/*
 * Copyright (C) 2017  Kevin Whitaker <eyecreate@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) 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 "GroovePlayer.h"
#include "db/UserAction.h"
#include <Wt/WLogger>
#include <Wt/WServer>
#include <Wt/WApplication>
#include "WebInterface.h"
#include <locale>
#include <Wt/WLogger>
#include <Wt/Dbo/Transaction>
#include <groovefingerprinter/fingerprinter.h>
#include <grooveplayer/player.h>

GroovePlayerMgr::GroovePlayerMgr (std::string dbFile) : sqliteConnection(dbFile), connectionPool(&sqliteConnection, 3)
{
    musicScanDir = std::filesystem::current_path()/"music";
    Wt::Dbo::Session sqlSession;
    sqlSession.setConnectionPool(connectionPool);
    sqlSession.mapClass<User>("user");
    sqlSession.mapClass<AudioTrack>("tracks");
    sqlSession.mapClass<UserAction>("actions");
    try
    {
        sqlSession.createTables();
    } catch(Wt::Dbo::Exception e) 
    {
        Wt::log("info") << "Using Existing DB.";
    }
    
    groove_init();
    /*bool emptyTrackListing = false;
    {
        Wt::Dbo::Transaction transaction(sqlSession);
        int trackCount = sqlSession.query<int>("select count(fingerprint) from tracks");
        emptyTrackListing = trackCount==0;
    }
    if(emptyTrackListing)
    {
        grooveAudioScanner = new std::thread([this](){grooveAudioScannerLoop();});
        grooveEvents = new std::thread([this](){while(!this->finishedLaunchScan){std::this_thread::sleep_for(std::chrono::milliseconds(200));}[this](){grooveEventLoop();};});
    }
    else
    {*/
        grooveAudioScanner = new std::thread([this](){grooveAudioScannerLoop();});
        grooveEvents = new std::thread([this](){grooveEventLoop();});
    //}
}

std::list<const AudioTrack*> GroovePlayerMgr::getNextVoteBatch(Wt::Dbo::Session* session)
{
    /**
     * This method will attempt to pick 3 tracks that will be up for selection next.
     * 
     * The first track should be from the same album or artist.
     * The second track should be from the same genre.
     * The third track should be from something in a different genre.
     * 
     * What is picked inside those requirements is a mix of random and TODO:based on past user actions(33% of time).
     * 
     * The third track will be replaced by a recent request item if one exists.
     */
    
    std::list<const AudioTrack*> selectedTracks;
    
    Wt::Dbo::Transaction transaction(*session);
    //First make sure there are at least 3 tracks to suggest. 
    int trackCount = session->query<int>("select count(fingerprint) from tracks");
    if(trackCount < 3)
    {
        //Return empty list to show there are not enough tracks to allow voting.
        return selectedTracks;
    }
    
    //Determine first track
    int trackAlbumCount = session->query<int>("select count(fingerprint) from tracks").where("album = ?").bind(getCurrentTrack(session)->trackAlbumName);
    int trackArtistCount = session->query<int>("select count(fingerprint) from tracks").where("artist = ?").bind(getCurrentTrack(session)->trackArtistName);
    int computerSlightOfHand = rand() % 10 + 1;
    if(trackAlbumCount > 0 && computerSlightOfHand > 3)
    {
        //Pick item from album
        Wt::Dbo::ptr<AudioTrack> eligibleTrack = session->find<AudioTrack>().where("album = ?").limit(1).offset(rand() % trackAlbumCount).bind(getCurrentTrack(session)->trackAlbumName);
        selectedTracks.push_back(eligibleTrack.get());
    }
    else if(trackArtistCount > 0)
    {
        //Pick item from artist
        Wt::Dbo::ptr<AudioTrack> eligibleTrack = session->find<AudioTrack>().where("artist = ?").limit(1).offset(rand() % trackArtistCount).bind(getCurrentTrack(session)->trackArtistName);
        selectedTracks.push_back(eligibleTrack.get());
    }
    
