app/main.py

from fastapi import FastAPI, Request
from contextlib import asynccontextmanager
from fastapi.middleware.cors import CORSMiddleware
from app.routes import router as api_router
from app.model import load_model
from dotenv import load_dotenv
import os
import time
import logging

load_dotenv()

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

raw_repo_id = os.getenv("MODEL_REPO_ID", "")
# Default to a highly capable model that is natively supported and FREE on Hugging Face Serverless InferenceAPI
REPO_ID = raw_repo_id.strip() if raw_repo_id and raw_repo_id.strip() else "Qwen/Qwen3.5-0.8B"

@asynccontextmanager
async def lifespan(app: FastAPI):
    print("\n" + "="*60, flush=True)
    print(f"🚀 INITIALIZING CHAT API: Setup remote LLM ({REPO_ID})", flush=True)
    print("="*60 + "\n", flush=True)
    
    # Store the LLM in the application state so routes can access it
    app.state.llm = load_model(repo_id=REPO_ID)    
    
    print("\n✅ API is LIVE on port 7860! Ready for requests.\n", flush=True)
    yield
    print("\n" + "="*60, flush=True)
    print("👋 Shutting down API. Goodbye!", flush=True)

app = FastAPI(
    title="Multimodal Chat API",
    description="Production-ready Chat API powered by LangChain and HuggingFaceEndpoint.",
    version="1.0.0",
    lifespan=lifespan,
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=os.getenv("CORS_ORIGINS", "*").split(","),
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

@app.middleware("http")
async def request_logging_middleware(request: Request, call_next):
    start = time.time()
    response = await call_next(request)
    duration_ms = (time.time() - start) * 1000
    if request.url.path != "/api/health":
        logger.info(
            f"{request.method} {request.url.path} "
            f"→ {response.status_code} [{duration_ms:.1f}ms]"
        )
    return response

app.include_router(api_router, prefix="/api")

@app.get("/", include_in_schema=False)
async def root():
    return {
        "message": "Welcome to the API!",
        "docs_url": "/docs",
        "endpoints": {
            "health": "/api/health",
            "chat": "/api/chat"
        }
    }

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        "app.main:app",
        host="0.0.0.0",
        port=7860,
        workers=1,
        log_level="info",
    )