arbret/backend/main.py

"""FastAPI application entry point."""

import asyncio
import logging
from contextlib import asynccontextmanager

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

from database import Base, async_session, engine
from models import PriceHistory
from price_fetcher import PAIR_BTC_EUR, SOURCE_BITFINEX, fetch_btc_eur_price
from routes import audit as audit_routes
from routes import auth as auth_routes
from routes import availability as availability_routes
from routes import exchange as exchange_routes
from routes import invites as invites_routes
from routes import meta as meta_routes
from routes import profile as profile_routes
from shared_constants import PRICE_REFRESH_SECONDS
from validate_constants import validate_shared_constants

logger = logging.getLogger(__name__)

# Background task handle
_price_fetch_task: asyncio.Task | None = None


async def periodic_price_fetcher():
    """Background task that fetches BTC/EUR price every minute."""
    logger.info(
        "Starting periodic price fetcher (every %d seconds)", PRICE_REFRESH_SECONDS
    )
    while True:
        try:
            price_value, timestamp = await fetch_btc_eur_price()
            async with async_session() as db:
                new_price = PriceHistory(
                    source=SOURCE_BITFINEX,
                    pair=PAIR_BTC_EUR,
                    price=price_value,
                    timestamp=timestamp,
                )
                db.add(new_price)
                await db.commit()
            logger.info("Fetched BTC/EUR price: €%.2f", price_value)
        except Exception as e:
            logger.error("Failed to fetch price: %s", e)

        await asyncio.sleep(PRICE_REFRESH_SECONDS)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Create database tables on startup and validate constants."""
    global _price_fetch_task

    # Validate shared constants match backend definitions
    validate_shared_constants()

    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)

    # Start background price fetcher
    _price_fetch_task = asyncio.create_task(periodic_price_fetcher())

    yield

    # Cancel background task on shutdown
    if _price_fetch_task:
        _price_fetch_task.cancel()
        try:
            await _price_fetch_task
        except asyncio.CancelledError:
            logger.info("Price fetcher task cancelled")


app = FastAPI(lifespan=lifespan)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["http://localhost:3000"],
    allow_methods=["*"],
    allow_headers=["*"],
    allow_credentials=True,
)

# Include routers - modules with single router
app.include_router(auth_routes.router)
app.include_router(audit_routes.router)
app.include_router(profile_routes.router)
app.include_router(availability_routes.router)
app.include_router(meta_routes.router)

# Include routers - modules with multiple routers
for r in invites_routes.routers:
    app.include_router(r)
for r in exchange_routes.routers:
    app.include_router(r)