Elevator Saga

program.js

{
  init: function(elevators, floors) { 
    const DIR_UP = 'up';
    const DIR_DOWN = 'down';
    const pendingPickupDirectionDownFloors = new Set();
    const pendingPickupDirectionUpFloors = new Set();

    const buttonPressedHandlerFactory = (floor, direction) => () => {
      console.log(`Button pressed on floor ${floor.floorNum()} going ${direction}`);

      // If there is already an elevator on the floor, we don't need to do anything
      if (elevators.some(elevator => elevator.currentFloor() === floor.floorNum())) {
        console.log(`Elevator already on floor ${floor.floorNum()}`);
        return;
      }

      // If an elevator is idle, we can just send it to the floor
      for (const elevator of elevators) {
        console.log(floor.floorNum(), direction, elevator.destinationQueue);
        if (elevator.destinationQueue.length === 0) {
          elevator.goToFloor(floor.floorNum());
          if (direction === DIR_DOWN) {
            elevator.goingUpIndicator(true);
          } else {
            elevator.goingDownIndicator(true);
          }
          return;
        }
      }

      // Otherwise, we need to add the floor to the pending pickup list
      if (direction === DIR_UP) {
        pendingPickupDirectionUpFloors.add(floor.floorNum());
      } else {
        pendingPickupDirectionDownFloors.add(floor.floorNum());
      }
    };

    const handlePassingFloorFactory = (elevator) => (floorNum, direction) => {
      console.log('Passing floor', floorNum, direction);
      const pendingPickupFloors = direction === DIR_UP ? pendingPickupDirectionUpFloors : pendingPickupDirectionDownFloors;
      if (pendingPickupFloors.has(floorNum)) {
        elevator.goToFloor(floorNum, true); 
        pendingPickupFloors.delete(floorNum);
        
        // Remove floor if already in queue
        const nextQueue = elevator.destinationQueue.filter((dest) => dest !== floorNum);
        elevator.destinationQueue = nextQueue;
        elevator.checkDestinationQueue();
      }
    };

    const handleFloorButtonPressedFactory = (elevator) => (floorNum) => {
      console.log('Floor button pressed', floorNum);
      elevator.goToFloor(floorNum);
    };

    const handleElevatorIdleFactory = (elevator) => () => {
      console.log('Elevator idle');
      // Find next pickup floor
      if (pendingPickupDirectionUpFloors.size > 0) {
        const nextFloor = Math.min(...pendingPickupDirectionUpFloors);
        elevator.goToFloor(nextFloor);
        pendingPickupDirectionUpFloors.delete(nextFloor);
        elevator.goingUpIndicator(true);
        elevator.goingDownIndicator(false);
      } else if (pendingPickupDirectionDownFloors.size > 0) {
        const nextFloor = Math.max(...pendingPickupDirectionDownFloors);
        elevator.goToFloor(nextFloor);
        pendingPickupDirectionDownFloors.delete(nextFloor);
        elevator.goingUpIndicator(false);
        elevator.goingDownIndicator(true);
      }
    };

    // Give all the elevators the same config
    for (const elevator of elevators) {
      // Whenever the elevator is idle (has no more queued destinations) ...
      elevator.on('idle', handleElevatorIdleFactory(elevator));
      elevator.on('floor_button_pressed', handleFloorButtonPressedFactory(elevator))
      elevator.on('passing_floor', handlePassingFloorFactory(elevator));
    }
      
    for (const floor of floors) {
      // Add to queue pickup queue when a button is pressed
      floor.on('up_button_pressed', buttonPressedHandlerFactory(floor, DIR_UP));
      floor.on('down_button_pressed', buttonPressedHandlerFactory(floor, DIR_DOWN));
    } 
  },
  update: function(dt, elevators, floors) {
    // We normally don't need to do anything here
  }
}