import sys
from typing import Any


class BaseCallbackHandler:
    """Class to handle callbacks for openai function agent"""

    def on_llm_start(self, **kwargs: Any) -> None:
        """Run when LLM starts running."""

    def on_llm_new_token(self, token: str, **kwargs: Any) -> None:
        """Run on new LLM token. Only available when streaming is enabled."""

    def on_llm_end(self, response: str, **kwargs: Any) -> None:
        """Run when LLM ends running."""


class PrintingCallBackHandler(BaseCallbackHandler):
    """Callback handler to call print function"""

    def on_llm_start(self, **kwargs: Any) -> None:
        """Run when LLM starts running."""

    def on_llm_new_token(self, token: str, **kwargs: Any) -> None:
        """Run on new LLM token. Only available when streaming is enabled."""
        print(token)

    def on_llm_end(self, response: str, **kwargs: Any) -> None:
        """Run when LLM ends running."""


class StreamingStdOutCallBackHandler(BaseCallbackHandler):
    """Callback handler to call print function"""

    def on_llm_start(self, **kwargs: Any) -> None:
        """Run when LLM starts running."""

    def on_llm_new_token(self, token: str, **kwargs: Any) -> None:
        """Run on new LLM token. Only available when streaming is enabled."""
        sys.stdout.write(token)
        sys.stdout.flush()

    def on_llm_end(self, response: str, **kwargs: Any) -> None:
        """Run when LLM ends running."""

class QueueCallback(BaseCallbackHandler):
    """Callback handler for streaming LLM responses to a queue."""

    def __init__(self, q):
        self.q = q

    def on_llm_new_token(self, token: str, **kwargs: any) -> None:
        self.q.put(token)

    def on_llm_end(self, *args, **kwargs: any) -> None:
        return self.q.empty()