# The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
from sql import Column
from sql.aggregate import Max
from sql.conditionals import Coalesce
from sql.operators import Concat
from trytond.model import fields
from trytond.pool import PoolMeta, Pool
from trytond.pyson import Eval
from trytond.transaction import Transaction

__all__ = ['Move', 'ShipmentIn', 'ShipmentOut']


class Move:
    __name__ = 'stock.move'
    __metaclass__ = PoolMeta

    last_prices = fields.Function(
        fields.Many2Many('stock.move', None, None, 'Last move prices',
                        domain=[('product', '=', Eval('product'))],
                        depends=['product']),
        'get_last_prices')

    @fields.depends('product', 'shipment', 'effective_date', 'planned_date')
    def on_change_with_last_prices(self):
        return self.get_last_prices([self])[self.id]

    @classmethod
    def get_last_prices(cls, records, name=None):
        pool = Pool()
        Date = pool.get('ir.date')
        move = cls.__table__()
        cursor = Transaction().connection.cursor()

        today = Date.today()
        res = {r.id: [] for r in records}
        for record in records:
            if not record.product or not record.shipment:
                continue
            _shipment_name = record.shipment.__name__
            Shipment = pool.get(_shipment_name)
            shipment = Shipment.__table__()
            _party = getattr(record.shipment,
                Shipment._get_last_price_party_fieldname(), None)
            if not _party:
                continue

            _date = (record.effective_date or record.planned_date or
                record.shipment.effective_date or
                record.shipment.planned_date or today)
            cursor.execute(*shipment.join(
                move, condition=(
                    move.shipment == Concat('%s,' % _shipment_name,
                        shipment.id))
                ).select(Max(move.id),
                    where=((move.product == record.product.id) &
                        (move.shipment != '%s,%s' % (_shipment_name,
                            record.shipment.id)) &
                        (move.state != 'cancelled') &
                        (Column(shipment,
                            Shipment._get_last_price_party_fieldname()) ==
                            _party.id) &
                        (Coalesce(shipment.effective_date,
                            shipment.planned_date) <= _date)),
                    order_by=(move.product, shipment.id),
                    group_by=(move.product, shipment.id),
                    limit=3)
            )
            res[record.id] = [row[0] for row in cursor.fetchall()] or []
        return res


class ShipmentLastPriceMixin(object):

    last_prices = fields.Function(
        fields.Many2Many('stock.move', None, 'Last move prices'),
        'get_last_prices')

    @classmethod
    def get_last_prices(cls, records, name=None):
        pool = Pool()
        Move = pool.get('stock.move')
        move = Move.__table__()
        active_move = Move.__table__()
        shipment = cls.__table__()
        cursor = Transaction().connection.cursor()

        res = {r.id: [] for r in records}
        for record in records:
            _products = set([m.product.id for m in record.outgoing_moves])
            party = getattr(record,
                cls._get_last_price_party_fieldname(), None)
            if not party or not _products:
                continue
            cursor.execute(*shipment.join(move, condition=(
                    move.shipment == Concat('%s,' % cls.__name__, shipment.id))
                ).join(active_move, condition=(
                    active_move.product == move.product)
                ).select(Max(move.id),
                    where=((active_move.shipment ==
                            Concat('%s,' % cls.__name__, record.id)) &
                        (shipment.id != record.id) &
                        (shipment.state != 'cancelled') &
                        (Column(shipment,
                            cls._get_last_price_party_fieldname()) ==
                            party.id) &
                        (Coalesce(shipment.effective_date,
                            shipment.planned_date) <= Coalesce(
                            record.effective_date,
                            record.planned_date))),
                    order_by=(move.product, shipment.id),
                    group_by=(move.product, shipment.id),
                    limit=len(_products) * 3)
            )
            res[record.id] = [row[0] for row in cursor.fetchall()] or []
        return res

    @classmethod
    def _get_last_price_party_fieldname(cls):
        raise NotImplementedError()


class ShipmentOut(ShipmentLastPriceMixin):
    __name__ = 'stock.shipment.out'
    __metaclass__ = PoolMeta

    @classmethod
    def _get_last_price_party_fieldname(cls):
        return 'customer'


class ShipmentIn(ShipmentLastPriceMixin):
    __name__ = 'stock.shipment.in'
    __metaclass__ = PoolMeta

    @classmethod
    def _get_last_price_party_fieldname(cls):
        return 'supplier'