var xtend = require('xtend');

function parseCookie(auth, cookieHeader) {
  var cookieParser = auth.cookieParser(auth.secret);
  var req = {
    headers:{
      cookie: cookieHeader
    }
  };
  var result;
  cookieParser(req, {}, function (err) {
    if (err) throw err;
    result = req.signedCookies;
  });
  return result;
}

function authorize(options) {
  var defaults = {
    passport:     require('passport'),
    key:          'connect.sid',
    secret:       null,
    store:        null,
    success:      null,
    fail:         null
  };

  var auth = xtend({}, defaults, options );

  auth.userProperty = auth.passport._userProperty || 'user';

  if (typeof auth.cookieParser === 'undefined' || !auth.cookieParser) {
    throw new Error('cookieParser is required use connect.cookieParser or express.cookieParser');
  }

  return function(data, accept){
    if (!data.headers.cookie) {
      return accept(null, false);
    }

    data.cookie =  parseCookie(auth, data.headers.cookie);

    data.sessionID = data.cookie[ auth.key ];

    auth.store.get(data.sessionID, function(err, session){
      if (err) {
        return accept('Error in session store.', false);
      } else if (!session) {
        return accept(null, false);
      }

      if( !session[ auth.passport._key ] ){
        return accept('passport was not initialized', false);
      }

      var userKey = session[ auth.passport._key ][ auth.userProperty ];

      if(userKey === undefined) {
        if(auth.fail)
          return auth.fail( data, accept );
        else
          return accept(null, false);
      }

      auth.passport.deserializeUser(userKey, function(err, user) {
        data[ auth.userProperty ] = user;
        if( auth.success ) {
          return auth.success( data, accept );
        }
        accept(null, true);
      });

    });
  };
}

function filterSocketsByUser(socketIo, filter){
  var handshaken = socketIo.sockets.manager.handshaken;
  return Object.keys(handshaken || {})
    .filter(function(skey){
      return filter(handshaken[skey].user);
    })
    .map(function(skey){
      return socketIo.sockets.manager.sockets.sockets[skey];
    });
}

exports.authorize = authorize;
exports.filterSocketsByUser = filterSocketsByUser;