1 files changed, 28 insertions, 0 deletions
diff --git a/app/validators/reaction_validator.rb b/app/validators/reaction_validator.rb
new file mode 100644
index 000000000..494b6041b
--- /dev/null
+++ b/app/validators/reaction_validator.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+class ReactionValidator < ActiveModel::Validator
+  SUPPORTED_EMOJIS = Oj.load(File.read(Rails.root.join('app', 'javascript', 'mastodon', 'features', 'emoji', 'emoji_map.json'))).keys.freeze
+
+  LIMIT = 8
+
+  def validate(reaction)
+    return if reaction.name.blank?
+
+    reaction.errors.add(:name, I18n.t('reactions.errors.unrecognized_emoji')) if reaction.custom_emoji_id.blank? && !unicode_emoji?(reaction.name)
+    reaction.errors.add(:base, I18n.t('reactions.errors.limit_reached')) if new_reaction?(reaction) && limit_reached?(reaction)
+  end
+
+  private
+
+  def unicode_emoji?(name)
+    SUPPORTED_EMOJIS.include?(name)
+  end
+
+  def new_reaction?(reaction)
+    !reaction.announcement.announcement_reactions.where(name: reaction.name).exists?
+  end
+
+  def limit_reached?(reaction)
+    reaction.announcement.announcement_reactions.where.not(name: reaction.name).count('distinct name') >= LIMIT
+  end
+end