Implement support for faceting in UI

app/assets/stylesheets/partials/_facets.scss

@@ -3,10 +3,15 @@
     margin-bottom: 0;
   }
 
+  .category {
+    margin-bottom: 1em;
+  }
+
   ul.category-terms {
     border-collapse: separate;
     border-spacing: 0px 4px;
     display: table;
+    margin-bottom: 0;
     table-layout: fixed;
     width: 100%;
 
@@ -18,7 +23,8 @@
         text-decoration: none;
 
         &:hover,
-        &:focus {
+        &:focus,
+        &.applied {
           background: #000;
           color: #fff;
         }

app/controllers/search_controller.rb

@@ -30,27 +30,13 @@ def extract_errors(response)
   end
 
   def extract_facets(response)
-    facets = response&.data&.search&.to_h&.dig('aggregations')
-
-    facets&.map { |k, v| { facet_labels[k] => v } }
+    response&.data&.search&.to_h&.dig('aggregations')
   end
 
   def extract_results(response)
     response&.data&.search&.to_h&.dig('records')
   end
 
-  def facet_labels
-    {
-      'contentFormat' => 'Formats',
-      'contentType' => 'Content types',
-      'contributors' => 'Contributors',
-      'languages' => 'Languages',
-      'literaryForm' => 'Literary forms',
-      'source' => 'Sources',
-      'subjects' => 'Subjects'
-    }
-  end
-
   def validate_q!
     return if params[:advanced]&.strip.present?
     return if params[:q]&.strip.present?

app/helpers/facet_helper.rb

@@ -0,0 +1,22 @@
+module FacetHelper
+  def add_facet(query, facet, term)
+    new_query = query.clone
+    new_query[:page] = 1
+    new_query[facet.to_sym] = term
+    new_query
+  end
+
+  def nice_labels
+    {
+      'contentType' => 'Content types',
+      'source' => 'Sources'
+    }
+  end
+
+  def remove_facet(query, facet)
+    new_query = query.clone
+    new_query[:page] = 1
+    new_query.delete facet.to_sym
+    new_query
+  end
+end

app/models/enhancer.rb

@@ -1,7 +1,7 @@
 class Enhancer
   attr_accessor :enhanced_query
 
-  QUERY_PARAMS = %i[q citation contributors fundingInformation identifiers locations subjects title].freeze
+  QUERY_PARAMS = %i[q citation contentType contributors fundingInformation identifiers locations subjects title].freeze
   FILTER_PARAMS = [:source].freeze
   # accepts all params as each enhancer may require different data
   def initialize(params)

app/models/query_builder.rb

@@ -2,7 +2,7 @@ class QueryBuilder
   attr_reader :query
 
   RESULTS_PER_PAGE = 20
-  QUERY_PARAMS = %w[q citation contributors fundingInformation identifiers locations subjects title].freeze
+  QUERY_PARAMS = %w[q citation contentType contributors fundingInformation identifiers locations subjects title].freeze
   FILTER_PARAMS = [:source].freeze
 
   def initialize(enhanced_query)

app/models/timdex_search.rb

@@ -14,6 +14,7 @@ class TimdexSearch < TimdexBase
       $title: String
       $sourceFacet: [String!]
       $from: String
+      $contentType: String
     ) {
       search(
         searchterm: $q
@@ -26,6 +27,7 @@ class TimdexSearch < TimdexBase
         title: $title
         sourceFacet: $sourceFacet
         from: $from
+        contentTypeFacet: $contentType
       ) {
         hits
         records {
@@ -51,34 +53,14 @@ class TimdexSearch < TimdexBase
           }
         }
         aggregations {
-          contentFormat {
-            key
-            docCount
-          }
           contentType {
             key
             docCount
           }
-          contributors {
-            key
-            docCount
-          }
-          languages {
-            key
-            docCount
-          }
-          literaryForm {
-            key
-            docCount
-          }
           source {
             key
             docCount
           }
-          subjects {
-            key
-            docCount
-          }
         }
       }
     }

app/views/search/_facet.html.erb

@@ -1,15 +1,19 @@
-<% return if facet.values[0].empty? %>
+<% return if values.empty? %>
 
 <div class="category">
-  <h3><%= facet.keys[0] %></h3>
+  <h3><%= nice_labels[category] || category %></h3>
   <ul class="category-terms list-unbulleted">
-  <% facet.values[0].each do |term| %>
+  <% values.each do |term| %>
     <li class="term">
-      <a href="#">
+      <a href="<%= results_path(add_facet(@enhanced_query, category, term['key'])) %>" class="<%= "applied" if @enhanced_query[category.to_sym] == term['key'] %>">
         <span class="name"><%= term['key'] %></span>
         <span class="count"><%= term['docCount'] %> <span class="sr">records</span></span>
       </a>
     </li>
   <% end %>
   </ul>
+  <% if @enhanced_query[category.to_sym].present? %>
+    <div><%= link_to "Show all #{nice_labels[category]&.downcase || category}", results_path(remove_facet(@enhanced_query, category)) %>
+    </div>
+  <% end %>
 </div>

