Add "Link to existing" option in SnapTrade Setup Accounts modal (#935)

* Add account linking functionality for SnapTrade items

- Introduced UI to link existing accounts when setting up SnapTrade items, preventing duplicate account creation.
- Updated controller to fetch linkable accounts.
- Added tests to verify proper filtering of accounts and linking behavior.

* Add `snaptrade_item_id` to account linking flow for SnapTrade items

- Updated controller to allow specifying `snaptrade_item_id` when linking accounts.
- Adjusted form and views to include `snaptrade_item_id` as a hidden field.
- Enhanced tests to validate behavior with the new parameter.

app/controllers/snaptrade_items_controller.rb

@@ -154,6 +154,14 @@ class SnaptradeItemsController < ApplicationController
       @snaptrade_item.sync_later
     end
 
+    # Existing unlinked, visible investment/crypto accounts that could be linked instead of creating duplicates
+    @linkable_accounts = Current.family.accounts
+      .visible
+      .where(accountable_type: %w[Investment Crypto])
+      .left_joins(:account_providers)
+      .where(account_providers: { id: nil })
+      .order(:name)
+
     # Determine view state
     @syncing = @snaptrade_item.syncing?
     @waiting_for_sync = no_accounts && @syncing
@@ -369,9 +377,10 @@ class SnaptradeItemsController < ApplicationController
   def link_existing_account
     account_id = params[:account_id]
     snaptrade_account_id = params[:snaptrade_account_id]
+    snaptrade_item_id = params[:snaptrade_item_id]
 
     account = Current.family.accounts.find_by(id: account_id)
-    snaptrade_item = Current.family.snaptrade_items.first
+    snaptrade_item = Current.family.snaptrade_items.find_by(id: snaptrade_item_id)
     snaptrade_account = snaptrade_item&.snaptrade_accounts&.find_by(id: snaptrade_account_id)
 
     if account && snaptrade_account

app/views/snaptrade_items/setup_accounts.html.erb

@@ -138,6 +138,7 @@
                       <%= t("snaptrade_items.setup_accounts.sync_start_date_help", default: "Leave blank for all available history") %>
                     </p>
                   </div>
+
                 </div>
               <% end %>
             </div>
@@ -160,40 +161,70 @@
             </div>
           <% end %>
 
-          <% if @linked_accounts.any? %>
-            <div class="<%= "border-t border-primary pt-6 mt-6" if @unlinked_accounts.any? %>">
-              <h3 class="font-medium text-primary mb-4"><%= t("snaptrade_items.setup_accounts.linked_accounts", default: "Already Linked") %></h3>
-              <% @linked_accounts.each do |snaptrade_account| %>
-                <div class="border border-success/20 bg-success/5 rounded-lg p-4 mb-2">
-                  <div class="flex items-center justify-between">
-                    <div class="flex items-center gap-3">
-                      <%= icon "check-circle", class: "text-success" %>
-                      <div>
-                        <h4 class="font-medium text-primary"><%= snaptrade_account.name %></h4>
-                        <p class="text-sm text-secondary">
-                          <%= t("snaptrade_items.setup_accounts.linked_to", default: "Linked to:") %>
-                          <%= link_to snaptrade_account.current_account.name, account_path(snaptrade_account.current_account), class: "link" %>
-                        </p>
-                      </div>
+        <% end %>
+
+        <%# Link-to-existing forms rendered OUTSIDE the create form to avoid nested <form> %>
+        <% if @unlinked_accounts.any? && @linkable_accounts.any? %>
+          <div class="border-t border-secondary pt-4 mt-2">
+            <p class="text-xs text-secondary mb-3">
+              <%= t("snaptrade_items.setup_accounts.or_link_existing", default: "Or link to an existing account instead of creating a new one:") %>
+            </p>
+            <div class="space-y-2">
+              <% @unlinked_accounts.each do |snaptrade_account| %>
+                <%= form_with url: link_existing_account_snaptrade_items_path, method: :post, data: { turbo_frame: "_top" } do |link_form| %>
+                  <%= link_form.hidden_field :snaptrade_account_id, value: snaptrade_account.id %>
+                  <%= link_form.hidden_field :snaptrade_item_id, value: @snaptrade_item.id %>
+                  <p class="text-xs text-primary mb-1"><%= snaptrade_account.name %></p>
+                  <div class="flex items-center gap-2">
+                    <%= link_form.select :account_id,
+                          options_for_select(@linkable_accounts.map { |a| ["#{a.name} (#{number_to_currency(a.balance, unit: Money::Currency.new(a.currency || "USD").symbol)})", a.id] }),
+                          { prompt: t("snaptrade_items.setup_accounts.select_account", default: "Select an account...") },
+                          class: "bg-container border border-primary rounded px-2 py-1 text-sm text-primary flex-1 min-w-0" %>
+                    <%= render DS::Button.new(
+                      text: t("snaptrade_items.setup_accounts.link_button", default: "Link"),
+                      variant: "secondary",
+                      size: "sm",
+                      type: "submit"
+                    ) %>
+                  </div>
+                <% end %>
+              <% end %>
+            </div>
+          </div>
+        <% end %>
+
+        <% if @linked_accounts.any? %>
+          <div class="<%= "border-t border-primary pt-6 mt-4" if @unlinked_accounts.any? %>">
+            <h3 class="font-medium text-primary mb-4"><%= t("snaptrade_items.setup_accounts.linked_accounts", default: "Already Linked") %></h3>
+            <% @linked_accounts.each do |snaptrade_account| %>
+              <div class="border border-success/20 bg-success/5 rounded-lg p-4 mb-2">
+                <div class="flex items-center justify-between">
+                  <div class="flex items-center gap-3">
+                    <%= icon "check-circle", class: "text-success" %>
+                    <div>
+                      <h4 class="font-medium text-primary"><%= snaptrade_account.name %></h4>
+                      <p class="text-sm text-secondary">
+                        <%= t("snaptrade_items.setup_accounts.linked_to", default: "Linked to:") %>
+                        <%= link_to snaptrade_account.current_account.name, account_path(snaptrade_account.current_account), class: "link" %>
+                      </p>
                     </div>
                   </div>
                 </div>
-              <% end %>
-            </div>
-
-            <%# Show Done button when all accounts are linked (no unlinked) %>
-            <% if @unlinked_accounts.blank? %>
-              <div class="flex justify-end mt-4">
-                <%= render DS::Link.new(
-                  text: t("snaptrade_items.setup_accounts.done_button", default: "Done"),
-                  variant: "primary",
-                  href: accounts_path,
-                  frame: "_top"
-                ) %>
               </div>
             <% end %>
-          <% end %>
+          </div>
 
