Undo Move mechanic [bounty: 222 XTR]

[DreadKnight]

As of #2701 brainstorm, there should be a feature to undo the very last action, called "Undo Move", which will replace the "Delay Turn" icon as soon as something happens if available, as they're mutually exclusive. This is usable only once per match round, at any point given, basically turning back time until before last action that was made. Ctrl+Z hotkeys to be used for it.

Icon for the action:
https://game-icons.net/1x1/delapouite/backward-time.html
Standard icon style: no background, white foreground, 4px black stroke.

[oleksandr-shvets]

@DreadKnight can I work on it?
Based on the initial plan:

1. Core Logic (Game State Management):

• File: src/game.ts
• Changes:
  • Add properties to the Game class to store the previous game state (previousGameState: any) and a flag to indicate if an undo is available (undoAvailable: boolean = false).
  • Implement a storeGameState() method to create a deep copy of the current game state and store it in previousGameState. This method should also set undoAvailable to true.
  • Implement a restoreGameState() method to revert the game state to the stored previousGameState. This method should also set undoAvailable to false.

2. Action Handling:

• Files: This will involve changes in the files where creature movement and actions are handled, likely within the src/abilities/ directory.
• Changes:
  • Modify the action handling functions to call storeGameState() before executing any action that modifies the game state.
  • After a successful action, ensure the UI is updated to reflect the availability of the "Undo Move" action.

3. UI Integration:

• Files: src/ui/interface.ts and potentially the HTML template.
• Changes:
  • Add the "Undo Move" icon to the UI, replacing the "Delay Turn" icon when undoAvailable is true.
  • Implement the logic to handle clicks on the "Undo Move" icon, triggering the restoreGameState() method.
  • Add the Ctrl + Z hotkey binding to also trigger the restoreGameState() method.

4. Testing:

• Files: Potentially create a new test file or modify existing ones in src/__tests__ to test the undo functionality.

In essence, the changes involve:

• Adding the ability to save and restore the game state.
• Integrating an "Undo Move" button into the UI.
• Wiring up the button and hotkey to the restore functionality.
• Adding tests to ensure the functionality works as expected.

[DreadKnight]

@oleksandr-shvets Although this was planned for way later, seems that you know well what you want to do about it.
Note that the UI change for icon could be done using fading perhaps to be a little less distracting and tedious, hmm...
What I mean by that is when doing the transition from Delay action into the "Undo Move" move one. Assigned you to it.

[DreadKnight]

@oleksandr-shvets I think your hotkey proposal (Ctrl+Z) is way better than the suggested one (U) as it's more standard usage, easier to remember overall (especially when considering localizations and way harder to trigger by accident 👍🏻

[DreadKnight]

@oleksandr-shvets Hey, any progress on this one? 🐻
We're pretty close to wrapping up v0.5 in the near future.