Add Undo/Redo Functionality

[MarquisMc]

Description

Implement an undo/redo feature to allow users to revert or reapply changes made to the state machine. This will enhance the usability and flexibility of the tool, allowing game designers to experiment without fear of making irreversible changes.

Suggested Solution

1. State History Management:

   • Maintain a history stack to keep track of state changes.
   • Each change to the state machine (e.g., adding, deleting, or modifying states and transitions) should be recorded as a snapshot in the history stack.

2. Undo Functionality:

   • Implement an undo function that reverts the state machine to the previous snapshot in the history stack.
   • Pop the last snapshot from the history stack and apply it to the state machine.

3. Redo Functionality:

   • Maintain a separate redo stack to store snapshots that have been undone.
   • Implement a redo function that reapplies the last undone snapshot from the redo stack.
   • Pop the last snapshot from the redo stack and apply it to the state machine.

4. UI Integration:

   • Add "Undo" and "Redo" buttons to the UI to allow users to easily trigger these functions.
   • Ensure the buttons are enabled/disabled based on the availability of actions to undo/redo.

5. Edge Cases:

   • Handle edge cases such as multiple rapid changes, ensuring the history stack does not grow indefinitely (e.g., by limiting its size).

Example Implementation

using System.Collections.Generic;

public class StateMachine
{
    private Stack<State> history = new Stack<State>();
    private Stack<State> redoStack = new Stack<State>();
    private State currentState;

    public StateMachine()
    {
        currentState = GetInitialState();
    }

    public void ExecuteChange(State newState)
    {
        history.Push(currentState);
        currentState = newState;
        redoStack.Clear(); // Clear redo stack on new change
    }

    public void Undo()
    {
        if (history.Count > 0)
        {
            redoStack.Push(currentState);
            currentState = history.Pop();
        }
    }

    public void Redo()
    {
        if (redoStack.Count > 0)
        {
            history.Push(currentState);
            currentState = redoStack.Pop();
        }
    }

    private State GetInitialState()
    {
        // Implementation of getting the initial state
        return new State();
    }
}

public class State
{
    // Implementation of the State class
}

Tasks

• Implement state history management.
• Develop undo and redo functions.
• Integrate undo/redo functionality with the UI.
• Test the functionality thoroughly to handle various edge cases.

References

• State Pattern
• Command Pattern