require 'set'
require 'sprockets/utils'

module Sprockets
  # Internal: Bundle processor takes a single file asset and prepends all the
  # `:required` URIs to the contents.
  #
  # Uses pipeline metadata:
  #
  #   :required - Ordered Set of asset URIs to prepend
  #   :stubbed  - Set of asset URIs to substract from the required set.
  #
  # Also see DirectiveProcessor.
  class Bundle
    def self.call(input)
      env  = input[:environment]
      type = input[:content_type]

      processed_uri = env.build_asset_uri(input[:filename], type: type, skip_bundle: true)

      find_required = proc { |uri| env.load(uri).metadata[:required] }
      required = Utils.dfs(processed_uri, &find_required)
      stubbed  = Utils.dfs(env.load(processed_uri).metadata[:stubbed], &find_required)
      required.subtract(stubbed)
      assets = required.map { |uri| env.load(uri) }

      dependencies = Set.new(input[:metadata][:dependencies])
      (required + stubbed).each do |uri|
        dependencies.merge(env.load(uri).metadata[:dependencies])
      end

      env.process_bundle_reducers(assets, env.load_bundle_reducers(type)).merge(dependencies: dependencies, included: assets.map(&:uri))
    end
  end
end