added email_sent field to student model, do not send mail twice if not needed

cntmanage/flightslot/actions/send_email.py

@@ -31,6 +31,7 @@ def send_mail_password(request: HttpRequest, queryset: QuerySet[Student]) -> Non
         img.add_header("Content-Disposition", "inline", filename="cantorair.png")     
     
     # build mail list filling template
+    queryset = queryset.filter(mail_sent=False)
     mails: List[EmailMultiAlternatives] = []
     for student in queryset:
         if not student.user or not student.email: # skip student if has not an associated user
@@ -56,18 +57,25 @@ def send_mail_password(request: HttpRequest, queryset: QuerySet[Student]) -> Non
             mail.attach(filename=img)
             mail.attach_alternative(content=html_message, mimetype="text/html")
             mails.append(mail)
+            student.mail_sent = True
+            student.save()
         except Exception as e:
             messages.error(request=request, message=f"General Error: {e}")
     
+    if len(mails) == 0:
+        messages.warning(request=request, message="No email will be sent")
+        return 
+    
     # Open only one conenction and send mass email
     try:
+        sent: int = 0
         with get_connection() as conn:
-            conn.send_messages(mails)
+            sent = conn.send_messages(mails)
     except SMTPException as e:
         messages.error(request=request, message=f"Send Mail SMTP error: {e.strerror}")
     except Exception as e:
         messages.error(request=request, message=f"Send Mail General error: {e}")
     else:
-        messages.success(request=request, message=f"Successfully sent {len(mails)} messages")
+        messages.success(request=request, message=f"Successfully sent {sent} messages")
     
     return 

cntmanage/flightslot/admins/student_adm.py

@@ -69,7 +69,7 @@ class ChangeAircraftForm(AdminActionForm):
 
 class StudentAdmin(ImportMixin, AdminConfirmMixin, AdminActionFormsMixin, admin.ModelAdmin):
     model = Student
-    list_display = ("surname", "name", "course", "course_color", "email", "phone", "username", "password", "active", )
+    list_display = ("surname", "name", "course", "course_color", "email", "phone", "username", "password", "active", "mail_sent")
     list_filter = ("course", "active", )
     search_fields = ("surname", "name", "phone", "email", )
     actions = ("change_course", "deactivate_students", "change_aircraft", "send_mail", )

cntmanage/flightslot/migrations/0031_student_mail_sent_alter_student_phone.py

@@ -0,0 +1,24 @@
+# Generated by Django 5.2.8 on 2025-12-10 10:28
+
+import phonenumber_field.modelfields
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('flightslot', '0030_weekpreference_inserted_alter_availability_week_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='student',
+            name='mail_sent',
+            field=models.BooleanField(default=False),
+        ),
+        migrations.AlterField(
+            model_name='student',
+            name='phone',
+            field=phonenumber_field.modelfields.PhoneNumberField(db_index=True, max_length=128, null=True, region=None, unique=True),
+        ),
+    ]

cntmanage/flightslot/models/students.py

@@ -19,6 +19,7 @@ class Student(models.Model):
 
     phone = modelfields.PhoneNumberField(
         null=True,
+        db_index=True,
         unique=True
     )
 
@@ -54,6 +55,11 @@ class Student(models.Model):
         Aircraft
     )
 
+    mail_sent = models.BooleanField(
+        null=False,
+        default=False
+    )
+
     def default_password(self) -> str:  # Maximum 4 digits for passowrd
         if self.pk:
             return f"{self.name.lower()[0]}{self.surname.lower()}{self.id % 10000}"