from abc import ABC, abstractmethod
from typing import Optional, Any
from app.context import FlowContext


class NodeExecutor(ABC):
    """Base class for all node executors"""

    @abstractmethod
    async def execute(
        self,
        config: dict,
        context: FlowContext,
        session: Any
    ) -> Optional[str]:
        """
        Execute the node logic.
        Returns: branch name for routing (e.g., "default", "true", "false")
                 or "wait" to pause execution
        """
        pass


class NodeRegistry:
    """Registry of all available node executors"""
    _executors: dict = {}

    @classmethod
    def register(cls, node_type: str, executor: NodeExecutor):
        cls._executors[node_type] = executor

    @classmethod
    def get(cls, node_type: str) -> Optional[NodeExecutor]:
        return cls._executors.get(node_type)