# -*- coding: utf-8 -*-
# This file is part of the investment-module from m-ds for Tryton.
# The COPYRIGHT file at the top level of this repository contains the
# full copyright notices and license terms.

from trytond.model import ModelView, ModelSQL, fields, Unique, Check
from trytond.transaction import Transaction
from trytond.pool import Pool
from trytond.pyson import Eval, Bool


class Rate(ModelSQL, ModelView):
    'Rate'
    __name__ = 'investment.rate'

    asset = fields.Many2One(string='Asset', required=True,
        select=True, ondelete='CASCADE',
        model_name='investment.asset')
    date = fields.Date(string='Date', required=True, select=True)
    rate = fields.Numeric(string='Rate', required=True,
        digits=(16, Eval('asset_digits', 4)),
        depends=['asset_digits'])

    asset_digits = fields.Function(fields.Integer(string='Digits',
        readonly=True), 'on_change_with_asset_digits')
    currency = fields.Function(fields.Many2One(string='Currency',
        readonly=True, model_name='currency.currency'),
        'on_change_with_currency')
    uom = fields.Function(fields.Many2One(string='Uom',
        readonly=True, model_name='product.uom'),
        'on_change_with_uom')

    @classmethod
    def __setup__(cls):
        super(Rate, cls).__setup__()
        t = cls.__table__()
        cls._sql_constraints = [
            ('date_asset_uniq',
                Unique(t, t.date, t.asset),
                'investment.msg_unique_rate_date'),
            ('check_rate',
                Check(t, t.rate >= 0),
                'currency.msg_rate_positive'),
            ]
        cls._order.insert(0, ('date', 'DESC'))

    @classmethod
    def default_date(cls):
        """ today
        """
        IrDate = Pool().get('ir.date')
        return IrDate.today()

    @fields.depends('asset', '_parent_asset.uom')
    def on_change_with_uom(self, name=None):
        """ get unit of asset
        """
        if self.asset:
            return self.asset.uom.id

    @fields.depends('asset', '_parent_asset.currency')
    def on_change_with_currency(self, name=None):
        """ get currency
        """
        if self.asset:
            return self.asset.currency.id

    @fields.depends('asset', '_parent_asset.currency_digits')
    def on_change_with_asset_digits(self, name=None):
        """ get digits for asset
        """
        if self.asset:
            return self.asset.currency_digits
        return 4

# Rate