    //Determine second track
    int trackGenreCount = session->query<int>("select count(fingerprint) from tracks").where("genre = ?").bind(getCurrentTrack(session)->trackGenre);
    if(trackGenreCount > 0)
    {
        //Pick item from genre
        Wt::Dbo::ptr<AudioTrack> eligibleTrack = session->find<AudioTrack>().where("genre = ?").limit(1).offset(rand() % trackGenreCount).bind(getCurrentTrack(session)->trackGenre);
        selectedTracks.push_back(eligibleTrack.get());
    }
    
    //Determine third track
    int trackNotGenreCount = session->query<int>("select count(fingerprint) from tracks").where("genre != ?").bind(getCurrentTrack(session)->trackGenre);
    if(requestQueue.size() > 0)
    {
        //There's a request. Pick one up front and put as third item.
        selectedTracks.push_back(requestQueue.front());
    }
    else if(trackNotGenreCount > 0)
    {
        //Pick from other genre
        Wt::Dbo::ptr<AudioTrack> eligibleTrack = session->find<AudioTrack>().where("genre != ?").limit(1).offset(rand() % trackNotGenreCount).bind(getCurrentTrack(session)->trackGenre);
        selectedTracks.push_back(eligibleTrack.get());
    }
    else
    {
        //Pick randomly
        Wt::Dbo::ptr<AudioTrack> eligibleTrack = session->find<AudioTrack>().limit(1).offset(rand() % trackCount);
        selectedTracks.push_back(eligibleTrack.get());
    }
    return selectedTracks;
}

void GroovePlayerMgr::grooveEventLoop()
{
    /**
     * On first boot, random track that has been voted before will start(or random if no track has been played before).
     * When voting ends, if no vote was cast, the first will be picked 60% of the time with second being 30% of the time and third being picked 10% of the time.
     * Exception is if third track is the top request, then it is picked. If another song is voted over this, it will be put in back of request queue.
     */
    
    Wt::Dbo::Session sqlSession;
    sqlSession.setConnectionPool(connectionPool);
    sqlSession.mapClass<User>("user");
    sqlSession.mapClass<AudioTrack>("tracks");
    sqlSession.mapClass<UserAction>("actions");
    Wt::Dbo::Transaction transaction(sqlSession);
    
    //Wait until at least one track is in DB.
    if(sqlSession.query<int>("select count(fingerprint) from tracks") < 1)
    {
        while(sqlSession.query<int>("select count(fingerprint) from tracks") < 1){}
    }

    //Pick initial track to bootstrap.
    int tracksPlayedBefore = sqlSession.query<int>("select count(fingerprint) from tracks as t join actions on (actions.action = 3 or actions.action = 2) and actions.track_id = t.id");
    const AudioTrack* selectedTrack;
    if (tracksPlayedBefore > 0)
    {
        selectedTrack = sqlSession.query<Wt::Dbo::ptr<AudioTrack>>("select t from tracks as t join actions on (actions.action = 3 or actions.action = 2) and actions.track_id = t.id").limit(1).offset(rand() % tracksPlayedBefore).resultValue().get();
    }
    else
    {
        int trackCount = sqlSession.query<int>("select count(fingerprint) from tracks");
        selectedTrack = sqlSession.find<AudioTrack>().limit(1).offset(rand() % trackCount).resultValue().get();
    }
    struct GroovePlaylist* playlist = groove_playlist_create();
    currentPlaylist = playlist;
    struct GroovePlayer* player = groove_player_create();
    if(!player) {return;}
    currentPlayer = player;
    
    groove_playlist_insert(playlist, groove_file_open(selectedTrack->trackPath.c_str()),1.0,1.0,nullptr);
    
