Resolve "Extract logic of who should receive notification into separate classes"

2 files changed, 312 insertions, 304 deletions

diff --git a/app/services/notification_recipient_service.rb b/app/services/notification_recipient_service.rb
new file mode 100644
index 00000000000..44ae23fad18
--- /dev/null
+++ b/app/services/notification_recipient_service.rb
@@ -0,0 +1,293 @@
+#
+# Used by NotificationService to determine who should receive notification
+#
+class NotificationRecipientService
+  attr_reader :project
+  
+  def initialize(project)
+    @project = project
+  end
+
+  def build_recipients(target, current_user, action: nil, previous_assignee: nil, skip_current_user: true)
+    custom_action = build_custom_key(action, target)
+
+    recipients = target.participants(current_user)
+
+    unless NotificationSetting::EXCLUDED_WATCHER_EVENTS.include?(custom_action)
+      recipients = add_project_watchers(recipients)
+    end
+
+    recipients = add_custom_notifications(recipients, custom_action)
+    recipients = reject_mention_users(recipients)
+
+    # Re-assign is considered as a mention of the new assignee so we add the
+    # new assignee to the list of recipients after we rejected users with
+    # the "on mention" notification level
+    if [:reassign_merge_request, :reassign_issue].include?(custom_action)
+      recipients << previous_assignee if previous_assignee
+      recipients << target.assignee
+    end
+
+    recipients = reject_muted_users(recipients)
+    recipients = add_subscribed_users(recipients, target)
+
+    if [:new_issue, :new_merge_request].include?(custom_action)
+      recipients = add_labels_subscribers(recipients, target)
+    end
+
+    recipients = reject_unsubscribed_users(recipients, target)
+    recipients = reject_users_without_access(recipients, target)
+
+    recipients.delete(current_user) if skip_current_user
+
+    recipients.uniq
+  end
+
+  def build_relabeled_recipients(target, current_user, labels:)
+    recipients = add_labels_subscribers([], target, labels: labels)
+    recipients = reject_unsubscribed_users(recipients, target)
+    recipients = reject_users_without_access(recipients, target)
+    recipients.delete(current_user)
+    recipients.uniq
+  end
+
+  def build_new_note_recipients(note)
+    target = note.noteable
+
+    ability, subject = if note.for_personal_snippet?
+                         [:read_personal_snippet, note.noteable]
+                       else
+                         [:read_project, note.project]
+                       end
+
+    mentioned_users = note.mentioned_users.select { |user| user.can?(ability, subject) }
+
+    # Add all users participating in the thread (author, assignee, comment authors)
+    recipients =
+      if target.respond_to?(:participants)
+        target.participants(note.author)
+      else
+        mentioned_users
+      end
+
+    unless note.for_personal_snippet?
+      # Merge project watchers
+      recipients = add_project_watchers(recipients)
+
+      # Merge project with custom notification
+      recipients = add_custom_notifications(recipients, :new_note)
+    end
+
+    # Reject users with Mention notification level, except those mentioned in _this_ note.
+    recipients = reject_mention_users(recipients - mentioned_users)
+    recipients = recipients + mentioned_users
+
+    recipients = reject_muted_users(recipients)
+
+    recipients = add_subscribed_users(recipients, note.noteable)
+    recipients = reject_unsubscribed_users(recipients, note.noteable)
+    recipients = reject_users_without_access(recipients, note.noteable)
+
+    recipients.delete(note.author)
+    recipients.uniq
+  end
+
+  # Remove users with disabled notifications from array
+  # Also remove duplications and nil recipients
+  def reject_muted_users(users)
+    reject_users(users, :disabled)
+  end
+
+  protected
+
+  # Get project/group users with CUSTOM notification level
+  def add_custom_notifications(recipients, action)
+    user_ids = []
+
+    # Users with a notification setting on group or project
+    user_ids += user_ids_notifiable_on(project, :custom, action)
+    user_ids += user_ids_notifiable_on(project.group, :custom, action)
+
+    # Users with global level custom
+    user_ids_with_project_level_global = user_ids_notifiable_on(project, :global)
+    user_ids_with_group_level_global   = user_ids_notifiable_on(project.group, :global)
+
+    global_users_ids = user_ids_with_project_level_global.concat(user_ids_with_group_level_global)
+    user_ids += user_ids_with_global_level_custom(global_users_ids, action)
+
+    recipients.concat(User.find(user_ids))
+  end
+
+  def add_project_watchers(recipients)
+    recipients.concat(project_watchers).compact
+  end
+
+  # Get project users with WATCH notification level
+  def project_watchers
+    project_members_ids = user_ids_notifiable_on(project)
+
+    user_ids_with_project_global = user_ids_notifiable_on(project, :global)
+    user_ids_with_group_global   = user_ids_notifiable_on(project.group, :global)
+
+    user_ids = user_ids_with_global_level_watch((user_ids_with_project_global + user_ids_with_group_global).uniq)
+
+    user_ids_with_project_setting = select_project_members_ids(project, user_ids_with_project_global, user_ids)
