/*
 * This file Copyright (C) 2008 Charles Kerr <charles@rebelbase.com>
 *
 * This file is licensed by the GPL version 2.  Works owned by the
 * Transmission project are granted a special exemption to clause 2(b)
 * so that the bulk of its code can remain under the MIT license. 
 * This exemption does not extend to derived works not owned by
 * the Transmission project.
 *
 * $Id$
 */

#include <unistd.h> /* unlink */

#include <string.h>

#include "transmission.h"
#include "bencode.h"
#include "completion.h"
#include "fastresume.h"
#include "peer-mgr.h" /* pex */
#include "platform.h" /* tr_getResumeDir */
#include "resume.h"
#include "torrent.h"
#include "utils.h" /* tr_buildPath */

#define KEY_ACTIVITY_DATE   "activity-date"
#define KEY_ADDED_DATE      "added-date"
#define KEY_CORRUPT         "corrupt"
#define KEY_DONE_DATE       "done-date"
#define KEY_DOWNLOAD_DIR    "destination"
#define KEY_DND             "dnd"
#define KEY_DOWNLOADED      "downloaded"
#define KEY_MAX_PEERS       "max-peers"
#define KEY_PAUSED          "paused"
#define KEY_PEERS           "peers"
#define KEY_PRIORITY        "priority"
#define KEY_PROGRESS        "progress"
#define KEY_SPEEDLIMIT      "speed-limit"
#define KEY_UPLOADED        "uploaded"

#define KEY_SPEEDLIMIT_DOWN_SPEED "down-speed"
#define KEY_SPEEDLIMIT_DOWN_MODE  "down-mode"
#define KEY_SPEEDLIMIT_UP_SPEED   "up-speed"
#define KEY_SPEEDLIMIT_UP_MODE    "up-mode"

#define KEY_PROGRESS_MTIMES   "mtimes"
#define KEY_PROGRESS_BITFIELD "bitfield"

static void
getResumeFilename( char * buf, size_t buflen, const tr_torrent * tor )
{
    const char * dir = tr_getResumeDir( tor->handle );
    char base[MAX_PATH_LENGTH];
    tr_snprintf( base, sizeof( base ), "%s.%16.16s.resume",
                 tor->info.name,
                 tor->info.hashString );
    tr_buildPath( buf, buflen, dir, base, NULL );
}

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

static void
savePeers( tr_benc * dict, const tr_torrent * tor )
{
    tr_pex * pex = NULL;
    const int count = tr_peerMgrGetPeers( tor->handle->peerMgr,
                                          tor->info.hash, &pex );
    if( count > 0 )
        tr_bencDictAddRaw( dict, KEY_PEERS, pex, sizeof(tr_pex)*count );
    tr_free( pex );
}

static uint64_t
loadPeers( tr_benc * dict, tr_torrent * tor )
{
    uint64_t ret = 0;
    tr_benc * p;

    if(( p = tr_bencDictFindType( dict, KEY_PEERS, TYPE_STR )))
    {
        int i;
        const char * str = p->val.s.s;
        const size_t len = p->val.s.i;
        const int count = len / sizeof( tr_pex );
        for( i=0; i<count; ++i ) {
            tr_pex pex;
            memcpy( &pex, str + (i*sizeof(tr_pex)), sizeof(tr_pex) );
            tr_peerMgrAddPex( tor->handle->peerMgr,
                              tor->info.hash, TR_PEER_FROM_CACHE, &pex );
        }
        tr_tordbg( tor, "Loaded %d peers from resume file", count );
        ret = TR_FR_PEERS;
    }

    return ret;
}

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

static void
saveDND( tr_benc * dict, const tr_torrent * tor )
{
    const tr_info * inf = tr_torrentInfo( tor );
    const tr_file_index_t n = inf->fileCount;
    tr_file_index_t i;
    tr_benc * list;

    list = tr_bencDictAddList( dict, KEY_DND, n );
    for( i=0; i<n; ++i )
        tr_bencListAddInt( list, inf->files[i].dnd ? 1 : 0 );
}

