"""user 表的 CRUD 工具函数。

业务策略 = "注册即登录":phone 不存在则 insert,存在则更新 last_login_at。
"""
from __future__ import annotations

from datetime import datetime, timezone

from sqlalchemy import select
from sqlalchemy.orm import Session

from app.models.user import User


def get_user_by_id(db: Session, user_id: int) -> User | None:
    return db.get(User, user_id)


def get_user_by_phone(db: Session, phone: str) -> User | None:
    stmt = select(User).where(User.phone == phone)
    return db.execute(stmt).scalar_one_or_none()


def upsert_user_for_login(
    db: Session,
    *,
    phone: str,
    register_channel: str,
) -> User:
    """登录入口统一调:有则更新 last_login_at,无则新建。

    返回 commit 后的 user。调用方拿到 user.id 直接签 JWT。
    """
    user = get_user_by_phone(db, phone)
    now = datetime.now(timezone.utc)
    if user is None:
        user = User(
            phone=phone,
            register_channel=register_channel,
            last_login_at=now,
        )
        db.add(user)
    else:
        user.last_login_at = now
        # 被禁用的账号被尝试登录时,不自动启用,直接抛(在调用方处理)
    db.commit()
    db.refresh(user)
    return user