# agents/core-logic/app.py
# OSVauco-NMTMD-GCOS — FastAPI HTTP entrypoint for Cloud Run
# Wraps the ADK root_agent with a /run endpoint and a /health check.
# Usage: uvicorn app:app --host 0.0.0.0 --port 8080

import os
import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI, HTTPException
from fastapi.responses import JSONResponse
from pydantic import BaseModel

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# ── ADK imports ───────────────────────────────────────────────
try:
    from google.adk.runners import Runner
    from google.adk.sessions import InMemorySessionService
    from google.genai.types import Content, Part
    from agent import root_agent
except ImportError as e:
    logger.error(f"Failed to import ADK dependencies: {e}")
    raise

# ── Session service (in-memory for stateless Cloud Run) ───────────────
session_service = InMemorySessionService()

APP_NAME = os.environ.get("CLOUD_RUN_SERVICE", "gcp-orchestrator")


# ── Lifespan ───────────────────────────────────────────────────
@asynccontextmanager
async def lifespan(app: FastAPI):
    logger.info(f"OSVauco agent '{APP_NAME}' starting up")
    yield
    logger.info(f"OSVauco agent '{APP_NAME}' shutting down")


# ── App ────────────────────────────────────────────────────────
app = FastAPI(
    title="OSVauco GCP Agent",
    description="ADK-based multi-agent orchestrator on Cloud Run",
    version="1.0.0",
    lifespan=lifespan,
)


# ── Models ─────────────────────────────────────────────────────
class RunRequest(BaseModel):
    user_id: str
    session_id: str
    message: str


class RunResponse(BaseModel):
    user_id: str
    session_id: str
    response: str


# ── Routes ─────────────────────────────────────────────────────
@app.get("/health")
async def health():
    """Cloud Run health check endpoint."""
    return JSONResponse({"status": "ok", "service": APP_NAME})


@app.post("/run", response_model=RunResponse)
async def run(req: RunRequest):
    """
    Run the OSVauco ADK agent for a single turn.
    Creates (or reuses) a session, sends the user message,
    and returns the final agent response.
    """
    try:
        # Create or reuse session
        try:
            session = await session_service.get_session(
                app_name=APP_NAME,
                user_id=req.user_id,
                session_id=req.session_id,
            )
        except Exception:
            session = await session_service.create_session(
                app_name=APP_NAME,
                user_id=req.user_id,
                session_id=req.session_id,
            )

        runner = Runner(
            agent=root_agent,
            app_name=APP_NAME,
            session_service=session_service,
        )

        user_content = Content(
            role="user",
            parts=[Part(text=req.message)],
        )

        final_response = ""
        async for event in runner.run_async(
            user_id=req.user_id,
            session_id=req.session_id,
            new_message=user_content,
        ):
            if event.is_final_response() and event.content:
                for part in event.content.parts:
                    if part.text:
                        final_response += part.text

        logger.info(
            f"[{req.user_id}/{req.session_id}] Agent response length: {len(final_response)}"
        )
        return RunResponse(
            user_id=req.user_id,
            session_id=req.session_id,
            response=final_response,
        )

    except Exception as e:
        logger.error(f"Agent run failed: {e}", exc_info=True)
        raise HTTPException(status_code=500, detail=str(e))