class PurchaseLine(metaclass=PoolMeta):
    __name__ = 'purchase.line'

    blanket_agreement_line = fields.Many2One(
        'purchase.blanket_agreement.line', "Purchase Blanket Agreement Line",
        ondelete='RESTRICT',
        domain=[
            If(Eval('purchase_state').in_(['draft', 'quotation']), [
                ('agreement.state', 'in', ['done', 'cancelled', 'running']),
                ('product', '=', Eval('product'))],
                []),
            ('agreement.supplier', '=',
                Eval('_parent_purchase', {}).get('party'),
            ),
        ],
        depends=['product', 'purchase_state'])

    @fields.depends('blanket_agreement_line', '_parent_purchase.party',
                    'purchase', methods=['compute_taxes'])
    def on_change_blanket_agreement_line(self):
        if self.blanket_agreement_line:
            self.product = self.blanket_agreement_line.product
            if not self.description:
                self.description = self.blanket_agreement_line.description
            self.unit = self.blanket_agreement_line.unit
            if not self.unit_price:
                self.unit_price = self.blanket_agreement_line.unit_price
            if not self.quantity:
                self.quantity = self.blanket_agreement_line.remaining_quantity
            self.taxes = self.compute_taxes(self.purchase.party)

    @fields.depends('blanket_agreement_line', 'product')
    def on_change_product(self):
        super().on_change_product()
        if self.blanket_agreement_line:
            if self.product != self.blanket_agreement_line.product:
                self.blanket_agreement_line = None