from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

class Annotations(db.Model):
    __tablename__ = 'annotations'

    _id = db.Column("id", db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
    sample_id = db.Column(db.Integer, db.ForeignKey('samples.id'), nullable=False)
    label = db.Column(db.String(32), nullable=False)

    def __init__(self, user_id, sample_id, label):
        self.user_id = user_id
        self.sample_id = sample_id
        self.label = label

class Users(db.Model):
    __tablename__ = 'users'

    _id = db.Column("id", db.Integer, primary_key=True)
    name = db.Column(db.String(32), nullable=False)
    surname = db.Column(db.String(32), nullable=False)
    email = db.Column(db.String(64), unique=True, nullable=False)
    annotations = db.relationship('Annotations', uselist=False, backref='user', lazy=True)

    def __init__(self, name, surname, email):
        self.name = name
        self.surname = surname
        self.email = email

class Samples(db.Model):
    __tablename__ = 'samples'

    _id = db.Column("id", db.Integer, primary_key=True)
    text = db.Column(db.String(512), nullable=False)
    annotations = db.relationship('Annotations', lazy=True, backref='sample')  # corrected relationship and added backref

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