1 files changed, 125 insertions, 0 deletions
diff --git a/app/models/notification_recipient.rb b/app/models/notification_recipient.rb
new file mode 100644
index 00000000000..418b42d8f1d
--- /dev/null
+++ b/app/models/notification_recipient.rb
@@ -0,0 +1,125 @@
+class NotificationRecipient
+  attr_reader :user, :type
+  def initialize(
+    user, type,
+    custom_action: nil,
+    target: nil,
+    acting_user: nil,
+    project: nil
+  )
+    @custom_action = custom_action
+    @acting_user = acting_user
+    @target = target
+    @project = project || @target&.project
+    @user = user
+    @type = type
+  end
+
+  def notification_setting
+    @notification_setting ||= find_notification_setting
+  end
+
+  def raw_notification_level
+    notification_setting&.level&.to_sym
+  end
+
+  def notification_level
+    # custom is treated the same as watch if it's enabled - otherwise it's
+    # set to :custom, meaning to send exactly when our type is :participating
+    # or :mention.
+    @notification_level ||=
+      case raw_notification_level
+      when :custom
+        if @custom_action && notification_setting&.event_enabled?(@custom_action)
+          :watch
+        else
+          :custom
+        end
+      else
+        raw_notification_level
+      end
+  end
+
+  def notifiable?
+    return false unless has_access?
+    return false if own_activity?
+
+    return true if @type == :subscription
+
+    return false if notification_level.nil? || notification_level == :disabled
+
+    return %i[participating mention].include?(@type) if notification_level == :custom
+
+    return false if %i[watch participating].include?(notification_level) && excluded_watcher_action?
+
+    return false unless NotificationSetting.levels[notification_level] <= NotificationSetting.levels[@type]
+
+    return false if unsubscribed?
+
+    true
+  end
+
+  def unsubscribed?
+    return false unless @target
+    return false unless @target.respond_to?(:subscriptions)
+
+    subscription = @target.subscriptions.find_by_user_id(@user.id)
+    subscription && !subscription.subscribed
+  end
+
+  def own_activity?
+    return false unless @acting_user
+    return false if @acting_user.notified_of_own_activity?
+
+    user == @acting_user
+  end
+
+  def has_access?
+    DeclarativePolicy.subject_scope do
+      return false unless user.can?(:receive_notifications)
+      return false if @project && !user.can?(:read_project, @project)
+
+      return true unless read_ability
+      return true unless DeclarativePolicy.has_policy?(@target)
+
+      user.can?(read_ability, @target)
+    end
+  end
+
+  def excluded_watcher_action?
+    return false unless @custom_action
+    return false if raw_notification_level == :custom
+
+    NotificationSetting::EXCLUDED_WATCHER_EVENTS.include?(@custom_action)
+  end
+
+  private
+
+  def read_ability
+    return @read_ability if instance_variable_defined?(:@read_ability)
+
+    @read_ability =
+      case @target
+      when Issuable
+        :"read_#{@target.to_ability_name}"
+      when Ci::Pipeline
+        :read_build # We have build trace in pipeline emails
+      when ActiveRecord::Base
+        :"read_#{@target.class.model_name.name.underscore}"
+      else
+        nil
+      end
+  end
+
+  def find_notification_setting
+    project_setting = @project && user.notification_settings_for(@project)
+
+    return project_setting unless project_setting.nil? || project_setting.global?
+
+    group_setting = @project&.group && user.notification_settings_for(@project.group)
+
+    return group_setting unless group_setting.nil? || group_setting.global?
+
+    user.global_notification_setting
+  end
+end