allow to resubmit form via shared link

app/controllers/start_form_controller.rb

@@ -13,12 +13,9 @@ class StartFormController < ApplicationController
   end
 
   def update
-    @submitter = Submitter.new(email: submitter_params[:email])
-
-    if params[:resubmit].blank?
     @submitter = Submitter.where(submission: @template.submissions.where(deleted_at: nil))
-                            .find_by(email: submitter_params[:email]) || @submitter
-    end
+                          .then { |rel| params[:resubmit].present? ? rel.where(completed_at: nil) : rel }
+                          .find_or_initialize_by(**submitter_params.compact_blank)
 
     if @submitter.completed_at?
       redirect_to start_form_completed_path(@template.slug, email: submitter_params[:email])
@@ -50,7 +47,7 @@ class StartFormController < ApplicationController
   private
 
   def submitter_params
-    params.require(:submitter).permit(:email).tap do |attrs|
+    params.require(:submitter).permit(:email, :phone).tap do |attrs|
       attrs[:email] = Submissions.normalize_email(attrs[:email])
     end
   end

app/views/submit_form/completed.html.erb

@@ -19,7 +19,11 @@
     <div>
       <% if Accounts.can_send_emails?(@submitter.submission.template.account) && @submitter.email.present? %>
         <%= button_to button_title(title: 'Send copy to Email', disabled_with: 'Sending', icon: svg_icon('mail_forward', class: 'w-6 h-6')), send_submission_email_index_path, params: { submitter_slug: @submitter.slug }, form: { onsubmit: 'event.submitter.disabled = true' }, class: 'white-button w-full' %>
+        <% if @submitter.submission.template.submitters.size != 1 %>
           <div class="divider">OR</div>
+        <% else %>
+          <div class="py-2"></div>
+        <% end %>
       <% end %>
       <download-button data-src="<%= submitter_download_index_path(@submitter.slug) %>" class="base-button w-full">
         <span class="flex items-center justify-center space-x-2" data-target="download-button.defaultButton">
@@ -32,6 +36,12 @@
         </span>
       </download-button>
     </div>
+    <% if @submitter.submission.template.submitters.size == 1 %>
+      <div class="divider">OR</div>
+      <div>
+        <%= button_to button_title(title: 'Resubmit', disabled_with: 'Resubmit', icon: svg_icon('reload', class: 'w-6 h-6')), start_form_path(@submitter.submission.template.slug), params: { submitter: { email: @submitter.email, phone: @submitter.phone }, resubmit: true }, method: :put, form: { onsubmit: 'event.submitter.disabled = true' }, class: 'white-button w-full' %>
+      </div>
+    <% end %>
   </div>
 </div>
 <%= render 'shared/attribution', link_path: '/start' %>