/*!
 * socket.io-node
 * Copyright(c) 2011 LearnBoost <dev@learnboost.com>
 * MIT Licensed
 */

/**
 * Module dependencies.
 */

var parser = require( './parser' );

/**
 * Expose the constructor.
 */

exports = module.exports = Transport;

/**
 * Transport constructor.
 *
 * @api public
 */

function Transport( mng, data, req ) {
	this.manager = mng;
	this.id = data.id;
	this.disconnected = false;
	this.drained = true;
	this.handleRequest( req );
}
;

/**
 * Access the logger.
 *
 * @api public
 */

Transport.prototype.__defineGetter__( 'log', function () {
	return this.manager.log;
} );

/**
 * Access the store.
 *
 * @api public
 */

Transport.prototype.__defineGetter__( 'store', function () {
	return this.manager.store;
} );

/**
 * Handles a request when it's set.
 *
 * @api private
 */

Transport.prototype.handleRequest = function ( req ) {
	this.log.debug( 'setting request', req.method, req.url );
	this.req = req;

	if ( req.method == 'GET' ) {
		this.socket = req.socket;
		this.open = true;
		this.drained = true;
		this.setHeartbeatInterval();

		this.setHandlers();
		this.onSocketConnect();
	}
};

/**
 * Called when a connection is first set.
 *
 * @api private
 */

Transport.prototype.onSocketConnect = function () {
};

/**
 * Sets transport handlers
 *
 * @api private
 */

Transport.prototype.setHandlers = function () {
	var self = this;

	// we need to do this in a pub/sub way since the client can POST the message
	// over a different socket (ie: different Transport instance)
	this.store.subscribe( 'heartbeat-clear:' + this.id, function () {
		self.onHeartbeatClear();
	} );

	this.store.subscribe( 'disconnect-force:' + this.id, function () {
		self.onForcedDisconnect();
	} );

	this.store.subscribe( 'dispatch:' + this.id, function ( packet, volatile ) {
		self.onDispatch( packet, volatile );
	} );

	this.bound = {
		end : this.onSocketEnd.bind( this ), close : this.onSocketClose.bind( this ), error : this.onSocketError.bind( this ), drain : this.onSocketDrain.bind( this )
	};

	this.socket.on( 'end', this.bound.end );
	this.socket.on( 'close', this.bound.close );
	this.socket.on( 'error', this.bound.error );
	this.socket.on( 'drain', this.bound.drain );

	this.handlersSet = true;
};

/**
 * Removes transport handlers
 *
 * @api private
 */

Transport.prototype.clearHandlers = function () {
	if ( this.handlersSet ) {
		this.store.unsubscribe( 'disconnect-force:' + this.id );
		this.store.unsubscribe( 'heartbeat-clear:' + this.id );
		this.store.unsubscribe( 'dispatch:' + this.id );

		this.socket.removeListener( 'end', this.bound.end );
		this.socket.removeListener( 'close', this.bound.close );
		this.socket.removeListener( 'error', this.bound.error );
		this.socket.removeListener( 'drain', this.bound.drain );
	}
};

/**
 * Called when the connection dies
 *
 * @api private
 */

Transport.prototype.onSocketEnd = function () {
	this.end( 'socket end' );
};

/**
 * Called when the connection dies
 *
 * @api private
 */

Transport.prototype.onSocketClose = function ( error ) {
	this.end( error ? 'socket error' : 'socket close' );
};

/**
 * Called when the connection has an error.
 *
 * @api private
 */

Transport.prototype.onSocketError = function ( err ) {
	if ( this.open ) {
		this.socket.destroy();
		this.onClose();
	}

	this.log.info( 'socket error ' + err.stack );
};

/**
 * Called when the connection is drained.
 *
 * @api private
 */

Transport.prototype.onSocketDrain = function () {
	this.drained = true;
};

/**
 * Called upon receiving a heartbeat packet.
 *
 * @api private
 */

Transport.prototype.onHeartbeatClear = function () {
	this.clearHeartbeatTimeout();
	this.setHeartbeatInterval();
};

