feature: Discounts (#244)

feature: Added invoice discounts

Author: TreyWW

backend/api/base/modal.py

@@ -44,6 +44,13 @@ def open_modal(request: HttpRequest, modal_name, context_type=None, context_valu
                     # context["to_city"] = invoice.client_city
                     # context["to_county"] = invoice.client_county
                     # context["to_country"] = invoice.client_country
+            elif context_type == "invoice":
+                try:
+                    invoice = Invoice.objects.get(id=context_value)
+                    if invoice.has_access(request.user):
+                        context["invoice"] = invoice
+                except Invoice.DoesNotExist:
+                    ...
             else:
                 context[context_type] = context_value
 

backend/api/invoices/edit.py

@@ -1,4 +1,5 @@
 from datetime import datetime
+from typing import NoReturn
 
 from django.contrib import messages
 from django.http import HttpRequest, JsonResponse, HttpResponse
@@ -99,12 +100,55 @@ def change_status(request: HttpRequest, invoice_id: int, status: str) -> HttpRes
     return render(request, "pages/invoices/dashboard/_modify_payment_status.html", {"status": status, "invoice_id": invoice_id})
 
 
+@require_POST
+def edit_discount(request: HttpRequest, invoice_id: str):
+    discount_type = "percentage" if request.POST.get("discount_type") == "on" else "amount"
+    discount_amount_str: str = request.POST.get("discount_amount")
+    percentage_amount_str: str = request.POST.get("percentage_amount")
+
+    if not request.htmx:
+        return redirect("invoices:dashboard")
+
+    try:
+        invoice: Invoice = Invoice.objects.get(id=invoice_id)
+    except Invoice.DoesNotExist:
+        return return_message(request, "Invoice not found", False)
+
+    if not invoice.has_access(request.user):
+        return return_message(request, "You don't have permission to make changes to this invoice.", False)
+
+    if discount_type == "percentage":
+        try:
+            percentage_amount = int(percentage_amount_str)
+            if percentage_amount < 0 or percentage_amount > 100:
+                raise ValueError
+        except ValueError:
+            return return_message(request, "Please enter a valid percentage amount (between 0 and 100)", False)
+        invoice.discount_percentage = percentage_amount
+    else:
+        try:
+            discount_amount = int(discount_amount_str)
+            if discount_amount < 0:
+                raise ValueError
+        except ValueError:
+            return return_message(request, "Please enter a valid discount amount", False)
+        invoice.discount_amount = discount_amount
+
+    invoice.save()
+
+    messages.success(request, "Discount was applied successfully")
+
+    response = render(request, "base/toasts.html")
+    response["HX-Trigger"] = "update_invoice"
+    return response
+
+
 def return_message(request: HttpRequest, message: str, success: bool = True) -> HttpResponse:
     send_message(request, message, success)
     return render(request, "base/toasts.html")
 
 
-def send_message(request: HttpRequest, message: str, success: bool = False) -> HttpResponse:
+def send_message(request: HttpRequest, message: str, success: bool = False) -> NoReturn:
     if success:
         messages.success(request, message)
     else:

backend/api/invoices/urls.py

@@ -31,6 +31,7 @@
         name="edit",
     ),
     path("edit/<int:invoice_id>/set_status/<str:status>/", edit.change_status, name="edit status"),
+    path("edit/<str:invoice_id>/discount/", edit.edit_discount, name="edit discount"),
     path("fetch/", fetch.fetch_all_invoices, name="fetch"),
     path("schedules/receive/", schedule.receive_scheduled_invoice, name="receive_scheduled_invoice"),
     path("create_schedule/", schedule.create_schedule, name="create_schedule"),

backend/migrations/0026_invoice_discount_amount_invoice_discount_percentage.py

@@ -0,0 +1,26 @@
+# Generated by Django 5.0.3 on 2024-03-29 20:00
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("backend", "0025_alter_invoiceonetimeschedule_stored_schedule_arn"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="invoice",
+            name="discount_amount",
+            field=models.DecimalField(decimal_places=2, default=0, max_digits=15),
+        ),
+        migrations.AddField(
+            model_name="invoice",
+            name="discount_percentage",
+            field=models.DecimalField(
+                decimal_places=2, default=0, max_digits=5, validators=[django.core.validators.MaxValueValidator(100)]
+            ),
+        ),
+    ]

backend/models.py

@@ -1,7 +1,9 @@
+from decimal import Decimal
 from uuid import uuid4
 
 from django.contrib.auth.hashers import make_password, check_password
 from django.contrib.auth.models import UserManager, AbstractUser, AnonymousUser
+from django.core.validators import MaxValueValidator
 from django.db import models
 from django.db.models import Count
 from django.utils import timezone
@@ -303,9 +305,23 @@ class Invoice(models.Model):
     date_due = models.DateField()
     date_issued = models.DateField(blank=True, null=True)
 
