tryton/customs.py

# This file is part of Tryton.  The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
import datetime
from decimal import Decimal

from sql import Null

from trytond.model import (
    ModelSQL, ModelView, DeactivableMixin, MatchMixin, fields)
from trytond.pyson import Eval, If, Bool
from trytond.pool import Pool

from trytond.modules.product import price_digits

__all__ = ['TariffCode', 'DutyRate']

# Use 2 chars numbering to allow string comparison
MONTHS = [
    (None, ''),
    ('01', 'January'),
    ('02', 'February'),
    ('03', 'March'),
    ('04', 'April'),
    ('05', 'May'),
    ('06', 'June'),
    ('07', 'July'),
    ('08', 'August'),
    ('09', 'September'),
    ('10', 'October'),
    ('11', 'November'),
    ('12', 'December'),
    ]


class TariffCode(DeactivableMixin, ModelSQL, ModelView, MatchMixin):
    'Tariff Code'
    __name__ = 'customs.tariff.code'
    _rec_name = 'code'
    code = fields.Char('Code', required=True,
        help='The code from Harmonized System of Nomenclature.')
    description = fields.Char('Description', translate=True)
    country = fields.Many2One('country.country', 'Country')
    # TODO country group
    start_month = fields.Selection(MONTHS, 'Start Month', sort=False,
        states={
            'required': Eval('end_month') | Eval('start_day'),
            },
        depends=['end_month', 'start_day'])
    start_day = fields.Integer('Start Day',
        domain=['OR',
            ('start_day', '<=', If(Eval('start_month').in_(
                        ['01', '03', '05', '07', '08', '10', '12']), 31,
                    If(Eval('start_month') == '02', 29, 30))),
            ('start_day', '=', None),
            ],
        states={
            'required': Bool(Eval('start_month')),
            },
        depends=['start_month'])
    end_month = fields.Selection(MONTHS, 'End Month', sort=False,
        states={
            'required': Eval('start_month') | Eval('end_day'),
            },
        depends=['start_month', 'end_day'])
    end_day = fields.Integer('End Day',
        domain=['OR',
            ('end_day', '<=', If(Eval('end_month').in_(
                        ['01', '03', '05', '07', '08', '10', '12']), 31,
                    If(Eval('end_month') == '02', 29, 30))),
            ('end_day', '=', None),
            ],
        states={
            'required': Bool(Eval('end_month')),
            },
        depends=['end_month'])
    duty_rates = fields.One2Many('customs.duty.rate', 'tariff_code',
        'Duty Rates')

    @classmethod
    def __setup__(cls):
        super(TariffCode, cls).__setup__()
        cls._order.insert(0, ('code', 'ASC'))

    def match(self, pattern):
        if 'date' in pattern:
            pattern = pattern.copy()
            date = pattern.pop('date')
            if self.start_month and self.end_month:
                start = (int(self.start_month), self.start_day)
                end = (int(self.end_month), self.end_day)
                date = (date.month, date.day)
                if start <= end:
                    if not (start <= date <= end):
                        return False
                else:
                    if end <= date <= start:
                        return False
        return super(TariffCode, self).match(pattern)

    def get_duty_rate(self, pattern):
        for rate in self.duty_rates:
            if rate.match(pattern):
                return rate


class DutyRate(ModelSQL, ModelView, MatchMixin):
    'Duty Rate'
    __name__ = 'customs.duty.rate'
    tariff_code = fields.Many2One('customs.tariff.code', 'Tariff Code',
        required=True, select=True)
    country = fields.Many2One('country.country', 'Country')
    # TODO country group
    type = fields.Selection([
            ('import', 'Import'),
            ('export', 'Export'),
            ], 'Type')
    start_date = fields.Date('Start Date',
        domain=['OR',
            ('start_date', '<=', If(Bool(Eval('end_date')),
                    Eval('end_date', datetime.date.max), datetime.date.max)),
            ('start_date', '=', None),
            ],
        depends=['end_date'])
    end_date = fields.Date('End Date',
        domain=['OR',
            ('end_date', '>=', If(Bool(Eval('start_date')),
                    Eval('start_date', datetime.date.min), datetime.date.min)),
            ('end_date', '=', None),
            ],
        depends=['start_date'])
    computation_type = fields.Selection([
            ('amount', 'Amount'),
            ('quantity', 'Quantity'),
            ], 'Computation Type')
    amount = fields.Numeric('Amount', digits=price_digits,
        states={
            'required': Eval('computation_type').in_(['amount', 'quantity']),
            'invisible': ~Eval('computation_type').in_(['amount', 'quantity']),
            },
        depends=['computation_type'])
    currency = fields.Many2One('currency.currency', 'Currency',
        states={
            'required': Eval('computation_type').in_(['amount', 'quantity']),
            'invisible': ~Eval('computation_type').in_(['amount', 'quantity']),
            },
        depends=['computation_type'])
    uom = fields.Many2One('product.uom', 'Uom',
        states={
            'required': Eval('computation_type') == 'quantity',
            'invisible': Eval('computation_type') != 'quantity',
            },
        depends=['computation_type'])

    @classmethod
    def __setup__(cls):
        super(DutyRate, cls).__setup__()
        cls._order.insert(0, ('start_date', 'ASC'))
        cls._order.insert(0, ('end_date', 'ASC'))

    @classmethod
    def default_type(cls):
        return 'import'

    @staticmethod
    def order_start_date(tables):
        table, _ = tables[None]
        return [table.start_date == Null, table.start_date]

    @staticmethod
    def order_end_date(tables):
        table, _ = tables[None]
        return [table.end_date == Null, table.end_date]

    def match(self, pattern):
        if 'date' in pattern:
            pattern = pattern.copy()
            start = self.start_date or datetime.date.min
            end = self.end_date or datetime.date.max
            if not (start <= pattern.pop('date') <= end):
                return False
        return super(DutyRate, self).match(pattern)

    def compute(self, currency, quantity, uom, **kwargs):
        return getattr(self, 'compute_%s' % self.computation_type)(
            currency, quantity, uom, **kwargs)

    def compute_amount(self, currency, quantity, uom, **kwargs):
        pool = Pool()
        Currency = pool.get('currency.currency')
        return Currency.compute(self.currency, self.amount, currency)

    def compute_quantity(self, currency, quantity, uom, **kwargs):
        pool = Pool()
        Currency = pool.get('currency.currency')
        Uom = pool.get('product.uom')

        amount = Uom.compute_price(self.uom, self.amount, uom)
        amount *= Decimal(str(quantity))
        return Currency.compute(self.currency, amount, currency)