"""通知服务 — 创建与查询系统通知"""
from __future__ import annotations

import logging
from datetime import datetime
from typing import List, Optional

from sqlalchemy.orm import Session

from app.models.notification import Notification

logger = logging.getLogger(__name__)


def create_notification(
    db: Session,
    user_id: str,
    title: str,
    content: Optional[str] = None,
    category: str = "system",
    ref_type: Optional[str] = None,
    ref_id: Optional[str] = None,
) -> Notification:
    """创建一条通知。

    Args:
        db: 数据库会话
        user_id: 接收用户 ID
        title: 通知标题
        content: 通知正文（可选）
        category: 分类，如 schedule / alert / system
        ref_type: 关联对象类型
        ref_id: 关联对象 ID

    Returns:
        创建的 Notification ORM 对象
    """
    notification = Notification(
        user_id=user_id,
        title=title,
        content=content,
        category=category,
        ref_type=ref_type,
        ref_id=ref_id,
    )
    db.add(notification)
    db.flush()
    logger.info("通知已创建: user=%s title=%s category=%s", user_id, title, category)
    return notification


def get_user_notifications(
    db: Session,
    user_id: str,
    unread_only: bool = False,
    category: Optional[str] = None,
    limit: int = 50,
    offset: int = 0,
) -> List[Notification]:
    """获取用户的通知列表（按创建时间倒序）。

    Args:
        db: 数据库会话
        user_id: 用户 ID
        unread_only: 仅未读
        category: 按分类过滤
        limit: 分页大小
        offset: 分页偏移

    Returns:
        通知列表
    """
    query = db.query(Notification).filter(Notification.user_id == user_id)

    if unread_only:
        query = query.filter(Notification.is_read == False)  # noqa: E712
    if category:
        query = query.filter(Notification.category == category)

    return query.order_by(Notification.created_at.desc()).offset(offset).limit(limit).all()


def get_unread_count(db: Session, user_id: str) -> int:
    """获取用户未读通知数。"""
    return (
        db.query(Notification)
        .filter(Notification.user_id == user_id, Notification.is_read == False)  # noqa: E712
        .count()
    )


def mark_as_read(db: Session, notification_id: str, user_id: str) -> Optional[Notification]:
    """将指定通知标记为已读。"""
    notification = (
        db.query(Notification)
        .filter(Notification.id == notification_id, Notification.user_id == user_id)
        .first()
    )
    if not notification:
        return None
    notification.is_read = True
    db.flush()
    return notification


def mark_all_as_read(db: Session, user_id: str) -> int:
    """将用户所有通知标记为已读。返回更新的条数。"""
    count = (
        db.query(Notification)
        .filter(Notification.user_id == user_id, Notification.is_read == False)  # noqa: E712
        .update({"is_read": True})
    )
    db.flush()
    return count


def delete_notification(db: Session, notification_id: str, user_id: str) -> bool:
    """删除一条通知。"""
    notification = (
        db.query(Notification)
        .filter(Notification.id == notification_id, Notification.user_id == user_id)
        .first()
    )
    if not notification:
        return False
    db.delete(notification)
    db.flush()
    return True