The problem is there is zero strategy to this in some stages. Or, rather, there is a strategy, but the optimal strategy for *both* sides is defensive and let the other side attack. So you can sit there forever waiting for the computer player to make a stupid move.
Obviously since you're versing a computer player, they can just retreat or remain as they are every single turn.
Even baiting the computer player doesn't work as you can put someone weak near their guys hoping they'll give chase and often they don't, or they'll decide to retreat.
So the problem is you have here a strategy game which has no winning strategy and no means to force the game to progress in the case of these endless stalemates. Maybe if after x amount of turns no side has won, give the win to the player, to force the computer to actually do something other than just retreat and hold.