var Mongolian = require("mongolian");
    bson = require('mongodb').BSONPure;




/**
 *  DatabaseHelper defines database collections and handles connect to the database.
 *
 * 	 Usage:
 *
 * 	 var db = require('DatabaseHelper.js');
 *
 *       db.myCollection.find(...);
 * 	 db.myCollection.save(...);
 *
 */

/////////////////////////////////////////////////////////////////////////
//++//
//++++//
//++//
//++++//      	             Constructor
//++//
//++++//
//++//
//////////////////////////////////////////////////////////////////////////


function DatabaseHelper() {};

//----------------------------------
//  Private members
//----------------------------------

// Create a server instance with default host and port, or provide your own configuraiton
var server = new Mongolian();

// store all collections in this database
var db = server.db('my_database');

// define another db if you want
var dev_db = server.db('dev_db');


//----------------------------------
//   Public Members
//----------------------------------

// Define some collections

// This is nice because if you accidentally mistype a collection, you'll
// get a javascript exception instead of stealth-saving to the wrong

DatabaseHelper.prototype.my_collection	= db.collection('my_collection');
DatabaseHelper.prototype.users		= db.collection('users');
DatabaseHelper.prototype.posts		= db.collection('posts');
DatabaseHelper.prototype.comments	= db.collection('comments');
DatabaseHelper.prototype.whatever	= db.collection('whatever');
DatabaseHelper.prototype.anotherDB	= dev_db.collection('myCollection');




//----------------------------------
// Session Store
//----------------------------------
// Usage:  app.use(express.session({secret: 'your secret here', store: db.session_store}));
var sessions = db.collection('sessions');
DatabaseHelper.prototype.session_store = {


	get: function(session_id, callback) {

		sessions.findOne({_id: session_id}, function(error, result) {

		   if(result)
			callback(null, JSON.parse(result.toString()));
		   else if(error)
		        callback(error);

		});

	},

	set: function(session_id, session, callback) {

    	var update = {_id: session_id, session: JSON.stringify(session)};

	    if(session && session.cookie && session.cookie.expires)
	    	update.expires = Date.parse(session.cookie.expires);

	    sessions.update({_id: session_id}, update, true, function(error, result)
		{
	      callback(error, result);
	    });

	},

	destroy: function(session_id, callback) {

	     sessions.remove({_id: session_id}, callback);

	},

	length: function(callback) {

   	     sessions.count({}, callback)

	},

	clear: function(callback) {

	     db.sessions.drop(callback);

	}

};


//----------------------------------
// Misc.
//----------------------------------

//helpers for converting to BSON types, avoid making a collection of the same name
DatabaseHelper.prototype.Long = bson.Long;
DatabaseHelper.prototype.ObjectId = bson.ObjectID;
DatabaseHelper.prototype.Timestamp = bson.Timestamp;
DatabaseHelper.prototype.Binary = bson.Binary;
DatabaseHelper.prototype.DBRef = bson.DBRef;
DatabaseHelper.prototype.Code = bson.Code;



module.exports = new DatabaseHelper();