LyricsPicker/lyricsnode/routes/round.js

/*
 * main page
 */

var sqlite3 = require('sqlite3');
var path = require('path');
var db = null;           // make it global

/**********************************************************************
 * Helper functions
 *********************************************************************/

/** db name */
function dbName() {
  return path.join(__dirname, '../../db/lyrics.sq3');
}

/** turn a phrase into a list of acronyms */
function acronymize(phrase) {
  var letters = [];
  phrase.split(' ').forEach(function (elem, idx, array) {
    letters.push(elem[0].toUpperCase());
  });

  return letters.join('');
}

/** return a json response */
function asJson(res, obj) {
  console.log(JSON.stringify(obj));
  res.writeHead(200, {'Content-Type': 'application/json'});
  res.write(JSON.stringify(obj));
  res.end();
}

/** mark a song as played */
function markAsDone(song_id, after) {
  var now = new Date();
  db.run('UPDATE songs SET done_in = ? WHERE id = ?', [
      now.toJSON(), song_id
    ], function (error) {
      if (error) {
        throw error;
      }

      if (after) {
        after();
      }
    }
  );
}

/**********************************************************************
 * Open the database
 *********************************************************************/
console.log('Opening the database ' + dbName() + '...');
db = new sqlite3.Database(dbName(), sqlite3.OPEN_READWRITE, function (error) {
  if (error) {
    db = null;    // keep it null, to point that it is broken
  }
});

/** small note: the db structure:
 * artists:
 *    id int primary key
 *    name text unique
 *
 * songs:
 *    id int primary key
 *    title text
 *    artist int
 *    done_in text
 *
 * lyrics:
 *    id int primary key
 *    song int
 *    lyrics text
 */

/**********************************************************************
 * Select a song and display it
 *********************************************************************/
function index(req, res) {
  if (!db) {
    res.render('db-error');
    return;
  }

  console.log('Picking song...');
  var query = [
    'SELECT',
    '      songs.id as song_id,',
    '      songs.title as song_title,',
    '      artists.name as artist_name,',
    '      lyrics.lyrics as lyrics',
    'FROM songs,',
    '     artists,',
    '     lyrics',
    'WHERE songs.done_in is NULL',
    '  AND songs.artist = artists.id',
    '  AND songs.id = lyrics.song',
    'ORDER BY random()',
    'LIMIT 1'
    ];
  console.log(query.join(' '));

  db.get(query.join(' '), function (err, selectSong) {
    if (err) {
      throw err;
    }

    console.log(selectSong);
    var params = {
      title: 'Round',
      lyrics: selectSong.lyrics,
      song_title: selectSong.song_title,
      song_artist: selectSong.artist_name,
      acronym_title: acronymize(selectSong.song_title),
      acronym_artist: acronymize(selectSong.artist_name),
      id: selectSong.song_id
    };
    res.render('index', params);
  });
}

exports.index = index;

/***********************************************************************
 * Support for the small box with the "others" picks
 **********************************************************************/

exports.others = function (req, res) {
  var posted_artist = req.body.artist.toLowerCase();
  var posted_song = req.body.song.toLowerCase();
    
  console.log('Artist: ' + posted_artist);
  console.log('Song: ' + posted_song);

  var result = {status: '', message: ''};

  function duplicateOrNotDone(err, song) {
    if (err) {
      throw err;
    }

    // the record will always exist, it's just a matter of "does it have a done_in"?
    console.log('Song done in ' + song.done_in);

    if (song.done_in) {
      // yup, already picked that song
      result.status = 'ERROR';
      result.message = 'Song already picked';

      asJson(res, result);
    } else {
      // it was one of your songs that someone else picked.
      // just tell the user that and update it in the background
      result.status = 'OK';
      result.message = 'Someone picked one of your songs';
      asJson(res, result);

      markAsDone(song.id);
    }
  }

  function insertSong(artist) {
    var now = new Date();
    console.log('Adding song as played in ' + now.toJSON() + '...');

    db.run('INSERT INTO songs (id, title, artist, done_in) VALUES (NULL, ?, ?, ?)', [
        posted_song,
        artist,
        now.toJSON()
      ], function (error) {
        if (error) {
          // expected: artist AND song already picked
          console.log('Insert failed, possible duplicate');
          db.get('SELECT * FROM songs WHERE artist = ? AND title = ?', [
              artist,
              posted_song
            ], duplicateOrNotDone
          );
        } else {
          console.log('Insert succeded');
          // things went alright
          result.status = 'OK';
          result.message = 'Added';
          asJson(res, result);
        }
      }
    );
  }

  db.run('INSERT INTO artists (id, name) VALUES (NULL, ?)', [
      posted_artist
    ],
    function (error) {
      if (error) {
        // expected error: artist already exists
        console.log('Artist exists, trying to find id...');
        db.get('SELECT id FROM artists WHERE name = ?', [posted_artist], function (err, artist) {
          if (err) {
            throw err;
          }

          console.log('Artist id = ' + artist.id);
          insertSong(artist.id);
        });
      } else {
        console.log('New artist id = ' + this.lastID);
        insertSong(this.lastID);
      }
    }
  );
};

/**********************************************************************
 * Mark a song as played
 *********************************************************************/

exports.played = function (req, res) {
  markAsDone(req.body.id);
  index(req, res);
};