from decimal import Decimal, InvalidOperation

from summer.models import session_scope
from summer.models.validation_exception import ValidationError


__author__ = 'tanshu'

from summer.models.master import Tax


def save_tax(json):
    name = json['Name'].strip()
    try:
        rate = Decimal(json['Rate'])
        if rate < 0:
            raise ValidationError("Rate must be a decimal >= 0")
    except (ValueError, InvalidOperation):
        raise ValidationError("Rate must be a decimal >= 0")
    item = Tax(name, rate)
    with session_scope() as DBSession:
        DBSession.add(item)
    return tax_info(item.id)


def update_tax(json):
    with session_scope() as DBSession:
        item = Tax.by_id(json['TaxID'], session=DBSession)
        if item.is_fixture:
            raise ValidationError("{0} is a fixture and cannot be edited or deleted.".format(item.name))
        item.name = json['Name'].strip()
        try:
            rate = Decimal(json['Rate'])
            if rate < 0:
                raise ValidationError("Rate must be a decimal >= 0")
        except (ValueError, InvalidOperation):
            raise ValidationError("Rate must be a decimal >= 0")
        item.rate = rate
    return tax_info(item.id)


def show_list():
    with session_scope() as DBSession:
        list = DBSession.query(Tax).order_by(Tax.name)
        taxes = []
        for item in list:
            taxes.append({'TaxID': item.id, 'Name': item.name, 'Rate': item.rate, 'IsFixture': item.is_fixture})
        return taxes


def tax_info(id):
    with session_scope() as DBSession:
        if id is None:
            item = {'Name': '', 'Rate': 0, 'IsFixture': False}
        else:
            tax = Tax.by_id(id, session=DBSession)
            return {'TaxID': tax.id, 'Name': tax.name, 'Rate': tax.rate, 'IsFixture': tax.is_fixture}
    return item