+    user_ids_with_group_setting = select_group_members_ids(project.group, project_members_ids, user_ids_with_group_global, user_ids)
+
+    User.where(id: user_ids_with_project_setting.concat(user_ids_with_group_setting).uniq).to_a
+  end
+
+  # Remove users with notification level 'Mentioned'
+  def reject_mention_users(users)
+    reject_users(users, :mention)
+  end
+
+  def add_subscribed_users(recipients, target)
+    return recipients unless target.respond_to? :subscribers
+
+    recipients + target.subscribers(project)
+  end
+
+  def user_ids_notifiable_on(resource, notification_level = nil, action = nil)
+    return [] unless resource
+
+    if notification_level
+      settings = resource.notification_settings.where(level: NotificationSetting.levels[notification_level])
+      settings = settings.select { |setting| setting.events[action] } if action.present?
+      settings.map(&:user_id)
+    else
+      resource.notification_settings.pluck(:user_id)
+    end
+  end
+
+  # Build a list of user_ids based on project notification settings
+  def select_project_members_ids(project, global_setting, user_ids_global_level_watch)
+    user_ids = user_ids_notifiable_on(project, :watch)
+
+    # If project setting is global, add to watch list if global setting is watch
+    global_setting.each do |user_id|
+      if user_ids_global_level_watch.include?(user_id)
+        user_ids << user_id
+      end
+    end
+
+    user_ids
+  end
+
+  # Build a list of user_ids based on group notification settings
+  def select_group_members_ids(group, project_members, global_setting, user_ids_global_level_watch)
+    uids = user_ids_notifiable_on(group, :watch)
+
+    # Group setting is watch, add to user_ids list if user is not project member
+    user_ids = []
+    uids.each do |user_id|
+      if project_members.exclude?(user_id)
+        user_ids << user_id
+      end
+    end
+
+    # Group setting is global, add to user_ids list if global setting is watch
+    global_setting.each do |user_id|
+      if project_members.exclude?(user_id) && user_ids_global_level_watch.include?(user_id)
+        user_ids << user_id
+      end
+    end
+
+    user_ids
+  end
+
+  def user_ids_with_global_level_watch(ids)
+    settings_with_global_level_of(:watch, ids).pluck(:user_id)
+  end
+
+  def user_ids_with_global_level_custom(ids, action)
+    settings = settings_with_global_level_of(:custom, ids)
+    settings = settings.select { |setting| setting.events[action] }
+    settings.map(&:user_id)
+  end
+
+  def settings_with_global_level_of(level, ids)
+    NotificationSetting.where(
+      user_id: ids,
+      source_type: nil,
+      level: NotificationSetting.levels[level]
+    )
+  end
+
+  # Reject users which has certain notification level
+  #
+  # Example:
+  #   reject_users(users, :watch, project)
+  #
+  def reject_users(users, level)
+    level = level.to_s
+
+    unless NotificationSetting.levels.keys.include?(level)
+      raise 'Invalid notification level'
+    end
+
+    users = users.to_a.compact.uniq
+    users = users.select { |u| u.can?(:receive_notifications) }
+
+    users.reject do |user|
+      global_notification_setting = user.global_notification_setting
+
+      next global_notification_setting.level == level unless project
+
+      setting = user.notification_settings_for(project)
+
+      if project.group && (setting.nil? || setting.global?)
+        setting = user.notification_settings_for(project.group)
+      end
+
+      # reject users who globally set mention notification and has no setting per project/group
+      next global_notification_setting.level == level unless setting
+
+      # reject users who set mention notification in project
+      next true if setting.level == level
+
+      # reject users who have mention level in project and disabled in global settings
+      setting.global? && global_notification_setting.level == level
+    end
+  end
+
+  def reject_unsubscribed_users(recipients, target)
+    return recipients unless target.respond_to? :subscriptions
+
+    recipients.reject do |user|
+      subscription = target.subscriptions.find_by_user_id(user.id)
+      subscription && !subscription.subscribed
+    end
+  end
+
+  def reject_users_without_access(recipients, target)
+    ability = case target
+              when Issuable
+                :"read_#{target.to_ability_name}"
+              when Ci::Pipeline
+                :read_build # We have build trace in pipeline emails
+              end
+
+    return recipients unless ability
+
+    recipients.select do |user|
+      user.can?(ability, target)
+    end
+  end
+
+  def add_labels_subscribers(recipients, target, labels: nil)
+    return recipients unless target.respond_to? :labels
+
+    (labels || target.labels).each do |label|
+      recipients += label.subscribers(project)
+    end
+
+    recipients
+  end
+
+  # Build event key to search on custom notification level
+  # Check NotificationSetting::EMAIL_EVENTS
+  def build_custom_key(action, object)
+    "#{action}_#{object.class.model_name.name.underscore}".to_sym
+  end
+end
diff --git a/app/services/notification_service.rb b/app/services/notification_service.rb
index fdaba9b95fb..f9aa2346759 100644
--- a/app/services/notification_service.rb
+++ b/app/services/notification_service.rb
@@ -150,7 +150,10 @@ class NotificationService
   end
 
