Implement 'investigating' email templates and tigger email send on admin domain application save, status change to investidated.

src/registrar/admin.py

@@ -1,11 +1,14 @@
+import logging
 from django.contrib import admin
 from django.contrib.auth.admin import UserAdmin
 from django.contrib.contenttypes.models import ContentType
 from django.http.response import HttpResponseRedirect
 from django.urls import reverse
-
+from .utility.email import send_templated_email, EmailSendingError
 from . import models
 
+logger = logging.getLogger(__name__)
+
 
 class AuditedAdmin(admin.ModelAdmin):
 
@@ -50,13 +53,51 @@ class MyHostAdmin(AuditedAdmin):
     inlines = [HostIPInline]
 
 
+class DomainApplicationAdmin(AuditedAdmin):
+
+    """Customize the applications listing view."""
+
+    # Trigger action when a fieldset is changed
+    def save_model(self, request, obj, form, change):
+        if change:  # Check if the application is being edited
+            # Get the original application from the database
+            original_obj = models.DomainApplication.objects.get(pk=obj.pk)
+
+            if obj.status != original_obj.status and obj.status == "investigating":
+                if (
+                    original_obj.submitter is None
+                    or original_obj.submitter.email is None
+                ):
+                    logger.warning(
+                        "Cannot send status change (in review) email,"
+                        "no submitter email address."
+                    )
+                    return
+                try:
+                    print(
+                        f"original_obj.submitter.email {original_obj.submitter.email}"
+                    )
+                    send_templated_email(
+                        "emails/status_change_in_review.txt",
+                        "emails/status_change_in_review_subject.txt",
+                        original_obj.submitter.email,
+                        context={"application": obj},
+                    )
+                except EmailSendingError:
+                    logger.warning(
+                        "Failed to send status change (in review) email", exc_info=True
+                    )
+
+        super().save_model(request, obj, form, change)
+
+
 admin.site.register(models.User, MyUserAdmin)
 admin.site.register(models.UserDomainRole, AuditedAdmin)
 admin.site.register(models.Contact, AuditedAdmin)
 admin.site.register(models.DomainInvitation, AuditedAdmin)
-admin.site.register(models.DomainApplication, AuditedAdmin)
 admin.site.register(models.DomainInformation, AuditedAdmin)
 admin.site.register(models.Domain, AuditedAdmin)
 admin.site.register(models.Host, MyHostAdmin)
 admin.site.register(models.Nameserver, MyHostAdmin)
 admin.site.register(models.Website, AuditedAdmin)
+admin.site.register(models.DomainApplication, DomainApplicationAdmin)