1 files changed, 65 insertions, 0 deletions
diff --git a/actiontext/lib/action_text/attachment_gallery.rb b/actiontext/lib/action_text/attachment_gallery.rb
new file mode 100644
index 0000000000..45afbff058
--- /dev/null
+++ b/actiontext/lib/action_text/attachment_gallery.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+module ActionText
+  class AttachmentGallery
+    include ActiveModel::Model
+
+    class << self
+      def fragment_by_canonicalizing_attachment_galleries(content)
+        fragment_by_replacing_attachment_gallery_nodes(content) do |node|
+          "<#{TAG_NAME}>#{node.inner_html}</#{TAG_NAME}>"
+        end
+      end
+
+      def fragment_by_replacing_attachment_gallery_nodes(content)
+        Fragment.wrap(content).update do |source|
+          find_attachment_gallery_nodes(source).each do |node|
+            node.replace(yield(node).to_s)
+          end
+        end
+      end
+
+      def find_attachment_gallery_nodes(content)
+        Fragment.wrap(content).find_all(SELECTOR).select do |node|
+          node.children.all? do |child|
+            if child.text?
+              child.text =~ /\A(\n|\ )*\z/
+            else
+              child.matches? ATTACHMENT_SELECTOR
+            end
+          end
+        end
+      end
+
+      def from_node(node)
+        new(node)
+      end
+    end
+
+    attr_reader :node
+
+    def initialize(node)
+      @node = node
+    end
+
+    def attachments
+      @attachments ||= node.css(ATTACHMENT_SELECTOR).map do |node|
+        ActionText::Attachment.from_node(node).with_full_attributes
+      end
+    end
+
+    def size
+      attachments.size
+    end
+
+    def inspect
+      "#<#{self.class.name} size=#{size.inspect}>"
+    end
+
+    TAG_NAME = "div"
+    ATTACHMENT_SELECTOR = "#{ActionText::Attachment::SELECTOR}[presentation=gallery]"
+    SELECTOR = "#{TAG_NAME}:has(#{ATTACHMENT_SELECTOR} + #{ATTACHMENT_SELECTOR})"
+
+    private_constant :TAG_NAME, :ATTACHMENT_SELECTOR, :SELECTOR
+  end
+end