+    discount_amount = models.DecimalField(max_digits=15, default=0, decimal_places=2)
+    discount_percentage = models.DecimalField(default=0, max_digits=5, decimal_places=2, validators=[MaxValueValidator(100)])
+
     class Meta:
         constraints = [USER_OR_ORGANIZATION_CONSTRAINT()]
 
+    def __str__(self):
+        invoice_id = self.invoice_id or self.id
+        if self.client_name:
+            client = self.client_name
+        elif self.client_to:
+            client = self.client_to.name
+        else:
+            client = "Unknown Client"
+
+        return f"Invoice #{invoice_id} for {client}"
+
     @property
     def dynamic_payment_status(self):
         if self.date_due and timezone.now().date() > self.date_due and self.payment_status == "pending":
@@ -328,29 +344,50 @@ def get_to_details(self) -> tuple[str, dict[str, str]]:
                 "company": self.client_company,
             }
 
-    def __str__(self):
-        invoice_id = self.invoice_id or self.id
-        if self.client_name:
-            client = self.client_name
-        elif self.client_to:
-            client = self.client_to.name
-        else:
-            client = "Unknown Client"
-
-        return f"Invoice #{invoice_id} for {client}"
-
     def get_subtotal(self):
         subtotal = 0
         for item in self.items.all():
             subtotal += item.get_total_price()
         return round(subtotal, 2)
 
+    def get_tax(self, amount: float = 0.00) -> float:
+        amount = amount or self.get_subtotal()
+        if self.vat_number:
+            return round(amount * 0.2, 2)
+        return 0
+
+    def get_percentage_amount(self, subtotal: float = 0.00) -> Decimal:
+        total = subtotal or self.get_subtotal()
+
+        if self.discount_percentage > 0:
+            return round(total * (self.discount_percentage / 100), 2)
+        return Decimal(0)
+
     def get_total_price(self):
-        total = 0
-        subtotal = self.get_subtotal()
-        total = subtotal * 1.2 if self.vat_number else subtotal
+        total = self.get_subtotal() or 0.00
+
+        total -= self.get_percentage_amount()
+
+        discount_amount = self.discount_amount
+
+        total -= discount_amount
+
+        if 0 > total:
+            total = 0
+        else:
+            total -= self.get_tax(total)
+
         return round(total, 2)
 
+    def has_access(self, user: User) -> bool:
+        if not user.is_authenticated:
+            return False
+
+        if user.logged_in_as_team:
+            return self.organization == user.logged_in_as_team
+        else:
+            return self.user == user
+
 
 class InvoiceURL(models.Model):
     uuid = ShortUUIDField(length=8, primary_key=True)

frontend/templates/base/_head.html

@@ -56,7 +56,6 @@
         htmx.config.globalViewTransitions = true
         htmx.config.useTemplateFragments = true // for swapping of table items
         Alpine.start()
-
     </script>
     {{ analytics|safe }}
     {% load tz_detect %}

frontend/templates/modals/invoices_edit_discount.html

@@ -0,0 +1,78 @@
+{% component_block "modal" id="modal_invoices_edit_discount" start_open="true" title="Edit invoice discount" %}
+{% fill "content" %}
+<form class="py-4"
+      id="modal_invoices_edit_discount-form"
+      hx-post="{% url 'api:invoices:edit discount' invoice_id=invoice.id %}"
+      hx-swap="none">
+    {% csrf_token %}
+    <div class="form-control my-4">
+        <label class="label cursor-pointer">
+            <span class="label-text">Fixed Amount</span>
+            <input data-discount="checkbox"
+                   name="discount_type"
+                   type="checkbox"
+                   class="toggle"
+                   checked />
+            <span class="label-text">Percentage</span>
+        </label>
+    </div>
+    <script>
+                const checkbox = document.querySelector('input[data-discount="checkbox"]');
+                const amount_label = document.querySelector('label[data-discount="amount"]')
+                const percentage_label = document.querySelector('label[data-discount="percentage"]')
+
+                checkbox.addEventListener("change", function () {
+                    if (checkbox.checked) {
+                        amount_label.classList.add("hidden")
+                        percentage_label.classList.remove("hidden")
+                        amount_label.querySelector("input").required = false;
+                        percentage_label.querySelector("input").required = true;
+                        amount_label.querySelector("input").pattern = "[0-9]+";
+                        percentage_label.querySelector("input").removeAttribute("pattern");
+                    } else {
+                        percentage_label.classList.add("hidden")
+                        amount_label.classList.remove("hidden")
+                        amount_label.querySelector("input").required = true;
+                        percentage_label.querySelector("input").required = false;
+                        amount_label.querySelector("input").pattern = "[0-9]+";
+                        percentage_label.querySelector("input").removeAttribute("pattern");
+                    }
+                })
+    </script>
+    <label data-discount="percentage"
+           class="input input-bordered flex items-center gap-2">
+        <i class="fa fa-solid fa-percentage mr-2"></i>
+        <input required
+               type="text"
+               class="grow"
+               placeholder="Percentage"
+               value="{{ invoice.discount_percentage|floatformat:0 }}"
+               name="percentage_amount"
+               pattern="[0-9]+" />
+    </label>
+    <label data-discount="amount"
+           class="input input-bordered flex items-center gap-2 hidden">
+        <i class="fa fa-solid fa-pound-sign mr-2"></i>
+        <input required
+               type="text"
+               class="grow"
+               value="{{ invoice.discount_percentage|floatformat:0 }}"
+               placeholder="Amount"
+               name="discount_amount"
+               pattern="[0-9]+" />
+    </label>
+    <div class="modal-action">
+        <button type="submit"
+                id="modal_invoices_edit_discount-submit"
+                class="btn btn-primary"
+                _="on click if #modal_invoices_edit_discount-form.checkValidity() call #modal_invoices_edit_discount.close() end">
+            Save
+        </button>
+        <button type="reset" class="btn btn-error">Reset</button>
+        <button type="button"
+                _="on click call #modal_invoices_edit_discount.close()"
+                class="btn">Close</button>
+    </div>
+</form>
+{% endfill %}
+{% endcomponent_block %}

