backend/api/main.py

"""FastAPI main application module for AI Survey Simulator.

This module initializes the FastAPI application and configures:
- CORS middleware for frontend communication
- WebSocket endpoints for real-time conversation streaming
- REST API routes for conversation and persona management
- Database connections and session management
- Global exception handlers and logging

Typical usage:
    uvicorn api.main:app --reload --host 0.0.0.0 --port 8000
"""

import logging
import sys
from pathlib import Path

from fastapi import FastAPI, WebSocket
from fastapi.middleware.cors import CORSMiddleware
import uvicorn

# Ensure project root is available for shared config imports
ROOT_DIR = Path(__file__).resolve().parents[2]
if str(ROOT_DIR) not in sys.path:
    sys.path.insert(0, str(ROOT_DIR))

from config.settings import get_settings  # noqa: E402

# Import WebSocket endpoint and manager
from .conversation_ws import websocket_endpoint, manager  # noqa: E402
from .routes import router as conversations_router  # noqa: E402
from .conversation_service import initialize_conversation_service  # noqa: E402

# Load application settings
settings = get_settings()

# Setup logging using configured level
log_level = getattr(logging, settings.log_level.upper(), logging.INFO)
logging.basicConfig(level=log_level)
logger = logging.getLogger(__name__)

# Initialize FastAPI app
app = FastAPI(
    title="AI Survey Simulator API",
    description="Backend API for AI-to-AI healthcare survey conversations",
    version="1.0.0"
)

# Configure CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=[
        "http://localhost:7860",  # Gradio default port
        "http://127.0.0.1:7860",  # Gradio alternative
    ],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Include API routes
app.include_router(conversations_router)


@app.on_event("startup")
async def startup_event():
    """Initialize services on startup."""
    logger.info("Initializing AI Survey Simulator API...")

    # Initialize conversation service with WebSocket manager and settings
    initialize_conversation_service(manager, settings)

    logger.info("API startup complete")


@app.get("/")
async def root():
    """Root endpoint providing API information."""
    return {
        "message": "AI Survey Simulator API",
        "version": "1.0.0",
        "docs": "/docs",
        "health": "/health"
    }


@app.get("/health")
async def health_check():
    """Health check endpoint for monitoring."""
    return {"status": "healthy"}


@app.websocket("/ws/conversation/{conversation_id}")
async def websocket_conversation_endpoint(websocket: WebSocket, conversation_id: str):
    """WebSocket endpoint for real-time conversation streaming.
    
    Args:
        websocket: WebSocket connection
        conversation_id: Unique identifier for the conversation
    """
    await websocket_endpoint(websocket, conversation_id)


if __name__ == "__main__":
    uvicorn.run(app, host=settings.api.host, port=settings.api.port)