# backend/core/celery.py

import os
import gc
import logging
from celery import Celery
from celery import Task

logger = logging.getLogger(__name__)

# Postavi Django settings modul
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'core.settings')

app = Celery('core')

# Koristi konfiguraciju iz settings.py s prefiksom 'CELERY_'
app.config_from_object('django.conf:settings', namespace='CELERY')


def _rss_memory_mb():
    try:
        import resource

        usage_kb = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
        # Na Linuxu je ru_maxrss u KiB.
        return round(float(usage_kb) / 1024.0, 2)
    except (ImportError, AttributeError, OSError, ValueError):
        return None


class MemoryAwareTask(Task):
    abstract = True

    def __call__(self, *args, **kwargs):
        gc.collect()
        return super().__call__(*args, **kwargs)

    def after_return(self, status, retval, task_id, args, kwargs, einfo):
        memory_before_gc = _rss_memory_mb()
        gc.collect()
        memory_after_gc = _rss_memory_mb()
        if memory_before_gc is not None and memory_after_gc is not None:
            logger.info(
                "Task %s (%s) status=%s RSS prije/poslije GC: %.2fMB -> %.2fMB",
                self.name,
                task_id,
                status,
                memory_before_gc,
                memory_after_gc,
            )
        return super().after_return(status, retval, task_id, args, kwargs, einfo)


app.Task = MemoryAwareTask

# Automatski pronalazi taskove u svim 'modules.*'
app.autodiscover_tasks()