   def resolve_all_discussions(merge_request, current_user)
-    recipients = build_recipients(merge_request, merge_request.target_project, current_user, action: "resolve_all_discussions")
+    recipients = NotificationRecipientService.new(merge_request.target_project).build_recipients(
+      merge_request,
+      current_user,
+      action: "resolve_all_discussions")
 
     recipients.each do |recipient|
       mailer.resolved_all_discussions_email(recipient.id, merge_request.id, current_user.id).deliver_later
@@ -164,64 +167,15 @@ class NotificationService
   end
 
   # Notify users on new note in system
-  #
-  # TODO: split on methods and refactor
-  #
   def new_note(note)
     return true unless note.noteable_type.present?
 
     # ignore gitlab service messages
     return true if note.cross_reference? && note.system?
 
-    target = note.noteable
-
-    recipients = []
-
-    mentioned_users = note.mentioned_users
-
-    ability, subject = if note.for_personal_snippet?
-                         [:read_personal_snippet, note.noteable]
-                       else
-                         [:read_project, note.project]
-                       end
-
-    mentioned_users.select! do |user|
-      user.can?(ability, subject)
-    end
-
-    # Add all users participating in the thread (author, assignee, comment authors)
-    participants =
-      if target.respond_to?(:participants)
-        target.participants(note.author)
-      else
-        mentioned_users
-      end
-
-    recipients = recipients.concat(participants)
-
-    unless note.for_personal_snippet?
-      # Merge project watchers
-      recipients = add_project_watchers(recipients, note.project)
-
-      # Merge project with custom notification
-      recipients = add_custom_notifications(recipients, note.project, :new_note)
-    end
-
-    # Reject users with Mention notification level, except those mentioned in _this_ note.
-    recipients = reject_mention_users(recipients - mentioned_users, note.project)
-    recipients = recipients + mentioned_users
-
-    recipients = reject_muted_users(recipients, note.project)
-
-    recipients = add_subscribed_users(recipients, note.project, note.noteable)
-    recipients = reject_unsubscribed_users(recipients, note.noteable)
-    recipients = reject_users_without_access(recipients, note.noteable)
-
-    recipients.delete(note.author)
-    recipients = recipients.uniq
-
     notify_method = "note_#{note.to_ability_name}_email".to_sym
 