app/views/search/results.html.erb

@@ -4,32 +4,35 @@
 
   <p>Showing results for:
       <ul>
-        <% if params[:q].present? %>
-          <li>Keyword anywhere: <%= params[:q] %></li>
+        <% if @enhanced_query[:q].present? %>
+          <li>Keyword anywhere: <%= @enhanced_query[:q] %></li>
         <% end %>
-        <% if params[:citation].present? %>
-          <li>Citation: <%= params[:citation] %></li>
+        <% if @enhanced_query[:citation].present? %>
+          <li>Citation: <%= @enhanced_query[:citation] %></li>
         <% end %>
-        <% if params[:contributors].present? %>
-          <li>Contributors: <%= params[:contributors] %></li>
+        <% if @enhanced_query[:contentType].present? %>
+          <li>Content type: <%= @enhanced_query[:contentType] %></li>
         <% end %>
-        <% if params[:fundingInformation].present? %>
-          <li>Funders: <%= params[:fundingInformation] %></li>
+        <% if @enhanced_query[:contributors].present? %>
+          <li>Contributors: <%= @enhanced_query[:contributors] %></li>
         <% end %>
-        <% if params[:identifiers].present? %>
-          <li>Identifiers: <%= params[:identifiers] %></li>
+        <% if @enhanced_query[:fundingInformation].present? %>
+          <li>Funders: <%= @enhanced_query[:fundingInformation] %></li>
         <% end %>
-        <% if params[:locations].present? %>
-          <li>Locations: <%= params[:locations] %></li>
+        <% if @enhanced_query[:identifiers].present? %>
+          <li>Identifiers: <%= @enhanced_query[:identifiers] %></li>
         <% end %>
-        <% if params[:subjects].present? %>
-          <li>Subjects: <%= params[:subjects] %></li>
+        <% if @enhanced_query[:locations].present? %>
+          <li>Locations: <%= @enhanced_query[:locations] %></li>
         <% end %>
-        <% if params[:title].present? %>
-          <li>Title: <%= params[:title] %></li>
+        <% if @enhanced_query[:subjects].present? %>
+          <li>Subjects: <%= @enhanced_query[:subjects] %></li>
         <% end %>
-        <% if params[:source].present? %>
-          <li>Source: <%= params[:source] %></li>
+        <% if @enhanced_query[:title].present? %>
+          <li>Title: <%= @enhanced_query[:title] %></li>
+        <% end %>
+        <% if @enhanced_query[:source].present? %>
+          <li>Source: <%= @enhanced_query[:source] %></li>
         <% end %>
       </ul>
   </p>
@@ -55,7 +58,9 @@
     <aside class="col1q facet-container">
       <div id="facets">
         <h2>Available filters</h2>
-        <%= render(partial: 'search/facet', collection: @facets) || render('facet_empty') %>
+        <% @facets&.each do |category, values| %>
+          <%= render(partial: 'search/facet', locals: {category: category, values: values}) %>
+        <% end %>
       </div>
     </aside>
   </div>

test/helpers/facet_helper_test.rb

@@ -0,0 +1,67 @@
+require 'test_helper'
+
+class FacetHelperTest < ActionView::TestCase
+  include FacetHelper
+
+  test 'add_facet will support adding a facet parameter to a search URL' do
+    original_query = {
+      page: 1,
+      q: 'data'
+    }
+    expected_query = {
+      page: 1,
+      q: 'data',
+      contentType: 'dataset'
+    }
+    assert_equal expected_query, add_facet(original_query, 'contentType', 'dataset')
+  end
+
+  test 'add_facet will reset a page count when called' do
+    original_query = {
+      page: 3,
+      q: 'data'
+    }
+    expected_query = {
+      page: 1,
+      q: 'data',
+      contentType: 'dataset'
+    }
+    assert_equal expected_query, add_facet(original_query, 'contentType', 'dataset')
+  end
+
+  test 'nice_labels allows translation of machine categories to human readable headings' do
+    needle = 'contentType'
+    assert_equal 'Content types', nice_labels[needle]
+  end
+
+  test 'nice_labels returns nil if a category is not mapped yet' do
+    needle = 'foo'
+    assert_nil nice_labels[needle]
+  end
+
+  test 'remove_facet will remove a specific facet parameter from a search URL' do
+    original_query = {
+      page: 1,
+      q: 'data',
+      contentType: 'dataset'
+    }
+    expected_query = {
+      page: 1,
+      q: 'data'
+    }
+    assert_equal expected_query, remove_facet(original_query, 'contentType')
+  end
+
+  test 'remove_facet will reset a page count when called' do
+    original_query = {
+      page: 3,
+      q: 'data',
+      contentType: 'dataset'
+    }
+    expected_query = {
+      page: 1,
+      q: 'data'
+    }
+    assert_equal expected_query, remove_facet(original_query, 'contentType')
+  end
+end