models.py

"""SQLAlchemy models for Warbler."""

from datetime import datetime

from flask_bcrypt import Bcrypt
from flask_sqlalchemy import SQLAlchemy

bcrypt = Bcrypt()
db = SQLAlchemy()

DEFAULT_IMAGE_URL = (
    "https://icon-library.com/images/default-user-icon/" +
    "default-user-icon-28.jpg")

DEFAULT_HEADER_IMAGE_URL = (
    "https://images.unsplash.com/photo-1519751138087-5bf79df62d5b?ixlib=" +
    "rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=for" +
    "mat&fit=crop&w=2070&q=80")


class Follow(db.Model):
    """Connection of a follower <-> followed_user."""

    __tablename__ = 'follows'

    user_being_followed_id = db.Column(
        db.Integer,
        db.ForeignKey('users.id', ondelete="cascade"),
        primary_key=True,
    )

    user_following_id = db.Column(
        db.Integer,
        db.ForeignKey('users.id', ondelete="cascade"),
        primary_key=True,
    )


class User(db.Model):
    """User in the system."""

    __tablename__ = 'users'

    id = db.Column(
        db.Integer,
        primary_key=True,
    )

    email = db.Column(
        db.String(50),
        nullable=False,
        unique=True,
    )

    username = db.Column(
        db.String(30),
        nullable=False,
        unique=True,
    )

    image_url = db.Column(
        db.String(255),
        nullable=False,
        default=DEFAULT_IMAGE_URL,
    )

    header_image_url = db.Column(
        db.String(255),
        nullable=False,
        default=DEFAULT_HEADER_IMAGE_URL,
    )

    bio = db.Column(
        db.Text,
        nullable=False,
        default="",
    )

    location = db.Column(
        db.String(30),
        nullable=False,
        default="",
    )

    password = db.Column(
        db.String(100),
        nullable=False,
    )

    messages = db.relationship('Message', backref="user", cascade="all, delete-orphan")

    followers = db.relationship(
        "User",
        secondary="follows",
        primaryjoin=(Follow.user_being_followed_id == id),
        secondaryjoin=(Follow.user_following_id == id),
        backref="following",
    )

    liked_messages = db.relationship('Message',
                                     secondary="likes",
                                     backref="liking_user")


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


    @classmethod
    def signup(cls, username, email, password, image_url=DEFAULT_IMAGE_URL):
        """Sign up user.

        Hashes password and adds user to session.
        """

        hashed_pwd = bcrypt.generate_password_hash(password).decode('UTF-8')

        user = User(
            username=username,
            email=email,
            password=hashed_pwd,
            image_url=image_url,
        )

        if user.username == "" or user.email == "":
            raise Exception("Empty username or email")

        db.session.add(user)
        return user


    @classmethod
    def authenticate(cls, username, password):
        """Find user with `username` and `password`.

        This is a class method (call it on the class, not an individual user.)
        It searches for a user whose password hash matches this password
        and, if it finds such a user, returns that user object.

        If this can't find matching user (or if password is wrong), returns
        False.
        """

        user = cls.query.filter_by(username=username).one_or_none()

        if user:
            is_auth = bcrypt.check_password_hash(user.password, password)
            if is_auth:
                return user

        return False


    def is_followed_by(self, other_user):
        """Is this user followed by `other_user`?"""

        found_user_list = [
            user for user in self.followers if user == other_user]
        return len(found_user_list) == 1


    def is_following(self, other_user):
        """Is this user following `other_use`?"""

        found_user_list = [
            user for user in self.following if user == other_user]
        return len(found_user_list) == 1


    def is_liking(self, msg):
        """Is this user liking message?"""

        liked_message_list = [
            message for message in self.liked_messages if message == msg]
        return len(liked_message_list) == 1


class Message(db.Model):
    """An individual message ("warble")."""

    __tablename__ = 'messages'

    id = db.Column(
        db.Integer,
        primary_key=True,
    )

    text = db.Column(
        db.String(140),
        nullable=False,
    )

    timestamp = db.Column(
        db.DateTime,
        nullable=False,
        default=datetime.utcnow,
    )

    user_id = db.Column(
        db.Integer,
        db.ForeignKey('users.id', ondelete="cascade"),
        nullable=False,
    )


class Like(db.Model):
    """Connection of a user <-> message."""

    __tablename__ = 'likes'

    liked_message_id = db.Column(
        db.Integer,
        db.ForeignKey('messages.id', ondelete="cascade"),
        primary_key=True,
    )

    user_liking_id = db.Column(
        db.Integer,
        db.ForeignKey('users.id', ondelete="cascade"),
        primary_key=True,
    )


def connect_db(app):
    """Connect this database to provided Flask app.

    You should call this in your Flask app.
    """

    app.app_context().push()
    db.app = app
    db.init_app(app)