from datetime import datetime, timezone
from enum import Enum
from sqlalchemy import Column, Integer, String, Text, DateTime, Enum as SQLEnum
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class UserRole(str, Enum):
    SYSTEM_ADMIN = "system_admin"
    ADMIN = "admin"
    USER = "user"

class User(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True, autoincrement=True)
    username = Column(String(50), unique=True, nullable=False)
    password = Column(String(255), nullable=False)
    role = Column(SQLEnum(UserRole), nullable=False, default=UserRole.USER)
    description = Column(Text)
    created_at = Column(DateTime, default=lambda: datetime.now(timezone.utc))
    updated_at = Column(DateTime, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc))

    def __repr__(self):
        return f"<User(id={self.id}, username={self.username}, role={self.role})>"