static uint64_t
loadDND( tr_benc * dict, tr_torrent * tor )
{
    uint64_t ret = 0;
    tr_info * inf = &tor->info;
    const tr_file_index_t n = inf->fileCount;
    tr_benc * list = NULL;

    if( tr_bencDictFindList( dict, KEY_DND, &list )
        && ( list->val.l.count == (int)n ) )
    {
        int64_t tmp;
        tr_file_index_t * dl = tr_new( tr_file_index_t, n );
        tr_file_index_t * dnd = tr_new( tr_file_index_t, n );
        tr_file_index_t i, dlCount=0, dndCount=0;

        for( i=0; i<n; ++i ) {
            if( tr_bencGetInt( &list->val.l.vals[i], &tmp ) && tmp )
                dnd[dndCount++] = i;
            else
                dl[dlCount++] = i;
        }

        if( dndCount ) {
            tr_torrentInitFileDLs ( tor, dnd, dndCount, FALSE );
            tr_tordbg( tor, "Resume file found %d files listed as dnd", dndCount );
        }
        if( dlCount ) {
            tr_torrentInitFileDLs ( tor, dl, dlCount, TRUE );
            tr_tordbg( tor, "Resume file found %d files marked for download", dlCount );
        }

        tr_free( dnd );
        tr_free( dl );
        ret = TR_FR_PRIORITY;
    }
    else
    {
        tr_tordbg( tor, "Couldn't load DND flags.  dnd list (%p) has %d children; torrent has %d files",
                   list, ( list ? list->val.l.count : -1 ), (int)n );
    }

    return ret;
}

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

static void
savePriorities( tr_benc * dict, const tr_torrent * tor )
{
    const tr_info * inf = tr_torrentInfo( tor );
    const tr_file_index_t n = inf->fileCount;
    tr_file_index_t i;
    tr_benc * list;

    list = tr_bencDictAddList( dict, KEY_PRIORITY, n );
    for( i=0; i<n; ++i )
        tr_bencListAddInt( list, inf->files[i].priority );
}

static uint64_t
loadPriorities( tr_benc * dict, tr_torrent * tor )
{
    uint64_t ret = 0;
    tr_info * inf = &tor->info;
    const tr_file_index_t n = inf->fileCount;
    tr_benc * list;

    if( tr_bencDictFindList( dict, KEY_PRIORITY, &list )
        && ( list->val.l.count == (int)n ) )
    {
        int64_t tmp;
        tr_file_index_t i;
        for( i=0; i<n; ++i )
            if( tr_bencGetInt( &list->val.l.vals[i], &tmp ) )
                inf->files[i].priority = tmp;
        ret = TR_FR_PRIORITY;
    }

    return ret;
}

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

static void
saveSpeedLimits( tr_benc * dict, const tr_torrent * tor )
{
    tr_benc * d = tr_bencDictAddDict( dict, KEY_SPEEDLIMIT, 4 );
    tr_bencDictAddInt( d, KEY_SPEEDLIMIT_DOWN_SPEED,
                       tr_torrentGetSpeedLimit( tor, TR_DOWN ) );
    tr_bencDictAddInt( d, KEY_SPEEDLIMIT_DOWN_MODE,
                       tr_torrentGetSpeedMode( tor, TR_DOWN ) );
    tr_bencDictAddInt( d, KEY_SPEEDLIMIT_UP_SPEED,
                       tr_torrentGetSpeedLimit( tor, TR_UP ) );
    tr_bencDictAddInt( d, KEY_SPEEDLIMIT_UP_MODE,
                       tr_torrentGetSpeedMode( tor, TR_UP ) );
}

static uint64_t
loadSpeedLimits( tr_benc * dict, tr_torrent * tor )
{
    uint64_t ret = 0;
    tr_benc * d;

