#434

backend/app/services/counts_defaults.rb

@@ -0,0 +1,46 @@
+# Only confirmed combinations belong here; all others retain the existing behaviour.
+class CountsDefaults
+  POST_COLUMNS = ['resource_id', 'version_no', 'is_latest', 'title', 'url',
+                  'thumbnail_base', 'tags', 'parents', 'original_created_from',
+                  'original_created_before', 'event_type', 'user', 'created_at'].freeze
+
+  def self.entries(resource)
+    result = [{ definition: 'history', mode: 'summary', params: {
+        'rows' => [{ field: 'created_at', grain: 'month' }].to_json,
+        'cols' => [{ field: 'event_type' }].to_json,
+        'sort' => 'a0:desc', 'conditions' => '[]' } }]
+    if resource == 'posts'
+      result += [{ definition: 'latest', mode: 'summary', params: {
+          'rows' => '[]', 'cols' => '[]', 'conditions' => '[]', 'tags' => '' } },
+          { definition: 'latest', mode: 'details', params: {
+              'columns' => POST_COLUMNS.join(','), 'order' => POST_COLUMNS.join(','),
+              'children' => 'tags.name,parents.id', 'nested_json' => '0',
+              'conditions' => '[]', 'tags' => '' } }]
+    end
+    result
+  end
+
+  def self.for(params)
+    settings = entries(params.fetch('resource', 'posts')).find do |entry|
+      entry[:definition] == params.fetch('definition', 'latest') &&
+          entry[:mode] == params.fetch('mode', 'summary')
+    end&.fetch(:params) || {}
+    if settings.key?('sort') && params.key?('rows')
+      actual = JSON.parse(params['rows'])
+      expected = JSON.parse(settings.fetch('rows'))
+      compatible = actual.is_a?(Array) && actual.first.is_a?(Hash) &&
+          actual.first['field'] == expected.first['field'] &&
+          actual.first.fetch('grain', 'month') == expected.first['grain']
+      unless compatible
+        settings = settings.except('sort')
+      end
+    end
+    settings
+  end
+
+  def self.metadata(resource)
+    entries(resource).map do |entry|
+      entry.merge(params: entry[:params].map { |key, value| { key:, value: } })
+    end
+  end
+end