class Webpacker::DevServerRunner

def detect_port!
  server = TCPServer.new(@hostname, @port)
  server.close
rescue Errno::EADDRINUSE
  $stdout.puts "Another program is running on port #{@port}. Set a new port in #{@config.config_path} for dev_server"
  exit!
end

def execute_cmd
  env = Webpacker::Compiler.env
  env["WEBPACKER_CONFIG"] = @webpacker_config
  cmd = if node_modules_bin_exist?
    ["#{@node_modules_bin_path}/webpack-dev-server"]
  else
    ["yarn", "webpack-dev-server"]
  end
  if @argv.include?("--debug-webpacker")
    cmd = [ "node", "--inspect-brk"] + cmd
  end
  cmd += ["--config", @webpack_config]
  cmd += ["--progress", "--color"] if @pretty
  Dir.chdir(@app_path) do
    Kernel.exec env, *cmd
  end
end

def load_config
  app_root = Pathname.new(@app_path)
  @config = Configuration.new(
    root_path: app_root,
    config_path: app_root.join("config/webpacker.yml"),
    env: ENV["RAILS_ENV"]
  )
  dev_server = DevServer.new(@config)
  @hostname          = dev_server.host
  @port              = dev_server.port
  @pretty            = dev_server.pretty?
rescue Errno::ENOENT, NoMethodError
  $stdout.puts "webpack dev_server configuration not found in #{@config.config_path}[#{ENV["RAILS_ENV"]}]."
  $stdout.puts "Please run bundle exec rails webpacker:install to install Webpacker"
  exit!
end

def node_modules_bin_exist?
  File.exist?("#{@node_modules_bin_path}/webpack-dev-server")
end

def run
  load_config
  detect_port!
  execute_cmd
end