    if( tr_bencDictFindDict( dict, KEY_SPEEDLIMIT, &d ) )
    {
        int64_t i;
        if( tr_bencDictFindInt( d, KEY_SPEEDLIMIT_DOWN_SPEED, &i ) )
            tr_torrentSetSpeedLimit( tor, TR_DOWN, i );
        if( tr_bencDictFindInt( d, KEY_SPEEDLIMIT_DOWN_MODE, &i ) )
            tr_torrentSetSpeedMode( tor, TR_DOWN, i );
        if( tr_bencDictFindInt( d, KEY_SPEEDLIMIT_UP_SPEED, &i ) )
            tr_torrentSetSpeedLimit( tor, TR_UP, i );
        if( tr_bencDictFindInt( d, KEY_SPEEDLIMIT_UP_MODE, &i ) )
            tr_torrentSetSpeedMode( tor, TR_UP, i );
        ret = TR_FR_SPEEDLIMIT;
    }

    return ret;
}

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

static void
saveProgress( tr_benc * dict, const tr_torrent * tor )
{
    int i;
    int n;
    time_t * mtimes;
    tr_benc * p;
    tr_benc * m;
    const tr_bitfield * bitfield;

    p = tr_bencDictAdd( dict, KEY_PROGRESS );
    tr_bencInitDict( p, 2 );

    /* add the mtimes */
    mtimes = tr_torrentGetMTimes( tor, &n );
    m = tr_bencDictAddList( p, KEY_PROGRESS_MTIMES, n );
    for( i=0; i<n; ++i ) {
        if( !tr_torrentIsFileChecked( tor, i ) )
            mtimes[i] = ~(time_t)0; /* force a recheck */
        tr_bencListAddInt( m, mtimes[i] );
    }

    /* add the bitfield */
    bitfield = tr_cpBlockBitfield( tor->completion );
    tr_bencDictAddRaw( p, KEY_PROGRESS_BITFIELD,
                       bitfield->bits, bitfield->byteCount );

    /* cleanup */
    tr_free( mtimes );
}

static uint64_t
loadProgress( tr_benc * dict, tr_torrent * tor )
{
    uint64_t ret = 0;
    tr_benc * p;

    if( tr_bencDictFindDict( dict, KEY_PROGRESS, &p ) )
    {
        tr_benc * m;
        tr_benc * b;
        int n;
        time_t * curMTimes = tr_torrentGetMTimes( tor, &n );

        if( tr_bencDictFindList( p, KEY_PROGRESS_MTIMES, &m )
            && ( m->val.l.count == (int64_t)tor->info.fileCount )
            && ( m->val.l.count == n ) )
        {
            int i;
            for( i=0; i<n; ++i )
            {
                int64_t tmp;
                if( !tr_bencGetInt( &m->val.l.vals[i], &tmp ) ) {
                    tr_tordbg( tor, "File #%d needs to be verified - couldn't find benc entry", i );
                    tr_torrentSetFileChecked( tor, i, FALSE );
                } else {
                    const time_t t = (time_t) tmp;
                    if( t == curMTimes[i] )
                        tr_torrentSetFileChecked( tor, i, TRUE );
                    else {
                        tr_tordbg( tor, "File #%d needs to be verified - times %lu and %lu don't match", i, t, curMTimes[i] );
                        tr_torrentSetFileChecked( tor, i, FALSE );
                    }
                }
            }
        }
        else
        {
            tr_torrentUncheck( tor );
            tr_tordbg( tor, "Torrent needs to be verified - unable to find mtimes" );
        }

        if(( b = tr_bencDictFindType( p, KEY_PROGRESS_BITFIELD, TYPE_STR )))
        {
            tr_bitfield tmp;
            tmp.byteCount = b->val.s.i;
            tmp.bitCount = tmp.byteCount * 8;
            tmp.bits = (uint8_t*) b->val.s.s;
            if( tr_cpBlockBitfieldSet( tor->completion, &tmp ) ) {
                tr_torrentUncheck( tor );
                tr_tordbg( tor, "Torrent needs to be verified - error loading bitfield" );
            }
        }
        else
        {
            tr_torrentUncheck( tor );
            tr_tordbg( tor, "Torrent needs to be verified - unable to find bitfield" );
        }
       
