import asyncio
import functools
from typing import Any, Callable

from pydantic import BaseModel

from .. import CancellationToken
from .._function_utils import (
    args_base_model_from_signature,
    get_typed_signature,
)
from ._base import BaseTool


class FunctionTool(BaseTool[BaseModel, BaseModel]):
    """
    Create custom tools by wrapping standard Python functions.

    `FunctionTool` offers an interface for executing Python functions either asynchronously or synchronously.
    Each function must include type annotations for all parameters and its return type. These annotations
    enable `FunctionTool` to generate a schema necessary for input validation, serialization, and for informing
    the LLM about expected parameters. When the LLM prepares a function call, it leverages this schema to
    generate arguments that align with the function's specifications.

    .. note::

        It is the user's responsibility to verify that the tool's output type matches the expected type.

    Args:
        func (Callable[..., ReturnT | Awaitable[ReturnT]]): The function to wrap and expose as a tool.
        description (str): A description to inform the model of the function's purpose, specifying what
            it does and the context in which it should be called.
        name (str, optional): An optional custom name for the tool. Defaults to
            the function's original name if not provided.

    Example:

        .. code-block:: python

            import random
            from autogen_core import CancellationToken
            from autogen_core.tools import FunctionTool
            from typing_extensions import Annotated
            import asyncio


            async def get_stock_price(ticker: str, date: Annotated[str, "Date in YYYY/MM/DD"]) -> float:
                # Simulates a stock price retrieval by returning a random float within a specified range.
                return random.uniform(10, 200)


            async def example():
                # Initialize a FunctionTool instance for retrieving stock prices.
                stock_price_tool = FunctionTool(get_stock_price, description="Fetch the stock price for a given ticker.")

                # Execute the tool with cancellation support.
                cancellation_token = CancellationToken()
                result = await stock_price_tool.run_json({"ticker": "AAPL", "date": "2021/01/01"}, cancellation_token)

                # Output the result as a formatted string.
                print(stock_price_tool.return_value_as_string(result))


            asyncio.run(example())
    """

    def __init__(self, func: Callable[..., Any], description: str, name: str | None = None) -> None:
        self._func = func
        signature = get_typed_signature(func)
        func_name = name or func.__name__
        args_model = args_base_model_from_signature(func_name + "args", signature)
        return_type = signature.return_annotation
        self._has_cancellation_support = "cancellation_token" in signature.parameters

        super().__init__(args_model, return_type, func_name, description)

    async def run(self, args: BaseModel, cancellation_token: CancellationToken) -> Any:
        if asyncio.iscoroutinefunction(self._func):
            if self._has_cancellation_support:
                result = await self._func(**args.model_dump(), cancellation_token=cancellation_token)
            else:
                result = await self._func(**args.model_dump())
        else:
            if self._has_cancellation_support:
                result = await asyncio.get_event_loop().run_in_executor(
                    None,
                    functools.partial(
                        self._func,
                        **args.model_dump(),
                        cancellation_token=cancellation_token,
                    ),
                )
            else:
                future = asyncio.get_event_loop().run_in_executor(
                    None, functools.partial(self._func, **args.model_dump())
                )
                cancellation_token.link_future(future)
                result = await future

        return result
