complete first version of main proccess

invoices/migrations/0003_alter_historicalpayment_reference_number_and_more.py

@@ -0,0 +1,23 @@
+# Generated by Django 5.2.4 on 2025-08-21 18:03
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('invoices', '0002_historicalpayment_receipt_image_and_more'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='historicalpayment',
+            name='reference_number',
+            field=models.CharField(blank=True, db_index=True, max_length=100, verbose_name='شماره مرجع'),
+        ),
+        migrations.AlterField(
+            model_name='payment',
+            name='reference_number',
+            field=models.CharField(blank=True, max_length=100, unique=True, verbose_name='شماره مرجع'),
+        ),
+    ]

invoices/migrations/0004_historicalpayment_direction_payment_direction.py

@@ -0,0 +1,23 @@
+# Generated by Django 5.2.4 on 2025-08-22 08:18
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('invoices', '0003_alter_historicalpayment_reference_number_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='historicalpayment',
+            name='direction',
+            field=models.CharField(choices=[('in', 'دریافتی'), ('out', 'پرداختی')], default='in', max_length=3, verbose_name='نوع تراکنش'),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='direction',
+            field=models.CharField(choices=[('in', 'دریافتی'), ('out', 'پرداختی')], default='in', max_length=3, verbose_name='نوع تراکنش'),
+        ),
+    ]

invoices/migrations/0005_historicalitem_is_special_and_more.py

@@ -0,0 +1,33 @@
+# Generated by Django 5.2.4 on 2025-08-22 08:54
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('invoices', '0004_historicalpayment_direction_payment_direction'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='historicalitem',
+            name='is_special',
+            field=models.BooleanField(default=False, verbose_name='ویژه برای فاکتور نهایی'),
+        ),
+        migrations.AddField(
+            model_name='historicalitem',
+            name='special_kind',
+            field=models.CharField(blank=True, choices=[('repair', 'تعمیر'), ('replace', 'تعویض')], max_length=10, verbose_name='نوع ویژه'),
+        ),
+        migrations.AddField(
+            model_name='item',
+            name='is_special',
+            field=models.BooleanField(default=False, verbose_name='ویژه برای فاکتور نهایی'),
+        ),
+        migrations.AddField(
+            model_name='item',
+            name='special_kind',
+            field=models.CharField(blank=True, choices=[('repair', 'تعمیر'), ('replace', 'تعویض')], max_length=10, verbose_name='نوع ویژه'),
+        ),
+    ]

invoices/migrations/0006_remove_historicalitem_special_kind_and_more.py

@@ -0,0 +1,21 @@
+# Generated by Django 5.2.4 on 2025-08-22 08:59
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('invoices', '0005_historicalitem_is_special_and_more'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='historicalitem',
+            name='special_kind',
+        ),
+        migrations.RemoveField(
+            model_name='item',
+            name='special_kind',
+        ),
+    ]

invoices/models.py

@@ -18,6 +18,7 @@ class Item(NameSlugModel):
         decimal_places=2, 
         verbose_name="قیمت واحد"
     )
+    is_special = models.BooleanField(default=False, verbose_name='ویژه برای فاکتور نهایی')
     default_quantity = models.PositiveIntegerField(
         default=1, 
         verbose_name="تعداد پیش‌فرض"
@@ -102,7 +103,8 @@ class Quote(NameSlugModel):
 
     def calculate_totals(self):
         """محاسبه مبالغ کل"""
-        total = sum(item.total_price for item in self.items.all())
+        total = sum(item.total_price for item in self.items.filter(is_deleted=False).all())
+        total = sum(item.total_price for item in self.items.filter(is_deleted=False).all())
         self.total_amount = total
         
         # محاسبه تخفیف
@@ -260,15 +262,19 @@ class Invoice(NameSlugModel):
             self.discount_amount = 0
         
         self.final_amount = self.total_amount - self.discount_amount
-        self.remaining_amount = self.final_amount - self.paid_amount
-        
-        # بروزرسانی وضعیت
-        if self.remaining_amount <= 0:
+        # خالص مانده به نفع شرکت (مثبت) یا به نفع مشتری (منفی)
+        net_due = self.final_amount - self.paid_amount
+        self.remaining_amount = net_due
+
+        # وضعیت بر اساس مانده خالص
+        if net_due == 0:
             self.status = 'paid'
-        elif self.paid_amount > 0:
-            self.status = 'partially_paid'
+        elif net_due > 0:
+            # مشتری هنوز باید پرداخت کند
+            self.status = 'partially_paid' if self.paid_amount > 0 else 'sent'
         else:
-            self.status = 'sent'
+            # شرکت باید به مشتری پرداخت کند
+            self.status = 'partially_paid'
         
         self.save()
 
@@ -314,6 +320,12 @@ class Payment(BaseModel):
     """مدل پرداخت‌ها"""
     invoice = models.ForeignKey(Invoice, on_delete=models.CASCADE, related_name='payments', verbose_name="فاکتور")
     amount = models.DecimalField(max_digits=15, decimal_places=2, verbose_name="مبلغ پرداخت")
+    direction = models.CharField(
+        max_length=3,
+        choices=[('in', 'دریافتی'), ('out', 'پرداختی')],
+        default='in',
+        verbose_name='نوع تراکنش'
+    )
     payment_method = models.CharField(
         max_length=20,
         choices=[
@@ -326,7 +338,7 @@ class Payment(BaseModel):
         default='cash',
         verbose_name="روش پرداخت"
     )
-    reference_number = models.CharField(max_length=100, verbose_name="شماره مرجع", blank=True)
+    reference_number = models.CharField(max_length=100, verbose_name="شماره مرجع", blank=True, unique=True)
     payment_date = models.DateField(verbose_name="تاریخ پرداخت")
     notes = models.TextField(verbose_name="یادداشت‌ها", blank=True)
     receipt_image = models.ImageField(upload_to='payments/%Y/%m/%d/', null=True, blank=True, verbose_name="تصویر فیش")
@@ -345,6 +357,17 @@ class Payment(BaseModel):
         """بروزرسانی مبالغ فاکتور"""
         super().save(*args, **kwargs)
         # بروزرسانی مبلغ پرداخت شده فاکتور
-        total_paid = sum(payment.amount for payment in self.invoice.payments.all())
+        total_paid = sum((p.amount if p.direction == 'in' else -p.amount) for p in self.invoice.payments.filter(is_deleted=False).all())
         self.invoice.paid_amount = total_paid
         self.invoice.calculate_totals()
+
+    def delete(self, using=None, keep_parents=False):
+        """حذف نرم و بروزرسانی مبالغ فاکتور پس از حذف"""
+        result = super().delete(using=using, keep_parents=keep_parents)
+        try:
+            total_paid = sum((p.amount if p.direction == 'in' else -p.amount) for p in self.invoice.payments.filter(is_deleted=False).all())
+            self.invoice.paid_amount = total_paid
+            self.invoice.calculate_totals()
+        except Exception:
+            pass
+        return result

