import os

from fastapi import FastAPI

try:
    # For module mode: `uvicorn app.main:app`
    from app.db import check_db_connection, close_db_engine
    from app.routers.health import router as health_router
    from app.routers.messages import router as messages_router
    from app.settings import settings
except ModuleNotFoundError:
    # For script mode: `python app/main.py` or VS Code "Run Python File"
    from db import check_db_connection, close_db_engine
    from routers.health import router as health_router
    from routers.messages import router as messages_router
    from settings import settings


def create_app() -> FastAPI:
    app = FastAPI(
        title=settings.app_name,
        version=settings.app_version,
        description=settings.app_description,
    )

    @app.on_event("startup")
    def on_startup() -> None:
        check_db_connection()

    @app.on_event("shutdown")
    def on_shutdown() -> None:
        close_db_engine()

    app.include_router(health_router)
    app.include_router(messages_router)
    return app


app = create_app()


if __name__ == "__main__":
    import uvicorn

    uvicorn.run(
        app,
        host=os.getenv("HOST", settings.host),
        port=int(os.getenv("PORT", str(settings.port))),
    )