/**
 * Called upon a forced disconnection.
 *
 * @api private
 */

Transport.prototype.onForcedDisconnect = function () {
	if ( !this.disconnected ) {
		this.log.info( 'transport end by forced client disconnection' );
		if ( this.open ) {
			this.packet( { type : 'disconnect' } );
		}
		this.end( 'booted' );
	}
};

/**
 * Dispatches a packet.
 *
 * @api private
 */

Transport.prototype.onDispatch = function ( packet, volatile ) {
	if ( volatile ) {
		this.writeVolatile( packet );
	} else {
		this.write( packet );
	}
};

/**
 * Sets the close timeout.
 */

Transport.prototype.setCloseTimeout = function () {
	if ( !this.closeTimeout ) {
		var self = this;

		this.closeTimeout = setTimeout( function () {
			self.log.debug( 'fired close timeout for client', self.id );
			self.closeTimeout = null;
			self.end( 'close timeout' );
		}, this.manager.get( 'close timeout' ) * 1000 );

		this.log.debug( 'set close timeout for client', this.id );
	}
};

/**
 * Clears the close timeout.
 */

Transport.prototype.clearCloseTimeout = function () {
	if ( this.closeTimeout ) {
		clearTimeout( this.closeTimeout );
		this.closeTimeout = null;

		this.log.debug( 'cleared close timeout for client', this.id );
	}
};

/**
 * Sets the heartbeat timeout
 */

Transport.prototype.setHeartbeatTimeout = function () {
	if ( !this.heartbeatTimeout && this.manager.enabled( 'heartbeats' ) ) {
		var self = this;

		this.heartbeatTimeout = setTimeout( function () {
			self.log.debug( 'fired heartbeat timeout for client', self.id );
			self.heartbeatTimeout = null;
			self.end( 'heartbeat timeout' );
		}, this.manager.get( 'heartbeat timeout' ) * 1000 );

		this.log.debug( 'set heartbeat timeout for client', this.id );
	}
};

/**
 * Clears the heartbeat timeout
 *
 * @param text
 */

Transport.prototype.clearHeartbeatTimeout = function () {
	if ( this.heartbeatTimeout && this.manager.enabled( 'heartbeats' ) ) {
		clearTimeout( this.heartbeatTimeout );
		this.heartbeatTimeout = null;
		this.log.debug( 'cleared heartbeat timeout for client', this.id );
	}
};

/**
 * Sets the heartbeat interval. To be called when a connection opens and when
 * a heartbeat is received.
 *
 * @api private
 */

Transport.prototype.setHeartbeatInterval = function () {
	if ( !this.heartbeatInterval && this.manager.enabled( 'heartbeats' ) ) {
		var self = this;

		this.heartbeatInterval = setTimeout( function () {
			self.heartbeat();
			self.heartbeatInterval = null;
		}, this.manager.get( 'heartbeat interval' ) * 1000 );

		this.log.debug( 'set heartbeat interval for client', this.id );
	}
};

/**
 * Clears all timeouts.
 *
 * @api private
 */

Transport.prototype.clearTimeouts = function () {
	this.clearCloseTimeout();
	this.clearHeartbeatTimeout();
	this.clearHeartbeatInterval();
};

/**
 * Sends a heartbeat
 *
 * @api private
 */

Transport.prototype.heartbeat = function () {
	if ( this.open ) {
		this.log.debug( 'emitting heartbeat for client', this.id );
		this.packet( { type : 'heartbeat' } );
		this.setHeartbeatTimeout();
	}

	return this;
};

/**
 * Handles a message.
 *
 * @param {Object} packet object
 * @api private
 */