        tr_free( curMTimes );
        ret = TR_FR_PROGRESS;
    }

    return ret;
}

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

void
tr_torrentSaveResume( const tr_torrent * tor )
{
    tr_benc top;
    char filename[MAX_PATH_LENGTH];

    if( !tor )
        return;

    tr_bencInitDict( &top, 14 );
    tr_bencDictAddInt( &top, KEY_ACTIVITY_DATE,
                             tor->activityDate );
    tr_bencDictAddInt( &top, KEY_ADDED_DATE,
                             tor->addedDate );
    tr_bencDictAddInt( &top, KEY_CORRUPT,
                             tor->corruptPrev + tor->corruptCur );
    tr_bencDictAddInt( &top, KEY_DONE_DATE,
                             tor->doneDate );
    tr_bencDictAddStr( &top, KEY_DOWNLOAD_DIR,
                             tor->downloadDir );
    tr_bencDictAddInt( &top, KEY_DOWNLOADED,
                             tor->downloadedPrev + tor->downloadedCur );
    tr_bencDictAddInt( &top, KEY_UPLOADED,
                             tor->uploadedPrev + tor->uploadedCur );
    tr_bencDictAddInt( &top, KEY_MAX_PEERS,
                             tor->maxConnectedPeers );
    tr_bencDictAddInt( &top, KEY_PAUSED,
                             tor->isRunning ? 0 : 1 );
    savePeers( &top, tor );
    savePriorities( &top, tor );
    saveDND( &top, tor );
    saveProgress( &top, tor );
    saveSpeedLimits( &top, tor );

    getResumeFilename( filename, sizeof( filename ), tor );
    tr_bencSaveFile( filename, &top );

    tr_bencFree( &top );
}

static uint64_t
loadFromFile( tr_torrent    * tor,
              uint64_t        fieldsToLoad )
{
    int64_t i;
    const char * str;
    uint64_t fieldsLoaded = 0;
    char filename[MAX_PATH_LENGTH];
    tr_benc top;

    getResumeFilename( filename, sizeof( filename ), tor );

    if( tr_bencLoadFile( filename, &top ) )
    {
        tr_tordbg( tor, "Couldn't read \"%s\"; trying old format.", filename );
        fieldsLoaded = tr_fastResumeLoad( tor, fieldsToLoad );

        if( ( fieldsLoaded != 0 ) && ( fieldsToLoad == ~(uint64_t)0 ) )
        {
            tr_torrentSaveResume( tor );
            tr_fastResumeRemove( tor );
            tr_tordbg( tor, "Migrated resume file to \"%s\"", filename );
        }

        return fieldsLoaded;
    }

    tr_tordbg( tor, "Read resume file \"%s\"", filename );

    if( ( fieldsToLoad & TR_FR_CORRUPT )
            && tr_bencDictFindInt( &top, KEY_CORRUPT, &i ) ) {
        tor->corruptPrev = i;
        fieldsLoaded |= TR_FR_CORRUPT;
    }

    if( ( fieldsToLoad & ( TR_FR_PROGRESS | TR_FR_DOWNLOAD_DIR ) )
            && tr_bencDictFindStr( &top, KEY_DOWNLOAD_DIR, &str ) ) {
        tr_free( tor->downloadDir );
        tor->downloadDir = tr_strdup( str );
        fieldsLoaded |= TR_FR_DOWNLOAD_DIR;
    }

    if( ( fieldsToLoad & TR_FR_DOWNLOADED )
            && tr_bencDictFindInt( &top, KEY_DOWNLOADED, &i ) ) {
        tor->downloadedPrev = i;
        fieldsLoaded |= TR_FR_DOWNLOADED;
    }

    if( ( fieldsToLoad & TR_FR_UPLOADED )
            && tr_bencDictFindInt( &top, KEY_UPLOADED, &i ) ) {
        tor->uploadedPrev = i;
        fieldsLoaded |= TR_FR_UPLOADED;
    }

    if( ( fieldsToLoad & TR_FR_MAX_PEERS )
            && tr_bencDictFindInt( &top, KEY_MAX_PEERS, &i ) ) {
        tor->maxConnectedPeers = i;
        fieldsLoaded |= TR_FR_MAX_PEERS;
    }