invoices/templates/invoices/final_invoice_print.html

@@ -0,0 +1,55 @@
+{% extends '_base.html' %}
+{% load humanize %}
+
+{% block content %}
+<div class="container py-4">
+  <div class="mb-4 d-flex justify-content-between align-items-center">
+    <div>
+      <h4 class="mb-1">فاکتور نهایی</h4>
+      <small class="text-muted">کد درخواست: {{ instance.code }}</small>
+    </div>
+    <div>
+      <!-- Placeholders for logo/signature -->
+      <div class="text-end">لوگو</div>
+    </div>
+  </div>
+  <div class="table-responsive">
+    <table class="table table-bordered">
+      <thead>
+        <tr>
+          <th>آیتم</th>
+          <th>تعداد</th>
+          <th>قیمت واحد</th>
+          <th>قیمت کل</th>
+        </tr>
+      </thead>
+      <tbody>
+        {% for it in items %}
+        <tr>
+          <td>{{ it.item.name }}</td>
+          <td>{{ it.quantity }}</td>
+          <td>{{ it.unit_price|floatformat:0|intcomma:False }}</td>
+          <td>{{ it.total_price|floatformat:0|intcomma:False }}</td>
+        </tr>
+        {% empty %}
+        <tr><td colspan="4" class="text-center text-muted">آیتمی ندارد</td></tr>
+        {% endfor %}
+      </tbody>
+      <tfoot>
+        <tr><th colspan="3" class="text-end">مبلغ کل</th><th>{{ invoice.total_amount|floatformat:0|intcomma:False }}</th></tr>
+        <tr><th colspan="3" class="text-end">تخفیف</th><th>{{ invoice.discount_amount|floatformat:0|intcomma:False }}</th></tr>
+        <tr><th colspan="3" class="text-end">مبلغ نهایی</th><th>{{ invoice.final_amount|floatformat:0|intcomma:False }}</th></tr>
+        <tr><th colspan="3" class="text-end">پرداختی‌ها</th><th>{{ invoice.paid_amount|floatformat:0|intcomma:False }}</th></tr>
+        <tr><th colspan="3" class="text-end">مانده</th><th>{{ invoice.remaining_amount|floatformat:0|intcomma:False }}</th></tr>
+      </tfoot>
+    </table>
+  </div>
+  <div class="mt-5 d-flex justify-content-between">
+    <div>امضا مشتری</div>
+    <div>امضا شرکت</div>
+  </div>
+</div>
+<script>window.print()</script>
+{% endblock %}
+
+