Transport.prototype.onMessage = function ( packet ) {
	var current = this.manager.transports[this.id];

	if ( 'heartbeat' == packet.type ) {
		this.log.debug( 'got heartbeat packet' );

		if ( current && current.open ) {
			current.onHeartbeatClear();
		} else {
			this.store.publish( 'heartbeat-clear:' + this.id );
		}
	} else {
		if ( 'disconnect' == packet.type && packet.endpoint == '' ) {
			this.log.debug( 'got disconnection packet' );

			if ( current ) {
				current.onForcedDisconnect();
			} else {
				this.store.publish( 'disconnect-force:' + this.id );
			}

			return;
		}

		if ( packet.id && packet.ack != 'data' ) {
			this.log.debug( 'acknowledging packet automatically' );

			var ack = parser.encodePacket( {
				type : 'ack', ackId : packet.id, endpoint : packet.endpoint || ''
			} );

			if ( current && current.open ) {
				current.onDispatch( ack );
			} else {
				this.manager.onClientDispatch( this.id, ack );
				this.store.publish( 'dispatch:' + this.id, ack );
			}
		}

		// handle packet locally or publish it
		if ( current ) {
			this.manager.onClientMessage( this.id, packet );
		} else {
			this.store.publish( 'message:' + this.id, packet );
		}
	}
};

/**
 * Clears the heartbeat interval
 *
 * @api private
 */

Transport.prototype.clearHeartbeatInterval = function () {
	if ( this.heartbeatInterval && this.manager.enabled( 'heartbeats' ) ) {
		clearTimeout( this.heartbeatInterval );
		this.heartbeatInterval = null;
		this.log.debug( 'cleared heartbeat interval for client', this.id );
	}
};

/**
 * Finishes the connection and makes sure client doesn't reopen
 *
 * @api private
 */

Transport.prototype.disconnect = function ( reason ) {
	this.packet( { type : 'disconnect' } );
	this.end( reason );

	return this;
};

/**
 * Closes the connection.
 *
 * @api private
 */

Transport.prototype.close = function () {
	if ( this.open ) {
		this.doClose();
		this.onClose();
	}
};

/**
 * Called upon a connection close.
 *
 * @api private
 */

Transport.prototype.onClose = function () {
	if ( this.open ) {
		this.setCloseTimeout();
		this.clearHandlers();
		this.open = false;
		this.manager.onClose( this.id );
		this.store.publish( 'close', this.id );
	}
};

/**
 * Cleans up the connection, considers the client disconnected.
 *
 * @api private
 */

Transport.prototype.end = function ( reason ) {
	if ( !this.disconnected ) {
		this.log.info( 'transport end' );

		var local = this.manager.transports[this.id];

		this.close();
		this.clearTimeouts();
		this.disconnected = true;

		if ( local ) {
			this.manager.onClientDisconnect( this.id, reason, true );
		} else {
			this.store.publish( 'disconnect:' + this.id, reason );
		}
	}
};

/**
 * Signals that the transport should pause and buffer data.
 *
 * @api public
 */

Transport.prototype.discard = function () {
	this.log.debug( 'discarding transport' );
	this.discarded = true;
	this.clearTimeouts();
	this.clearHandlers();

	return this;
};

/**
 * Writes an error packet with the specified reason and advice.
 *
 * @param {Number} advice
 * @param {Number} reason
 * @api public
 */

Transport.prototype.error = function ( reason, advice ) {
	this.packet( {
		type : 'error', reason : reason, advice : advice
	} );

	this.log.warn( reason, advice ? ('client should ' + advice) : '' );
	this.end( 'error' );
};

/**
 * Write a packet.
 *
 * @api public
 */

Transport.prototype.packet = function ( obj ) {
	return this.write( parser.encodePacket( obj ) );
};

/**
 * Writes a volatile message.
 *
 * @api private
 */

Transport.prototype.writeVolatile = function ( msg ) {
	if ( this.open ) {
		if ( this.drained ) {
			this.write( msg );
		} else {
			this.log.debug( 'ignoring volatile packet, buffer not drained' );
		}
	} else {
		this.log.debug( 'ignoring volatile packet, transport not open' );
	}
};