C#•2y ago

Handling events in "blocks"

Hi,

I am dealing with a problem where I need to move an Elevator based on the inputs received. The inputs are received by a comma delimited string.
For example: 9,8,2,d3,7,4,3
The d3 indicates that the input is delayed by 3. The event for 9, 8, and 2 will all fire in a sequence. After the Elevator was moved 3 times the events for 7, 4, and 3 will fire.
Basically 9, 8, 2 are pressed "at the same time" and 7, 4, 3 are pressed at the same time after the Elevator was moved 3 times.

The issue is that when the 9 event occurs, the Elevator has started moving towards 9 and that by the time event 2 fires the Elevator has already passed floor 2.
The Elevator does end up going to 2 eventually on its way back down but I need it to go to 2 on the way up since 2 should have been received together with the first block of 9, 8, 2.
How can I wait for the first block of events to occur before moving the Elevator?

  private void OnButtonPushed(object sender, ElevatorControllerEventArgs e)
  {
      requestsQueue.AddLast(e.Floor);
      SetDirection();
  }

private void MoveElevator()
{
    while (requestsQueue.Count > 0)
    {
        if (requestsQueue.Contains(currentFloor))
        {
            requestsQueue.Remove(currentFloor);
            controller.Stop();
        }
        else if (isMovingUp)
        {
            currentFloor++;
            controller.MoveUp();
        }
        else
        {
            currentFloor--;
            controller.MoveDown();
        }

        SetDirection();
    }
}

private void SetDirection()
{
    LinkedList<int> requestsGoingUp = GetAllRequestsAboveCurrentFloor(requestsQueue, currentFloor);
    LinkedList<int> requestsGoingDown = GetAllRequestsBelowCurrentFloor(requestsQueue, currentFloor);
    if (currentFloor == topFloor || requestsGoingUp.Count == 0)
    {
        isMovingUp = false;
    }
    else if (currentFloor == 1 || requestsGoingDown.Count == 0)
    {
        isMovingUp = true;
    }
    MoveElevator();
}

  private void OnButtonPushed(object sender, ElevatorControllerEventArgs e)
  {
      requestsQueue.AddLast(e.Floor);
      SetDirection();
  }

private void MoveElevator()
{
    while (requestsQueue.Count > 0)
    {
        if (requestsQueue.Contains(currentFloor))
        {
            requestsQueue.Remove(currentFloor);
            controller.Stop();
        }
        else if (isMovingUp)
        {
            currentFloor++;
            controller.MoveUp();
        }
        else
        {
            currentFloor--;
            controller.MoveDown();
        }

        SetDirection();
    }
}

private void SetDirection()
{
    LinkedList<int> requestsGoingUp = GetAllRequestsAboveCurrentFloor(requestsQueue, currentFloor);
    LinkedList<int> requestsGoingDown = GetAllRequestsBelowCurrentFloor(requestsQueue, currentFloor);
    if (currentFloor == topFloor || requestsGoingUp.Count == 0)
    {
        isMovingUp = false;
    }
    else if (currentFloor == 1 || requestsGoingDown.Count == 0)
    {
        isMovingUp = true;
    }
    MoveElevator();
}

Pobiega•2/4/24, 12:15 PM

You'll need to process all events until a delay/end of sequence before you start moving

Pobiega•2/4/24, 12:16 PM

In your example above 9 8 and 2 are all happening at the exact same time, right?

Pobiega•2/4/24, 12:17 PM

Ie, the elevator should know where it needs to stop before it starts moving. An ordered queue, of sorts

RomeOP•2/4/24, 6:08 PM

Yes the elevator knows when to stop. The events for 9,8,2 happen at the same time in theory but the controllers fires them sequentially. Unfortunately I cannot edit the controller.

Pobiega•2/4/24, 6:11 PM

what is "the controller"?

Pobiega•2/4/24, 6:12 PM

by your snippet, it seems you have all the control of it yourself in the method

RomeOP•2/4/24, 6:26 PM

The controller processes the events in order of the sequence order. Here is the part that's relevant to that process.
My example sequence above would look something like i9,o8,o2,d3,i7,i4,o3. I removed the i's and o's because they're not relevant to the order, however the d's are.

ProcessEvent() is called in proper order of the sequence i9,o8,o2,d3,i7,i4,o3.
The sequence is stored in a dictionary that'll look like { {0: [i9,o8,o2], 3: [i7,i4,o3] } } .
A for loop goes through the sequence, here's the part that does that.

Pobiega•2/4/24, 6:27 PM

great, and all this code is set in stone, just to clarify?

RomeOP•2/4/24, 6:27 PM

At index 0 it'll process 9,8,2
index 1 - nothing
index 2 - nothing
index 3 - it'll process 7,4,3

PPobiega great, and all this code is set in stone, just to clarify?

RomeOP•2/4/24, 6:28 PM

correct, yes

Pobiega•2/4/24, 6:28 PM

great

RomeOP•2/4/24, 6:29 PM

I was googling around and was thinking a delay could work or a ManualResetEvent but I was unsure as where to place it. It could be a valid solution as I have not ruled it out.