invoices/templates/invoices/final_invoice_step.html

@@ -0,0 +1,260 @@
+{% extends '_base.html' %}
+{% load static %}
+{% load processes_tags %}
+{% load humanize %}
+
+{% block sidebar %}
+    {% include 'sidebars/admin.html' %}
+{% endblock sidebar %}
+
+{% block navbar %}
+    {% include 'navbars/admin.html' %}
+{% endblock navbar %}
+
+{% block title %}{{ step.name }} - درخواست {{ instance.code }}{% endblock %}
+
+{% block style %}
+<link rel="stylesheet" href="{% static 'assets/vendor/libs/bs-stepper/bs-stepper.css' %}">
+<style>
+@media print {
+  .no-print { display: none !important; }
+}
+</style>
+{% endblock %}
+
+{% block content %}
+{% include '_toasts.html' %}
+{% csrf_token %}
+<div class="container-xxl flex-grow-1 container-p-y">
+  <div class="row">
+    <div class="col-12 mb-4">
+      <div class="d-flex align-items-center justify-content-between mb-3 no-print">
+        <div>
+          <h4 class="mb-1">{{ step.name }}: {{ instance.process.name }}</h4>
+          <small class="text-muted d-block">
+            اشتراک آب: {{ instance.well.water_subscription_number|default:"-" }}
+            | نماینده: {{ instance.representative.profile.national_code|default:"-" }}
+          </small>
+        </div>
+        <div class="d-flex gap-2">
+        <a href="{% url 'invoices:final_invoice_print' instance.id %}" target="_blank" class="btn btn-outline-secondary"><i class="bx bx-printer"></i> پرینت</a>
+
+          <a href="{% url 'processes:request_list' %}" class="btn btn-outline-secondary">بازگشت</a>
+        </div>
+      </div>
+
+      <div class="bs-stepper wizard-vertical vertical mt-2 no-print">
+        {% stepper_header instance step %}
+        <div class="bs-stepper-content">
+
+      <div class="card border">
+        <div class="card-header d-flex justify-content-between align-items-center">
+          <h5 class="mb-0">فاکتور نهایی</h5>
+          <button type="button" class="btn btn-sm btn-outline-primary" onclick="openSpecialChargeModal()"><i class="bx bx-plus"></i> افزودن هزینه تعمیر/تعویض</button>
+        </div>
+
+        <div class="card-body">
+          <div class="row g-3 mb-3">
+            <div class="col-6 col-md-3">
+              <div class="border rounded p-3 h-100">
+                <div class="small text-muted">مبلغ نهایی</div>
+                <div class="h5 mt-1">{{ invoice.final_amount|floatformat:0|intcomma:False }} تومان</div>
+              </div>
+            </div>
+            <div class="col-6 col-md-3">
+              <div class="border rounded p-3 h-100">
+                <div class="small text-muted">پرداختی‌ها</div>
+                <div class="h5 mt-1 text-success">{{ invoice.paid_amount|floatformat:0|intcomma:False }} تومان</div>
+              </div>
+            </div>
+            <div class="col-6 col-md-3">
+              <div class="border rounded p-3 h-100">
+                <div class="small text-muted">مانده</div>
+                <div class="h5 mt-1 {% if invoice.remaining_amount <= 0 %}text-success{% else %}text-danger{% endif %}">{{ invoice.remaining_amount|floatformat:0|intcomma:False }} تومان</div>
+              </div>
+            </div>
+            <div class="col-6 col-md-3 d-flex align-items-center">
+              {% if invoice.remaining_amount <= 0 %}
+                <span class="badge bg-success">تسویه کامل</span>
+              {% else %}
+                <span class="badge bg-warning text-dark">باقی‌مانده دارد</span>
+              {% endif %}
+            </div>
+          </div>
+          <div class="table-responsive">
+            <table class="table table-striped">
+              <thead>
+                <tr>
+                  <th>آیتم</th>
+                  <th class="text-center">تعداد پایه</th>
+                  <th class="text-center">افزوده</th>
+                  <th class="text-center">حذف</th>
+                  <th class="text-center">تعداد نهایی</th>
+                  <th class="text-end">قیمت واحد (تومان)</th>
+                  <th class="text-end">قیمت کل (تومان)</th>
+                </tr>
+              </thead>
+              <tbody>
+                {% for r in rows %}
+                <tr>
+                  <td>
+                    <div class="d-flex flex-column">
+                      <span class="fw-semibold">{{ r.item.name }}</span>
+                      {% if r.item.description %}<small class="text-muted">{{ r.item.description }}</small>{% endif %}
+                    </div>
+                  </td>
+                  <td class="text-center">{{ r.base_qty }}</td>
+                  <td class="text-center text-success">{{ r.added_qty }}</td>
+                  <td class="text-center text-danger">{{ r.removed_qty }}</td>
+                  <td class="text-center">{{ r.quantity }}</td>
+                  <td class="text-end">{{ r.unit_price|floatformat:0|intcomma:False }}</td>
+                  <td class="text-end">{{ r.total_price|floatformat:0|intcomma:False }}</td>
+                </tr>
+                {% empty %}
+                <tr><td colspan="7" class="text-center text-muted">آیتمی یافت نشد</td></tr>
+                {% endfor %}
+                {% for si in invoice_specials %}
+                <tr class="table-warning">
+                  <td>
+                    <div class="d-flex flex-column">
+                      <span class="fw-semibold">{{ si.item.name }}<span class="badge bg-info mx-2">ویژه</span></span>                      
+                    </div>
+                  </td>
+                  <td class="text-center">-</td>
+                  <td class="text-center">-</td>
+                  <td class="text-center">-</td>
+                  <td class="text-center">{{ si.quantity }}</td>
+                  <td class="text-end">{{ si.unit_price|floatformat:0|intcomma:False }}</td>
+                  <td class="text-end">
+                    {{ si.total_price|floatformat:0|intcomma:False }}
+                    <button type="button" class="btn btn-sm btn-outline-danger ms-2" onclick="deleteSpecial('{{ si.id }}')" title="حذف"><i class="bx bx-trash"></i></button>
