# models/user.py
from extensions import db
from flask_login import UserMixin
from werkzeug.security import generate_password_hash, check_password_hash
from datetime import datetime

class User(db.Model, UserMixin):
    __tablename__ = 'users'
    
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(64), unique=True, nullable=False, index=True)
    email = db.Column(db.String(120), unique=True, nullable=False, index=True)
    password_hash = db.Column(db.String(255), nullable=False)
    role = db.Column(db.Enum('student', 'teacher', 'admin'), nullable=False, default='student')
    created_at = db.Column(db.DateTime, default=datetime.utcnow, index=True)
    last_login = db.Column(db.DateTime, nullable=True)  # ✅ 修复：允许为空
    is_active = db.Column(db.Boolean, default=True)
    avatar = db.Column(db.String(255), default='default-avatar.png', nullable=True)
    
    # 关系
    teacher_profile = db.relationship('Teacher', backref='user', uselist=False, cascade='all, delete-orphan')
    student_profile = db.relationship('Student', backref='user', uselist=False, cascade='all, delete-orphan')
    
    def set_password(self, password):
        """设置密码哈希"""
        self.password_hash = generate_password_hash(password)
    
    def check_password(self, password):
        """验证密码"""
        return check_password_hash(self.password_hash, password)
    
    @property
    def is_student(self):
        return self.role == 'student'
    
    @property
    def is_teacher(self):
        return self.role == 'teacher'
    
    @property
    def is_admin(self):
        return self.role == 'admin'
    
    def __repr__(self):
        return f'<User {self.username} ({self.role})>'