from datetime import datetime

import click
from flask.cli import with_appcontext
from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()


def init_db():
    db.create_all()


@click.command('init-db')
@with_appcontext
def init_db_command():
    """Clear the existing data and create new tables."""
    init_db()
    click.echo('Initialized the database.')


def init_app(app):
    db.init_app(app)  # Initialize the sql alchemy database
    app.cli.add_command(init_db_command)


# Model definitions
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.Text, nullable=False)
    password = db.Column(db.Text, nullable=False)
    posts = db.relationship('Post', backref='user', lazy=True)

    def __repr__(self):
        return '<User %r>' % self.username


class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
    created = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    title = db.Column(db.Text, nullable=False)
    body = db.Column(db.Text, nullable=False)

    def __repr__(self):
        return '<Post %r>' % self.title