try:
    from langgraph.checkpoint.base import BaseCheckpointSaver
except ImportError:
    # Creating a dummy base class if langgraph is not installed
    # so code can still be imported/inspected without crashing
    class BaseCheckpointSaver:
        pass

class ArkNativeCheckpointer(BaseCheckpointSaver):
    """
    KAIROS-ARK Native Checkpointer for LangGraph.
    
    Replaces Python dict persistence with ARK's high-performance
    Zero-Copy State Store.
    """
    def __init__(self, agent_instance):
        super().__init__()
        self.kernel = agent_instance.kernel

    def put(self, config, checkpoint, metadata, new_releases):
        """Store state in ARK kernel."""
        thread_id = config["configurable"]["thread_id"]
        # Serialize checkpoint using ARK's state store
        # This uses the Rust backend (~4us latency) instead of disk/DB
        import json
        
        # In a real scenario, we might optimize serialization further
        payload = json.dumps(checkpoint)
        
        # Use Phase 5 state_set binding
        self.kernel.state_set(f"thread:{thread_id}", payload)
        
        # Create durable checkpoint
        self.kernel.state_checkpoint(f"chk:{thread_id}:{checkpoint['v']}")
        
        return config

    def get_tuple(self, config):
        """Retrieve state from ARK kernel."""
        thread_id = config["configurable"]["thread_id"]
        import json
        
        # Use Phase 5 state_get binding
        payload = self.kernel.state_get(f"thread:{thread_id}")
        
        if payload:
            state = json.loads(payload)
            # Metadata implies retrieving the specific version if needed
            # For this MVP adapter, we just return the latest state
            return state
        return None
