Add support for editing for published statuses (#16697)

* Add support for editing for published statuses

* Fix references to stripped-out code

* Various fixes and improvements

* Further fixes and improvements

* Fix updates being potentially sent to unauthorized recipients

* Various fixes and improvements

* Fix wrong words in test

* Fix notifying accounts that were tagged but were not in the audience

* Fix mistake

app/lib/activitypub/parser/poll_parser.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+class ActivityPub::Parser::PollParser
+  include JsonLdHelper
+
+  def initialize(json)
+    @json = json
+  end
+
+  def valid?
+    equals_or_includes?(@json['type'], 'Question') && items.is_a?(Array)
+  end
+
+  # @param [Poll] previous_record
+  def significantly_changes?(previous_record)
+    options != previous_record.options ||
+      multiple != previous_record.multiple
+  end
+
+  def options
+    items.filter_map { |item| item['name'].presence || item['content'] }
+  end
+
+  def multiple
+    @json['anyOf'].is_a?(Array)
+  end
+
+  def expires_at
+    if @json['closed'].is_a?(String)
+      @json['closed'].to_datetime
+    elsif !@json['closed'].nil? && !@json['closed'].is_a?(FalseClass)
+      Time.now.utc
+    else
+      @json['endTime']&.to_datetime
+    end
+  rescue ArgumentError
+    nil
+  end
+
+  def voters_count
+    @json['votersCount']
+  end
+
+  def cached_tallies
+    items.map { |item| item.dig('replies', 'totalItems') || 0 }
+  end
+
+  private
+
+  def items
+    @json['anyOf'] || @json['oneOf']
+  end
+end