File indexing completed on 2024-05-19 04:49:50

 /****************************************************************************************
  * Copyright (c) 2009 Edward Toroshchin <edward.hades@gmail.com>                        *
  * Copyright (c) 2010 Nanno Langstraat <langstr@gmail.com>                              *
  *                                                                                      *
  * 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) version 3 or        *
  * any later version accepted by the membership of KDE e.V. (or its successor approved  *
  * by the membership of KDE e.V.), which shall act as a proxy defined in Section 14 of  *
  * version 3 of the license.                                                            *
  *                                                                                      *
  * 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, see <http://www.gnu.org/licenses/>.                           *
  ****************************************************************************************/
 
 #include "FavoredRandomTrackNavigator.h"
 
 #include "playlist/PlaylistModelStack.h"
 
 #include "amarokconfig.h"
 #include "core/meta/Meta.h"
 #include "core/meta/Statistics.h"
 #include "core/support/Debug.h"
 
 #include <QRandomGenerator>
 
 
 Playlist::FavoredRandomTrackNavigator::FavoredRandomTrackNavigator()
 {
     loadFromSourceModel();
 }
 
 void
 Playlist::FavoredRandomTrackNavigator::planOne()
 {
     DEBUG_BLOCK
 
     if ( m_plannedItems.isEmpty() && !allItemsList().isEmpty() )
     {
         int avoidRecentlyPlayedSize = AVOID_RECENTLY_PLAYED_MAX;    // Start with being very picky.
 
         // Don't over-constrain ourself:
         //   - Keep enough headroom to be unpredictable.
         //   - Make sure that 'chooseRandomItem()' doesn't need to find a needle in a haystack.
         avoidRecentlyPlayedSize = qMin( avoidRecentlyPlayedSize, allItemsList().size() / 2 );
 
         QSet<quint64> avoidSet = getRecentHistory( avoidRecentlyPlayedSize );
 
         QList<qreal> weights = rowWeights( avoidSet );
 
         // Choose a weighed random row.
         if( !weights.isEmpty() )
         {
             qreal totalWeight = 0.0;
             foreach ( qreal weight, weights )
                 totalWeight += weight;
 
             qreal randomCumulWeight = ( QRandomGenerator::global()->generate() / qreal( RAND_MAX ) ) * totalWeight;
 
             int row = 0;
             qreal rowCumulWeight = weights[ row ];
             while ( randomCumulWeight > rowCumulWeight + 0.0000000001 )
                 rowCumulWeight += weights[ ++row ];
 
             m_plannedItems.append( m_model->idAt( row ) );
         }
     }
 }
 
 QList<qreal>
 Playlist::FavoredRandomTrackNavigator::rowWeights(const QSet<quint64> &avoidSet )
 {
     QList<qreal> weights;
 
     int favorType = AmarokConfig::favorTracks();
     int rowCount = m_model->qaim()->rowCount();
 
     for( int row = 0; row < rowCount; row++ )
     {
         qreal weight = 0.0;
         Meta::StatisticsPtr statistics = m_model->trackAt( row )->statistics();
 
         if ( !avoidSet.contains( m_model->idAt( row ) ) )
         {
             switch( favorType )
             {
                 case AmarokConfig::EnumFavorTracks::HigherScores:
                 {
                     int score = statistics->score();
                     weight = score ? score : 50.0;    // "Unknown" weight: in the middle, 50%
                     break;
                 }
 
                 case AmarokConfig::EnumFavorTracks::HigherRatings:
                 {
                     int rating = statistics->rating();
                     weight = rating ? rating : 5.0;
                     break;
                 }
 
                 case AmarokConfig::EnumFavorTracks::LessRecentlyPlayed:
                 {
                     QDateTime lastPlayed = statistics->lastPlayed();
                     if ( lastPlayed.isValid() )
                     {
                         weight = lastPlayed.secsTo( QDateTime::currentDateTime() );
                         if ( weight < 0 )    // If 'lastPlayed()' is nonsense, or the system clock has been set back:
                             weight = 1 * 60 * 60;    // "Nonsense" weight: 1 hour.
                     }
                     else
                         weight = 365 * 24 * 60 * 60;    // "Never" weight: 1 year.
                     break;
                 }
             }
         }
 
         weights.append( weight );
     }
 
     return weights;
 }
 
 QSet<quint64>
 Playlist::FavoredRandomTrackNavigator::getRecentHistory( int size )
 {
     QList<quint64> allHistory = historyItems();
     QSet<quint64> recentHistory;
 
     if ( size > 0 ) {    // If '== 0', we even need to consider playing the same item again.
         recentHistory.insert( currentItem() );    // Might be '0'
         size--;
     }
 
     for ( int i = allHistory.size() - 1; ( i >= 0 ) && ( i >= allHistory.size() - size ); i-- )
         recentHistory.insert( allHistory.at( i ) );
 
     return recentHistory;
 }