Pobiega•2/4/24, 6:30 PM

I'm not entirely following your logic in regards to the delay

RomeOP•2/4/24, 6:31 PM

Trust me, me neither LOL. My thought process was to delay before calling MoveElevator but I had no idea what I was doing so I scrapped the idea but it could work?

Pobiega•2/4/24, 6:31 PM

nah so the problem is that your MoveElevator blocks

Pobiega•2/4/24, 6:31 PM

once you call it, it starts moving until its request list is empty

Pobiega•2/4/24, 6:32 PM

with no chance of adding anything new to that list while its working

Pobiega•2/4/24, 6:32 PM

so when someone presses 9, it moves to 9 before seeing 8

Pobiega•2/4/24, 6:33 PM

considering your desired result of it stopping at 2 when is pressed at index 0, I'm leaning towards thinking the elevator only moves when the index increases...

RomeOP•2/4/24, 6:33 PM

yes and no. It starts moving to 9 but somewhere between 1 and 9 the event for 8 occurs and the queue is updated accordingly. It will stop at 8. The problem is that it should've stopped at 2 as well.

Pobiega•2/4/24, 6:34 PM

that makes no sense with

Pobiega•2/4/24, 6:34 PM

that loop will not stop until its reached its destination

RomeOP•2/4/24, 6:37 PM

Sure, I did not paste the in between steps where the queue is updated as I did not think the logic for that was important to the problem but I updated the original post.

Pobiega•2/4/24, 6:37 PM

is the button press events all the information you get from the controller?

Pobiega•2/4/24, 6:38 PM

im not entirely sure how your elevator is supposed to... "respect time" so to speak

Pobiega•2/4/24, 6:38 PM

meaning, how much is it allowed to move "per turn"? does calling advance the timer?

RomeOP•2/4/24, 6:39 PM

Pretty much, yes. The controller returns the destination floor when the event happens (e.g. 9 8 2). The methods to Stop, MoveUp, and MoveDown are also exposed but that doesn't affect the event order in any way.

Pobiega•2/4/24, 6:39 PM

ok so for the 9 8 2 d3 7 4 3 scenario...

Pobiega•2/4/24, 6:39 PM

when do we see the 7?

Pobiega•2/4/24, 6:41 PM

I'm sorta thinking 9 8 2 app happen in one "frame" of time, then the elevator moves to 2 and starts heading towards 8 before 3 "units of time" have expired (one per ? One on too?) and sees 7 before it reaches 8

Pobiega•2/4/24, 6:41 PM

so it heads to 7, 8 then 9 (because its moving up), then goes back down to 4 and 3

RomeOP•2/4/24, 6:41 PM

that's exactly how it's supposed to go

Pobiega•2/4/24, 6:42 PM

okay, then I think I've figured it out

RomeOP•2/4/24, 6:42 PM

each MoveUp, MoveDown, and Stop is 1 unit of time

Pobiega•2/4/24, 6:42 PM

perrrfect

Pobiega•2/4/24, 6:44 PM

The problem we need to solve is that any new button press must be able to stop the current move..

Pobiega•2/4/24, 6:44 PM

what kinda app is this? forms?

RomeOP•2/4/24, 6:44 PM

just a console app

Pobiega•2/4/24, 6:44 PM

okay

Pobiega•2/4/24, 6:52 PM

can you post the top level code that "runs" this entire thing?

Pobiega•2/4/24, 6:53 PM

I'm guessing it looks like

Pobiega•2/4/24, 6:53 PM

or something along those lines

Pobiega•2/4/24, 6:57 PM

in fact, can you paste all the code you currently have for this at $paste ?

PPobiega in fact, can you paste all the code you currently have for this at $paste ?

MODiX•2/4/24, 6:57 PM

If your code is too long, you can post to https://paste.mod.gg/ and copy the link into chat for others to see your shared code!

RomeOP•2/4/24, 6:59 PM

Oh that's perfect. I was getting annoyed by the character limit lol.
Here's what I have so far. The only part that's stopping me from meeting the requirements is processing each "block" of inputs together.
The logic file is the only thing that can be edited.
https://paste.mod.gg/lljkatnacblm/0

BlazeBin - lljkatnacblm

A tool for sharing your source code with the world!

RomeOP•2/4/24, 7:06 PM

I have to leave for a few hours. I'll try to think about the problem while I'm gone but if you do find the solution please don't give it to me right away. Maybe just give a hint to point me in the proper direction

... thanks for your help!

Pobiega•2/4/24, 7:06 PM

sure

Pobiega•2/4/24, 7:06 PM

I need to put the kids to bed, so I'll be a while too

Pobiega•2/4/24, 7:07 PM

if you do find the solution please don't give it to me right away

Love that attitude. Keep that shit up and you'll do great.

Pobiega•2/4/24, 8:07 PM

I've looked at it for a bit and I'm still unsure about what the expected end result should be... The time aspect is still confusing - since the button push event (or the controller) doesn't expose any time information, we can never tell the time (or even current floor, wtf) unless we track it ourselves.