require 'tsort'

class Updater
  module Js
    def update_javascript_assets
      log_status 'Updating javascripts...'
      save_to  = @save_to[:js]
      read_files('js/dist', bootstrap_js_files).each do |name, content|
        content = content.sub(%r{^//# sourceMappingURL=.*\n?\z}, '')
        save_file("#{save_to}/#{name}", content)
      end
      log_processed "#{bootstrap_js_files * ' '}"

      log_status 'Updating javascript manifest'
      manifest = ''
      bootstrap_js_files.each do |name|
        name = name.gsub(/\.js$/, '')
        manifest << "//= require ./bootstrap/#{name}\n"
      end
      dist_js = read_files('dist/js', %w(bootstrap.js bootstrap.min.js))
      {
          'assets/javascripts/bootstrap-sprockets.js' => manifest,
          'assets/javascripts/bootstrap.js'           => dist_js['bootstrap.js'],
          'assets/javascripts/bootstrap.min.js'       => dist_js['bootstrap.min.js'],
      }.each do |path, content|
        save_file path, content
        log_processed path
      end
    end

    def bootstrap_js_files
      @bootstrap_js_files ||= begin
        src_files = get_paths_by_type('js/src', /\.js$/) - %w[index.js]
        imports = Deps.new
        # Get the imports from the ES6 files to order requires correctly.
        read_files('js/src', src_files).each do |name, content|
          imports.add name,
                      *content.scan(%r{import [a-zA-Z]* from '\./(\w+)})
                           .flatten(1).map { |f| "#{f}.js" }
        end
        imports.tsort
      end
    end

    class Deps
      include TSort

      def initialize
        @imports = {}
      end

      def add(from, *tos)
        (@imports[from] ||= []).push(*tos)
      end

      def tsort_each_child(node, &block)
        @imports[node].each(&block)
      end

      def tsort_each_node(&block)
        @imports.each_key(&block)
      end
    end
  end
end