+                  </td>
+                </tr>
+                {% endfor %}
+              </tbody>
+              <tfoot>
+                <tr>
+                  <th colspan="6" class="text-end">مبلغ کل</th>
+                  <th class="text-end">{{ invoice.total_amount|floatformat:0|intcomma:False }} تومان</th>
+                </tr>
+                <tr>
+                  <th colspan="6" class="text-end">تخفیف</th>
+                  <th class="text-end">{{ invoice.discount_amount|floatformat:0|intcomma:False }} تومان</th>
+                </tr>
+                <tr>
+                  <th colspan="6" class="text-end">مبلغ نهایی</th>
+                  <th class="text-end">{{ invoice.final_amount|floatformat:0|intcomma:False }} تومان</th>
+                </tr>
+                <tr>
+                  <th colspan="6" class="text-end">پرداختی‌ها</th>
+                  <th class="text-end">{{ invoice.paid_amount|floatformat:0|intcomma:False }} تومان</th>
+                </tr>
+                <tr>
+                  <th colspan="6" class="text-end">مانده</th>
+                  <th class="text-end {% if invoice.remaining_amount <= 0 %}text-success{% else %}text-danger{% endif %}">{{ invoice.remaining_amount|floatformat:0|intcomma:False }} تومان</th>
+                </tr>
+              </tfoot>
+            </table>
+          </div>
+        </div>
+        <div class="card-footer d-flex justify-content-between">
+          {% if previous_step %}
+            <a href="{% url 'processes:step_detail' instance.id previous_step.id %}" class="btn btn-label-secondary">قبلی</a>
+          {% else %}
+            <span></span>
+          {% endif %}
+          {% if next_step %}
+            <button type="button" class="btn btn-primary" id="btnApproveFinalInvoice">تایید و ادامه</button>
+          {% endif %}
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+<!-- Special Charge Modal -->
+<div class="modal fade" id="specialChargeModal" tabindex="-1" aria-labelledby="specialChargeModalLabel" aria-hidden="true">
+  <div class="modal-dialog">
+    <div class="modal-content">
+      <div class="modal-header">
+        <h5 class="modal-title" id="specialChargeModalLabel">افزودن هزینه تعمیر/تعویض</h5>
+        <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
+      </div>
+      <div class="modal-body">
+        <form id="specialChargeForm" onsubmit="return false;">
+          {% csrf_token %}
+          <div class="mb-3">
+            <label class="form-label">انتخاب آیتم ویژه</label>
+            <select class="form-select" name="item_id" id="id_special_item" required>
+              <option value="">انتخاب کنید...</option>
+              {% for s in special_choices %}
+                <option value="{{ s.id }}">{{ s.name }}</option>
+              {% endfor %}
+            </select>
+          </div>
+          <div class="mb-3">
+            <label class="form-label">مبلغ (تومان)</label>
+            <input type="number" class="form-control" name="amount" id="id_charge_amount" min="1" required>
+          </div>
+        </form>
+      </div>
+      <div class="modal-footer">
+        <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">انصراف</button>
+        <button type="button" class="btn btn-primary" onclick="submitSpecialCharge()">افزودن</button>
+      </div>
+    </div>
+  </div>
+</div>
+{% endblock %}
+
+{% block script %}
+<script>
+  function openSpecialChargeModal(){
+    const el = document.getElementById('specialChargeModal');
+    if (window.$ && typeof $(el).modal === 'function') { $(el).modal('show'); }
+    else if (window.bootstrap && window.bootstrap.Modal) { new window.bootstrap.Modal(el).show(); }
+    else { el.classList.add('show'); el.style.display = 'block'; }
+  }
+  function submitSpecialCharge(){
+    const fd = new FormData(document.getElementById('specialChargeForm'));
+    fd.append('csrfmiddlewaretoken', document.querySelector('input[name=csrfmiddlewaretoken]').value);
+    fetch('{% url "invoices:add_special_charge" instance.id step.id %}', { method: 'POST', body: fd })
+      .then(r=>r.json()).then(resp=>{
+        if (resp.success){
+          showToast('هزینه ویژه اضافه شد', 'success');
+          if (resp.redirect) setTimeout(()=>{ window.location.href = resp.redirect; }, 600);
+        } else {
+          showToast(resp.message || 'خطا در افزودن هزینه', 'danger');
+        }
+      }).catch(()=> showToast('خطا در ارتباط با سرور', 'danger'));
+  }
+  // No filtering needed; show all special items
+  function deleteSpecial(id){
+    const fd = new FormData();
+    fd.append('csrfmiddlewaretoken', document.querySelector('input[name=csrfmiddlewaretoken]').value);
+    fetch(`{% url "invoices:delete_special_charge" instance.id step.id 0 %}`.replace('/0/', `/${id}/`), { method: 'POST', body: fd })
+      .then(r=>r.json()).then(resp=>{
+        if (resp.success){
+          showToast('حذف شد', 'success');
+          if (resp.redirect) setTimeout(()=>{ window.location.href = resp.redirect; }, 500);
+        } else {
+          showToast(resp.message || 'خطا در حذف', 'danger');
+        }
+      }).catch(()=> showToast('خطا در ارتباط با سرور', 'danger'));
+  }
+  document.getElementById('btnApproveFinalInvoice')?.addEventListener('click', function(){
+    const fd = new FormData();
+    fd.append('csrfmiddlewaretoken', document.querySelector('input[name=csrfmiddlewaretoken]').value);
+    fetch('{% url "invoices:approve_final_invoice" instance.id step.id %}', { method:'POST', body: fd })
+      .then(r=>r.json()).then(resp=>{
+        if (resp.success){
+          showToast(resp.message || 'تایید شد', 'success');
+          if (resp.redirect) setTimeout(()=>{ window.location.href = resp.redirect; }, 600);
+        } else {
+          showToast(resp.message || 'خطا در تایید', 'danger');
+        }
+      }).catch(()=> showToast('خطا در ارتباط با سرور', 'danger'));
+  });
+</script>
+{% endblock %}
+
+

