import os

from celery import Celery
from kombu import Queue

from app.config import settings


def _env_flag(name: str, default: bool = False) -> bool:
    value = os.getenv(name)
    if value is None:
        return default
    return value.strip().lower() in {"1", "true", "yes", "on"}


def create_celery_app() -> Celery:
    app = Celery("wolai-backend")
    app.conf.broker_url = settings.redis_url
    app.conf.result_backend = settings.redis_url
    app.conf.task_default_queue = "wolai-index"
    app.conf.task_queues = (
        Queue("wolai-ocr", routing_key="tasks.ocr", max_priority=10),
        Queue("wolai-index", routing_key="tasks.index", max_priority=10),
    )
    app.conf.task_routes = {
        "app.workers.tasks.ocr_pipeline": {
            "queue": "wolai-ocr",
            "routing_key": "tasks.ocr",
            "priority": 0,
        },
        "app.workers.tasks.media_ocr_pipeline": {
            "queue": "wolai-ocr",
            "routing_key": "tasks.ocr",
            "priority": 1,
        },
        "app.workers.tasks.lightrag_index_pipeline": {
            "queue": "wolai-index",
            "routing_key": "tasks.index",
            "priority": 5,
        },
    }
    app.conf.broker_transport_options = {"priority_steps": list(range(10))}
    app.conf.worker_prefetch_multiplier = 1
    app.conf.task_acks_late = True
    app.conf.worker_concurrency = 3
    app.conf.task_always_eager = _env_flag("CELERY_TASK_ALWAYS_EAGER", False)
    app.conf.task_eager_propagates = _env_flag("CELERY_TASK_EAGER_PROPAGATES", True)
    app.autodiscover_tasks(["app.workers"])
    return app


celery_app = create_celery_app()
celery_app.set_default()