Added the ability to apply discounts to the invoice.

Author: Saska Kolehmainen

src/pages/invoices/$id/_layout.js

@@ -28,25 +28,45 @@ import LineItems from '../../../components/invoices/line-items';
 import FooterToolbar from '../../../components/layout/footer-toolbar';
 import { OrganizationContext } from '../../../providers/contexts';
 
+let discountValue;
+let discountType;
+
 const totals = (lineItems, taxRates) => {
   let subTotal = currency(0, { separator: '', symbol: '' });
   let taxTotal = currency(0, { separator: '', symbol: '' });
+  let discount = currency(0, { separator: '', symbol: '' });
+
 
   forEach(lineItems, line => {
     if (has(line, 'subtotal')) {
       subTotal = subTotal.add(line.subtotal);
+
+      let lineDiscount;
+      if(discountValue !== 0 | discountValue !== ""){
+        if(discountType === "%"){
+          lineDiscount = currency(line.subtotal).multiply(discountValue / 100);
+        } else if(discountType==="currency"){
+          lineDiscount = currency(lineDiscount).add(discountValue / lineItems.length);
+        }
+      }
       if (has(line, 'taxRate')) {
-        const taxRate = get(taxRates.items, line.taxRate);
+        const taxRate = get(taxRates.items, line.taxRate) 
+
         if (taxRate) {
-          const lineTax = currency(line.subtotal).multiply(taxRate.percentage / 100);
+          const afterDiscount = currency(line.subtotal).subtract(lineDiscount)
+          const lineTax = afterDiscount.multiply(taxRate.percentage / 100);
           taxTotal = taxTotal.add(lineTax);
         }
       }
+
+      discount = discount.add(lineDiscount)
     }
   });
 
-  const total = subTotal.add(taxTotal);
-  return { subTotal, taxTotal, total };
+
+  const total = currency(subTotal, { separator: '', symbol: '' }).subtract(discount).add(taxTotal);
+  return { subTotal, taxTotal, total, discount};
+ 
 };
 
 class InvoiceForm extends Component {
@@ -83,6 +103,16 @@ class InvoiceForm extends Component {
     }
   };
 
+  onDiscountTypeChange = (value) => {
+    discountType = value
+  }
+
+  onDiscountChange = (value) => {
+    if (value !== "" | value !== 0) {
+      discountValue = value
+    }
+  }; 
+
   onStateSelect = (_id, _rev, key) => {
     this.props.dispatch({
       type: 'invoices/state',
@@ -132,7 +162,7 @@ class InvoiceForm extends Component {
       handleSubmit,
       submitting,
     } = this.props;
-    const { subTotal, taxTotal, total } = totals(lineItems, taxRates);
+    const { subTotal, taxTotal, total, discount } = totals(lineItems, taxRates);
     const invoice = get(invoices.items, get(this.props, ['match', 'params', 'id']));
 
     const stateMenu = (_id, _rev) => (
@@ -261,6 +291,24 @@ class InvoiceForm extends Component {
             </Col>
           </Row>
 
+          <Row gutter={16}>
+            <Col span={5} style={{ marginTop: '20px' }}>
+              <Field
+                name="discountValue"
+                component={AInput}
+                label={<Trans>Discount</Trans>}
+                onChange={(event, newValue) => 
+                  this.onDiscountChange(newValue)
+                }
+              />
+            </Col>
+            <Col span={3} style={{ marginTop: '20px'}}>
+             <Field name="discountType" component={ASelect} onDrop={e => e.preventDefault()} label=" " defaultValue="%" onChange={(value) => this.onDiscountTypeChange(value)}>
+                <Select.Option value="%">%</Select.Option>
+                <Select.Option value="currency">{currency}</Select.Option>
+              </Field>
+            </Col>
+          </Row>
           <Row gutter={16}>
             <Col span={8} style={{ marginTop: '20px' }}>
               <Field
@@ -299,6 +347,26 @@ class InvoiceForm extends Component {
                           </h4>
                         </td>
                       </tr>
+                      { discount > 0 && <tr>
+                        <td style={{ textAlign: 'right' }}>
+                          <Trans>Discount</Trans>
+                        </td>
+                        <td style={{ textAlign: 'right' }}>
+                          <NumberFormat
+                            value={discount}
+                            format={{
+                              style: 'currency',
+                              currency:
+                                currency || get(context.state, 'organization.currency', 'EUR'),
+                              minimumFractionDigits: get(
+                                context.state,
+                                'organization.minimum_fraction_digits',
+                                2
+                              ),
+                            }}
+                          />
+                        </td>
+                      </tr>}
                       <tr>
                         <td style={{ textAlign: 'right' }}>
                           <Trans>Tax</Trans>
@@ -432,18 +500,22 @@ export default withI18n()(
             ''
           ),
           lineItems: [{}],
+          discountValue: selector(state, 'discountValue'),
+          discountType: selector(state, 'discountType'),
+          discount: selector(state, 'discount'),
         },
       }))(
         reduxForm({
           form: 'invoice',
           onSubmit: async (data, dispatch, props) => {
             const { lineItems, taxRates } = props;
-            const { subTotal, taxTotal, total } = totals(lineItems, taxRates);
+            const { subTotal, taxTotal, total, discount } = totals(lineItems, taxRates);
             return await dispatch({
               type: 'invoices/save',
               data: {
                 ...data,
                 subTotal: subTotal.format(),
+                discount: discount.format(),
                 taxTotal: taxTotal.format(),
                 total: total.format(),
               },

src/pages/invoices/$id/pdf.js

@@ -239,6 +239,22 @@ class Invoice extends Component {
                         />
                       </td>
                     </tr>
+                    { invoice.discount > 0 && <tr>
+                      <td colSpan="2" className="border-top-0" />
+                      <td colSpan="2" className="border-top-0">
+                        <Trans>Discount</Trans>
+                      </td>
+                      <td className="text-right border-top-0">
+                        <NumberFormat
+                          value={invoice.discount}
+                          format={{
+                            style: 'currency',
+                            currency: invoice.currency,
+                            minimumFractionDigits: get(organization, 'minimum_fraction_digits', 2),
+                          }}
+                        />
+                      </td>
+                    </tr>}
                     <tr>
                       <td colSpan="2" className="border-top-0" />
                       <td colSpan="2" className="border-top-0">