Porting essential blacklight range limit functionality

app/components/blacklight/facet_field_list_range_component.html.erb

@@ -0,0 +1,17 @@
+<%= render(@layout.new(facet_field: @facet_field)) do |component| %>
+  <% component.with_label do %>
+    <%= @facet_field.label %>
+  <% end %>
+
+  <% component.with_body do %>
+    <%# Don't display form if the missing facet is selected. Otherwise provide
+        the form as an easy way for users to updated the range. %>
+    <% unless @facet_field.missing_selected? %>
+        <%= render Blacklight::FacetFieldListRangeFormComponent.new(facet_field: @facet_field) %>
+    <% end %>
+
+    <ul class="facet-values list-unstyled">
+      <%= render facet_items %>
+    </ul>
+  <% end %>
+<% end %>

app/components/blacklight/facet_field_list_range_component.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Blacklight
+  class FacetFieldListRangeComponent < Blacklight::Component
+    # @param [Blacklight::FacetFieldRangePresenter] facet_field
+    def initialize(facet_field:, layout: nil)
+      @facet_field = facet_field
+      @layout = layout == false ? FacetFieldNoLayoutComponent : Blacklight::FacetFieldComponent
+    end
+
+    def facet_items(wrapping_element: :li, **item_args)
+      facet_item_component_class.with_collection(facet_item_presenters, wrapping_element: wrapping_element, **item_args)
+    end
+
+    def facet_item_presenters
+      @facet_field.paginator.items.map do |item|
+        facet_item_presenter(item)
+      end
+    end
+
+    def facet_item_presenter(facet_item, deprecated_facet_config = nil, facet_field = nil)
+      (deprecated_facet_config || facet_config).item_presenter.new(facet_item, deprecated_facet_config || facet_config, helpers, facet_field || @facet_field.key)
+    end
+
+    def facet_item_component_class(deprecated_facet_config = nil)
+      (deprecated_facet_config || facet_config).item_component
+    end
+
+    def facet_config
+      @facet_field.facet_field
+    end
+  end
+end

app/components/blacklight/facet_field_list_range_form_component.html.erb

@@ -0,0 +1,12 @@
+<%= form_tag search_action_path, method: :get, class: ['range_limit subsection form-inline', "range_#{@facet_field.key} d-flex justify-content-center"].join(' ') do %>
+  <%= render hidden_search_state %>
+
+  <div class="input-group input-group-sm mb-3 flex-nowrap range-limit-input-group">
+    <%= render_range_input(:start, start_label) %>
+    <%= render_range_input(:end, end_label) %>
+    <div class="input-group-append visually-hidden">
+      <%= submit_tag t('blacklight.search.facets.range.form.submit'), class: 'submit btn btn-secondary', name: nil %>
+    </div>
+    <%= submit_tag t('blacklight.search.facets.range.form.submit'), class: "submit btn btn-secondary sr-only", "aria-hidden": "true", name: nil %>
+  </div>
+<% end %>

app/components/blacklight/facet_field_list_range_form_component.rb

@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module Blacklight
+  class FacetFieldListRangeFormComponent < Blacklight::Component
+    delegate :search_action_path, to: :helpers
+
+    def initialize(facet_field:)
+      @facet_field = facet_field
+    end
+
+    def start_label
+      t('blacklight.search.facets.range.form.start_label', field_label: @facet_field.label)
+    end
+
+    def end_label
+      t('blacklight.search.facets.range.form.end_label', field_label: @facet_field.label)
+    end
+
+    def input_options
+      return {} unless range_config
+
+      range_config.fetch(:input, {})
+                  .slice(:min, :max, :placeholder, :step)
+    end
+
+    # type is 'start' or 'end'
+    def render_range_input(type, input_label = nil)
+      type = type.to_s
+
+      default = if @facet_field.selected_range.is_a?(Range)
+                  case type
+                  when 'start' then @facet_field.selected_range.first
+                  when 'end' then @facet_field.selected_range.last
+                  end
+                end
+      html = number_field_tag("range[#{@facet_field.key}][#{type}]", default, class: "form-control text-center range_#{type}", **input_options)
+      html += label_tag("range[#{@facet_field.key}][#{type}]", input_label, class: 'sr-only visually-hidden') if input_label.present?
+      html
+    end
+
+    private
+
+    ##
+    # the form needs to serialize any search parameters, including other potential range filters,
+    # as hidden fields. The parameters for this component's range filter are serialized as number
+    # inputs, and should not be in the hidden params.
+    # @return [Blacklight::HiddenSearchStateComponent]
+    def hidden_search_state
+      hidden_search_params = @facet_field.search_state.params_for_search.except(:utf8, :page)
+      hidden_search_params[:range]&.except!(@facet_field.key)
+      Blacklight::HiddenSearchStateComponent.new(params: hidden_search_params)
+    end
+
+    def range_config
+      config = @facet_field.facet_field.range
+      config == true ? {} : config
+    end
+  end
+end

