"""FastAPI application factory."""

from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

from customer_intelligence.api.dependencies import _load_churn_model, _load_segmentation_model
from customer_intelligence.api.routers import customers, health, predictions


@asynccontextmanager
async def lifespan(app: FastAPI):
    # Pre-load models at startup so first request is fast
    try:
        _load_churn_model()
        _load_segmentation_model()
        print("Models loaded from MLflow registry.")
    except Exception as e:
        print(f"WARNING: Could not pre-load models: {e}")
    yield


app = FastAPI(
    title="Customer Intelligence API",
    description="Churn prediction and customer segmentation for Olist e-commerce data",
    version="1.0.0",
    lifespan=lifespan,
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)

app.include_router(health.router)
app.include_router(customers.router)
app.include_router(predictions.router)


@app.get("/")
def root():
    return {
        "name": "Customer Intelligence API",
        "docs": "/docs",
        "health": "/health",
    }