# -*- 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, SymbolMixin
from trytond.transaction import Transaction
from trytond.pool import Pool
from trytond.pyson import Eval, Bool


class Rate(SymbolMixin, 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')
    symbol = fields.Function(fields.Char(string='Symbol',
        readonly=True), 'on_change_with_symbol')

    @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()

    def on_change_with_symbol(self, name=None):
        """ symbol:%
        """
        return '%'

    @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