"""
backend/workers/celeryconfig.py

Creates and configures the Celery app for the project.

Usage (development):
    # start a worker:
    celery -A backend.workers.celeryconfig worker --loglevel=info

    # start beat:
    celery -A backend.workers.celeryconfig beat --loglevel=info

Notes:
 - Requires CELERY_BROKER_URL (no default broker is assumed)
 - Tasks autodiscover from 'backend.workers' package
 - This file also loads schedule from scheduler.py (SCHEDULE mapping)
"""

import os
from celery import Celery
from celery.schedules import crontab
import logging

# Basic logging
logging.basicConfig(level=os.getenv("LOG_LEVEL", "INFO"))
logger = logging.getLogger("celeryconfig")

BROKER_URL = os.getenv("CELERY_BROKER_URL")
if not BROKER_URL:
    raise RuntimeError(
        "CELERY_BROKER_URL is not set. Configure a broker such as amqp://, redis://, or sqs:// before starting workers."
    )

RESULT_BACKEND = os.getenv("CELERY_RESULT_BACKEND", BROKER_URL)
if not RESULT_BACKEND:
    raise RuntimeError(
        "CELERY_RESULT_BACKEND is not set. Provide a backend URL or reuse CELERY_BROKER_URL."
    )

celery_app = Celery(
    "integrachat_workers",
    broker=BROKER_URL,
    backend=RESULT_BACKEND,
)

# Recommended worker options
celery_app.conf.update(
    task_serializer="json",
    result_serializer="json",
    accept_content=["json"],
    task_acks_late=True,
    worker_prefetch_multiplier=1,
    worker_max_tasks_per_child=100,
    broker_pool_limit=10,
    timezone="UTC",
    enable_utc=True,
)

# Auto-discover tasks in the workers package
celery_app.autodiscover_tasks(["backend.workers"])

# Load schedule from scheduler.SCHEDULE and convert crontab-like entries
try:
    from backend.workers.scheduler import SCHEDULE as CUSTOM_SCHEDULE
    beat_schedule = {}
    for name, cfg in CUSTOM_SCHEDULE.items():
        task_name = cfg["task"]
        schedule_cfg = cfg["schedule"]
        args = cfg.get("args", ())
        # Determine schedule type
        if isinstance(schedule_cfg, dict) and schedule_cfg.get("type") == "crontab":
            hour = schedule_cfg.get("hour", 0)
            minute = schedule_cfg.get("minute", 0)
            beat_schedule[name] = {"task": task_name, "schedule": crontab(minute=minute, hour=hour), "args": args}
        else:
            # fallback: expect a timedelta or seconds (for quick dev)
            beat_schedule[name] = {"task": task_name, "schedule": schedule_cfg, "args": args}
    celery_app.conf.beat_schedule = beat_schedule
    logger.info("Loaded Celery beat schedule with %d jobs", len(beat_schedule))
except Exception as e:
    logger.exception("Failed to load scheduler.SCHEDULE: %s", e)

# Export celery_app symbol for import by tasks
__all__ = ["celery_app"]