app/presenters/blacklight/facet_field_range_presenter.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Blacklight
+  class FacetFieldRangePresenter < Blacklight::FacetFieldPresenter
+    delegate :response, to: :display_facet
+    delegate :blacklight_config, to: :search_state
+
+    # Paginator will return the selected item or if no facet is selected, the [Missing] facet.
+    def paginator
+      return unless display_facet
+
+      @paginator ||= blacklight_config.facet_paginator_class.new(
+        Array.wrap(selected_item || display_facet.items.select(&:missing)),
+        sort: display_facet.sort,
+        offset: display_facet.offset,
+        prefix: display_facet.prefix,
+        limit: facet_limit
+      )
+    end
+
+    def selected_range
+      values&.first
+    end
+
+    # Wraps selected range in Blacklight::Solr::Response::Facets::FacetItem object.
+    #
+    # @return [Blacklight::Solr::Response::Facets::FacetItem] if range is selected
+    # @return [NilClass] if no range is selected
+    def selected_item
+      return unless selected_range
+
+      Blacklight::Solr::Response::Facets::FacetItem.new(value: selected_range, hits: response.total)
+    end
+
+    # Returns true if [Missing] facet is selected.
+    def missing_selected?
+      selected_range == Blacklight::SearchState::FilterField::MISSING
+    end
+  end
+end

app/presenters/blacklight/facet_item_range_presenter.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module Blacklight
+  # Override the default item presenter to provide custom labels for
+  # range data.
+  class FacetItemRangePresenter < Blacklight::FacetItemPresenter
+    # Overriding method to generate a more descriptive label
+    def label
+      label_for_range || super
+    end
+
+    private
+
+    def label_for_range
+      return unless value.is_a? Range
+
+      view_context.t(range_limit_label_key, start: value.first, end: value.last)
+    end
+
+    def range_limit_label_key
+      if value.first == value.last
+        'blacklight.search.facets.range.single_value'
+      else
+        'blacklight.search.facets.range.range_value'
+      end
+    end
+  end
+end

config/locales/blacklight.ar.yml

@@ -113,6 +113,13 @@ ar:
           count: ترتيب رقمي
           index: ترتيب أبجدي
         title: تحديد نطاق البحث
+        range:
+          form:
+            start_label: "%{field_label} بداية المدة"
+            end_label: "%{field_label} نهاية المدة"
+            submit: 'تطبيق'
+          single_value: '%{begin}'
+          range_value: '%{begin} الى %{end}'
       filters:
         label: "%{label}:"
         remove:

config/locales/blacklight.de.yml

@@ -104,6 +104,13 @@ de:
           count: Numerisch ordnen
           index: A-Z Ordnen
         title: Suche beschränken
+        range:
+          form:
+            start_label: "%{field_label} Bereichsanfang"
+            end_label: "%{field_label} Bereichsende"
+            submit: 'Anwenden'
+          single_value: '%{begin}'
+          range_value: '%{begin} bis %{end}'
       filters:
         label: "%{label}:"
         remove:

config/locales/blacklight.en.yml

@@ -194,6 +194,13 @@ en:
           toggle: Toggle facets
           open: Show facets
           close: Hide facets
+        range:
+          form:
+            start_label: "%{field_label} range start"
+            end_label: "%{field_label} range end"
+            submit: 'Apply'
+          single_value: "%{start}"
+          range_value: "%{start} to %{end}"
       group:
         more: 'more »'
       filters:

config/locales/blacklight.it.yml

@@ -104,6 +104,13 @@ it:
           count: Ordina per numero
           index: Ordina A-Z
         title: Affina la ricerca
+        range:
+          form:
+            start_label: "%{field_label} da"
+            end_label: "%{field_label} a"
+            submit: 'Invia'
+          single_value: '%{begin}'
+          range_value: '%{begin} a %{end}'
       filters:
         label: "%{label}:"
         remove:

