearch( hashStr,
                                             h->metainfoLookup,
                                             h->metainfoLookupCount,
                                             sizeof( struct tr_metainfo_lookup ),
                                             compareHashStringToLookupEntry );
    return l ? l->filename : NULL;
}

static void
metainfoLookupRescan( tr_handle * h )
{
    int i;
    int n;
    struct stat sb;
    const char * dirname = tr_getTorrentDir( h );
    DIR * odir = NULL;
    tr_ctor * ctor = NULL;
    tr_list * list = NULL;

    /* walk through the directory and find the mappings */
    ctor = tr_ctorNew( h );
    tr_ctorSetSave( ctor, FALSE ); /* since we already have them */
    if( !stat( dirname, &sb ) && S_ISDIR( sb.st_mode ) && (( odir = opendir( dirname ))))
    {
        struct dirent *d;
        for (d = readdir( odir ); d!=NULL; d=readdir( odir ) )
        {
            if( d->d_name && d->d_name[0]!='.' ) /* skip dotfiles, ., and .. */
            {
                tr_info inf;
                char filename[MAX_PATH_LENGTH];
                tr_buildPath( filename, sizeof(filename), dirname, d->d_name, NULL );
                tr_ctorSetMetainfoFromFile( ctor, filename );
                if( !tr_torrentParse( h, ctor, &inf ) )
                {
                    tr_list_append( &list, tr_strdup( inf.hashString ) );
                    tr_list_append( &list, tr_strdup( filename ) );
                    tr_metainfoFree( &inf );
                }
            }
        }
        closedir( odir );
    }
    tr_ctorFree( ctor );

    n = tr_list_size( list ) / 2;
    h->metainfoLookup = tr_new0( struct tr_metainfo_lookup, n );
    h->metainfoLookupCount = n;
    for( i=0; i<n; ++i )
    {
        char * hashString = tr_list_pop_front( &list );
        char * filename = tr_list_pop_front( &list );

        memcpy( h->metainfoLookup[i].hashString, hashString, 2*SHA_DIGEST_LENGTH+1 );
        tr_free( hashString );
        h->metainfoLookup[i].filename = filename;
    }

    metainfoLookupResort( h );
    tr_dbg( "Found %d torrents in \"%s\"", n, dirname );
}

void
tr_sessionSetTorrentFile( tr_handle    * h,
                          const char   * hashString,
                          const char   * filename )
{
    struct tr_metainfo_lookup * l = bsearch( hashString,
                                             h->metainfoLookup,
                                             h->metainfoLookupCount,
                                             sizeof( struct tr_metainfo_lookup ),
                                             compareHashStringToLookupEntry );
    if( l != NULL )
    {
        if( l->filename != filename )
        {
            tr_free( l->filename );
            l->filename = tr_strdup( filename );
        }
    }
    else
    {
        const int n = h->metainfoLookupCount++;
        struct tr_metainfo_lookup * node;
        h->metainfoLookup = tr_renew( struct tr_metainfo_lookup,
                                      h->metainfoLookup,
                                      h->metainfoLookupCount );
        node = h->metainfoLookup + n;
        memcpy( node->hashString, hashString, 2*SHA_DIGEST_LENGTH+1 );
        node->filename = tr_strdup( filename );
        metainfoLookupResort( h );
    }
}

tr_torrent*
tr_torrentNext( tr_handle * session, tr_torrent * tor )
{
    return tor ? tor->next : session->torrentList;
}

/***
****
***/

void
tr_sessionSetRPCEnabled( tr_handle * session, int isEnabled )
{
    tr_rpcSetEnabled( session->rpcServer, isEnabled );
}
int
tr_sessionIsRPCEnabled( const tr_handle * session )
{
    return tr_rpcIsEnabled( session->rpcServer );
}
void
tr_sessionSetRPCPort( tr_handle * session, int port )
{
    tr_rpcSetPort( session->rpcServer, port );
}
int
tr_sessionGetRPCPort( const tr_handle * session )
{
    return tr_rpcGetPort( session->rpcServer );
}
void
tr_sessionSetRPCCallback( tr_handle    * session,
                          tr_rpc_func    func,
                          void         * user_data )
{
    session->rpc_func = func;
    session->rpc_func_user_data = user_data;
}

void
tr_sessionSetRPCACL( tr_handle * session, const char * acl )
{
    tr_rpcSetACL( session->rpcServer, acl );
}

const char*
tr_sessionGetRPCACL( const tr_session * session )
{
    return tr_rpcGetACL( session->rpcServer );
}