module SewingKit
  module Webpack
    class NodeSewingKitNotInstalled < StandardError
      def initialize()
        super(
          "sewing-kit is not available.  " +
          "Please add `@shopify/sewing-kit` to package.json's `devDependencies`, " +
          "and run  `yarn install`."
        )
      end
    end

    class Dev
      attr_accessor :pid

      def start
        @pid = spawn
        detach
      end

      private

      def spawn
        sewing_kit_bin = 'node_modules/.bin/sewing-kit'
        raise NodeSewingKitNotInstalled.new unless File.exist?(sewing_kit_bin)

        Kernel.spawn(
          {
            'NODE_ENV' => 'development',
            'BLUEBIRD_DEBUG' => '0',
            'BLUEBIRD_LONG_STACK_TRACES' => '0',
          },
          sewing_kit_bin,
          'dev',
          chdir: Rails.root.to_s,
          out: $stdout,
          err: $stderr,
        ) || exit(1)
      end

      def detach
        Process.detach pid
      end
    end
  end
end