elevator-saga/elevator.js

eval({
	init: function(elevators, floors) {
		// Get elevator/building info
		let elevatorCount = elevators.length;
		let floorCount    = floors.length;
		let topFloor      = floorCount - 1;
		let bottomFloor   = 0;

		console.clear();
		console.log("Starting (" + floorCount + " floors; " + elevatorCount + " elevator" + ((floorCount == 1) ? "s" : "") +")...");

		// Direction constants
		const UP   = 0;
		const DOWN = 1;
		const IDLE = 2;

		// Data structure for floor requests
		let requests = [new Set(), new Set()];

		// ----
		// Functions
		// ----

		// getNextFloor chooses the best destination for an elevator
		// when given the index of the elevator, along with all
		// destinations, requests, and rest floors.
		function getNextFloor(elevators, elevatorIndex, destinations, requests, restFloors) {
			let elevator = elevators[elevatorIndex];
			let floorNum = restFloors[1];

			if (requests[UP].size == 0 && requests[DOWN].size == 0 && destinations.size == 0) {
				// No people; send to rest floor
			} else if (destinations.size == 0) {
				// No destinations; send to pick up passengers
				try {
					floorNum = getClosestFloor(elevator.currentFloor(), new Set([...requests[UP], ...requests[DOWN]]));
				} catch (e) {
					console.log("ERROR: Requests set was empty");
				}
			} else {
				// Prioritize dropping off current passengers
				try {
					floorNum = getClosestFloor(elevator.currentFloor(), destinations);
				} catch (e) {
					console.log("ERROR: Destinations set was empty");
				}
			}
			return floorNum;
		}

		// getClosestFloor takes a floor, a list of floors, an optional
		// list of ignored floors, and an optional direction. It
		// returns the closest floor from that list in the given
		// direction that is not part of the ignored floors list.
		function getClosestFloor(currentFloor, floorList, ignoredFloors = new Set(), direction = IDLE) {
			let closestFloor = currentFloor;
			let distance     = floorCount;
			let newDistance  = distance;

			floorList.forEach(function(floorNum) {
				switch (direction) {
					case UP:
						newDistance = floorNum - currentFloor;
						break;
					case DOWN:
						newDistance = currentFloor - floorNum;
						break;
					case IDLE:
						newDistance = Math.abs(floorNum - currentFloor);
				}
				if (newDistance < distance && newDistance > 0 && !(ignoredFloors.has(floorNum))) {
					closestFloor = floorNum;
					distance = newDistance;
				}
			});

			if (closestFloor != currentFloor) {
				return closestFloor;
			} else {
				throw new Error("No floor in selected direction");
			}
		}

		// getClosestElevator takes a floor number and returns the
		// index of the closest elevator.
		function getClosestElevator(floorNum) {
			let closestElevator = 0;
			let distance        = floorCount;
			let newDistance     = distance;

			elevators.forEach(function (elevator, elevatorIndex) {
				newDistance = Math.abs(elevator.currentFloor() - floorNum);
				if (newDistance < distance) {
					distance = newDistance;
					closestElevator = elevatorIndex;
				}
			});

			//console.log("Closest is elevator[" + closestElevator + "]")
			return closestElevator;
		}

		// getDirection get the direction (up or down) that an elevator
		// will need to travel to get to a specified floor
		function getDirection(currentFloor, floorNum) {
			let distance = currentFloor - floorNum;
			if (distance > 0 || currentFloor == topFloor) {
				return DOWN;
			} else if (distance < 0 || currentFloor == 0) {
				return UP;
			} else {
				return IDLE;
			}
		}

		// setDirection changes the indicator lights on a specified
		// elevator to match the given direction.
		function setDirection(elevator, direction) {
			switch (direction) {
				case UP:
					elevator.goingUpIndicator(true);
					elevator.goingDownIndicator(false);
					break;
				case DOWN:
					elevator.goingUpIndicator(false);
					elevator.goingDownIndicator(true);
					break;
				default:
					elevator.goingUpIndicator(true);
					elevator.goingDownIndicator(true);
			}
		}

		// ----
		// Floors
		// ----

		floors.forEach(function (floor) {
			floor.on("up_button_pressed", function() {
				//console.log("> Up request on floor[" + floor.level + "]");
				requests[UP].add(floor.level);
			});
			floor.on("down_button_pressed", function() {
				//console.log("> Down request on floor[" + floor.level + "]");
				requests[DOWN].add(floor.level);
			});
		});

		// ----
		// Elevators
		// ----

		elevators.forEach(function (elevator, elevatorIndex) {
			// Elevator info and variables
			let destinations = new Set();

			const restFloors = [
				elevatorIndex * Math.floor(floorCount / (elevatorCount + 1)),
				(elevatorIndex + 1) * Math.floor(floorCount / (elevatorCount + 1)),
				(elevatorIndex + 2) * Math.floor(floorCount / (elevatorCount + 1))
			];

			// Next primary stop
			let nextFloor = restFloors[0];

			// Start
			setDirection(elevator, UP); // Starts on the ground floor, must be going up
			console.log("> Elevator[" + elevatorIndex + "] rest floors are " + restFloors[0] + ", " + restFloors[1] + ", and " + restFloors[2] + ". Starting at " + restFloors[0] + ".");
			elevator.goToFloor(nextFloor); // Nearest rest floor

			// Idle
			elevator.on("idle", function() {
				//console.log("> Elevator[" + elevatorIndex + "] is idle")
				nextFloor = getNextFloor(elevators, elevatorIndex, destinations, requests, restFloors);
				elevator.goToFloor(nextFloor);
			});

			// Passing
			elevator.on("passing_floor", function(floorNum, direction) {
				if (destinations.has(floorNum)
				  || (elevator.loadFactor() < 1 && elevator.destinationDirection() == "up" && requests[UP].has(floorNum))
				  || (elevator.loadFactor() < 1 && elevator.destinationDirection() == "down" && requests[DOWN].has(floorNum))) {
					elevator.goToFloor(floorNum, true);
				}
			});

			// Buttons
			elevator.on("floor_button_pressed", function(floorNum) {
				//console.log("> Pressed floor[" + floorNum + "] on elevator[" + elevatorIndex + "]");
				destinations.add(floorNum);
			});

			// Stopped
			elevator.on("stopped_at_floor", function(floorNum) {
				//console.log("> elevator[" + elevatorIndex + "] stopped at floor[" + floorNum + "]");
				setDirection(elevator, getDirection(elevator.currentFloor(), nextFloor));
				destinations.delete(floorNum);
				if (elevator.goingUpIndicator() == true) {
					requests[UP].delete(floorNum);
				}
				if (elevator.goingDownIndicator() == true) {
					requests[DOWN].delete(floorNum);
				}
			});
		});
	},

	update: function(dt, elevators, floors) {}
});