frontend/templates/pages/invoices/dashboard/manage.html

@@ -24,10 +24,11 @@ <h1 class="text-center col-span-2">Invoice #{{ invoice.id }}</h1>
     <div class="card bg-base-100 shadow-xl w-full p-6 flex-col gap-y-4">
         <div class="flex flex-wrap gap-y-4">
             <button class="btn btn-md btn-outline btn-default grow loading-htmx mr-4"
+                    data-htmx="preview-button"
                     hx-target="#container"
                     hx-get="{% url "api:invoices:tab preview" invoice_id=invoice.id %}"
                     hx-swap="innerHTML"
-                    hx-trigger="load,click,queue:last"
+                    hx-trigger="load,click,update_invoice from:body,queue:last"
                     hx-indicator="this">
                 <span class="loading-htmx-text">
                     <i class="fa-solid fa-file-pdf"></i>
@@ -90,6 +91,15 @@ <h1 class="text-center col-span-2">Invoice #{{ invoice.id }}</h1>
                         </li>
                     </ul>
                 </div>
+                <button class="btn btn-secondary"
+                        hx-trigger="click once"
+                        hx-swap="beforeend"
+                        hx-target="#modal_container"
+                        _="on click call modal_invoices_edit_discount.showModal()"
+                        hx-get="{% url "api:base:modal retrieve with context" context_type="invoice" context_value=invoice.id modal_name="invoices_edit_discount" %}">
+                    <i class="fa fa-solid fa-pound-sign mr-2"></i>
+                    Edit Discount
+                </button>
             </div>
         </div>
     </div>

frontend/templates/pages/invoices/view/invoice.html

@@ -102,14 +102,25 @@ <h2 class="text-2xl font-bold text-gray-800">INVOICE</h2>
                         </td>
                     </tr>
                 {% endif %}
-                {% if invoice.discount %}
+                {% if invoice.discount_percentage %}
                     <tr class="bg-gray-50">
                         <th colspan="3"
                             class="px-6 py-3 text-left text-sm font-medium text-gray-500 uppercase tracking-wider">
                             Discount
                         </th>
-                        <td class="px-6 py-3 text-right text-sm font-medium text-gray-500 uppercase tracking-wider">
-                            -{{ invoice.discount }}%
+                        <td class="px-6 py-3 text-right text-sm font-medium text-error uppercase tracking-wider text-balance">
+                            {{ invoice.discount_percentage }}% off (-{{ currency_symbol }}{{ invoice.get_percentage_amount }})
+                        </td>
+                    </tr>
+                {% endif %}
+                {% if invoice.discount_amount %}
+                    <tr class="bg-gray-50">
+                        <th colspan="3"
+                            class="px-6 py-3 text-left text-sm font-medium text-gray-500 uppercase tracking-wider">
+                            {% if not invoice.discount_percentage %}Discount{% endif %}
+                        </th>
+                        <td class="px-6 py-3 text-right text-sm font-medium text-error uppercase tracking-wider">
+                            -{{ currency_symbol }}{{ invoice.discount_amount }}
                         </td>
                     </tr>
                 {% endif %}

frontend/templates/pages/invoices/view/invoice_page.html

@@ -52,7 +52,7 @@
                         Print
                     </button>
                     <a class="btn btn-sm gradient-btn me-8"
-                       href="{% url "invoices: manage_access" invoice_id=invoice.id %}">Share Invoice</a>
+                       href="{% url "invoices:manage_access" invoice_id=invoice.id %}">Share Invoice</a>
                     <div class="flex items-center">
                         <button onclick="document.getElementById('status_banner').remove();"
                                 type="button"