invoices/templates/invoices/final_settlement_step.html

@@ -0,0 +1,248 @@
+{% extends '_base.html' %}
+{% load static %}
+{% load processes_tags %}
+{% load common_tags %}
+{% load humanize %}
+
+{% block sidebar %}
+    {% include 'sidebars/admin.html' %}
+{% endblock sidebar %}
+
+{% block navbar %}
+    {% include 'navbars/admin.html' %}
+{% endblock navbar %}
+
+{% block title %}{{ step.name }} - درخواست {{ instance.code }}{% endblock %}
+
+{% block style %}
+<link rel="stylesheet" href="{% static 'assets/vendor/libs/bs-stepper/bs-stepper.css' %}">
+<!-- Persian Date Picker CSS -->
+<link rel="stylesheet" href="https://unpkg.com/persian-datepicker@latest/dist/css/persian-datepicker.min.css">
+{% endblock %}
+
+{% block content %}
+{% include '_toasts.html' %}
+{% csrf_token %}
+<div class="container-xxl flex-grow-1 container-p-y">
+  <div class="row">
+    <div class="col-12 mb-4">
+      <div class="d-flex align-items-center justify-content-between mb-3 no-print">
+        <div>
+          <h4 class="mb-1">{{ step.name }}: {{ instance.process.name }}</h4>
+          <small class="text-muted d-block">
+            اشتراک آب: {{ instance.well.water_subscription_number|default:"-" }}
+            | نماینده: {{ instance.representative.profile.national_code|default:"-" }}
+          </small>
+        </div>
+        <div class="d-flex gap-2">
+          <a href="{% url 'invoices:final_invoice_print' instance.id %}" target="_blank" class="btn btn-outline-secondary"><i class="bx bx-printer"></i> پرینت</a>
+
+          <a href="{% url 'processes:request_list' %}" class="btn btn-outline-secondary">بازگشت</a>
+        </div>
+      </div>
+
+      <div class="bs-stepper wizard-vertical vertical mt-2 no-print">
+        {% stepper_header instance step %}
+        <div class="bs-stepper-content">
+
+      <div class="row g-3">
+        <div class="col-12 col-lg-5">
+          <div class="card border h-100">
+            <div class="card-header"><h5 class="mb-0">ثبت تراکنش تسویه</h5></div>
+            <div class="card-body">
+              <form id="formFinalPayment" enctype="multipart/form-data" onsubmit="return false;">
+                {% csrf_token %}
+                <div class="mb-3">
+                  <label class="form-label">نوع تراکنش</label>
+                  <select class="form-select" name="direction" id="id_direction" required>
+                    <option value="in">دریافتی از مشتری</option>
+                    <option value="out">پرداخت به مشتری</option>
+                  </select>
+                </div>
+                <div class="mb-3">
+                  <label class="form-label">مبلغ (تومان)</label>
+                  <input type="number" min="1" class="form-control" name="amount" id="id_amount" required>
+                </div>
+                <div class="mb-3">
+                  <label class="form-label">تاریخ</label>
+                  <input type="text" class="form-control" id="id_payment_date" name="payment_date" placeholder="انتخاب تاریخ" readonly required>
+                </div>
+                <div class="mb-3">
+                  <label class="form-label">روش پرداخت</label>
+                  <select class="form-select" name="payment_method" id="id_payment_method" required>
+                    <option value="bank_transfer">انتقال بانکی</option>
+                    <option value="card">کارت بانکی</option>
+                    <option value="cash">نقدی</option>
+                    <option value="check">چک</option>
+                    <option value="other">سایر</option>
+                  </select>
+                </div>
+                <div class="mb-3">
+                  <label class="form-label">شماره مرجع</label>
+                  <input type="text" class="form-control" name="reference_number" id="id_reference_number" required>
+                </div>
+                <div class="mb-3">
+                  <label class="form-label">تصویر فیش</label>
+                  <input type="file" class="form-control" name="receipt_image" id="id_receipt_image" accept="image/*" required>
+                </div>
+                <div class="d-flex justify-content-end">
+                  <button type="button" id="btnAddFinalPayment" class="btn btn-primary">افزودن</button>
+                </div>
+              </form>
+            </div>
+          </div>
+        </div>
+        <div class="col-12 col-lg-7">
+          <div class="card mb-3 border">
+            <div class="card-header"><h5 class="mb-0">وضعیت فاکتور</h5></div>
+            <div class="card-body">
+              <div class="row g-3">
+                <div class="col-6">
+                  <div class="border rounded p-3">
+                    <div class="small text-muted">مبلغ نهایی</div>
+                    <div class="h5 mt-1">{{ invoice.final_amount|floatformat:0|intcomma:False }} تومان</div>
+                  </div>
+                </div>
+                <div class="col-6">
+                  <div class="border rounded p-3">
+                    <div class="small text-muted">مانده</div>
+                    <div class="h5 mt-1 {% if invoice.remaining_amount <= 0 %}text-success{% else %}text-danger{% endif %}">{{ invoice.remaining_amount|floatformat:0|intcomma:False }} تومان</div>
+                  </div>
+                </div>
+              </div>
+            </div>
+          </div>
+
+          <div class="card border">
+            <div class="card-header"><h5 class="mb-0">تراکنش‌ها</h5></div>
+            <div class="table-responsive">
+              <table class="table table-striped mb-0">
+                <thead>
+                  <tr>
+                    <th>نوع</th>
+                    <th>مبلغ</th>
+                    <th>تاریخ</th>
+                    <th>روش</th>
+                    <th>شماره مرجع</th>
+                    <th style="width:150px">عملیات</th>
+                  </tr>
+                </thead>
+                <tbody>
+                  {% for p in payments %}
+                  <tr>
+                    <td>{% if p.direction == 'in' %}<span class="badge bg-success">دریافتی{% else %}<span class="badge bg-warning text-dark">پرداختی{% endif %}</span></td>
+                    <td>{{ p.amount|floatformat:0|intcomma:False }} تومان</td>
+                    <td>{{ p.payment_date|to_jalali }}</td>
+                    <td>{{ p.get_payment_method_display }}</td>
+                    <td>{{ p.reference_number|default:'-' }}</td>
+                    <td>
+                      <div class="btn-group">
+                        {% if p.receipt_image %}
+                          <a href="{{ p.receipt_image.url }}" target="_blank" class="btn btn-sm btn-outline-secondary" title="مشاهده" aria-label="مشاهده">
+                            <i class="bx bx-show"></i>
+                          </a>
+                        {% endif %}
+                        <button type="button" class="btn btn-sm btn-outline-danger" onclick="deleteFinalPayment({{ p.id }})" title="حذف" aria-label="حذف"><i class="bx bx-trash"></i></button>
+                      </div>
+                    </td>
+                  </tr>
+                  {% empty %}
+                  <tr><td colspan="6" class="text-center text-muted">تراکنشی ندارد</td></tr>
+                  {% endfor %}
+                </tbody>
+              </table>
+            </div>
+            <div class="card-footer d-flex justify-content-between">
+              {% if previous_step %}
+                <a href="{% url 'processes:step_detail' instance.id previous_step.id %}" class="btn btn-label-secondary">قبلی</a>
+              {% else %}
+                <span></span>
+              {% endif %}
+              <button type="button" id="btnApproveFinalSettlement" class="btn btn-primary">تایید و ادامه</button>
+            </div>
+          </div>
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+{% endblock %}
+
+{% block script %}
+<script src="https://unpkg.com/persian-date@latest/dist/persian-date.min.js"></script>
+<script src="https://unpkg.com/persian-datepicker@latest/dist/js/persian-datepicker.min.js"></script>
+<script>
+  (function initPersianDatePicker(){
+    if (window.$ && $.fn.persianDatepicker && $('#id_payment_date').length) {
+      $('#id_payment_date').persianDatepicker({
+        format: 'YYYY/MM/DD', initialValue: false, autoClose: true, persianDigit: false, observer: true,
+        calendar: { persian: { locale: 'fa', leapYearMode: 'astronomical' } },
+        onSelect: function(unix){
+          const g = new window.persianDate(unix).toCalendar('gregorian').format('YYYY-MM-DD');
+          $('#id_payment_date').attr('data-gregorian', g);
+        }
+      });
+    }
+  })();
+
+  function buildForm(){
+    const fd = new FormData(document.getElementById('formFinalPayment'));
+    const g = document.getElementById('id_payment_date').getAttribute('data-gregorian');
+    if (g) { fd.set('payment_date', g); }
+    return fd;
+  }
+  document.getElementById('btnAddFinalPayment').addEventListener('click', function(){
+    const fd = buildForm();
+    // Frontend validation
+    const amount = document.getElementById('id_amount').value.trim();
+    const payDate = document.getElementById('id_payment_date').value.trim();
+    const method = document.getElementById('id_payment_method').value.trim();
+    const ref = document.getElementById('id_reference_number').value.trim();
+    const img = document.getElementById('id_receipt_image').files[0];
+    const dir = document.getElementById('id_direction').value;
+    if (!amount || !payDate || !method || !ref || !img) {
+      showToast('همه فیلدها الزامی است', 'danger');
+      return;
+    }
+    fetch('{% url "invoices:add_final_payment" instance.id step.id %}', { method:'POST', body: fd })
+      .then(r=>r.json()).then(resp=>{
+        if (resp.success) {
+          showToast('تراکنش ثبت شد', 'success');
+          if (resp.redirect) setTimeout(()=>{ window.location.href = resp.redirect; }, 700);
+        } else {
+          showToast(resp.message || 'خطا در ثبت تراکنش', 'danger');
+        }
+      }).catch(()=> showToast('خطا در ارتباط با سرور', 'danger'));
+  });
+
+  function deleteFinalPayment(id){
+    const fd = new FormData();
+    fd.append('csrfmiddlewaretoken', document.querySelector('input[name=csrfmiddlewaretoken]').value);
+    fetch(`{% url "invoices:delete_final_payment" instance.id step.id 0 %}`.replace('/0/', `/${id}/`), { method:'POST', body: fd })
+      .then(r=>r.json()).then(resp=>{
+        if (resp.success) {
+          showToast('حذف شد', 'success');
+          if (resp.redirect) setTimeout(()=>{ window.location.href = resp.redirect; }, 500);
+        } else {
+          showToast(resp.message || 'خطا در حذف', 'danger');
+        }
+      }).catch(()=> showToast('خطا در ارتباط با سرور', 'danger'));
+  }
+
+  document.getElementById('btnApproveFinalSettlement').addEventListener('click', function(){
+    const fd = new FormData();
+    fd.append('csrfmiddlewaretoken', document.querySelector('input[name=csrfmiddlewaretoken]').value);
+    fetch('{% url "invoices:approve_final_settlement" instance.id step.id %}', { method:'POST', body: fd })
+      .then(r=>r.json()).then(resp=>{
+        if (resp.success) {
+          showToast(resp.message || 'تایید شد', 'success');
+          if (resp.redirect) setTimeout(()=>{ window.location.href = resp.redirect; }, 600);
+        } else {
+          showToast(resp.message || 'خطا در تایید', 'danger');
+        }
+      }).catch(()=> showToast('خطا در ارتباط با سرور', 'danger'));
+  });
+</script>
+{% endblock %}
+
+

