from celery import Celery
from flask import current_app
import os
import logging

# Configure logging
logger = logging.getLogger(__name__)

# Get Redis URL from environment variable or use default
REDIS_URL = os.getenv('REDIS_URL', 'redis://localhost:6379/0')

# Configure Celery
celery = Celery(
    'docupulse',
    backend=REDIS_URL,
    broker=REDIS_URL,
    # Add some default configuration
    task_serializer='json',
    accept_content=['json'],
    result_serializer='json',
    timezone='UTC',
    enable_utc=True,
    # Add retry configuration
    task_acks_late=True,
    task_reject_on_worker_lost=True,
    task_default_retry_delay=300,  # 5 minutes
    task_max_retries=3
)

def init_celery(app):
    """Initialize Celery with Flask app context"""
    celery.conf.update(app.config)

    class ContextTask(celery.Task):
        """Celery task that runs within Flask app context"""
        def __call__(self, *args, **kwargs):
            with app.app_context():
                return self.run(*args, **kwargs)

        def on_failure(self, exc, task_id, args, kwargs, einfo):
            """Handle task failure"""
            logger.error(f'Task {task_id} failed: {exc}')
            super().on_failure(exc, task_id, args, kwargs, einfo)

        def on_retry(self, exc, task_id, args, kwargs, einfo):
            """Handle task retry"""
            logger.warning(f'Task {task_id} is being retried: {exc}')
            super().on_retry(exc, task_id, args, kwargs, einfo)

    celery.Task = ContextTask
    return celery