"""
Celery tasks for billing operations
"""
import logging
from celery import shared_task
from django.utils import timezone
from django.db import transaction
from igny8_core.auth.models import Account
from .services import CreditService

logger = logging.getLogger(__name__)


@shared_task(name='igny8_core.modules.billing.tasks.replenish_monthly_credits')
def replenish_monthly_credits():
    """
    Replenish monthly credits for all active accounts.
    Runs on the first day of each month at midnight.
    
    For each active account with a plan:
    - Resets credits to plan.included_credits
    - Creates a CreditTransaction record
    - Logs the replenishment
    """
    logger.info("=" * 80)
    logger.info("MONTHLY CREDIT REPLENISHMENT TASK STARTED")
    logger.info(f"Timestamp: {timezone.now()}")
    logger.info("=" * 80)
    
    # Get all active accounts with plans
    accounts = Account.objects.filter(
        status='active',
        plan__isnull=False
    ).select_related('plan')
    
    total_accounts = accounts.count()
    logger.info(f"Found {total_accounts} active accounts with plans")
    
    replenished = 0
    skipped = 0
    errors = 0
    
    for account in accounts:
        try:
            plan = account.plan
            
            # Get monthly credits from plan
            monthly_credits = plan.included_credits or plan.credits_per_month or 0
            
            if monthly_credits <= 0:
                logger.info(f"Account {account.id} ({account.name}): Plan has no included credits, skipping")
                skipped += 1
                continue
            
            # Reset credits using CreditService
            with transaction.atomic():
                new_balance = CreditService.reset_credits_for_renewal(
                    account=account,
                    new_amount=monthly_credits,
                    description=f"Monthly credit replenishment - {plan.name} plan",
                    metadata={
                        'plan_id': plan.id,
                        'plan_name': plan.name,
                        'monthly_credits': monthly_credits,
                        'replenishment_date': timezone.now().isoformat()
                    }
                )
            
            logger.info(
                f"Account {account.id} ({account.name}): "
                f"Reset credits to {monthly_credits} (balance: {new_balance})"
            )
            replenished += 1
            
        except Exception as e:
            logger.error(
                f"Account {account.id} ({account.name}): "
                f"Failed to replenish credits: {str(e)}",
                exc_info=True
            )
            errors += 1
    
    logger.info("=" * 80)
    logger.info("MONTHLY CREDIT REPLENISHMENT TASK COMPLETED")
    logger.info(f"Total accounts: {total_accounts}")
    logger.info(f"Replenished: {replenished}")
    logger.info(f"Skipped: {skipped}")
    logger.info(f"Errors: {errors}")
    logger.info("=" * 80)
    
    return {
        'success': True,
        'total_accounts': total_accounts,
        'replenished': replenished,
        'skipped': skipped,
        'errors': errors
    }