    //Now boostrap player with initial data
    groove_player_attach(player, playlist);
    groove_playlist_play(playlist);
    Wt::WServer::instance()->postAll([&]() {
        Wt::WApplication* app = Wt::WApplication::instance();
        if(app != nullptr)
        {
            static_cast<WebInterface*>(app)->songChangedFromServer(getCurrentTrack(&sqlSession).get());
        }
    }
    );
    
    //Now start loop
    while(getInstance()->continueEventLoop)
    {
        std::this_thread::sleep_for(std::chrono::milliseconds(200));
        PlayerEvents event = getNextPlayerEvent(&sqlSession);
        if(event == NOTHING)
        {
            continue;
        }
        else if(event == GROOVE_NOWPLAYING)
        {
            //Pick new batch of tracks to vote on and inform UI of update.
            currentVoteBatch = getNextVoteBatch(&sqlSession);
            currentVoteStatus = std::map<const AudioTrack*, int>();
            std::for_each(currentVoteBatch.begin(),currentVoteBatch.end(),[&](const AudioTrack* item){
                currentVoteStatus.insert(std::pair<const AudioTrack*, int>(item,0));
            });
            Wt::WServer::instance()->postAll([&]() {
                Wt::WApplication* app = Wt::WApplication::instance();
                if(app != nullptr)
                    {
                        static_cast<WebInterface*>(app)->songChangedFromServer(getCurrentTrack(&sqlSession).get());
                        static_cast<WebInterface*>(app)->voteTracksUpdatedFromServer(currentVoteBatch);
                    }
            }
            );
            Wt::log("info") << "Track playing changed to: " << getCurrentTrack(&sqlSession).get()->trackName;
        }
        else if(event == VOTING_ENDED)
        {
            //Look at votes and add correct track to end of playlist.
            //If more than one track has highest votes, pick random. TODO:maybe base off of other play data instead.
            
            std::list<std::pair<const AudioTrack*,int>> trackWinners;
            for(std::map<const AudioTrack*,int>::iterator track = currentVoteStatus.begin(); track != currentVoteStatus.end(); track++)
            {
                //There nothing yet and there was at least a vote is an initial winner.
                if(trackWinners.size() == 0 && track->second > 0)
                {
                    trackWinners.push_back(std::pair<const AudioTrack*, int>(track->first,track->second));
                    continue;
                }
                //If there is a winner. Check if higher. If so, clear the list and add this one. If equal, add to list.
                if(trackWinners.size() > 0)
                {
                    if(trackWinners.front().second < track->second)
                    {
                        trackWinners.clear();
                        trackWinners.push_back(std::pair<const AudioTrack*,int>(track->first, track->second));
                    }
                    else if(trackWinners.front().second == track->second)
                    {
                        trackWinners.push_back(std::pair<const AudioTrack*, int>(track->first, track->second));
                    }
                }
            }
            
            const AudioTrack* winner;
            //Randomly pick from winners(in case of tie), if there are any.
            if(trackWinners.size() > 0)
            {
                auto iter = trackWinners.begin();
                std::advance(iter,rand() % trackWinners.size());
                winner = (*iter).first;
                
