[Admin] Improve performance of admin email list

app/controllers/admin_controller.rb

@@ -1301,6 +1301,10 @@ def account_numbers
   end
 
   def email
+    @message = Ahoy::Message.find(params[:message_id])
+  end
+
+  def email_html
     @message_id = params[:message_id]
 
     respond_to do |format|
@@ -1323,7 +1327,6 @@ def emails
     @count = messages.count
 
     @messages = messages.page(@page).per(@per).order(sent_at: :desc)
-
   end
 
   def unknown_merchants

app/views/admin/email.html.erb

@@ -0,0 +1,14 @@
+<%#
+We're doing this crazy level of nesting to prevent excess web requests.
+
+emails (index page) -> lazy turboframe with inside iframe -> email_html action
+
+This is because just having iframes on the index page causes a huge number of
+web requests from browser extensions, etc. So, we lazy load the iframes.
+
+And, Rails has a hard time with the email HTML when passed through ERB, so we
+respond with the email HTML directly in the controller action.
+%>
+<%= turbo_frame_tag dom_id(@message) do %>
+  <iframe loading="lazy" src="<%= url_for(controller: "admin", action: "email_html", message_id: @message.id) %>" class="w-full h-full absolute border-none -mt-8 -ml-8 pb-24">iframes are not supported</iframe>
+<% end %>

app/views/admin/emails.html.erb

@@ -3,8 +3,7 @@
 <%= form_with local: true, url: emails_admin_index_path, method: :get do |form| %>
   <%= form.text_field :q, value: params[:q], placeholder: "Search" %>
   <%= form.text_field :to, value: params[:to], placeholder: "Email address (to)" %>
-
-  <%= form.collection_select(:user_id, User.all.order(Arel.sql("COALESCE(preferred_name, full_name, email) ASC")), :id, :admin_dropdown_description, { include_blank: "Select a user", selected: @user_id }, { width: 250, style: "max-width: 250px" }) %>
+  <%= form.text_field :user_id, value: params[:user_id], placeholder: "User ID" %>
 
   <div>
     <%= form.submit "Search" %>
@@ -29,10 +28,6 @@
   </thead>
   <tbody>
     <% @messages.each do |msg| %>
-      <section class="modal bg-snow" style="height: 60vh;" data-behavior="modal" role="dialog" id="message_<%= msg.id %>">
-        <%= modal_header "Email to #{msg.user&.name || "unknown user"}" %>
-        <iframe loading="lazy" src="<%= url_for(controller: "admin", action: "email", message_id: msg.id) %>" class="w-full h-full absolute border-none -mt-8 -ml-8 pb-24">iframes are not supported</iframe>
-      </section>
       <tr>
         <td><%= msg.id %></td>
         <td><%= msg.sent_at.strftime("%Y-%m-%d") %></td>
@@ -56,4 +51,13 @@
   </tbody>
 </table>
 
+<% @messages.each do |msg| %>
+  <section class="modal bg-snow" style="height: 60vh;" data-behavior="modal" role="dialog" id="message_<%= msg.id %>">
+    <%= modal_header "Email to #{msg.user&.name || "unknown user"}" %>
+    <%= turbo_frame_tag dom_id(msg), src: url_for(controller: "admin", action: "email", message_id: msg.id), loading: "lazy" do %>
+      Loading...
+    <% end %>
+  </section>
+<% end %>
+
 <%= paginate @messages %>

config/routes.rb

@@ -252,6 +252,7 @@
       get "employee_payments", to: "admin#employee_payments"
       get "emails", to: "admin#emails"
       get "email", to: "admin#email"
+      get "email_html", to: "admin#email_html"
       get "merchant_memo_check", to: "admin#merchant_memo_check"
       get "referral_programs", to: "admin#referral_programs"
       post "referral_program_create", to: "admin#referral_program_create"