+          <%# Show Done button when all accounts are linked (no unlinked) %>
+          <% if @unlinked_accounts.blank? %>
+            <div class="flex justify-end mt-4">
+              <%= render DS::Link.new(
+                text: t("snaptrade_items.setup_accounts.done_button", default: "Done"),
+                variant: "primary",
+                href: accounts_path,
+                frame: "_top"
+              ) %>
+            </div>
+          <% end %>
         <% end %>
       <% end %>
     </div>

config/locales/views/snaptrade_items/en.yml

@@ -75,6 +75,9 @@ en:
       cancel_button: "Cancel"
       creating: "Creating Accounts..."
       done_button: "Done"
+      or_link_existing: "Or link to an existing account instead of creating a new one:"
+      select_account: "Select an account..."
+      link_button: "Link"
       linked_accounts: "Already Linked"
       linked_to: "Linked to:"
     snaptrade_item:

test/controllers/snaptrade_items_controller_test.rb

@@ -38,4 +38,69 @@ class SnaptradeItemsControllerTest < ActionDispatch::IntegrationTest
 
     assert_redirected_to portal_url
   end
+
+  test "setup_accounts shows linkable investment and crypto accounts in dropdown" do
+    get setup_accounts_snaptrade_item_url(@snaptrade_item)
+
+    assert_response :success
+
+    # Investment and crypto accounts (no provider) should appear in the link dropdown
+    assert_match accounts(:investment).name, response.body
+    assert_match accounts(:crypto).name, response.body
+
+    # Depository should NOT appear in the link dropdown (wrong type)
+    # The depository name may appear elsewhere on the page, so check the select options specifically
+    refute_match(/option.*#{accounts(:depository).name}/, response.body)
+  end
+
+  test "setup_accounts excludes accounts that already have a provider from dropdown" do
+    # Link the investment account to a snaptrade_account
+    AccountProvider.create!(
+      account: accounts(:investment),
+      provider: snaptrade_accounts(:fidelity_401k)
+    )
+
+    get setup_accounts_snaptrade_item_url(@snaptrade_item)
+
+    assert_response :success
+
+    # Investment account is now linked → should NOT appear in link dropdown options
+    refute_match(/option.*#{accounts(:investment).name}/, response.body)
+    # Crypto still unlinked → should appear
+    assert_match accounts(:crypto).name, response.body
+  end
+
+  test "link_existing_account links account to snaptrade_account" do
+    account = accounts(:investment)
+    snaptrade_account = snaptrade_accounts(:fidelity_401k)
+
+    assert_difference "AccountProvider.count", 1 do
+      post link_existing_account_snaptrade_items_url, params: {
+        account_id: account.id,
+        snaptrade_account_id: snaptrade_account.id,
+        snaptrade_item_id: @snaptrade_item.id
+      }
+    end
+
+    assert_redirected_to account_path(account)
+    assert_match(/Successfully linked/, flash[:notice])
+
+    snaptrade_account.reload
+    assert_equal account, snaptrade_account.current_account
+  end
+
+  test "link_existing_account handles missing account gracefully" do
+    snaptrade_account = snaptrade_accounts(:fidelity_401k)
+
+    assert_no_difference "AccountProvider.count" do
+      post link_existing_account_snaptrade_items_url, params: {
+        account_id: "nonexistent",
+        snaptrade_account_id: snaptrade_account.id,
+        snaptrade_item_id: @snaptrade_item.id
+      }
+    end
+
+    assert_redirected_to settings_providers_path
+    assert_match(/not found/i, flash[:alert])
+  end
 end