"""用户服务"""

from datetime import datetime, timezone

from sqlalchemy import select, or_, func
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.user import User
from app.utils.security import hash_password, verify_password


class UserService:
    def __init__(self, db: AsyncSession):
        self.db = db

    async def get_by_id(self, user_id: str) -> User | None:
        """根据 ID 获取用户"""
        result = await self.db.execute(select(User).where(User.id == user_id))
        return result.scalars().first()

    async def get_by_username(self, username: str) -> User | None:
        """根据用户名获取用户"""
        result = await self.db.execute(select(User).where(User.username == username))
        return result.scalars().first()

    async def search_users(self, query: str, current_user_id: str, limit: int = 20) -> list[User]:
        """搜索用户（支持用户名、昵称、邮箱）"""
        result = await self.db.execute(
            select(User).where(
                or_(
                    User.username.ilike(f"%{query}%"),
                    User.nickname.ilike(f"%{query}%"),
                    User.email.ilike(f"%{query}%"),
                ),
                User.id != current_user_id,
                User.is_banned == False,
            ).limit(limit)
        )
        return list(result.scalars().all())

    async def update_profile(self, user_id: str, **kwargs) -> User:
        """更新用户资料"""
        user = await self.get_by_id(user_id)
        if not user:
            raise ValueError("用户不存在")

        for key, value in kwargs.items():
            if value is not None and hasattr(user, key):
                setattr(user, key, value)

        user.updated_at = datetime.utcnow()
        return user

    async def change_password(self, user_id: str, old_password: str, new_password: str):
        """修改密码"""
        user = await self.get_by_id(user_id)
        if not user:
            raise ValueError("用户不存在")
        if not verify_password(old_password, user.password_hash):
            raise ValueError("原密码错误")
        user.password_hash = hash_password(new_password)
        user.updated_at = datetime.utcnow()

    async def change_email(self, user_id: str, new_email: str, password: str):
        """更换绑定邮箱"""
        user = await self.get_by_id(user_id)
        if not user:
            raise ValueError("用户不存在")
        if not verify_password(password, user.password_hash):
            raise ValueError("密码错误")
        # 检查邮箱是否已被使用
        result = await self.db.execute(
            select(User).where(User.email == new_email, User.id != user_id)
        )
        if result.scalars().first():
            raise ValueError("该邮箱已被其他账号使用")
        user.email = new_email
        user.updated_at = datetime.utcnow()

    async def update_status(self, user_id: str, status: str):
        """更新用户在线状态"""
        user = await self.get_by_id(user_id)
        if user:
            user.status = status
            user.last_seen_at = datetime.utcnow()

    async def get_total_count(self) -> int:
        """获取用户总数"""
        result = await self.db.execute(select(func.count(User.id)))
        return result.scalar() or 0

    async def get_online_count(self) -> int:
        """获取在线用户数"""
        result = await self.db.execute(
            select(func.count(User.id)).where(User.status == "online")
        )
        return result.scalar() or 0