lib/blacklight/configuration/facet_field.rb

@@ -70,6 +70,7 @@ def normalize! blacklight_config = nil
       query.stringify_keys! if query
 
       normalize_pivot_config! if pivot
+      normalize_range_config! if range
       self.collapse = true if collapse.nil?
       self.show = true if show.nil?
       self.if = show if self.if.nil?
@@ -98,5 +99,13 @@ def normalize_pivot_config!
       self.filter_class ||= Blacklight::SearchState::PivotFilterField
       self.filter_query_builder ||= Blacklight::SearchState::PivotFilterField::QueryBuilder
     end
+
+    def normalize_range_config!
+      self.presenter ||= Blacklight::FacetFieldRangePresenter
+      self.item_presenter ||= Blacklight::FacetItemRangePresenter
+      self.component ||= Blacklight::FacetFieldListRangeComponent
+      self.filter_class ||= Blacklight::SearchState::RangeFilterField
+      self.solr_params = (solr_params || {}).merge({ 'facet.missing' => true })
+    end
   end
 end

lib/blacklight/search_state.rb

@@ -2,6 +2,7 @@
 
 require 'blacklight/search_state/filter_field'
 require 'blacklight/search_state/pivot_filter_field'
+require 'blacklight/search_state/range_filter_field'
 
 module Blacklight
   # This class encapsulates the search state as represented by the query

lib/blacklight/search_state/range_filter_field.rb

@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+module Blacklight
+  class SearchState
+    # Modeling access to filter query parameters
+    class RangeFilterField < FilterField
+      # this accessor is unnecessary after Blacklight 7.25.0
+      attr_accessor :filters_key
+
+      def initialize(config, search_state)
+        super
+        @filters_key = :range
+      end
+
+      # @param [String,#value] a filter item to add to the url
+      # @return [Blacklight::SearchState] new state
+      def add(item)
+        new_state = search_state.reset_search
+        params = new_state.params
+        value = as_url_parameter(item)
+
+        if value.is_a? Range
+          param_key = filters_key
+          params[param_key] = (params[param_key] || {}).dup
+          params[param_key][config.key] = { start: value.first, end: value.last }
+          new_state.reset(params)
+        else
+          super
+        end
+      end
+
+      # @param [String,#value] a filter to remove from the url
+      # @return [Blacklight::SearchState] new state
+      def remove(item)
+        new_state = search_state.reset_search
+        params = new_state.params
+        value = as_url_parameter(item)
+
+        if value.is_a? Range
+          param_key = filters_key
+          params[param_key] = (params[param_key] || {}).dup
+          params[param_key]&.delete(config.key)
+          new_state.reset(params)
+        else
+          super
+        end
+      end
+
+      # @return [Array] an array of applied filters
+      def values(except: [])
+        params = search_state.params
+        param_key = filters_key
+
+        range = if params.dig(param_key, config.key).is_a? Range
+                  params.dig(param_key, config.key)
+                elsif params.dig(param_key, config.key).is_a? Hash
+                  b_bound = params.dig(param_key, config.key, :start).presence
+                  e_bound = params.dig(param_key, config.key, :end).presence
+                  Range.new(b_bound&.to_i, e_bound&.to_i) if b_bound && e_bound
+                end
+
+        f = except.include?(:filters) ? [] : [range].compact
+        f_missing = [Blacklight::SearchState::FilterField::MISSING] if params.dig(filters_key, "-#{key}")&.any? { |v| v == Blacklight::Engine.config.blacklight.facet_missing_param }
+        f_missing = [] if except.include?(:missing)
+
+        f + (f_missing || [])
+      end
+
+      # @param [String,#value] a filter to remove from the url
+      # @return [Boolean] whether the provided filter is currently applied/selected
+      delegate :include?, to: :values
+
+      # @since Blacklight v7.25.2
+      # normal filter fields demangle when they encounter a hash, which they assume to be a number-indexed map
+      # this filter should allow (expect) hashes if the keys include 'start' or 'end'
+      def permitted_params
+        {
+          filters_key => { config.key => [:start, :end], "-#{config.key}" => [] },
+          inclusive_filters_key => { config.key => [:start, :end] }
+        }
+      end
+    end
+  end
+end