"""
FastAPI application factory with lifespan management.
"""
from contextlib import asynccontextmanager

import structlog
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from redis.asyncio import Redis, from_url

from app.config import get_settings
from app.core.middleware import CSRFMiddleware, SecurityHeadersMiddleware
from app.db.base import create_engine, create_session_factory
from app.dependencies import set_redis_client, set_session_factory

logger = structlog.get_logger()


@asynccontextmanager
async def lifespan(app: FastAPI):
    settings = get_settings()

    # Database
    engine = create_engine()
    session_factory = create_session_factory(engine)
    set_session_factory(session_factory)

    # Redis
    redis: Redis = from_url(settings.redis_url, decode_responses=False)
    set_redis_client(redis)

    # Seed system categories if needed
    from app.services.category_service import seed_system_categories
    async with session_factory() as db:
        await seed_system_categories(db)
        await db.commit()

    # Background scheduler
    from app.workers.scheduler import start_scheduler, stop_scheduler
    await start_scheduler()

    logger.info("startup_complete", env=settings.environment)
    yield

    await stop_scheduler()
    await redis.aclose()
    await engine.dispose()
    logger.info("shutdown_complete")


def create_app() -> FastAPI:
    settings = get_settings()

    app = FastAPI(
        title="Finance Tracker",
        version="0.1.0",
        docs_url="/docs" if settings.is_development else None,
        redoc_url="/redoc" if settings.is_development else None,
        openapi_url="/openapi.json" if settings.is_development else None,
        lifespan=lifespan,
    )

    # CORS — only allow same origin in production
    origins = ["http://localhost:5173"] if settings.is_development else []
    app.add_middleware(
        CORSMiddleware,
        allow_origins=origins,
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )

    app.add_middleware(SecurityHeadersMiddleware)
    app.add_middleware(CSRFMiddleware)

    # Health check (no auth required)
    @app.get("/health")
    async def health():
        return {"status": "ok"}

    # API routers
    from app.api.router import router
    app.include_router(router, prefix="/api/v1")

    return app


app = create_app()