/*
 * 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('');
}

/**********************************************************************
 * 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
 *********************************************************************/
exports.index = function (req, res) {
  var song = null;
  var artist = null;
  var lyrics = null;

  if (!db) {
    res.render('db-error');
    return;
  }

  function pickArtist() {
    console.log('Retrieving artist for song...');
    db.get('SELECT * FROM artists WHERE id = ' + song.artist, function (err, selectArtist) {
      if (err) {
        throw err;
      }

      artist = selectArtist;
      console.log(artist);
      pickLyrics();
    });
  }

  function pickLyrics() {
    console.log('Retrieving lyrics for song... ');
    db.get('SELECT * FROM lyrics WHERE song = ' + song.id, function (err, selectLyrics) {
      if (err) {
        throw err;
      }

      lyrics = selectLyrics;
      console.log(lyrics);
      answer();
    });
  }

  function answer() {
    var params = {
      title: 'Round',
      lyrics: lyrics.lyrics,
      song_title: song.title,
      song_artist: artist.name,
      acronym_title: acronymize(song.title),
      acronym_artist: acronymize(artist.name),
      id: song.id
    };
    res.render('index', params);
  }
  
  console.log('Picking song...');
  db.get('SELECT * FROM songs WHERE done_in IS NULL ORDER BY random() LIMIT 1', function (err, selectSong) {
    if (err) {
      throw err;
    }

    song = selectSong;
    console.log(song);
    pickArtist();
  });
}

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

    var stmt = 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');
          result.status = 'ERROR';
          result.message = 'Song already picked';
        } else {
          console.log('Insert succeded');
          // things went alright
          result.status = 'OK'
        }

        console.log(JSON.stringify(result));
        res.writeHead(200, {'Content-Type': 'application/json'});
        res.write(JSON.stringify(result));
        res.end();
      }
    );
  }

  var stmt = 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);
      }
    }
  );
};