module Google::Cloud

def self.auto_load_files
  return Gem.find_latest_files "google-cloud-*.rb" if Gem.respond_to? :find_latest_files
  # Ruby 2.0 does not have Gem.find_latest_files
  Gem.find_files "google-cloud-*.rb"
end

def self.auto_load_gems
  currently_loaded_files = loaded_files
  auto_load_files.each do |auto_load_file|
    auto_load_file = File.realpath auto_load_file
    next if currently_loaded_files.include? auto_load_file
    require auto_load_file
  end
end

def self.configure
  @config ||= Config.create
  yield @config if block_given?
  @config
end

def self.init_configuration
  configure do |config|
    default_project = Google::Cloud::Config.deferred do
      ENV["GOOGLE_CLOUD_PROJECT"] || ENV["GCLOUD_PROJECT"]
    end
    default_creds = Google::Cloud::Config.deferred do
      Google::Cloud::Config.credentials_from_env \
        "GOOGLE_CLOUD_CREDENTIALS", "GOOGLE_CLOUD_CREDENTIALS_JSON",
        "GOOGLE_CLOUD_KEYFILE", "GOOGLE_CLOUD_KEYFILE_JSON",
        "GCLOUD_KEYFILE", "GCLOUD_KEYFILE_JSON"
    end
    config.add_field! :project_id, default_project,
                      match: String, allow_nil: true
    config.add_alias! :project, :project_id
    config.add_field! :credentials, default_creds, match: Object
    config.add_alias! :keyfile, :credentials
    config.add_field! :on_error, nil, match: Proc
  end
end

def self.loaded_files
  files = Array(caller).map do |backtrace_line|
    until backtrace_line.split(":").size < 2 || File.file?(backtrace_line)
      backtrace_line = backtrace_line.split(":")[0..-2].join ":"
    end
    backtrace_line
  end
  files.uniq!
  files.select! { |file| File.file? file }
  files.map { |file| File.realpath file }
end

def self.new project_id = nil, credentials = nil, retries: nil, timeout: nil
  gcloud = Object.new
  gcloud.instance_variable_set :@project, project_id
  gcloud.instance_variable_set :@keyfile, credentials
  gcloud.instance_variable_set :@retries, retries
  gcloud.instance_variable_set :@timeout, timeout
  gcloud.extend Google::Cloud
  gcloud
end