Support AND combinations of multiple tags in search

The topic filter is now a multi-select. Selecting multiple tags finds
items tagged with ALL of them (AND logic) using GROUP BY / HAVING COUNT.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: zalepa

app/controllers/search_controller.rb

@@ -18,7 +18,8 @@ def index
       scope = apply_date_filters(scope)
       scope = apply_result_filter(scope)
 
-      @total_count = scope.count
+      count_result = scope.count
+      @total_count = count_result.is_a?(Hash) ? count_result.size : count_result
       @page = [ params[:page].to_i, 1 ].max
       @total_pages = (@total_count.to_f / PER_PAGE).ceil
       @agenda_items = scope.order("meetings.date DESC, agenda_items.position ASC")
@@ -47,7 +48,7 @@ def any_filters?
     params[:q].present? ||
       params[:file_number].present? ||
       params[:council_member_id].present? ||
-      params[:tag_id].present? ||
+      Array(params[:tag_ids]).reject(&:blank?).any? ||
       params[:date_from].present? ||
       params[:date_to].present? ||
       (params[:result].present? && AgendaItem::VALID_RESULTS.include?(params[:result]))
@@ -74,9 +75,13 @@ def apply_council_member_filter(scope)
   end
 
   def apply_tag_filter(scope)
-    return scope unless params[:tag_id].present?
+    tag_ids = Array(params[:tag_ids]).reject(&:blank?).map(&:to_i)
+    return scope unless tag_ids.any?
 
-    scope.joins(:agenda_item_tags).where(agenda_item_tags: { tag_id: params[:tag_id] })
+    scope.joins(:agenda_item_tags)
+         .where(agenda_item_tags: { tag_id: tag_ids })
+         .group("agenda_items.id")
+         .having("COUNT(DISTINCT agenda_item_tags.tag_id) = ?", tag_ids.size)
   end
 
   def apply_date_filters(scope)

app/views/search/index.html.erb

@@ -54,12 +54,12 @@
         <%# Row 3: Topic + Result %>
         <div class="grid sm:grid-cols-2 gap-4">
           <div>
-            <label for="tag_id" class="block text-sm font-medium text-gray-700">Topic</label>
-            <select name="tag_id" id="tag_id"
-                    class="mt-1 block w-full h-[42px] rounded-md border border-gray-300 px-3 text-sm shadow-sm focus:border-blue-500 focus:ring-blue-500">
-              <option value="">All topics</option>
+            <label for="tag_ids" class="block text-sm font-medium text-gray-700">Topics <span class="font-normal text-gray-400">(select multiple for AND)</span></label>
+            <select name="tag_ids[]" id="tag_ids" multiple
+                    class="mt-1 block w-full rounded-md border border-gray-300 px-3 py-2 text-sm shadow-sm focus:border-blue-500 focus:ring-blue-500 h-[84px]">
+              <% selected_tag_ids = Array(params[:tag_ids]).map(&:to_s) %>
               <% @tags.each do |tag| %>
-                <option value="<%= tag.id %>" <%= "selected" if params[:tag_id] == tag.id.to_s %>><%= tag.name %></option>
+                <option value="<%= tag.id %>" <%= "selected" if selected_tag_ids.include?(tag.id.to_s) %>><%= tag.name %></option>
               <% end %>
             </select>
           </div>

test/controllers/search_controller_test.rb

@@ -79,13 +79,26 @@ class SearchControllerTest < ActionDispatch::IntegrationTest
   end
 
   test "tag filter finds tagged items" do
-    get search_path, params: { tag_id: tags(:budget).id }
+    get search_path, params: { tag_ids: [ tags(:budget).id ] }
     assert_response :success
     assert_select "td", text: /Fees and Charges/
   end
 
   test "tag filter excludes untagged items" do
-    get search_path, params: { tag_id: tags(:housing).id }
+    get search_path, params: { tag_ids: [ tags(:housing).id ] }
+    assert_response :success
+    assert_select "p", text: /No agenda items match/
+  end
+
+  test "multiple tags filter with AND logic" do
+    item = agenda_items(:ordinance_with_details)
+    item.tags << tags(:infrastructure) unless item.tags.include?(tags(:infrastructure))
+
+    get search_path, params: { tag_ids: [ tags(:budget).id, tags(:infrastructure).id ] }
+    assert_response :success
+    assert_select "td", text: /Fees and Charges/
+
+    get search_path, params: { tag_ids: [ tags(:budget).id, tags(:housing).id ] }
     assert_response :success
     assert_select "p", text: /No agenda items match/
   end
@@ -120,11 +133,11 @@ class SearchControllerTest < ActionDispatch::IntegrationTest
   end
 
   test "combined filters compose together" do
-    get search_path, params: { q: "Fees", tag_id: tags(:budget).id, result: "approved" }
+    get search_path, params: { q: "Fees", tag_ids: [ tags(:budget).id ], result: "approved" }
     assert_response :success
     assert_select "td", text: /Fees and Charges/
 
-    get search_path, params: { q: "Fees", tag_id: tags(:housing).id }
+    get search_path, params: { q: "Fees", tag_ids: [ tags(:housing).id ] }
     assert_response :success
     assert_select "p", text: /No agenda items match/
   end