+    recipients = NotificationRecipientService.new(note.project).build_new_note_recipients(note)
     recipients.each do |recipient|
       mailer.send(notify_method, recipient.id, note.id).deliver_later
     end
@@ -290,7 +244,7 @@ class NotificationService
 
   def project_was_moved(project, old_path_with_namespace)
     recipients = project.team.members
-    recipients = reject_muted_users(recipients, project)
+    recipients = NotificationRecipientService.new(project).reject_muted_users(recipients)
 
     recipients.each do |recipient|
       mailer.project_was_moved_email(
@@ -302,7 +256,7 @@ class NotificationService
   end
 
   def issue_moved(issue, new_issue, current_user)
-    recipients = build_recipients(issue, issue.project, current_user)
+    recipients = NotificationRecipientService.new(issue.project).build_recipients(issue, current_user)
 
     recipients.map do |recipient|
       email = mailer.issue_moved_email(recipient, issue, new_issue, current_user)
@@ -324,9 +278,8 @@ class NotificationService
 
     return unless mailer.respond_to?(email_template)
 
-    recipients ||= build_recipients(
+    recipients ||= NotificationRecipientService.new(pipeline.project).build_recipients(
       pipeline,
-      pipeline.project,
       nil, # The acting user, who won't be added to recipients
       action: pipeline.status).map(&:notification_email)
 