                //Deal with requests if there are any.
                if(requestQueue.size() > 0)
                {
                    //If winning track was a request, now you can remove it from request queue.
                    if(requestQueue.front()->trackFingerprint == winner->trackFingerprint)
                    {
                        requestQueue.pop_front();
                    }
                    //Request didn't win. Put request at bottom of queue.
                    else
                    {
                        requestQueue.push_back(requestQueue.front());
                        requestQueue.pop_front();
                    }
                }
            }
            else
            {
                //Pick request song if there are any.
                if(requestQueue.size() > 0)
                {
                    winner = requestQueue.front();
                    requestQueue.pop_front();
                } 
                else
                {
                    //Pick based on percentages.
                    int pick = rand() % 10 +1;
                    if(pick <= 6)
                    {
                        //First track wins
                        winner = currentVoteBatch.front();
                    }
                    else if(pick <= 9)
                    {
                        //Second track wins.
                        winner = (*currentVoteBatch.begin()++);
                    }
                    else
                    {
                        //Third track wins
                        winner = (*currentVoteBatch.begin()+=2);
                    }
                }
            }
            groove_playlist_insert(currentPlaylist,groove_file_open(winner->trackPath.c_str()),1.0,1.0,nullptr);
            Wt::log("info")<< "Voting has ended. Next track is: " << winner->trackName;
        }
        else if(event == VOTE_CAST)
        {
            //
        }
        else if(event == PLAYING_PAUSED)
        {
            //
        }
        else if(event == PLAYING_RESUMED)
        {
            //
        }
        else if(event == SKIP_REQUESTED)
        {
            //
        }
        else if(event == SKIP_VOTE_CAST)
        {
            //
        }
        else if(event == SKIP_VOTING_ENDED)
        {
            //
        }
        else if(event == ADMIN_FORCE_SKIP)
        {
            //
        }
        //TODO
    }
    
    currentPlaylist = nullptr;
    currentPlayer = nullptr;
    groove_player_detach(player);
    groove_player_destroy(player);
    groove_playlist_destroy(playlist);
}

void GroovePlayerMgr::shutdown()
{
    continueEventLoop = false;
}

GroovePlayerMgr::PlayerEvents GroovePlayerMgr::getNextPlayerEvent(Wt::Dbo::Session* session)
{
    double timeIntoTrack;
    groove_player_position(currentPlayer,nullptr,&timeIntoTrack);
    if(getCurrentTrack(session).get() != nullptr && getCurrentTrack(session)->trackLengthSeconds-timeIntoTrack < 3)
    {
        return VOTING_ENDED;
    }
    GroovePlayerEvent event;
    if(groove_player_event_get(this->currentPlayer,&event, 0) > 0)
    {
        if(event.type == GROOVE_EVENT_NOWPLAYING)
        {
            return GROOVE_NOWPLAYING;
        }
    }
    if(lastInternalEvents.size() > 0)
    {
        PlayerEvents event = lastInternalEvents.front();
        lastInternalEvents.pop_front();
        return event;
    }
    return NOTHING;
}

Wt::Dbo::ptr<AudioTrack> GroovePlayerMgr::getCurrentTrack(Wt::Dbo::Session* session)
{
    Wt::Dbo::Transaction transaction(*session);
    GroovePlaylistItem* currentItem;
    groove_player_position(this->currentPlayer,&currentItem,nullptr);
    if(currentItem != nullptr)
    {
        Wt::Dbo::ptr<AudioTrack> track = session->find<AudioTrack>().where("path = ?").bind(currentItem->file->filename);
        return track;
    }
    return Wt::Dbo::ptr<AudioTrack>();
}


bool GroovePlayerMgr::addFileToTrackDBIfTagged(Wt::Dbo::Session* session, std::filesystem::path file)
{
    //Now check if tags exist and put into DB.
    struct GrooveFile* gfile = groove_file_open(file.c_str());
    struct GrooveTag* artist_tag = groove_file_metadata_get(gfile, "artist", nullptr, 0);
    struct GrooveTag* album_tag = groove_file_metadata_get(gfile, "album", nullptr, 0);
    struct GrooveTag* name_tag = groove_file_metadata_get(gfile, "title", nullptr, 0);
    struct GrooveTag* genre_tag = groove_file_metadata_get(gfile, "genre", nullptr, 0);
    if(artist_tag == nullptr || album_tag == nullptr || name_tag == nullptr || genre_tag == nullptr)
    {
        //Only accept song with all metadata for DB.
        groove_file_close(gfile);
        return false;
    }
    
