Use FSM instead

src/registrar/assets/js/get-gov-admin.js

@@ -49,6 +49,41 @@ function openInNewTab(el, removeAttribute = false){
     }
 
     createPhantomModalFormButtons();
+
+    document.addEventListener("DOMContentLoaded", function() {
+        const statusSelect = document.getElementById('id_status');
+        const investigatorSelect = document.getElementById('id_investigator'); // Adjust the ID based on your actual field name
+    
+        function checkInvestigatorAndShowMessage() {
+            // Assuming the first option is the default "---------" or similar
+            const investigatorSelected = investigatorSelect.selectedIndex > 0;
+    
+            // Remove existing messages to prevent duplicates
+            const existingMessage = document.querySelector('.no-investigator-exists');
+            if (existingMessage) {
+                existingMessage.remove();
+            }
+
+            const flexContainerParent = statusSelect.closest('.flex-container');
+            if (!investigatorSelected && flexContainerParent) {
+                const message = document.createElement("div");
+                message.classList.add("no-investigator-exists");
+                message.classList.add("padding-top-1")
+                message.classList.add("font-1")
+                message.textContent = '* An investigator must be added before other options will display.';
+                
+                // Insert the message before the flex-container parent
+                flexContainerParent.insertAdjacentElement('afterend', message);
+            }
+
+        }
+    
+        // Initial check in case the form is loaded with a selection already
+        checkInvestigatorAndShowMessage();
+    
+        // Add event listener to re-check whenever the investigator selection changes
+        investigatorSelect.addEventListener('change', checkInvestigatorAndShowMessage);
+    });
 })();
 /** An IIFE for pages in DjangoAdmin which may need custom JS implementation.
  * Currently only appends target="_blank" to the domain_form object,

src/registrar/models/domain_application.py

@@ -619,6 +619,14 @@ class DomainApplication(TimeStampedModel):
         except EmailSendingError:
             logger.warning("Failed to send confirmation email", exc_info=True)
 
+    def investigator_exists_and_is_staff(self):
+        """Checks if the current investigator is in a valid state for a state transition"""
+        is_valid = True
+        # Check if an investigator is assigned. No approval is possible without one.
+        if self.investigator is None or not self.investigator.is_staff:
+            is_valid = False
+        return is_valid
+
     @transition(
         field="status",
         source=[
@@ -669,7 +677,7 @@ class DomainApplication(TimeStampedModel):
             ApplicationStatus.INELIGIBLE,
         ],
         target=ApplicationStatus.IN_REVIEW,
-        conditions=[domain_is_not_active],
+        conditions=[domain_is_not_active, investigator_exists_and_is_staff],
     )
     def in_review(self):
         """Investigate an application that has been submitted.
@@ -696,7 +704,7 @@ class DomainApplication(TimeStampedModel):
             ApplicationStatus.INELIGIBLE,
         ],
         target=ApplicationStatus.ACTION_NEEDED,
-        conditions=[domain_is_not_active],
+        conditions=[domain_is_not_active, investigator_exists_and_is_staff],
     )
     def action_needed(self):
         """Send back an application that is under investigation or rejected.
@@ -723,6 +731,7 @@ class DomainApplication(TimeStampedModel):
             ApplicationStatus.REJECTED,
         ],
         target=ApplicationStatus.APPROVED,
+        conditions=[investigator_exists_and_is_staff]
     )
     def approve(self, send_email=True):
         """Approve an application that has been submitted.
@@ -739,15 +748,6 @@ class DomainApplication(TimeStampedModel):
         if Domain.objects.filter(name=self.requested_domain.name).exists():
             raise ApplicationStatusError(code=FSMErrorCodes.APPROVE_DOMAIN_IN_USE)
 
-        # Check if an investigator is assigned. No approval is possible without one.
-        if self.investigator is None:
-            raise ApplicationStatusError(code=FSMErrorCodes.APPROVE_NO_INVESTIGATOR)
-
-        # Investigators must be staff users.
-        # This is handled elsewhere, but we should check here as a precaution.
-        if not self.investigator.is_staff:
-            raise ApplicationStatusError(code=FSMErrorCodes.APPROVE_INVESTIGATOR_NOT_STAFF)
-
         # == Create the domain and related components == #
         created_domain = Domain.objects.create(name=self.requested_domain.name)
         self.approved_domain = created_domain
@@ -788,7 +788,7 @@ class DomainApplication(TimeStampedModel):
         field="status",
         source=[ApplicationStatus.IN_REVIEW, ApplicationStatus.ACTION_NEEDED, ApplicationStatus.APPROVED],
         target=ApplicationStatus.REJECTED,
-        conditions=[domain_is_not_active],
+        conditions=[domain_is_not_active, investigator_exists_and_is_staff],
     )
     def reject(self):
         """Reject an application that has been submitted.
@@ -814,7 +814,7 @@ class DomainApplication(TimeStampedModel):
             ApplicationStatus.REJECTED,
         ],
         target=ApplicationStatus.INELIGIBLE,
-        conditions=[domain_is_not_active],
+        conditions=[domain_is_not_active, investigator_exists_and_is_staff],
     )
     def reject_with_prejudice(self):
         """The applicant is a bad actor, reject with prejudice.