"""
Database models for employee workstation activity tracking.

This module defines the SQLAlchemy models used for storing activity events.
"""
from app import db

class WorkEvent(db.Model):
    """
    Represents a user activity event with state transitions (working/stopped).
    
    Attributes:
        id (int): Primary key for the event
        user (str): Username of the person whose activity is being tracked
        state (str): Current activity state ('working' or 'stopped')
        ts (datetime): Timestamp when the event occurred
    """
    __tablename__ = 'work_events'
    
    id = db.Column(db.Integer, primary_key=True)
    user = db.Column(db.String(100), nullable=False, index=True)
    state = db.Column(db.String(10), nullable=False)  # 'working' or 'stopped'
    ts = db.Column(db.DateTime, nullable=False, 
                  server_default=db.func.current_timestamp(),
                  index=True)
    
    def __repr__(self):
        """Return a string representation of the model."""
        return f"<WorkEvent(user='{self.user}', state='{self.state}', ts='{self.ts}')>"
    
    def to_dict(self):
        """Convert model to dictionary for API responses."""
        return {
            'id': self.id,
            'user': self.user,
            'state': self.state,
            'ts': self.ts.isoformat() if self.ts else None
        }