    //Take fingerprint and compare to DB.
    struct GrooveFingerprinter* fingerprinter = groove_fingerprinter_create();
    struct GrooveFingerprinterInfo info;
    struct GroovePlaylist* playlist = groove_playlist_create();
    groove_playlist_insert(playlist,gfile,1.0,1.0,nullptr);
    groove_fingerprinter_attach(fingerprinter, playlist);
    groove_fingerprinter_info_get(fingerprinter, &info, 1);
    double trackLen = info.duration;
    char* encodedFP;
    groove_fingerprinter_encode(info.fingerprint,info.fingerprint_size,&encodedFP);
    std::string fingerprint = std::string(encodedFP);
    groove_fingerprinter_dealloc(encodedFP);
    groove_fingerprinter_free_info(&info);
    groove_fingerprinter_detach(fingerprinter);
    groove_fingerprinter_destroy(fingerprinter);
    groove_playlist_destroy(playlist);
    
    Wt::Dbo::Transaction transaction(*session);
    int existing = session->query<int>("select count(fingerprint) from tracks").where("fingerprint = ?").bind(fingerprint);
    if(existing >0)
    {
        //This track has a duplicate already.
        groove_file_close(gfile);
        return false;
    }
    
    //Add to DB.
    AudioTrack* newTrack = new AudioTrack();
    newTrack->trackName = groove_tag_value(name_tag);
    newTrack->trackAlbumName = groove_tag_value(album_tag);
    newTrack->trackArtistName = groove_tag_value(artist_tag);
    newTrack->trackGenre = groove_tag_value(genre_tag);
    newTrack->trackLengthSeconds = trackLen;
    newTrack->trackFingerprint = fingerprint;
    newTrack->trackPath = file.string();
    session->add(newTrack);
    groove_file_close(gfile);
    return true;
}

void GroovePlayerMgr::removeOrphanedTracks(Wt::Dbo::Session* session)
{
    Wt::Dbo::Transaction transaction(*session);
    Wt::Dbo::collection<Wt::Dbo::ptr<AudioTrack>> tracks = session->find<AudioTrack>();
    for(Wt::Dbo::collection<Wt::Dbo::ptr<AudioTrack>>::const_iterator i = tracks.begin(); i != tracks.end(); ++i)
    {
        if(!std::filesystem::exists(std::filesystem::path((*i)->trackPath)))
        {
            Wt::Dbo::ptr<AudioTrack> item = session->find<AudioTrack>().where("fingerprint = ?").bind((*i)->trackFingerprint);
            Wt::log("info") << (*i)->trackPath + " not found in filesystem. Removed from DB.";
            item.remove();
        }
    }
}



void GroovePlayerMgr::grooveAudioScannerLoop()
{
    Wt::Dbo::Session sqlSession;
    sqlSession.setConnectionPool(connectionPool);
    sqlSession.mapClass<User>("user");
    sqlSession.mapClass<AudioTrack>("tracks");
    sqlSession.mapClass<UserAction>("actions");
    if(!std::filesystem::exists(musicScanDir))
    {
        std::filesystem::create_directory(musicScanDir);
        Wt::log("info") << "Directory "+std::filesystem::canonical(musicScanDir).string()+" didn't exist, so created.";
    } else 
    {
        Wt::log("info") << "Directory "+std::filesystem::canonical(musicScanDir).string()+" exists.";
    }
    for(std::filesystem::directory_entry p: std::filesystem::directory_iterator(musicScanDir))
    {
        std::string extensionLowered;
        for(auto elem : p.path().extension().string())
        {
            extensionLowered.push_back(std::tolower(elem));
        }
        if(extensionLowered == ".mp3") //TODO:think about supporting more than mp3s.
        {
            if(addFileToTrackDBIfTagged(&sqlSession, p.path()))
            {
                Wt::log("info") << p.path().string() << " was added to DB";
            }
        }
        else
        {
            Wt::log("info") << p.path().string() + " was not an accepted audio file.";
        }
    }
    //Now check for tracks in DB without a file.
    removeOrphanedTracks(&sqlSession);
    finishedLaunchScan = true;
}