1 files changed, 56 insertions, 1 deletions
diff --git a/app/assets/javascripts/pages/admin/application_settings/account_and_limits.js b/app/assets/javascripts/pages/admin/application_settings/account_and_limits.js
index 455c637a6b3..8b8147425bc 100644
--- a/app/assets/javascripts/pages/admin/application_settings/account_and_limits.js
+++ b/app/assets/javascripts/pages/admin/application_settings/account_and_limits.js
@@ -20,10 +20,65 @@ function setUserInternalRegexPlaceholder(checkbox) {
   }
 }
 
-export default function initUserInternalRegexPlaceholder() {
+function initUserInternalRegexPlaceholder() {
   const checkbox = document.getElementById('application_setting_user_default_external');
   setUserInternalRegexPlaceholder(checkbox);
   checkbox.addEventListener('change', () => {
     setUserInternalRegexPlaceholder(checkbox);
   });
 }
+
+/**
+ * Sets up logic inside "Dormant users" subsection:
+ * - checkbox enables/disables additional input
+ * - shows/hides an inline error on input validation
+ */
+function initDeactivateDormantUsersPeriodInputSection() {
+  const DISPLAY_NONE_CLASS = 'gl-display-none';
+
+  /** @type {HTMLInputElement} */
+  const checkbox = document.getElementById('application_setting_deactivate_dormant_users');
+  /** @type {HTMLInputElement} */
+  const input = document.getElementById('application_setting_deactivate_dormant_users_period');
+  /** @type {HTMLDivElement} */
+  const errorLabel = document.getElementById(
+    'application_setting_deactivate_dormant_users_period_error',
+  );
+
+  if (!checkbox || !input || !errorLabel) return;
+
+  const hideInputErrorLabel = () => {
+    if (input.checkValidity()) {
+      errorLabel.classList.add(DISPLAY_NONE_CLASS);
+    }
+  };
+
+  const handleInputInvalidState = (event) => {
+    event.preventDefault();
+    event.stopImmediatePropagation();
+    errorLabel.classList.remove(DISPLAY_NONE_CLASS);
+    return false;
+  };
+
+  const updateInputDisabledState = () => {
+    input.disabled = !checkbox.checked;
+    if (input.disabled) {
+      hideInputErrorLabel();
+    }
+  };
+
+  // Show error when input is invalid
+  input.addEventListener('invalid', handleInputInvalidState);
+  // Hide error when input changes
+  input.addEventListener('input', hideInputErrorLabel);
+  input.addEventListener('change', hideInputErrorLabel);
+
+  // Handle checkbox change and set initial state
+  checkbox.addEventListener('change', updateInputDisabledState);
+  updateInputDisabledState();
+}
+
+export default function initAccountAndLimitsSection() {
+  initUserInternalRegexPlaceholder();
+  initDeactivateDormantUsersPeriodInputSection();
+}