"""FastAPI application factory."""

from __future__ import annotations

import logging
from contextlib import asynccontextmanager

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

from app import db as dbmod
from app.config import get_settings
from app.routes import admin, chat, health, widget

log = logging.getLogger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    settings = get_settings()
    if not dbmod.is_initialized():
        dbmod.init_engine(settings.database_url)

    if not settings.testing:
        # Dev convenience for sqlite; Postgres uses Alembic migrations.
        if dbmod.get_engine().dialect.name == "sqlite":
            await dbmod.create_all()
        # Warm the embedding model so the first chat isn't slow.
        try:
            from app.embeddings import embed_query

            await embed_query("warmup")
        except Exception:  # noqa: BLE001 - warmup is best-effort
            log.warning("embedding warmup failed", exc_info=True)
        # Ensure a 'default' tenant exists + GDPR retention sweep at boot.
        try:
            from app.retention import purge_old_sessions
            from app.tenancy import ensure_default_tenant

            async with dbmod.get_sessionmaker()() as session:
                await ensure_default_tenant(session)
                await purge_old_sessions(session, settings.session_retention_days)
                await session.commit()
        except Exception:  # noqa: BLE001 - best-effort
            log.warning("startup sweep failed", exc_info=True)
    yield


def create_app() -> FastAPI:
    settings = get_settings()
    if not dbmod.is_initialized():
        dbmod.init_engine(settings.database_url)

    if not settings.testing and not settings.admin_token:
        log.warning("ADMIN_TOKEN is empty — the admin panel/API will reject all requests")

    app = FastAPI(title="Shopify Support Bot", version="0.1.0", lifespan=lifespan)
    app.add_middleware(
        CORSMiddleware,
        allow_origins=settings.allowed_origins,
        allow_credentials=False,
        allow_methods=["*"],
        allow_headers=["*"],
    )
    app.include_router(health.router)
    app.include_router(widget.router)
    app.include_router(chat.router)
    app.include_router(admin.router)
    return app


app = create_app()