Add service classes for mutating AwardEmoji

Adding, destroying and toggling emoji previously lacked services and
instead were performed through methods called on Awardable models.

This led to inconsistencies where relevant todos would be marked as done
only when emoji were awarded through our controllers, but not through
the API. Todos could also be marked as done when an emoji was being
removed.

Behaviour changes

- Awarding emoji through the API will now mark a relevant Todo as done
- Toggling an emoji off (destroying it) through our controllers will no
  longer mark a relevant Todo as done

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/63372

4 files changed, 108 insertions, 0 deletions

diff --git a/app/services/award_emojis/add_service.rb b/app/services/award_emojis/add_service.rb
new file mode 100644
index 00000000000..eac15dabbf0
--- /dev/null
+++ b/app/services/award_emojis/add_service.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module AwardEmojis
+  class AddService < AwardEmojis::BaseService
+    include Gitlab::Utils::StrongMemoize
+
+    def execute
+      unless awardable.user_can_award?(current_user)
+        return error('User cannot award emoji to awardable', status: :forbidden)
+      end
+
+      unless awardable.emoji_awardable?
+        return error('Awardable cannot be awarded emoji', status: :unprocessable_entity)
+      end
+
+      award = awardable.award_emoji.create(name: name, user: current_user)
+
+      if award.persisted?
+        TodoService.new.new_award_emoji(todoable, current_user) if todoable
+        success(award: award)
+      else
+        error(award.errors.full_messages, award: award)
+      end
+    end
+
+    private
+
+    def todoable
+      strong_memoize(:todoable) do
+        case awardable
+        when Note
+          # We don't create todos for personal snippet comments for now
+          awardable.noteable unless awardable.for_personal_snippet?
+        when MergeRequest, Issue
+          awardable
+        when Snippet
+          nil
+        end
+      end
+    end
+  end
+end
diff --git a/app/services/award_emojis/base_service.rb b/app/services/award_emojis/base_service.rb
new file mode 100644
index 00000000000..a677d03a221
--- /dev/null
+++ b/app/services/award_emojis/base_service.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module AwardEmojis
+  class BaseService < ::BaseService
+    attr_accessor :awardable, :name
+
+    def initialize(awardable, name, current_user)
+      @awardable = awardable
+      @name = normalize_name(name)
+
+      super(awardable.project, current_user)
+    end
+
+    private
+
+    def normalize_name(name)
+      Gitlab::Emoji.normalize_emoji_name(name)
+    end
+
+    # Provide more error state data than what BaseService allows.
+    # - An array of errors
+    # - The `AwardEmoji` if present
+    def error(errors, award: nil, status: nil)
+      errors = Array.wrap(errors)
+
+      super(errors.to_sentence.presence, status).merge({
+        award: award,
+        errors: errors
+      })
+    end
+  end
+end
diff --git a/app/services/award_emojis/destroy_service.rb b/app/services/award_emojis/destroy_service.rb
new file mode 100644
index 00000000000..3789a8403bc
--- /dev/null
+++ b/app/services/award_emojis/destroy_service.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module AwardEmojis
+  class DestroyService < AwardEmojis::BaseService
+    def execute
+      unless awardable.user_can_award?(current_user)
+        return error('User cannot destroy emoji on the awardable', status: :forbidden)
+      end
+
+      awards = AwardEmojisFinder.new(awardable, name: name, awarded_by: current_user).execute
+
+      if awards.empty?
+        return error("User has not awarded emoji of type #{name} on the awardable", status: :forbidden)
+      end
+
+      award = awards.destroy_all.first # rubocop: disable DestroyAll
+
+      success(award: award)
+    end
+  end
+end
diff --git a/app/services/award_emojis/toggle_service.rb b/app/services/award_emojis/toggle_service.rb
new file mode 100644
index 00000000000..812dd1c2889
--- /dev/null
+++ b/app/services/award_emojis/toggle_service.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module AwardEmojis
+  class ToggleService < AwardEmojis::BaseService
+    def execute
+      if awardable.awarded_emoji?(name, current_user)
+        DestroyService.new(awardable, name, current_user).execute
+      else
+        AddService.new(awardable, name, current_user).execute
+      end
+    end
+  end
+end