"""Item model for Work Statistics System."""
from datetime import datetime, timezone
from app import db


class Item(db.Model):
    """Item model representing a work item with unit price.
    
    Attributes:
        id: Primary key, auto-incremented
        name: Item's name (required, non-empty)
        unit_price: Price per unit (required, positive float)
        created_at: Timestamp when the record was created
        updated_at: Timestamp when the record was last updated
    """
    __tablename__ = 'items'
    
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    name = db.Column(db.String(100), nullable=False, index=True)
    unit_price = db.Column(db.Float, nullable=False)
    created_at = db.Column(db.DateTime, default=lambda: datetime.now(timezone.utc))
    updated_at = db.Column(db.DateTime, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc))
    
    def to_dict(self):
        """Convert model to dictionary for JSON serialization.
        
        Returns:
            Dictionary representation of the item
        """
        return {
            'id': self.id,
            'name': self.name,
            'unit_price': self.unit_price,
            'created_at': self.created_at.isoformat() if self.created_at else None,
            'updated_at': self.updated_at.isoformat() if self.updated_at else None
        }
    
    def __repr__(self):
        return f'<Item {self.id}: {self.name} @ {self.unit_price}>'