first commit

modules/sale_discount/sale.py

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+# 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.model import fields
+from trytond.modules.currency.fields import Monetary
+from trytond.modules.product import price_digits, round_price
+from trytond.pool import Pool, PoolMeta
+from trytond.pyson import Eval
+
+
+class Line(metaclass=PoolMeta):
+    __name__ = 'sale.line'
+
+    base_price = Monetary(
+        "Base Price", currency='currency', digits=price_digits,
+        states={
+            'invisible': Eval('type') != 'line',
+            'readonly': Eval('sale_state') != 'draft',
+            })
+
+    discount_rate = fields.Function(fields.Numeric(
+            "Discount Rate", digits=(None, 4),
+            states={
+                'invisible': Eval('type') != 'line',
+                'readonly': Eval('sale_state') != 'draft',
+                }),
+        'on_change_with_discount_rate', setter='set_discount_rate')
+    discount_amount = fields.Function(Monetary(
+            "Discount Amount", currency='currency', digits=price_digits,
+            states={
+                'invisible': Eval('type') != 'line',
+                'readonly': Eval('sale_state') != 'draft',
+                }),
+        'on_change_with_discount_amount', setter='set_discount_amount')
+
+    discount = fields.Function(fields.Char(
+            "Discount",
+            states={
+                'invisible': ~Eval('discount'),
+                }),
+        'on_change_with_discount')
+
+    @fields.depends(
+        methods=[
+            'compute_base_price', 'on_change_with_discount_rate',
+            'on_change_with_discount_amount', 'on_change_with_discount'])
+    def on_change_product(self):
+        super().on_change_product()
+        if self.product:
+            self.base_price = self.compute_base_price()
+            self.discount_rate = self.on_change_with_discount_rate()
+            self.discount_amount = self.on_change_with_discount_amount()
+            self.discount = self.on_change_with_discount()
+
+    @fields.depends('product', 'unit')
+    def compute_base_price(self):
+        pool = Pool()
+        Uom = pool.get('product.uom')
+        if (self.product
+                and (price := self.product.list_price_used) is not None):
+            if self.unit:
+                price = Uom.compute_price(
+                    self.product.default_uom, price, self.unit)
+            return round_price(price)
+
+    @fields.depends(
+        methods=[
+            'compute_base_price', 'on_change_with_discount_rate',
+            'on_change_with_discount_amount', 'on_change_with_discount'])
+    def on_change_quantity(self):
+        super().on_change_quantity()
+        self.base_price = self.compute_base_price()
+        self.discount_rate = self.on_change_with_discount_rate()
+        self.discount_amount = self.on_change_with_discount_amount()
+        self.discount = self.on_change_with_discount()
+
+    @fields.depends('unit_price', 'base_price')
+    def on_change_with_discount_rate(self, name=None):
+        if self.unit_price is None or not self.base_price:
+            return
+        rate = 1 - self.unit_price / self.base_price
+        return rate.quantize(
+            Decimal(1) / 10 ** self.__class__.discount_rate.digits[1])
+
+    @fields.depends(
+        'base_price', 'discount_rate',
+        methods=['on_change_with_discount_amount', 'on_change_with_discount',
+            'on_change_with_amount'])
+    def on_change_discount_rate(self):
+        if self.base_price is not None and self.discount_rate is not None:
+            self.unit_price = round_price(
+                self.base_price * (1 - self.discount_rate))
+            self.discount_amount = self.on_change_with_discount_amount()
+            self.discount = self.on_change_with_discount()
+            self.amount = self.on_change_with_amount()
+
+    @classmethod
+    def set_discount_rate(cls, lines, name, value):
+        pass
+
+    @fields.depends('unit_price', 'base_price')
+    def on_change_with_discount_amount(self, name=None):
+        if self.unit_price is None or self.base_price is None:
+            return
+        return round_price(self.base_price - self.unit_price)
+
+    @fields.depends(
+        'base_price', 'discount_amount',
+        methods=['on_change_with_discount_rate', 'on_change_with_discount',
+            'on_change_with_amount'])
+    def on_change_discount_amount(self):
+        if self.base_price is not None and self.discount_amount is not None:
+            self.unit_price = round_price(
+                self.base_price - self.discount_amount)
+            self.discount_rate = self.on_change_with_discount_rate()
+            self.discount = self.on_change_with_discount()
+            self.amount = self.on_change_with_amount()
+
+    @classmethod
+    def set_discount_amount(cls, lines, name, value):
+        pass
+
+    @fields.depends(
+        'sale', '_parent_sale.currency',
+        methods=[
+            'on_change_with_discount_rate', 'on_change_with_discount_amount'])
+    def on_change_with_discount(self, name=None):
+        pool = Pool()
+        Lang = pool.get('ir.lang')
+        lang = Lang.get()
+        rate = self.on_change_with_discount_rate()
+        if not rate or rate % Decimal('0.01'):
+            amount = self.on_change_with_discount_amount()
+            if amount:
+                if self.sale and self.sale.currency:
+                    return lang.currency(
+                        amount, self.sale.currency, digits=price_digits[1])
+                else:
+                    return lang.format_number(
+                        amount, digits=price_digits[1], monetary=True)
+        else:
+            return lang.format('%i', rate * 100) + '%'
+
+    @classmethod
+    def view_attributes(cls):
+        return super().view_attributes() + [
+            ('/form//label[@id="discount"]', 'states', {
+                'invisible': Eval('type') != 'line',
+                }, ['type']),
+            ]