"""Tool middleware — pre/post execute hooks.

Middleware runs around every tool call. Useful for logging, metrics,
rate limiting, and authorization without modifying individual tools.
"""

from abc import ABC, abstractmethod
from typing import Awaitable, Callable

from .base import ToolResult

MiddlewareFunc = Callable[[str, dict], Awaitable[None]]
PostExecuteFunc = Callable[[str, dict, ToolResult], Awaitable[None]]


class ToolMiddleware(ABC):
    """Base class for tool middleware.

    Subclasses override `before_execute` and/or `after_execute`.
    """

    async def before_execute(self, tool_name: str, params: dict) -> None:
        """Called before the tool executes."""
        pass

    async def after_execute(self, tool_name: str, params: dict, result: ToolResult) -> None:
        """Called after the tool executes."""
        pass


class MiddlewareChain:
    """Chains multiple middleware instances around a tool execution."""

    def __init__(self, middlewares: list[ToolMiddleware]) -> None:
        self._middlewares = middlewares

    async def run(self, tool_name: str, params: dict, execute: Callable[[], Awaitable[ToolResult]]) -> ToolResult:
        for mw in self._middlewares:
            await mw.before_execute(tool_name, params)
        try:
            result = await execute()
        finally:
            # We don't have result on exception, but we can still call after_execute
            # with a synthetic failure result if needed. For now, call only on success.
            pass
        for mw in self._middlewares:
            await mw.after_execute(tool_name, params, result)
        return result
