from typing import Any, AsyncGenerator
from agents import Agent, Runner
from agents import RunHooks, ModelResponse
from openai.types.responses import ResponseTextDeltaEvent

class MyRunHooks(RunHooks):
    """RunHooks for logging the lifecycle of an agent."""
    async def on_agent_start(self, context, agent) -> None:
        print(f"\n 🐾[RunHooks] {agent.name} started.\n")

    async def on_agent_end(self, context, agent, output: Any) -> None:
        print(f"\n 🚪[RunHooks] {agent.name} ended.\n")

async def stream_response(agent: Agent, prompt: str) -> AsyncGenerator[str, None]:
    """Stream agent response and update the UI."""
    try:
        result = Runner.run_streamed(agent, input=prompt, hooks=MyRunHooks())
        async for event in result.stream_events():
            if event.type == "raw_response_event" and isinstance(event.data, ResponseTextDeltaEvent):
                yield event.data.delta # <-- sends the next piece of response text

    except Exception as e:
        yield f"⚠️🖨️ Error: {e}"