"""P2-05 WebSocket 推送 helper

把好感度变化事件推到 `device_{user_id}` channel layer group，
设备端和手机端的 DeviceConsumer 都加入此分组，会同时收到（设计文档 §9.3）。

推送是「fire-and-forget」语义 — channel layer 故障或用户不在线时不应阻塞 service
主流程，全部用 try/except 包裹并仅日志记录。
"""

from __future__ import annotations

import logging
from typing import Any, Dict, List, Optional

from asgiref.sync import async_to_sync
from channels.layers import get_channel_layer

logger = logging.getLogger(__name__)


def _send(user_id: int, payload: Dict[str, Any]) -> None:
    """内部统一推送入口。channel_layer 不可用 / group_send 异常时静默吞掉但记日志。"""
    try:
        channel_layer = get_channel_layer()
        if channel_layer is None:
            logger.warning('[affinity.ws] channel_layer 未配置，跳过推送 payload=%s', payload)
            return
        async_to_sync(channel_layer.group_send)(f'device_{user_id}', payload)
    except Exception as exc:  # pragma: no cover — 推送失败不影响业务
        logger.warning('[affinity.ws] group_send 失败 user_id=%s err=%s', user_id, exc)


def push_affinity_update(
    user_id: int,
    device_id: Optional[int],
    *,
    change: int,
    before: int,
    after: int,
    rule_key: str,
    source: str,
) -> None:
    """好感度数值变化事件。所有触发点（设备 / 手机 / 衰减 / 管理员调整）共用此事件。"""
    _send(user_id, {
        'type': 'affinity.update',  # consumer 端 handler 名（消费者用 .replace('.', '_')）
        'event': 'affinity_update',
        'device_id': device_id,
        'change': change,
        'before': before,
        'after': after,
        'rule_key': rule_key,
        'source': source,
    })


def push_level_up(
    user_id: int,
    device_id: Optional[int],
    *,
    old_level: int,
    new_level: int,
    rewards: List[Dict[str, Any]],
) -> None:
    """升级事件。rewards 是本次跨级一次性发放的奖励列表，每级一项。"""
    _send(user_id, {
        'type': 'affinity.level.up',
        'event': 'level_up',
        'device_id': device_id,
        'old_level': old_level,
        'new_level': new_level,
        'rewards': rewards,
    })


def push_level_down(
    user_id: int,
    device_id: Optional[int],
    *,
    old_level: int,
    new_level: int,
) -> None:
    """降级事件。衰减导致的等级回退，不追回奖励但取消等级解锁内容。"""
    _send(user_id, {
        'type': 'affinity.level.down',
        'event': 'level_down',
        'device_id': device_id,
        'old_level': old_level,
        'new_level': new_level,
    })