GraphQL mutations for add, remove and toggle emoji

Adding new `AddAwardEmoji`, `RemoveAwardEmoji` and `ToggleAwardEmoji`
GraphQL mutations.

Adding new `#authorized_find_with_pre_checks!` and (unused, but for
completeness `#authorized_find_with_post_checks!`) authorization
methods. These allow us to perform an authorized find, and run our own
additional checks before or after the authorization runs.

https://gitlab.com/gitlab-org/gitlab-ce/issues/62826

6 files changed, 146 insertions, 0 deletions

diff --git a/app/graphql/mutations/.keep b/app/graphql/mutations/.keep
deleted file mode 100644
index e69de29bb2d..00000000000
--- a/app/graphql/mutations/.keep
+++ /dev/null
diff --git a/app/graphql/mutations/award_emojis/add.rb b/app/graphql/mutations/award_emojis/add.rb
new file mode 100644
index 00000000000..8e050dd6d29
--- /dev/null
+++ b/app/graphql/mutations/award_emojis/add.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Mutations
+  module AwardEmojis
+    class Add < Base
+      graphql_name 'AddAwardEmoji'
+
+      def resolve(args)
+        awardable = authorized_find!(id: args[:awardable_id])
+
+        check_object_is_awardable!(awardable)
+
+        # TODO this will be handled by AwardEmoji::AddService
+        # See https://gitlab.com/gitlab-org/gitlab-ce/issues/63372 and
+        # https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/29782
+        award = awardable.create_award_emoji(args[:name], current_user)
+
+        {
+          award_emoji: (award if award.persisted?),
+          errors: errors_on_object(award)
+        }
+      end
+    end
+  end
+end
diff --git a/app/graphql/mutations/award_emojis/base.rb b/app/graphql/mutations/award_emojis/base.rb
new file mode 100644
index 00000000000..d868db84f9d
--- /dev/null
+++ b/app/graphql/mutations/award_emojis/base.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module Mutations
+  module AwardEmojis
+    class Base < BaseMutation
+      include Gitlab::Graphql::Authorize::AuthorizeResource
+
+      authorize :award_emoji
+
+      argument :awardable_id,
+               GraphQL::ID_TYPE,
+               required: true,
+               description: 'The global id of the awardable resource'
+
+      argument :name,
+               GraphQL::STRING_TYPE,
+               required: true,
+               description: copy_field_description(Types::AwardEmojis::AwardEmojiType, :name)
+
+      field :award_emoji,
+            Types::AwardEmojis::AwardEmojiType,
+            null: true,
+            description: 'The award emoji after mutation'
+
+      private
+
+      def find_object(id:)
+        GitlabSchema.object_from_id(id)
+      end
+
+      # Called by mutations methods after performing an authorization check
+      # of an awardable object.
+      def check_object_is_awardable!(object)
+        unless object.is_a?(Awardable) && object.emoji_awardable?
+          raise Gitlab::Graphql::Errors::ResourceNotAvailable,
+                'Cannot award emoji to this resource'
+        end
+      end
+    end
+  end
+end
diff --git a/app/graphql/mutations/award_emojis/remove.rb b/app/graphql/mutations/award_emojis/remove.rb
new file mode 100644
index 00000000000..3ba85e445b8
--- /dev/null
+++ b/app/graphql/mutations/award_emojis/remove.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Mutations
+  module AwardEmojis
+    class Remove < Base
+      graphql_name 'RemoveAwardEmoji'
+
+      def resolve(args)
+        awardable = authorized_find!(id: args[:awardable_id])
+
+        check_object_is_awardable!(awardable)
+
+        # TODO this check can be removed once AwardEmoji services are available.
+        # See https://gitlab.com/gitlab-org/gitlab-ce/issues/63372 and
+        # https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/29782
+        unless awardable.awarded_emoji?(args[:name], current_user)
+          raise Gitlab::Graphql::Errors::ResourceNotAvailable,
+                'You have not awarded emoji of type name to the awardable'
+        end
+
+        # TODO this will be handled by AwardEmoji::DestroyService
+        # See https://gitlab.com/gitlab-org/gitlab-ce/issues/63372 and
+        # https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/29782
+        awardable.remove_award_emoji(args[:name], current_user)
+
+        {
+          # Mutation response is always a `nil` award_emoji
+          errors: []
+        }
+      end
+    end
+  end
+end
diff --git a/app/graphql/mutations/award_emojis/toggle.rb b/app/graphql/mutations/award_emojis/toggle.rb
new file mode 100644
index 00000000000..c03902e8035
--- /dev/null
+++ b/app/graphql/mutations/award_emojis/toggle.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Mutations
+  module AwardEmojis
+    class Toggle < Base
+      graphql_name 'ToggleAwardEmoji'
+
+      field :toggledOn,
+            GraphQL::BOOLEAN_TYPE,
+            null: false,
+            description: 'True when the emoji was awarded, false when it was removed'
+
+      def resolve(args)
+        awardable = authorized_find!(id: args[:awardable_id])
+
+        check_object_is_awardable!(awardable)
+
+        # TODO this will be handled by AwardEmoji::ToggleService
+        # See https://gitlab.com/gitlab-org/gitlab-ce/issues/63372 and
+        # https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/29782
+        award = awardable.toggle_award_emoji(args[:name], current_user)
+
+        # Destroy returns a collection :(
+        award = award.first if award.is_a?(Array)
+
+        errors = errors_on_object(award)
+
+        toggled_on = awardable.awarded_emoji?(args[:name], current_user)
+
+        {
+          # For consistency with the AwardEmojis::Remove mutation, only return
+          # the AwardEmoji if it was created and not destroyed
+          award_emoji: (award if toggled_on),
+          errors: errors,
+          toggled_on: toggled_on
+        }
+      end
+    end
+  end
+end
diff --git a/app/graphql/mutations/base_mutation.rb b/app/graphql/mutations/base_mutation.rb
index eb03dfe1624..08d2a1f18a3 100644
--- a/app/graphql/mutations/base_mutation.rb
+++ b/app/graphql/mutations/base_mutation.rb
@@ -2,6 +2,8 @@
 
 module Mutations
   class BaseMutation < GraphQL::Schema::RelayClassicMutation
+    prepend Gitlab::Graphql::CopyFieldDescription
+
     field :errors, [GraphQL::STRING_TYPE],
           null: false,
           description: "Reasons why the mutation failed."
@@ -9,5 +11,10 @@ module Mutations
     def current_user
       context[:current_user]
     end
+
+    # Returns Array of errors on an ActiveRecord object
+    def errors_on_object(record)
+      record.errors.full_messages
+    end
   end
 end