Merge pull request #3484 from alphagov/filter-pres

Implement filter summary

app/controllers/finders_controller.rb

@@ -66,7 +66,7 @@ class UnsupportedContentItem < StandardError; end
 
   attr_reader :search_query
 
-  helper_method :facet_tags, :i_am_a_topic_page_finder, :result_set_presenter, :content_item, :signup_links, :filter_params, :facets
+  helper_method :facet_tags, :i_am_a_topic_page_finder, :result_set_presenter, :content_item, :signup_links, :filter_params, :facets, :filters_presenter
 
   def redirect_to_destination
     @redirect = content_item.redirect
@@ -130,7 +130,7 @@ def all_facets
       value_hash: filter_params,
     ).facets.tap do |built_facets|
       if content_item.all_content_finder? && enable_new_all_content_finder_ui?
-        built_facets.prepend(SortFacet.new)
+        built_facets.prepend(SortFacet.new(content_item, filter_params))
       end
     end
   end
@@ -166,6 +166,10 @@ def sort_presenter
     @sort_presenter ||= content_item.sorter_class.new(content_item, filter_params)
   end
 
+  def filters_presenter
+    @filters_presenter ||= FiltersPresenter.new(facets, finder_url_builder)
+  end
+
   def pagination_presenter
     PaginationPresenter.new(
       per_page: content_item.default_documents_per_page,

app/lib/facets_iterator.rb

@@ -1,5 +1,6 @@
 class FacetsIterator
-  delegate :select, :any?, to: :@facets
+  include Enumerable
+  delegate :each, to: :@facets
 
   def initialize(facets)
     @facets = facets

app/lib/hash_with_deep_except.rb

@@ -0,0 +1,38 @@
+module HashWithDeepExcept
+  refine Hash do
+    # Allows removing arbitarily nested params from a hash, used for clearing specific filters from
+    # a user's search.
+    #
+    # For example, given:
+    #   { a: 1, b: { c: 2, d: 3 } }
+    # Removing
+    #   { b: { c: 2 } }
+    # would result in
+    #   { a: 1, b: { d: 3 } }
+    def deep_except(other)
+      each_with_object({}) do |(key, value), result|
+        if other.key?(key)
+          child = other[key]
+
+          if value.is_a?(Hash) && child.is_a?(Hash)
+            # Recursively remove nested values
+            nested_result = value.deep_except(child)
+            result[key] = nested_result unless nested_result.empty?
+          elsif value.is_a?(Array) && child.is_a?(Array)
+            result[key] = value - child
+          elsif child.is_a?(Array) && child == [value]
+            # Some parameters can be given both as an array and a single value (e.g. `organisation`),
+            # and should be removed if a single value is present that's equal to the only array
+            # element
+            #
+            # Skip this key-value pair, effectively removing it
+          elsif value != child
+            result[key] = value
+          end
+        else
+          result[key] = value
+        end
+      end
+    end
+  end
+end

app/lib/url_builder.rb

@@ -1,19 +1,29 @@
 # The UrlBuilder class is responsible for creating URLs to be rendered as
 # HTML links.
 class UrlBuilder
+  using HashWithDeepExcept
+
   def initialize(path, query_params = {})
     @path = path
     @query_params = query_params
   end
 
   def url(additional_params = {})
-    [
-      path,
-      query_params.merge(additional_params).to_query,
-    ].reject(&:blank?).join("?")
+    build_url(query_params.merge(additional_params))
+  end
+
+  def url_except(excepted_param)
+    build_url(query_params.deep_except(excepted_param))
   end
 
 private
 
   attr_reader :path, :query_params
+
+  def build_url(params)
+    [
+      path,
+      params.to_query,
+    ].reject(&:blank?).join("?")
+  end
 end

app/models/date_facet.rb

@@ -37,6 +37,17 @@ def sentence_fragment
     }
   end
 
+  def applied_filters
+    present_values.map do |type, date|
+      preposition = preposition_mappings[type]
+      {
+        name: "#{name} #{preposition}",
+        label: date.date.strftime("%e %B %Y"),
+        query_params: { key => { type => date.original_input } },
+      }
+    end
+  end
+
   def has_filters?
     present_values.any?
   end

app/models/facet.rb

@@ -56,6 +56,10 @@ def allowed_values
     facet["allowed_values"] || []
   end
 
+  def applied_filters
+    []
+  end
+
   def query_params
     {}
   end

app/models/hidden_clearable_facet.rb

@@ -23,6 +23,16 @@ def has_filters?
     selected_values.any?
   end
 
+  def applied_filters
+    selected_values.map do |value|
+      {
+        name:,
+        label: value["label"],
+        query_params: { key => [value["value"]] },
+      }
+    end
+  end
+
   def query_params
     { key => selected_values.map { |value| value["value"] } }
   end

app/models/option_select_facet.rb

@@ -36,6 +36,16 @@ def has_filters?
     selected_values.any?
   end
 
+  def applied_filters
+    selected_values.map do |value|
+      {
+        name:,
+        label: value["label"],
+        query_params: { key => [value["value"]] },
+      }
+    end
+  end
+
   def unselected?
     selected_values.empty?
   end

app/models/sort_facet.rb

@@ -2,6 +2,12 @@
 # sorting forms part of the overall filtering UI instead of being separate
 class SortFacet
   KEY = "order".freeze
+  DEFAULT_SORT_OPTIONS = %w[relevance most-viewed].freeze
+
+  def initialize(content_item, filter_params)
+    @content_item = content_item
+    @filter_params = filter_params
+  end
 
   def name
     "Sort by"
@@ -20,13 +26,25 @@ def user_visible?
     true
   end
 
-  # The methods below are the minimum required for this virtual facet to take the place of a real
-  # `Facet`
-
   def has_filters?
-    false
+    sort_options.keys.include?(selected_sort_option) &&
+      !DEFAULT_SORT_OPTIONS.include?(selected_sort_option)
+  end
+
+  def applied_filters
+    return [] unless has_filters?
+
+    [{
+      name:,
+      label: sort_options[selected_sort_option],
+      query_params: { KEY => selected_sort_option },
+      visually_hidden_prefix: "Remove",
+    }]
   end
 
