Battleship Game Engine

Design a two-player grid battleship engine. Ships occupy straight contiguous cells, cannot overlap and remain hidden from the opponent. Repeated shots are invalid and must not consume a turn.

• Validate complete nonoverlapping fleets before play starts.
• Enforce actor, phase and coordinate rules.
• Track unique shots, hits, sunk ships and terminal victory.
• Return player-scoped views without leaking hidden ship positions.