Elevator Saga Challenge #4

ElevatorSagaChallenge4.js

// URL: http://play.elevatorsaga.com/#challenge=4
{
    init: function(elevators, floors) {
        
        function initElevator(elevator) {
            elevator.on("idle", function() {});
            elevator.on("floor_button_pressed", function(floorNum) {
                elevator.goToFloor(floorNum, true);
            });
            elevator.on("passing_floor", function(floorNum, direction) {
                var stopAtFloor = false;
                elevator.destinationQueue = elevator.destinationQueue.filter(function (n, i) {
                    if (n == floorNum) { 
                        stopAtFloor = true;
                    }
                    return n != floorNum;
                });
                if (stopAtFloor) {
                    elevator.checkDestinationQueue();
                    elevator.goToFloor(floorNum, true);                
                }
            });
        };
        
        function findNearestElevator(floor) {
            var possibilities = elevators
                .map(function (e) { 
                    return { 
                        elevator: e, 
                        distance: e.destinationQueue.length == 0 ? -1 : Math.abs(floor.floorNum() - e.currentFloor()),
                    }; 
                });
            possibilities.sort(function (left, right) {
                return left.distance - right.distance;
            });
            return possibilities[0].elevator;
        };
        
        function initFloor(floor) {
            floor.on("up_button_pressed", function() {
                // Maybe tell an elevator to go to this floor?
                findNearestElevator(floor).goToFloor(floor.floorNum());
            });
            floor.on("down_button_pressed", function() {
                // Maybe tell an elevator to go to this floor?
                findNearestElevator(floor).goToFloor(floor.floorNum());
            });
        };
        
        elevators.forEach(initElevator);
        floors.forEach(initFloor);
    },
    update: function(dt, elevators, floors) {
        // We normally don't need to do anything here
    }
}