invoices/templates/invoices/quote_payment_step.html

@@ -243,12 +243,12 @@
       body: fd
     }).then(r => r.json()).then(resp => {
       if (resp.success) {
-        showToast('فیش با موفقیت ثبت شد', 'success');
+        showToast(resp.message || 'فیش با موفقیت ثبت شد', 'success');
         if (resp.redirect) {
           setTimeout(() => { window.location.href = resp.redirect; }, 700);
         }
       } else {
-        showToast(resp.message || 'خطا در ثبت فیش', 'danger');
+        showToast(resp.message + ':' + resp.error || 'خطا در ثبت فیش', 'danger');
       }
     }).catch(() => showToast('خطا در ارتباط با سرور', 'danger'));
   });
@@ -267,11 +267,13 @@
       method: 'POST',
       body: fd
     }).then(r => r.json()).then(resp => {
-      if (resp.success && resp.redirect) {
-        showToast('فیش با موفقیت حذف شد', 'success');
-        setTimeout(() => { window.location.href = resp.redirect; }, 700);
+      if (resp.success) {
+        showToast(resp.message || 'فیش با موفقیت حذف شد', 'success');
+        if (resp.redirect) {
+          setTimeout(() => { window.location.href = resp.redirect; }, 700);
+        }
       } else {
-        showToast(resp.message || 'خطا در حذف فیش', 'danger');
+        showToast(resp.message || resp.error || 'خطا در حذف فیش', 'danger');
       }
     }).catch(() => showToast('خطا در ارتباط با سرور', 'danger'));
   }
@@ -288,11 +290,13 @@
       method: 'POST',
       body: fd
     }).then(r => r.json()).then(resp => {
-      if (resp.success && resp.redirect) {
-        showToast(resp.message, 'success');
-        setTimeout(() => { window.location.href = resp.redirect; }, 600);
+      if (resp.success) {
+        showToast(resp.message || 'پرداخت‌ها تایید شد', 'success');
+        if (resp.redirect) {
+          setTimeout(() => { window.location.href = resp.redirect; }, 600);
+        }
       } else {
-        showToast(resp.message || 'خطا در تایید پرداخت‌ها', 'danger');
+        showToast(resp.message || resp.error || 'خطا در تایید پرداخت‌ها', 'danger');
       }
     }).catch(() => showToast('خطا در ارتباط با سرور', 'danger'));
   }

invoices/templates/invoices/quote_preview_step.html

@@ -48,7 +48,7 @@
         {% stepper_header instance step %}
         <div class="bs-stepper-content">
             <!-- Invoice Preview Card -->
-      <div class="card invoice-preview-card mt-4">
+      <div class="card invoice-preview-card mt-4 border">
         <div class="card-body">
           <div class="d-flex justify-content-between flex-xl-row flex-md-column flex-sm-row flex-column p-sm-3 p-0">
             <div class="mb-xl-0 mb-4">

invoices/urls.py

@@ -21,4 +21,17 @@ urlpatterns = [
 
     # Quote print
     path('instance/<int:instance_id>/quote/print/', views.quote_print, name='quote_print'),
+
+    # Final invoice (step 7?) and print
+    path('instance/<int:instance_id>/step/<int:step_id>/final-invoice/', views.final_invoice_step, name='final_invoice_step'),
+    path('instance/<int:instance_id>/final-invoice/print/', views.final_invoice_print, name='final_invoice_print'),
+    path('instance/<int:instance_id>/step/<int:step_id>/final-invoice/special/add/', views.add_special_charge, name='add_special_charge'),
+    path('instance/<int:instance_id>/step/<int:step_id>/final-invoice/special/<int:item_id>/delete/', views.delete_special_charge, name='delete_special_charge'),
+    path('instance/<int:instance_id>/step/<int:step_id>/final-invoice/approve/', views.approve_final_invoice, name='approve_final_invoice'),
+
+    # Final settlement payments (step 8?)
+    path('instance/<int:instance_id>/step/<int:step_id>/final-settlement/', views.final_settlement_step, name='final_settlement_step'),
+    path('instance/<int:instance_id>/step/<int:step_id>/final-settlement/add/', views.add_final_payment, name='add_final_payment'),
+    path('instance/<int:instance_id>/step/<int:step_id>/final-settlement/<int:payment_id>/delete/', views.delete_final_payment, name='delete_final_payment'),
+    path('instance/<int:instance_id>/step/<int:step_id>/final-settlement/approve/', views.approve_final_settlement, name='approve_final_settlement'),
 ]

invoices/views.py

@@ -11,6 +11,7 @@ import json
 
 from processes.models import ProcessInstance, ProcessStep, StepInstance
 from .models import Item, Quote, QuoteItem, Payment, Invoice
+from installations.models import InstallationReport, InstallationItemChange
 
 @login_required
 def quote_step(request, instance_id, step_id):
@@ -413,3 +414,358 @@ def approve_payments(request, instance_id, step_id):
         msg += ' - توجه: مبلغ پیش‌فاکتور به طور کامل پرداخت نشده است.'
 
