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

from trytond.i18n import gettext
from trytond.model import Workflow, ModelView, fields, Check
from trytond.model.exceptions import AccessError
from trytond.pool import Pool, PoolMeta
from trytond.transaction import Transaction

__all__ = ['Move']


class Move(metaclass=PoolMeta):
    __name__ = 'stock.move'
    fifo_quantity = fields.Float('FIFO Quantity')

    @classmethod
    def __setup__(cls):
        super(Move, cls).__setup__()
        cls._allow_modify_closed_period.add('fifo_quantity')

        t = cls.__table__()
        cls._sql_constraints += [
            ('check_fifo_quantity_out',
                Check(t, t.quantity >= t.fifo_quantity),
                'product_cost_fifo.msg_move_fifo_quantity_greater'),
            ]

    @staticmethod
    def default_fifo_quantity():
        return 0.0

    def _update_fifo_out_product_cost_price(self):
        '''
        Update the product cost price of the given product on the move. Update
        fifo_quantity on the concerned incomming moves. Return the
        cost price for outputing the given product and quantity.
        '''
        pool = Pool()
        Uom = pool.get('product.uom')
        Currency = pool.get('currency.currency')

        total_qty = Uom.compute_qty(self.uom, self.quantity,
            self.product.default_uom, round=False)

        fifo_moves = self.product.get_fifo_move(total_qty)

        cost_price = Decimal("0.0")
        consumed_qty = 0.0
        to_save = []
        for move, move_qty in fifo_moves:
            consumed_qty += move_qty

            with Transaction().set_context(date=move.effective_date):
                move_unit_price = Currency.compute(
                    move.currency, move.unit_price,
                    self.company.currency, round=False)
            move_unit_price = Uom.compute_price(move.uom, move_unit_price,
                    move.product.default_uom)
            cost_price += move_unit_price * Decimal(str(move_qty))

            move_qty = Uom.compute_qty(self.product.default_uom, move_qty,
                    move.uom, round=False)
            move.fifo_quantity = (move.fifo_quantity or 0.0) + move_qty
            to_save.append(move)
        if to_save:
            # TODO save in do method when product change
            self.__class__.save(to_save)

        if Decimal(str(consumed_qty)) != Decimal("0"):
            cost_price = cost_price / Decimal(str(consumed_qty))

        # Compute average cost price
        unit_price = self.unit_price
        self.unit_price = Uom.compute_price(
            self.product.default_uom, cost_price, self.uom)
        average_cost_price = self._compute_product_cost_price('out')
        self.unit_price = unit_price

        if cost_price != Decimal("0"):
            digits = self.__class__.cost_price.digits
            cost_price = cost_price.quantize(
                Decimal(str(10.0 ** -digits[1])))
        else:
            cost_price = average_cost_price
        return cost_price, average_cost_price

    def _do(self):
        cost_price = super(Move, self)._do()
        if (self.from_location.type in ('supplier', 'production')
                and self.to_location.type == 'storage'
                and self.product.cost_price_method == 'fifo'):
            cost_price = self._compute_product_cost_price('in')
        elif (self.to_location.type == 'supplier'
                and self.from_location.type == 'storage'
                and self.product.cost_price_method == 'fifo'):
            cost_price = self._compute_product_cost_price('out')
        elif (self.from_location.type == 'storage'
                and self.to_location.type != 'storage'
                and self.product.cost_price_method == 'fifo'):
            fifo_cost_price, cost_price = (
                self._update_fifo_out_product_cost_price())
            if self.cost_price is None:
                self.cost_price = fifo_cost_price
        return cost_price

    @classmethod
    @ModelView.button
    @Workflow.transition('cancel')
    def cancel(cls, moves):
        pass

    @classmethod
    def delete(cls, moves):
        fifo_moves = cls.search([
                ('id', 'in', [m.id for m in moves]),
                ('fifo_quantity', '!=', 0.0),
                ])
        if fifo_moves:
            raise AccessError(
                gettext('product_cost_fifo.msg_move_delete_fifo',
                    move=fifo_moves[0].rec_name))
        super(Move, cls).delete(moves)
