followers = db.Table('followers',
    db.Column('follower_id', db.Integer, db.ForeignKey('user.id')),
    db.Column('followed_id', db.Integer, db.ForeignKey('user.id'))
)

likes = db.Table('likes',
    db.Column('userlikes', db.Integer, db.ForeignKey('user.id')),
    db.Column('artistliked', db.Integer, db.ForeignKey('artist.id'))
)

class User(db.Model):
    __searchable__ = ['nickname']
    id = db.Column(db.Integer, primary_key = True)
    nickname = db.Column(db.String(64), unique = True)
    lower = db.Column(db.String())
    email = db.Column(db.String(120), index = True, unique = True)
    role = db.Column(db.SmallInteger, default = ROLE_USER)
    posts = db.relationship('Post', backref = 'author', lazy = 'dynamic')
    about_me = db.Column(db.String(140))
    last_seen = db.Column(db.DateTime)
    followed = db.relationship('User',
        secondary = followers,
        primaryjoin = (followers.c.follower_id == id),
        secondaryjoin = (followers.c.followed_id == id),
        backref = db.backref('followers', lazy = 'dynamic'),
        lazy = 'dynamic')
    liked = db.relationship('Artist',
        secondary = likes,
        primaryjoin = (likes.c.userlikes == id),
        secondaryjoin = (likes.c.artistliked == id),
        backref = db.backref('likes', lazy = 'dynamic'),
        lazy = 'dynamic')

    def follow(self, user):
        if not self.is_following(user):
            self.followed.append(user)
            return self

    def like(self, artist):
        if not self.is_liking(artist):
            self.liked.append(artist)
            return self

    def unfollow(self, user):
        if self.is_following(user):
            self.followed.remove(user)
            return self

    def unlike(self, artist):
        if self.is_liking(artist):
            self.liked.remove(artist)
            return self

    def is_following(self, user):
        return self.followed.filter(followers.c.followed_id == user.id).count() > 0

    def is_liking(self, artist):
        return self.liked.filter(likes.c.artistliked == artist.id).count() > 0

    def followed_posts(self):
        return Post.query.join(followers, (followers.c.followed_id == Post.user_id)).filter(followers.c.follower_id == self.id).order_by(Post.timestamp.desc())

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


class Artist(db.Model):
    id = db.Column(db.Integer, primary_key = True)
    name = db.Column(db.String(40))