     return JsonResponse({'success': True, 'message': msg, 'redirect': redirect_url, 'is_fully_paid': is_fully_paid})
+
+
+@login_required
+def final_invoice_step(request, instance_id, step_id):
+    """تجمیع اقلام پیش‌فاکتور با تغییرات نصب و صدور فاکتور نهایی"""
+    instance = get_object_or_404(
+        ProcessInstance.objects.select_related('process', 'well', 'requester', 'representative', 'representative__profile'),
+        id=instance_id
+    )
+    step = get_object_or_404(instance.process.steps, id=step_id)
+
+    if not instance.can_access_step(step):
+        messages.error(request, 'شما به این مرحله دسترسی ندارید. ابتدا مراحل قبلی را تکمیل کنید.')
+        return redirect('processes:request_list')
+
+    quote = get_object_or_404(Quote, process_instance=instance)
+
+    # Helper to make safe Decimal from various inputs (handles commas/persian digits)
+    def _to_decimal(value):
+        if isinstance(value, Decimal):
+            return value
+        try:
+            if isinstance(value, (int, float)):
+                return Decimal(str(value))
+            s = str(value or '').strip()
+            if not s:
+                return Decimal('0')
+            # normalize commas and Persian digits
+            persian = '۰۱۲۳۴۵۶۷۸۹'
+            latin = '0123456789'
+            tbl = str.maketrans({persian[i]: latin[i] for i in range(10)})
+            s = s.translate(tbl).replace(',', '')
+            return Decimal(s)
+        except Exception:
+            return Decimal('0')
+
+    # Build initial map from quote
+    item_id_to_row = {}
+    for qi in quote.items.all():
+        item_id_to_row[qi.item_id] = {
+            'item': qi.item,
+            'base_qty': qi.quantity,
+            'base_price': _to_decimal(qi.unit_price),
+            'added_qty': 0,
+            'removed_qty': 0,
+        }
+
+    # Read installation changes from latest report (if any)
+    latest_report = InstallationReport.objects.filter(assignment__process_instance=instance).order_by('-created').first()
+    if latest_report:
+        for ch in latest_report.item_changes.all():
+            row = item_id_to_row.setdefault(ch.item_id, {
+                'item': ch.item,
+                'base_qty': 0,
+                'base_price': _to_decimal(ch.unit_price or ch.item.unit_price),
+                'added_qty': 0,
+                'removed_qty': 0,
+            })
+            if ch.change_type == 'add':
+                row['added_qty'] += ch.quantity
+                if ch.unit_price:
+                    row['base_price'] = _to_decimal(ch.unit_price)
+            else:
+                row['removed_qty'] += ch.quantity
+                if ch.unit_price:
+                    row['base_price'] = _to_decimal(ch.unit_price)
+
+    # Compute final invoice lines
+    rows = []
+    total_amount = Decimal('0')
+    for _, r in item_id_to_row.items():
+        final_qty = max(0, (r['base_qty'] + r['added_qty'] - r['removed_qty']))
+        if final_qty == 0:
+            continue
+        unit_price_dec = _to_decimal(r['base_price'])
+        line_total = Decimal(final_qty) * unit_price_dec
+        total_amount += line_total
+        rows.append({
+            'item': r['item'],
+            'quantity': final_qty,
+            'unit_price': unit_price_dec,
+            'total_price': line_total,
+            'base_qty': r['base_qty'],
+            'added_qty': r['added_qty'],
+            'removed_qty': r['removed_qty'],
+        })
+
+    # Create or reuse final invoice
+    invoice, _ = Invoice.objects.get_or_create(
+        process_instance=instance,
+        customer=quote.customer,
+        quote=quote,
+        defaults={
+            'name': f"فاکتور نهایی {instance.code}",
+            'due_date': timezone.now().date(),
+            'created_by': request.user,
+        }
+    )
+    # Replace only non-special items (preserve special charges added by user)
+    qs = invoice.items.select_related('item').filter(item__is_special=False)
+    try:
+        qs._raw_delete(qs.db)
+    except Exception:
+        qs.delete()
+    for r in rows:
+        from .models import InvoiceItem
+        InvoiceItem.objects.create(
+            invoice=invoice,
+            item=r['item'],
+            quantity=r['quantity'],
+            unit_price=r['unit_price'],
+        )
+    invoice.calculate_totals()
+
+    previous_step = instance.process.steps.filter(order__lt=step.order).last()
+    next_step = instance.process.steps.filter(order__gt=step.order).first()
+
+    # Choices for special items from DB
+    special_choices = list(Item.objects.filter(is_special=True).values('id', 'name'))
+
+    return render(request, 'invoices/final_invoice_step.html', {
+        'instance': instance,
+        'step': step,
+        'invoice': invoice,
+        'rows': rows,
+        'special_choices': special_choices,
+        'invoice_specials': invoice.items.select_related('item').filter(item__is_special=True, is_deleted=False).all(),
+        'previous_step': previous_step,
+        'next_step': next_step,
+    })
+
+
+@login_required
+def final_invoice_print(request, instance_id):
+    instance = get_object_or_404(ProcessInstance, id=instance_id)
+    invoice = get_object_or_404(Invoice, process_instance=instance)
+    items = invoice.items.select_related('item').filter(is_deleted=False).all()
+    return render(request, 'invoices/final_invoice_print.html', {
+        'instance': instance,
+        'invoice': invoice,
+        'items': items,
+    })
+
+
+@require_POST
+@login_required
+def approve_final_invoice(request, instance_id, step_id):
+    instance = get_object_or_404(ProcessInstance, id=instance_id)
+    step = get_object_or_404(instance.process.steps, id=step_id)
+    invoice = get_object_or_404(Invoice, process_instance=instance)
+    # Block approval when there is any remaining (positive or negative)
+    invoice.calculate_totals()
+    if invoice.remaining_amount != 0:
+        return JsonResponse({
+            'success': False,
+            'message': f"تا زمانی که مانده فاکتور صفر نشده امکان تایید نیست (مانده فعلی: {invoice.remaining_amount})"
+        })
+    # mark step completed
+    step_instance, _ = StepInstance.objects.get_or_create(process_instance=instance, step=step)
+    step_instance.status = 'completed'
+    step_instance.completed_at = timezone.now()
+    step_instance.save()
+    # move to next
+    next_step = instance.process.steps.filter(order__gt=step.order).first()
+    redirect_url = reverse('processes:request_list')
+    if next_step:
+        instance.current_step = next_step
+        instance.save()
+        redirect_url = reverse('processes:step_detail', args=[instance.id, next_step.id])
+    return JsonResponse({'success': True, 'message': 'فاکتور نهایی تایید شد', 'redirect': redirect_url})
+
+
+@require_POST
+@login_required
+def add_special_charge(request, instance_id, step_id):
+    """افزودن هزینه ویژه تعمیر/تعویض به فاکتور نهایی به‌صورت آیتم جداگانه"""
+    instance = get_object_or_404(ProcessInstance, id=instance_id)
+    invoice = get_object_or_404(Invoice, process_instance=instance)
+    # charge_type was removed from UI; we no longer require it
+    item_id = request.POST.get('item_id')
+    amount = (request.POST.get('amount') or '').strip()
+    if not item_id:
+        return JsonResponse({'success': False, 'message': 'آیتم را انتخاب کنید'})
+    try:
+        amount_dec = Decimal(amount)
+    except (InvalidOperation, TypeError):
+        return JsonResponse({'success': False, 'message': 'مبلغ نامعتبر است'})
+    if amount_dec <= 0:
+        return JsonResponse({'success': False, 'message': 'مبلغ باید مثبت باشد'})
+
