from lernplattform import db
from sqlalchemy.sql import func

# Define a User model that represents the user table in the database
class User(db.Model):
    """
    A class representing the user table in the database.
    
    Attributes:
        id (int): The unique identifier for each user, set as the primary key.
        username (str): The username of the user, must be unique and cannot be null.
        email (str): The email address of the user, must be unique and cannot be null.
        password (str): The hashed password of the user, cannot be null.
        email_check (str): A string field to store email verification status.
        register_date (datetime): The date and time when the user registered, defaults to the current timestamp.
    
    Methods:
        __repr__(): Returns a string representation of the User object in the format "User('username', 'email')".
    """
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(20), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    password = db.Column(db.String(60), nullable=False)
    email_check = db.Column(db.String(10), nullable=True)
    register_date = db.Column(db.DateTime, nullable=False, default=func.now())

    # Magic method to represent the object as a string when printed or used in string context
    def __repr__(self):
        return f"User('{self.username}', '{self.email}')"

# Function to initialize the database by creating all tables defined in models if they do not exist
def initialize_database():
    from lernplattform import app
    # Create an application context before running operations on the database within this function
    with app.app_context():
        db.create_all()