    if( ( fieldsToLoad & TR_FR_RUN )
            && tr_bencDictFindInt( &top, KEY_PAUSED, &i ) ) {
        tor->isRunning = i ? 0 : 1;
        fieldsLoaded |= TR_FR_RUN;
    }

    if( ( fieldsToLoad & TR_FR_ADDED_DATE )
        && tr_bencDictFindInt( &top, KEY_ADDED_DATE, &i ) ) {
        tor->addedDate = i;
        fieldsLoaded |= TR_FR_ADDED_DATE;
    }

    if( ( fieldsToLoad & TR_FR_DONE_DATE )
        && tr_bencDictFindInt( &top, KEY_DONE_DATE, &i ) ) {
        tor->doneDate = i;
        fieldsLoaded |= TR_FR_DONE_DATE;
    }

    if( ( fieldsToLoad & TR_FR_ACTIVITY_DATE )
        && tr_bencDictFindInt( &top, KEY_ACTIVITY_DATE, &i ) ) {
        tor->activityDate = i;
        fieldsLoaded |= TR_FR_ACTIVITY_DATE;
    }

    if( fieldsToLoad & TR_FR_PEERS )
        fieldsLoaded |= loadPeers( &top, tor );

    if( fieldsToLoad & TR_FR_PRIORITY )
        fieldsLoaded |= loadPriorities( &top, tor );

    if( fieldsToLoad & TR_FR_PROGRESS )
        fieldsLoaded |= loadProgress( &top, tor );

    if( fieldsToLoad & TR_FR_DND )
        fieldsLoaded |= loadDND( &top, tor );

    if( fieldsToLoad & TR_FR_SPEEDLIMIT )
        fieldsLoaded |= loadSpeedLimits( &top, tor );

    tr_bencFree( &top );
    return fieldsLoaded;
}

static uint64_t
setFromCtor( tr_torrent * tor, uint64_t fields, const tr_ctor * ctor, int mode )
{
    uint64_t ret = 0;

    if( fields & TR_FR_RUN ) {
        uint8_t isPaused;
        if( !tr_ctorGetPaused( ctor, mode, &isPaused ) ) {
            tor->isRunning = !isPaused;
            ret |= TR_FR_RUN;
        }
    }

    if( fields & TR_FR_MAX_PEERS ) 
        if( !tr_ctorGetPeerLimit( ctor, mode, &tor->maxConnectedPeers ) )
            ret |= TR_FR_MAX_PEERS;

    if( fields & TR_FR_DOWNLOAD_DIR ) {
        const char * downloadDir;
        if( !tr_ctorGetDownloadDir( ctor, mode, &downloadDir ) ) {
            ret |= TR_FR_DOWNLOAD_DIR;
            tr_free( tor->downloadDir );
            tor->downloadDir = tr_strdup( downloadDir );
        }
    }

    return ret;
}

static uint64_t
useManditoryFields( tr_torrent * tor, uint64_t fields, const tr_ctor * ctor )
{
    return setFromCtor( tor, fields, ctor, TR_FORCE );
}

static uint64_t
useFallbackFields( tr_torrent * tor, uint64_t fields, const tr_ctor * ctor )
{
    return setFromCtor( tor, fields, ctor, TR_FALLBACK );
}

uint64_t
tr_torrentLoadResume( tr_torrent    * tor,
                      uint64_t        fieldsToLoad,
                      const tr_ctor * ctor )
{
    uint64_t ret = 0;

    ret |= useManditoryFields( tor, fieldsToLoad, ctor );
    fieldsToLoad &= ~ret;
    ret |= loadFromFile( tor, fieldsToLoad );
    fieldsToLoad &= ~ret;
    ret |= useFallbackFields( tor, fieldsToLoad, ctor );

    return ret;
}

void
tr_torrentRemoveResume( const tr_torrent * tor )
{
    char filename[MAX_PATH_LENGTH];
    getResumeFilename( filename, sizeof( filename ), tor );
    unlink( filename );
    tr_fastResumeRemove( tor );
}