#This file is part sale_discount module for Tryton.
#The COPYRIGHT file at the top level of this repository contains 
#the full copyright notices and license terms.
import copy
from decimal import Decimal
from trytond.model import fields
from trytond.pyson import Not, Equal, Eval
from trytond.transaction import Transaction
from trytond.pool import Pool, PoolMeta

__all__ = ['SaleLine']
__metaclass__ = PoolMeta

class SaleLine:
    'Sale Line'
    __name__ = 'sale.line'

    discount = fields.Numeric('Discount %', 
        digits=(16, Eval('currency_digits', 2)), 
        states={
        'invisible': Not(Equal(Eval('type'), 'line')),
        }, on_change=['discount', 'product', 'quantity', 'type', 'unit_price'],
        depends=['type','unit_price', 'quantity', 'amount'])

    @staticmethod
    def default_discount():
        return 0.0

    def on_change_discount(self):
        res = {}
        if self.discount == Decimal(0.0) and self.quantity != None:
            res['amount'] = Decimal(self.quantity)*self.unit_price
        if self.discount and self.unit_price and self.type == 'line':
            res['amount'] = Decimal(self.quantity)*(self.unit_price -
                self.unit_price * self.discount * Decimal('0.01'))
        return res

    def on_change_product(self):
        res = super(SaleLine, self).on_change_product()
        res['discount'] = Decimal(0.0)
        return res

    def on_change_quantity(self):
        res = super(SaleLine, self).on_change_quantity()
        res['discount'] = Decimal(0.0)
        return res

    def get_amount(self, name):
        Currency = Pool().get('currency.currency')
        res = super(SaleLine, self).get_amount(name)
        if self.type == 'line' and self.discount and self.discount != None:
            currency = self.sale and self.sale.currency \
                    or self.currency
            res = Currency.round(currency, \
                    Decimal(str(self.quantity)) * self.unit_price - \
                        (Decimal(str(self.quantity)) * self.unit_price *\
                        (self.discount * Decimal('0.01'))))
        return res