+  # The methods below are the minimum required for this virtual facet to take the place of a real
+  # `Facet`
+
   def filterable?
     true
   end
@@ -41,5 +59,15 @@ def metadata?
 
 private
 
-  attr_reader :sort_presenter
+  attr_reader :content_item, :filter_params
+
+  def sort_options
+    # Finder Frontend's sort handling is somewhat bizarre - it doesn't use the sort option keys from
+    # the content item, but rather the sort options' names parameterized.
+    content_item.sort_options.to_h { [_1["name"].parameterize, _1["name"]] }
+  end
+
+  def selected_sort_option
+    filter_params[KEY]
+  end
 end

app/models/taxon_facet.rb

@@ -36,6 +36,30 @@ def has_filters?
     selected_level_one_value.present?
   end
 
+  def applied_filters
+    return [] unless has_filters?
+
+    level_one_filter = {
+      name: "Topic",
+      label: selected_level_one_value[:text],
+      query_params: {
+        # Note that removing a topic should always remove the sub-topic too
+        LEVEL_ONE_TAXON_KEY => selected_level_one_value[:value],
+        LEVEL_TWO_TAXON_KEY => selected_level_two_value&.fetch(:value),
+      }.compact,
+    }
+
+    if selected_level_two_value
+      level_two_filter = {
+        name: "Sub-topic",
+        label: selected_level_two_value[:text],
+        query_params: { LEVEL_TWO_TAXON_KEY => selected_level_two_value[:value] },
+      }
+    end
+
+    [level_one_filter, level_two_filter].compact
+  end
+
   def query_params
     {
       LEVEL_ONE_TAXON_KEY => (selected_level_one_value || {})[:value],

app/presenters/filters_presenter.rb

@@ -0,0 +1,29 @@
+class FiltersPresenter
+  def initialize(facets, finder_url_builder)
+    @facets = facets
+    @finder_url_builder = finder_url_builder
+  end
+
+  def any_filters?
+    facets.any?(&:has_filters?)
+  end
+
+  def summary_items
+    facets.flat_map(&:applied_filters).map do |filter|
+      {
+        label: filter[:name],
+        value: filter[:label],
+        remove_href: finder_url_builder.url_except(filter[:query_params]),
+        visually_hidden_prefix: "Remove filter",
+      }
+    end
+  end
+
+  def reset_url
+    "#"
+  end
+
+private
+
+  attr_reader :facets, :finder_url_builder
+end

app/views/finders/show_all_content_finder.html.erb

@@ -49,6 +49,8 @@
           button_text: "Filter and sort",
           result_text: result_set_presenter.displayed_total,
           open: @search_query.invalid?,
+          show_reset_link: filters_presenter.any_filters?,
+          reset_link_href: filters_presenter.reset_url,
         } do %>
           <% facets.each_with_visible_index_and_count do |facet, index, count| %>
             <%=
@@ -59,32 +61,15 @@
           <% end %>
         <% end %>
 
-        <%= render "components/filter_summary", {
-          clear_all_href: "#",
-          clear_all_text: "Clear all filters",
-          heading_level: 3,
-          heading_text: "Selected filters",
-          filters: [
-            {
-              label: "Filter 1",
-              value: "Value 1",
-              remove_href: "#",
-              visually_hidden_prefix: "Remove filter"
-            },
-            {
-              label: "Filter 2",
-              value: "Value 2",
-              remove_href: "#",
-              visually_hidden_prefix: "Remove filter"
-            },
-            {
-              label: "Filter 3",
-              value: "Value 3",
-              remove_href: "#",
-              visually_hidden_prefix: "Remove filter"
-            }
-          ]
-        } %>
+        <% if filters_presenter.any_filters? %>
+          <%= render "components/filter_summary", {
+            clear_all_href: filters_presenter.reset_url,
+            clear_all_text: "Clear all filters",
+            heading_level: 3,
+            heading_text: "Selected filters",
+            filters: filters_presenter.summary_items,
+          } %>
+        <% end %>
 
         <% if result_set_presenter.total_count.positive? %>
           <%= render "govuk_publishing_components/components/document_list", {

features/all_content_finder.feature

@@ -41,6 +41,17 @@ Feature: All content finder ("site search")
     And I apply the filters
     Then I can see sorted results
 
+  Scenario: Removing a filter
+    When I search all content for "chandeliers flickering"
+    And I open the filter panel
+    And I open the "Topic" filter section
+    And I select "Music" as the Topic
+    And I select "Best songs" as the Sub-topic
+    And I apply the filters
+    And I click on the "Sub-topic: Best songs" filter tag
+    Then the "Sub-topic: Best songs" filter has been removed
+
+
   @javascript
   Scenario: Entering an incorrect date
     When I search all content for "chandeliers flickering"

features/step_definitions/site_search_steps.rb

@@ -37,6 +37,14 @@
   fill_in field, with: text
 end
 
+When(/I click on the "([^"]*)" filter tag/) do |filter|
+  click_on filter
+end
+
+Then(/the "([^"]*)" filter has been removed/) do |filter|
+  expect(page).not_to have_link(filter)
+end
+
 Then("I can see filtered results") do
   expect(page).to have_link("Death by a thousand cuts")
 end