models.py

from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.sql.expression import func
from sqlalchemy.exc import IntegrityError
from werkzeug.security import generate_password_hash
from app import app

db = SQLAlchemy(app)


class User(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  username = db.Column(db.String(80), unique=True, nullable=False)
  email = db.Column(db.String(120), unique=True, nullable=False)
  password = db.Column(db.String(120), nullable=False)
  todos =db.relationship('Todo',backref='user',lazy=True,cascade="all, delete-orphan")

  def __init__(self, username, email, password):
    self.username = username
    self.email = email
    self.set_password(password)

  def set_password(self, password):
    """Create hashed password."""
    self.password = generate_password_hash(password, method='scrypt')

  def __repr__(self):
    return f'<User {self.id} {self.username} - {self.email}>'

class Todo(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False) #set userid as a foreign key to user.id 
  text = db.Column(db.String(255), nullable=False)
  done = db.Column(db.Boolean, default=False)

  def toggle(self):
    self.done = not self.done
    db.session.add(self)
    db.session.commit()

  def __init__(self, text):
      self.text = text

  def __repr__(self):
      category_names = ', '.join([category.text for category in self.categories])
      return f'<Todo: {self.id} | {self.user.username} | {self.text} | { "done" if self.done else "not done" } | categories [{category_names}]>' 

class TodoCategory(db.Model):
  __tablename__ ='todo_category'
  id = db.Column(db.Integer, primary_key=True)
  todo_id = db.Column(db.Integer, db.ForeignKey('todo.id'), nullable=False)
  category_id = db.Column(db.Integer, db.ForeignKey('category.id'), nullable=False)
  last_modified = db.Column(db.DateTime, default=func.now(), onupdate=func.now())

  def __repr__(self):
    return f'<TodoCategory last modified {self.last_modified.strftime("%Y/%m/%d, %H:%M:%S")}>'


class Category(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
  text = db.Column(db.String(255), nullable=False)
  user = db.relationship('User', backref=db.backref('categories', lazy='joined'))
  todos = db.relationship('Todo', secondary='todo_category', backref=db.backref('categories', lazy=True))

  def __init__(self, user_id, text):
    self.user_id = user_id
    self.text = text

  def __repr__(self):
    return f'<Category user:{self.user.username} - {self.text}>'