startRight = function(self){ return function(){self.thrusters.left(true)}}(this)
startLeft = function(self){ return function(){self.thrusters.right(true)}}(this)
startUp = function(self){ return function(){self.thrusters.bottom(true)}}(this)
startDown = function(self){ return function(){self.thrusters.top(true)}}(this)
stopRight = function(self){ return function(){self.thrusters.left(false)}}(this)
stopLeft = function(self){ return function(){self.thrusters.right(false)}}(this)
stopUp = function(self){ return function(){self.thrusters.bottom(false)}}(this)
stopDown = function(self){ return function(){self.thrusters.top(false)}}(this)

function fullStop(){stopUp(); stopDown(); stopLeft(); stopRight()}

function moveRight(){stopLeft(); startRight();}
function moveUp(){stopDown(); startUp();}
function moveLeft(){stopRight(); startLeft();}
function moveDown(){stopUp(); startDown();}
function moveDownRight(){moveDown(); moveRight();}
function moveDownLeft(){moveDown(); moveLeft();}
function moveUpRight(){moveUp(); moveRight();}
function moveUpLeft(){moveUp(); moveLeft();}

function forceRight(){fullStop(); startRight();}
function forceUp(){fullStop(); startUp();}
function forceLeft(){fullStop(); startLeft();}
function forceDown(){fullStop(); startDown();}
function forceDownRight(){fullStop(); moveDown(); moveRight();}
function forceDownLeft(){fullStop(); moveDown(); moveLeft();}
function forceUpRight(){fullStop(); moveUp(); moveRight();}
function forceUpLeft(){fullStop(); moveUp(); moveLeft();}

function select()
{
    for(var i = 0; i < arguments.length; ++i){
        if(arguments[i] != null && arguments[i] != undefined)
            return arguments[i]
    }
}


current_state = ''
next_state = ''
function signal(signal)
{
    var state = select(current_state, "")
    var key = state + "__" + signal

    if(key in STATES){
        next_state = select(STATES[key][0], current_state, '')
        console.log('RECV ' + key + ' --> [' + next_state + ']')
        var rstate = next_state
        var _func = STATES[key][1]
        _func()
        current_state = next_state
        if(current_state != rstate){
            console.log('Next state overriden to ' + current_state)
        }
        next_state = ''
    } else {
        console.log('RECV ' + key + '(ignoring)')
    }

}


function signalSensor(sensor, contact){
    if(contact) signal('hit_'+sensor)
    else signal('free_'+sensor)
}

this.on('start', function() { signal('start') });
this.on('sensor:right', function(contact) {signalSensor('right', contact)});
this.on('sensor:left', function(contact) {signalSensor('left', contact)});
this.on('sensor:bottom', function(contact) {signalSensor('down', contact)});
this.on('sensor:top', function(contact) {signalSensor('up', contact)});


STATES = {
    '__start':          ['p1', forceUp], //p1 - place first block
    'p1__hit_up':       [null, forceRight],
    'p1__hit_right':    [null, forceDown],
    'p1__hit_left':     ['tr', forceRight], //tr - transit

    'tr__hit_right':    [null, forceDown],
    'tr__hit_down':     ['tr2', forceRight],
    'tr2__hit_right':   ['p2', forceUp],

    'p2__hit_left':     ['ext', forceRight]

}