+    # Fetch existing special item from DB
+    special_item = get_object_or_404(Item, id=item_id, is_special=True)
+
+    from .models import InvoiceItem
+    InvoiceItem.objects.create(
+        invoice=invoice,
+        item=special_item,
+        quantity=1,
+        unit_price=amount_dec,
+    )
+    invoice.calculate_totals()
+    return JsonResponse({'success': True, 'redirect': reverse('invoices:final_invoice_step', args=[instance.id, step_id])})
+
+
+@require_POST
+@login_required
+def delete_special_charge(request, instance_id, step_id, item_id):
+    instance = get_object_or_404(ProcessInstance, id=instance_id)
+    invoice = get_object_or_404(Invoice, process_instance=instance)
+    from .models import InvoiceItem
+    inv_item = get_object_or_404(InvoiceItem, id=item_id, invoice=invoice)
+    # allow deletion only for special items
+    try:
+        if not getattr(inv_item.item, 'is_special', False):
+            return JsonResponse({'success': False, 'message': 'امکان حذف این مورد وجود ندارد'})
+    except Exception:
+        return JsonResponse({'success': False, 'message': 'امکان حذف این مورد وجود ندارد'})
+    inv_item.hard_delete()
+    invoice.calculate_totals()
+    return JsonResponse({'success': True, 'redirect': reverse('invoices:final_invoice_step', args=[instance.id, step_id])})
+
+
+@login_required
+def final_settlement_step(request, instance_id, step_id):
+    instance = get_object_or_404(ProcessInstance, id=instance_id)
+    step = get_object_or_404(instance.process.steps, id=step_id)
+    if not instance.can_access_step(step):
+        messages.error(request, 'شما به این مرحله دسترسی ندارید. ابتدا مراحل قبلی را تکمیل کنید.')
+        return redirect('processes:request_list')
+    invoice = get_object_or_404(Invoice, process_instance=instance)
+
+    previous_step = instance.process.steps.filter(order__lt=step.order).last()
+    next_step = instance.process.steps.filter(order__gt=step.order).first()
+
+    return render(request, 'invoices/final_settlement_step.html', {
+        'instance': instance,
+        'step': step,
+        'invoice': invoice,
+        'payments': invoice.payments.filter(is_deleted=False).all(),
+        'previous_step': previous_step,
+        'next_step': next_step,
+    })
+
+
+@require_POST
+@login_required
+def add_final_payment(request, instance_id, step_id):
+    instance = get_object_or_404(ProcessInstance, id=instance_id)
+    invoice = get_object_or_404(Invoice, process_instance=instance)
+    amount = (request.POST.get('amount') or '').strip()
+    payment_date = (request.POST.get('payment_date') or '').strip()
+    payment_method = (request.POST.get('payment_method') or '').strip()
+    reference_number = (request.POST.get('reference_number') or '').strip()
+    direction = (request.POST.get('direction') or 'in').strip()
+    receipt_image = request.FILES.get('receipt_image')
+    if not amount:
+        return JsonResponse({'success': False, 'message': 'مبلغ را وارد کنید'})
+    if not payment_date:
+        return JsonResponse({'success': False, 'message': 'تاریخ پرداخت را وارد کنید'})
+    if not payment_method:
+        return JsonResponse({'success': False, 'message': 'روش پرداخت را انتخاب کنید'})
+    if not reference_number:
+        return JsonResponse({'success': False, 'message': 'شماره مرجع را وارد کنید'})
+    if not receipt_image:
+        return JsonResponse({'success': False, 'message': 'تصویر فیش الزامی است'})
+    if '/' in payment_date:
+        payment_date = payment_date.replace('/', '-')
+    try:
+        amount_dec = Decimal(amount)
+    except InvalidOperation:
+        return JsonResponse({'success': False, 'message': 'مبلغ نامعتبر است'})
+    # Only allow outgoing (پرداخت به مشتری) when current net due is negative
+    # Compute net due explicitly from current items/payments
+    try:
+        current_paid = sum((p.amount if p.direction == 'in' else -p.amount) for p in invoice.payments.filter(is_deleted=False).all())
+    except Exception:
+        current_paid = Decimal('0')
+    # Ensure invoice totals are up-to-date for final_amount
+    invoice.calculate_totals()
+    net_due = invoice.final_amount - current_paid
+    if direction == 'out' and net_due >= 0:
+        return JsonResponse({'success': False, 'message': 'در حال حاضر مانده به نفع مشتری نیست'})
+
+    # Amount constraints by sign of net due
+    if net_due > 0 and direction == 'in' and amount_dec > net_due:
+        return JsonResponse({'success': False, 'message': 'مبلغ فیش بیشتر از مانده فاکتور است'})
+    if net_due < 0 and direction == 'out' and amount_dec > abs(net_due):
+        return JsonResponse({'success': False, 'message': 'مبلغ فیش بیشتر از مانده بدهی شرکت به مشتری است'})
+    if net_due < 0 and direction == 'in':
+        return JsonResponse({'success': False, 'message': 'در حال حاضر مانده به نفع مشتری است؛ دریافت از مشتری مجاز نیست'})
+
+    Payment.objects.create(
+        invoice=invoice,
+        amount=amount_dec,
+        payment_date=payment_date,
+        payment_method=payment_method,
+        reference_number=reference_number,
+        direction='in' if direction != 'out' else 'out',
+        receipt_image=receipt_image,
+        created_by=request.user,
+    )
+    # After creation, totals auto-updated by model save. Respond with redirect and new totals for UX.
+    invoice.refresh_from_db()
+    return JsonResponse({
+        'success': True,
+        'redirect': reverse('invoices:final_settlement_step', args=[instance.id, step_id]),
+        'totals': {
+            'final_amount': str(invoice.final_amount),
+            'paid_amount': str(invoice.paid_amount),
+            'remaining_amount': str(invoice.remaining_amount),
+        }
+    })
+
+
+@require_POST
+@login_required
+def delete_final_payment(request, instance_id, step_id, payment_id):
+    instance = get_object_or_404(ProcessInstance, id=instance_id)
+    invoice = get_object_or_404(Invoice, process_instance=instance)
+    payment = get_object_or_404(Payment, id=payment_id, invoice=invoice)
+    payment.delete()
+    invoice.refresh_from_db()
+    return JsonResponse({'success': True, 'redirect': reverse('invoices:final_settlement_step', args=[instance.id, step_id]), 'totals': {
+        'final_amount': str(invoice.final_amount),
+        'paid_amount': str(invoice.paid_amount),
+        'remaining_amount': str(invoice.remaining_amount),
+    }})
+
+
+@require_POST
+@login_required
+def approve_final_settlement(request, instance_id, step_id):
+    instance = get_object_or_404(ProcessInstance, id=instance_id)
+    step = get_object_or_404(instance.process.steps, id=step_id)
+    invoice = get_object_or_404(Invoice, process_instance=instance)
+    # Block approval if any remaining exists (positive or negative)
+    invoice.calculate_totals()
+    if invoice.remaining_amount != 0:
+        return JsonResponse({
+            'success': False,
+            'message': f"تا زمانی که مانده فاکتور صفر نشده امکان تایید نیست (مانده فعلی: {invoice.remaining_amount})"
+        })
+    # complete step
+    step_instance, _ = StepInstance.objects.get_or_create(process_instance=instance, step=step)
+    step_instance.status = 'completed'
+    step_instance.completed_at = timezone.now()
+    step_instance.save()
+    # move next
+    next_step = instance.process.steps.filter(order__gt=step.order).first()
+    redirect_url = reverse('processes:request_list')
+    if next_step:
+        instance.current_step = next_step
+        instance.save()
+        redirect_url = reverse('processes:step_detail', args=[instance.id, next_step.id])
+    return JsonResponse({'success': True, 'message': 'تسویه حساب نهایی ثبت شد', 'redirect': redirect_url})