"""
ERP 模块信号处理
在任务创建/更新时清除缓存，实现实时推送
"""
from django.db.models.signals import post_save, post_delete
from django.dispatch import receiver
from django.core.cache import cache
from .models import InboundBill, OutboundBill
import logging

logger = logging.getLogger(__name__)

# 缓存键名（与 sse_views.py 中的保持一致）
CACHE_KEY_TASK_COUNTS = 'erp_task_counts'


def invalidate_task_counts_cache():
    """清除任务数缓存"""
    cache.delete(CACHE_KEY_TASK_COUNTS)
    logger.debug("已清除 ERP 任务数缓存")


@receiver(post_save, sender=InboundBill)
def inbound_bill_saved(sender, instance, **kwargs):
    """入库单保存时清除缓存"""
    # 只要 bound_status 或 is_delete 字段变化，都可能影响任务数，清除缓存
    # 任务数统计条件：bound_status=0 且 is_delete=False
    # 所以任何保存操作都可能影响计数，直接清除缓存
    invalidate_task_counts_cache()
    logger.debug(f"入库单 {instance.number} 保存（bound_status={instance.bound_status}, is_delete={instance.is_delete}），已清除任务数缓存")


@receiver(post_save, sender=OutboundBill)
def outbound_bill_saved(sender, instance, **kwargs):
    """出库单保存时清除缓存"""
    # 只要 bound_status 或 is_delete 字段变化，都可能影响任务数，清除缓存
    # 任务数统计条件：bound_status=0 且 is_delete=False
    # 所以任何保存操作都可能影响计数，直接清除缓存
    invalidate_task_counts_cache()
    logger.debug(f"出库单 {instance.number} 保存（bound_status={instance.bound_status}, is_delete={instance.is_delete}），已清除任务数缓存")


@receiver(post_delete, sender=InboundBill)
def inbound_bill_deleted(sender, instance, **kwargs):
    """入库单删除时清除缓存"""
    invalidate_task_counts_cache()
    logger.debug(f"入库单 {instance.number} 删除，已清除任务数缓存")


@receiver(post_delete, sender=OutboundBill)
def outbound_bill_deleted(sender, instance, **kwargs):
    """出库单删除时清除缓存"""
    invalidate_task_counts_cache()
    logger.debug(f"出库单 {instance.number} 删除，已清除任务数缓存")