Allow saving of "AI Play" games

[drewhannay]

Users are currently unable to save games being played against an AI plugin. One possible complication to adding this feature is this use case:

• User plays a game with AI plugin "MyAI"
• User saves their game and quits the app
• User removes the "MyAI" plugin
• User tries to resume their saved game and the plugin is missing

The app should able to handle this situation gracefully.

[AlisaMaas]

I don't believe removing the plugin should be a problem, as long as we can save the list of moves both the AI player makes and the human player makes, rather than trying to use the AI to recompute the moves it makes.

[drewhannay]

I mean save as in save before completing the game and resume it later, in which case removing the AI plugin WOULD be an issue. I believe we already have the ability to save records of completed AI games.

[AlisaMaas]

I see. So we need to actually check that the plugin exists before we can resume their game, otherwise we have to tell them that the AI plugin wasn't found. Do you think one way of handling this would be to allow them to select a different AI to continue the saved game?

[drewhannay]

That's a possibility. Would that be weird though, from a user's perspective?

[AlisaMaas]

I'm not sure. Maybe it wouldn't be if it were only one of two options, so something like, "The AI plugin used to start this game is missing. Do you want to quit, or select another AI to finish the game?"

I'm pretty sure I've seen chess programs that allow you to adjust the difficulty of the AI you play against in midgame. Admittedly, that's usually hidden away in the options menu somewhere, so it's not as obvious as this would need to be, but on the other hand this is a pretty unlikely circumstance. I think it's going to be fairly unusual that a user will start deleting files, but it's always a possibility so it's good to plan for.