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

    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=True)
    password_hash = db.Column(db.String(128), nullable=False)
    profile_image_url = db.Column(db.String(255), nullable=True)
    bio = db.Column(db.Text, nullable=True)
    created_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    updated_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow)

    workouts = db.relationship('Workout', backref='user', lazy=True, cascade="all, delete-orphan")

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

class Workout(db.Model):
    __tablename__ = 'workouts'

    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
    title = db.Column(db.String(120), nullable=False)
    workout_date = db.Column(db.Date, nullable=False, default=date.today)
    memo = db.Column(db.Text, nullable=True)
    created_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    updated_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow)

    logs = db.relationship('WorkoutLog', backref='workout', lazy=True, cascade="all, delete-orphan")

    def __repr__(self):
        return f'<Workout {self.title} on {self.workout_date}>'

class Exercise(db.Model):
    __tablename__ = 'exercises'

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(120), unique=True, nullable=False)
    target_muscle_group = db.Column(db.String(80), nullable=True)
    description = db.Column(db.Text, nullable=True)
    image_url = db.Column(db.String(255), nullable=True)

    logs = db.relationship('WorkoutLog', backref='exercise', lazy=True)

    def __repr__(self):
        return f'<Exercise {self.name}>'

class WorkoutLog(db.Model):
    __tablename__ = 'workout_logs'

    id = db.Column(db.Integer, primary_key=True)
    workout_id = db.Column(db.Integer, db.ForeignKey('workouts.id'), nullable=False)
    exercise_id = db.Column(db.Integer, db.ForeignKey('exercises.id'), nullable=False)
    set_number = db.Column(db.Integer, nullable=False)
    weight = db.Column(db.Float, nullable=False)
    reps = db.Column(db.Integer, nullable=False)
    unit = db.Column(db.String(10), nullable=False, default='kg')
    created_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    updated_at = db.Column(db.DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow)

    def __repr__(self):
        return f'<Log: Set {self.set_number} of {self.exercise.name}>'