@@ -337,199 +290,8 @@ class NotificationService
 
   protected
 
-  # Get project/group users with CUSTOM notification level
-  def add_custom_notifications(recipients, project, action)
-    user_ids = []
-
-    # Users with a notification setting on group or project
-    user_ids += notification_settings_for(project, :custom, action)
-    user_ids += notification_settings_for(project.group, :custom, action)
-
-    # Users with global level custom
-    users_with_project_level_global = notification_settings_for(project, :global)
-    users_with_group_level_global   = notification_settings_for(project.group, :global)
-
-    global_users_ids = users_with_project_level_global.concat(users_with_group_level_global)
-    user_ids += users_with_global_level_custom(global_users_ids, action)
-
-    recipients.concat(User.find(user_ids))
-  end
-
-  # Get project users with WATCH notification level
-  def project_watchers(project)
-    project_members = notification_settings_for(project)
-
-    users_with_project_level_global = notification_settings_for(project, :global)
-    users_with_group_level_global   = notification_settings_for(project.group, :global)
-
-    users = users_with_global_level_watch([users_with_project_level_global, users_with_group_level_global].flatten.uniq)
-
-    users_with_project_setting = select_project_member_setting(project, users_with_project_level_global, users)
-    users_with_group_setting = select_group_member_setting(project.group, project_members, users_with_group_level_global, users)
-
-    User.where(id: users_with_project_setting.concat(users_with_group_setting).uniq).to_a
-  end
-
-  def notification_settings_for(resource, notification_level = nil, action = nil)
-    return [] unless resource
-
-    if notification_level
-      settings = resource.notification_settings.where(level: NotificationSetting.levels[notification_level])
-      settings = settings.select { |setting| setting.events[action] } if action.present?
-      settings.map(&:user_id)
-    else
-      resource.notification_settings.pluck(:user_id)
-    end
-  end
-
-  def users_with_global_level_watch(ids)
-    settings_with_global_level_of(:watch, ids).pluck(:user_id)
-  end
-
-  def users_with_global_level_custom(ids, action)
-    settings = settings_with_global_level_of(:custom, ids)
-    settings = settings.select { |setting| setting.events[action] }
-    settings.map(&:user_id)
-  end
-
-  def settings_with_global_level_of(level, ids)
-    NotificationSetting.where(
-      user_id: ids,
-      source_type: nil,
-      level: NotificationSetting.levels[level]
-    )
-  end
-
-  # Build a list of users based on project notification settings
-  def select_project_member_setting(project, global_setting, users_global_level_watch)
-    users = notification_settings_for(project, :watch)
-
-    # If project setting is global, add to watch list if global setting is watch
-    global_setting.each do |user_id|
-      if users_global_level_watch.include?(user_id)
-        users << user_id
-      end
-    end
-
-    users
-  end
-
-  # Build a list of users based on group notification settings
-  def select_group_member_setting(group, project_members, global_setting, users_global_level_watch)
-    uids = notification_settings_for(group, :watch)
-
-    # Group setting is watch, add to users list if user is not project member
-    users = []
-    uids.each do |user_id|
-      if project_members.exclude?(user_id)
-        users << user_id
-      end
-    end
-
-    # Group setting is global, add to users list if global setting is watch
-    global_setting.each do |user_id|
-      if project_members.exclude?(user_id) && users_global_level_watch.include?(user_id)
-        users << user_id
-      end
-    end
-
-    users
-  end
-
-  def add_project_watchers(recipients, project)
-    recipients.concat(project_watchers(project)).compact
-  end
-
-  # Remove users with disabled notifications from array
-  # Also remove duplications and nil recipients
-  def reject_muted_users(users, project = nil)
-    reject_users(users, :disabled, project)
-  end
-
-  # Remove users with notification level 'Mentioned'
-  def reject_mention_users(users, project = nil)
-    reject_users(users, :mention, project)
-  end
-
-  # Reject users which has certain notification level
-  #
-  # Example:
-  #   reject_users(users, :watch, project)
-  #
-  def reject_users(users, level, project = nil)
-    level = level.to_s
-
-    unless NotificationSetting.levels.keys.include?(level)
-      raise 'Invalid notification level'
-    end
-
-    users = users.to_a.compact.uniq
-    users = users.select { |u| u.can?(:receive_notifications) }
-
-    users.reject do |user|
-      global_notification_setting = user.global_notification_setting
-
-      next global_notification_setting.level == level unless project
-
-      setting = user.notification_settings_for(project)
-
-      if project.group && (setting.nil? || setting.global?)
-        setting = user.notification_settings_for(project.group)
-      end
-
-      # reject users who globally set mention notification and has no setting per project/group
-      next global_notification_setting.level == level unless setting
-
-      # reject users who set mention notification in project
-      next true if setting.level == level
-
-      # reject users who have mention level in project and disabled in global settings
-      setting.global? && global_notification_setting.level == level
-    end
-  end
-
-  def reject_unsubscribed_users(recipients, target)
-    return recipients unless target.respond_to? :subscriptions
-
-    recipients.reject do |user|
-      subscription = target.subscriptions.find_by_user_id(user.id)
-      subscription && !subscription.subscribed
-    end
-  end
-
-  def reject_users_without_access(recipients, target)
-    ability = case target
-              when Issuable
-                :"read_#{target.to_ability_name}"
-              when Ci::Pipeline
-                :read_build # We have build trace in pipeline emails
-              end
-
-    return recipients unless ability
-
-    recipients.select do |user|
-      user.can?(ability, target)
-    end
-  end
-
-  def add_subscribed_users(recipients, project, target)
-    return recipients unless target.respond_to? :subscribers
-
-    recipients + target.subscribers(project)
-  end
-
-  def add_labels_subscribers(recipients, project, target, labels: nil)
-    return recipients unless target.respond_to? :labels
-
-    (labels || target.labels).each do |label|
-      recipients += label.subscribers(project)
-    end
-
-    recipients
-  end
-
   def new_resource_email(target, project, method)
-    recipients = build_recipients(target, project, target.author, action: "new")
+    recipients = NotificationRecipientService.new(project).build_recipients(target, target.author, action: "new")
 
     recipients.each do |recipient|
       mailer.send(method, recipient.id, target.id).deliver_later
@@ -537,7 +299,7 @@ class NotificationService
   end
 
   def new_mentions_in_resource_email(target, project, new_mentioned_users, current_user, method)
-    recipients = build_recipients(target, project, current_user, action: "new")
+    recipients = NotificationRecipientService.new(project).build_recipients(target, current_user, action: "new")
     recipients = recipients & new_mentioned_users
 
     recipients.each do |recipient|
@@ -548,9 +310,8 @@ class NotificationService
   def close_resource_email(target, project, current_user, method, skip_current_user: true)
     action = method == :merged_merge_request_email ? "merge" : "close"
 
