Set provider prefix on creation and when editing a provider with no topics

app/views/providers/_form.html.erb

@@ -11,7 +11,7 @@
           <span class="text-red-500">*</span>
         <% end %>
         <%= form.text_field :name,
-            placeholder: "Enter provider name (e.g., Johns Hopkins, Mayo Clinic)",
+            placeholder: "e.g., Johns Hopkins, Mayo Clinic",
             autofocus: true,
             class: "input-field bg-gray-50" %>
         <p class="help-text">The official name of the healthcare provider or organization.</p>
@@ -29,6 +29,19 @@
         <p class="help-text">The type or category of healthcare provider.</p>
       </div>
 
+      <!-- File name prefix -->
+      <% unless @provider&.topics.any? %>
+        <div>
+          <%= form.label :file_name_prefix, class: "input-label" do %>
+            File name prefix
+          <% end %>
+          <%= form.text_field :file_name_prefix,
+              placeholder: "e.g., 123_who_guidelines",
+              class: "input-field bg-gray-50" %>
+          <p class="help-text">The prefix to use for this provider's uploads.</p>
+        </div>
+      <% end %>
+
       <!-- Regions -->
       <div>
         <%= form.label :region, class: "input-label" do %>

spec/views/providers/edit.html.erb_spec.rb

@@ -16,4 +16,26 @@
       assert_select "input[type='submit'][value='Update Provider']"
     end
   end
+
+  context "when the provider has associated topics" do
+    before { create(:topic, provider: provider) }
+
+    it "does not have the File name prefix field" do
+      render
+
+      assert_select "form[action=?][method=?]", provider_path(provider), "post" do
+        assert_select "input[name=?]", "provider[file_name_prefix]", false
+      end
+    end
+  end
+
+  context "when the provider that has no associated topics" do
+    it "has the File name prefix field" do
+      render
+
+      assert_select "form[action=?][method=?]", provider_path(provider), "post" do
+        assert_select "input[name=?]", "provider[file_name_prefix]"
+      end
+    end
+  end
 end

spec/views/providers/new.html.erb_spec.rb

@@ -14,6 +14,7 @@
     assert_select "form[action=?][method=?]", providers_path, "post" do
       assert_select "input[name=?]", "provider[name]"
       assert_select "input[name=?]", "provider[provider_type]"
+      assert_select "input[name=?]", "provider[file_name_prefix]"
       assert_select "input[type='submit'][value='Create Provider']"
     end
   end