from app import db
from app.utils.timezone import now_in_app_timezone


class TaskActivity(db.Model):
    """Lightweight audit log for significant task events."""
    __tablename__ = 'task_activities'

    id = db.Column(db.Integer, primary_key=True)
    task_id = db.Column(db.Integer, db.ForeignKey('tasks.id'), nullable=False, index=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=True, index=True)
    event = db.Column(db.String(50), nullable=False, index=True)
    details = db.Column(db.Text, nullable=True)
    created_at = db.Column(db.DateTime, default=now_in_app_timezone, nullable=False, index=True)

    task = db.relationship('Task', backref=db.backref('activities', lazy='dynamic', cascade='all, delete-orphan'))
    user = db.relationship('User')

    def __init__(self, task_id, event, user_id=None, details=None):
        self.task_id = task_id
        self.user_id = user_id
        self.event = event
        self.details = details

    def __repr__(self):
        return f'<TaskActivity task={self.task_id} event={self.event}>'