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/*
IMMS: Intelligent Multimedia Management System
Copyright (C) 2001-2009 Michael Grigoriev
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) any later version.
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include <iostream>
#include <algorithm>
#include <map>
#include <math.h>
#include "picker.h"
#include "strmanip.h"
#include "immsutil.h"
#define SAMPLE_SIZE 100
#define MIN_SAMPLE_SIZE 35
#define MAX_ATTEMPTS (SAMPLE_SIZE*2)
#define EXP 1.10
#define _TICKETS(x) pow(EXP, x) * 99.0 / pow(EXP, 100)
#define TICKETS(x) ROUND(_TICKETS(x) + 1)
using std::endl;
using std::cerr;
using std::map;
SongPicker::SongPicker()
: current(0, "current"), acquired(0), winner(0, "winner")
{
reschedule_requested = playlist_known = 0;
reset();
}
void SongPicker::reset()
{
candidates.clear();
metacandidates.clear();
acquired = attempts = 0;
selection_ready = false;
if (reschedule_requested)
--reschedule_requested;
}
void SongPicker::playlist_changed(int length)
{
playlist_known = 0;
reset();
}
bool SongPicker::add_candidate(bool urgent)
{
int want = urgent ? MIN_SAMPLE_SIZE : SAMPLE_SIZE;
if (candidates.empty() && metacandidates.empty())
get_metacandidates(want);
if (attempts > MAX_ATTEMPTS)
return false;
++attempts;
if (acquired >= want || metacandidates.empty())
return false;
int position = metacandidates.back();
metacandidates.pop_back();
string path = ImmsDb::get_item_from_playlist(position);
request_playlist_item(position);
if (path == "")
return false;
SongData data(position, path);
if (find(candidates.begin(), candidates.end(), data)
!= candidates.end())
return true;
if (fetch_song_info(data))
{
++acquired;
candidates.push_back(data);
if (urgent && data.effective_rating > 80)
attempts = MAX_ATTEMPTS + 1;
}
return true;
}
bool SongPicker::do_events()
{
if (!playlist_known || !pl_length)
return true;
for (int i = 0; i < 5 && !selection_ready ; ++i)
if (!add_candidate())
{
selection_ready = true;
if (reschedule_requested)
{
reschedule_requested = 0;
reset_selection();
}
}
if (playlist_known == 2)
return false;
int pos = ImmsDb::get_unknown_playlist_item();
if (pos < 0)
{
playlist_known = 2;
return false;
}
identify_playlist_item(pos);
return true;
}
void SongPicker::revalidate_current(int pos, const string &path)
{
if (winner.position == pos && winner.get_path() == path)
{
current = winner;
}
else if (current.get_path() != path || current.position != pos)
{
current = SongData(pos, path);
fetch_song_info(current);
}
}
int SongPicker::select_next()
{
if (PlaylistDb::get_real_playlist_length() < pl_length)
return -1;
if (add_candidate())
request_reschedule();
if (candidates.size() < MIN_SAMPLE_SIZE)
while (add_candidate(true));
if (candidates.empty())
{
LOG(ERROR) << "warning: no candidates!" << endl;
return 0;
}
typedef map<int, vector<SongData *> > Ratings;
Ratings ratings;
Candidates::iterator i;
float max_last_played = 0;
for (i = candidates.begin(); i != candidates.end(); ++i)
if (i->last_played > max_last_played)
max_last_played = i->last_played;
for (i = candidates.begin(); i != candidates.end(); ++i)
{
i->effective_rating += i->relation + i->acoustic;
i->effective_rating = ROUND(i->effective_rating
* i->last_played / max_last_played);
int tickets = TICKETS(i->effective_rating);
ratings[tickets].push_back(&*i);
}
unsigned total = 0;
for (Ratings::iterator i = ratings.begin(); i != ratings.end(); ++i)
total += i->first;
int winning_ticket = imms_random(total);
#ifdef DEBUG
cerr << string(80, '-') << endl;
cerr << " >>> ";
#endif
for (Ratings::iterator i = ratings.begin(); i != ratings.end(); ++i)
{
#ifdef DEBUG
cerr << i->first << ":" << i->second.size();
#endif
winning_ticket -= i->first;
if (winning_ticket < 0)
{
#ifdef DEBUG
cerr << "* ";
#endif
winner = *i->second[imms_random(i->second.size())];
#ifndef DEBUG
break;
}
#else
winning_ticket = INT_MAX;
}
else
cerr << " ";
#endif
}
#ifdef DEBUG
cerr << endl;
#endif
reset();
next_sid = winner.get_sid();
return winner.position;
}
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