-    recipients = build_recipients(
+    recipients = NotificationRecipientService.new(project).build_recipients(
       target,
-      project,
       current_user,
       action: action,
       skip_current_user: skip_current_user
@@ -565,7 +326,12 @@ class NotificationService
     previous_assignee_id = previous_record(target, 'assignee_id')
     previous_assignee = User.find_by(id: previous_assignee_id) if previous_assignee_id
 
-    recipients = build_recipients(target, project, current_user, action: "reassign", previous_assignee: previous_assignee)
+    recipients = NotificationRecipientService.new(project).build_recipients(
+      target,
+      current_user,
+      action: "reassign",
+      previous_assignee: previous_assignee
+    )
 
     recipients.each do |recipient|
       mailer.send(
@@ -579,7 +345,7 @@ class NotificationService
   end
 
   def relabeled_resource_email(target, project, labels, current_user, method)
-    recipients = build_relabeled_recipients(target, project, current_user, labels: labels)
+    recipients = NotificationRecipientService.new(project).build_relabeled_recipients(target, current_user, labels: labels)
     label_names = labels.map(&:name)
 
     recipients.each do |recipient|
@@ -588,58 +354,13 @@ class NotificationService
   end
 
   def reopen_resource_email(target, project, current_user, method, status)
-    recipients = build_recipients(target, project, current_user, action: "reopen")
+    recipients = NotificationRecipientService.new(project).build_recipients(target, current_user, action: "reopen")
 
     recipients.each do |recipient|
       mailer.send(method, recipient.id, target.id, status, current_user.id).deliver_later
     end
   end
 
-  def build_recipients(target, project, current_user, action: nil, previous_assignee: nil, skip_current_user: true)
-    custom_action = build_custom_key(action, target)
-
-    recipients = target.participants(current_user)
-
-    unless NotificationSetting::EXCLUDED_WATCHER_EVENTS.include?(custom_action)
-      recipients = add_project_watchers(recipients, project)
-    end
-
-    recipients = add_custom_notifications(recipients, project, custom_action)
-    recipients = reject_mention_users(recipients, project)
-
-    recipients = recipients.uniq
-
-    # Re-assign is considered as a mention of the new assignee so we add the
-    # new assignee to the list of recipients after we rejected users with
-    # the "on mention" notification level
-    if [:reassign_merge_request, :reassign_issue].include?(custom_action)
-      recipients << previous_assignee if previous_assignee
-      recipients << target.assignee
-    end
-
-    recipients = reject_muted_users(recipients, project)
-    recipients = add_subscribed_users(recipients, project, target)
-
-    if [:new_issue, :new_merge_request].include?(custom_action)
-      recipients = add_labels_subscribers(recipients, project, target)
-    end
-
-    recipients = reject_unsubscribed_users(recipients, target)
-    recipients = reject_users_without_access(recipients, target)
-
-    recipients.delete(current_user) if skip_current_user
-
-    recipients.uniq
-  end
-
-  def build_relabeled_recipients(target, project, current_user, labels:)
-    recipients = add_labels_subscribers([], project, target, labels: labels)
-    recipients = reject_unsubscribed_users(recipients, target)
-    recipients = reject_users_without_access(recipients, target)
-    recipients.delete(current_user)
-    recipients.uniq
-  end
-
   def mailer
     Notify
   end
@@ -651,10 +372,4 @@ class NotificationService
       end
     end
   end
-
-  # Build event key to search on custom notification level
-  # Check NotificationSetting::EMAIL_EVENTS
-  def build_custom_key(action, object)
-    "#{action}_#{object.class.model_name.name.underscore}".to_sym
-  end
 end