from django_ledger.models.invoice import InvoiceModel

class InvoiceModelBase(InvoiceModel):
    """
    Custom Invoice Model with Net 15 payment terms.
    """    
    
    TERMS_ON_RECEIPT = 'on_receipt'
    TERMS_NET_15 = 'net_15'
    TERMS_NET_30 = 'net_30'
    TERMS_NET_60 = 'net_60'
    TERMS_NET_90 = 'net_90'
    TERMS_NET_90_PLUS = 'net_90+'

    TERM_CHOICES = [
        (TERMS_ON_RECEIPT, 'Due On Receipt'),
        (TERMS_NET_15, 'Net 15 Days'),
        (TERMS_NET_30, 'Net 30 Days'),
        (TERMS_NET_60, 'Net 60 Days'),
        (TERMS_NET_90, 'Net 90 Days'),
    ]
    TERM_CHOICES_VALID = tuple(i[0] for i in TERM_CHOICES)

    TERM_DAYS_MAPPING = {
        TERMS_ON_RECEIPT: 0,
        TERMS_NET_15: 15,
        TERMS_NET_30: 30,
        TERMS_NET_60: 60,
        TERMS_NET_90: 90,
        TERMS_NET_90_PLUS: 120
    }


    def net_due_group(self):
        """
        Determines the group where the financial instrument falls based on the number of days until the due date.

        Returns
        -------
        str
            The terms group as a string.
        """
        due_in = self.due_in_days()
        if due_in == 0:
            return self.TERMS_ON_RECEIPT
        elif due_in <= 15:
            return self.TERMS_NET_15
        elif due_in <= 30:
            return self.TERMS_NET_30
        elif due_in <= 60:
            return self.TERMS_NET_60
        elif due_in <= 90:
            return self.TERMS_NET_90
        return self.TERMS_NET_90_PLUS
    
    class Meta:
        proxy = True