class Xcodeproj::Project::Object::AbstractBuildPhase

def add_file_reference(file_ref, avoid_duplicates = false)
  if avoid_duplicates && existing = build_file(file_ref)
    existing
  else
    build_file = project.new(PBXBuildFile)
    build_file.file_ref = file_ref
    files << build_file
    build_file
  end
end

def build_file(file_ref)
  (file_ref.referrers & files).first
end

def clear
  files.objects.each do |bf|
    remove_build_file(bf)
  end
end

def file_display_names
  files.map(&:display_name)
end

def files_references
  files.map(&:file_ref)
end

def include?(file_ref)
  !build_file(file_ref).nil?
end

def remove_build_file(build_file)
  build_file.file_ref = nil
  build_file.remove_from_project
end

def remove_file_reference(file_ref)
  build_file = files.find { |bf| bf.file_ref == file_ref }
  remove_build_file(build_file) if build_file
end