module RubyCliDaemon

# File lib/ruby_cli_daemon.rb, line 10
def install(path)
  File.unlink(path) if File.exist?(path)
  File.symlink(File.expand_path("../bin/ruby-cli-daemon.sh", __dir__), path)
end

# File lib/ruby_cli_daemon.rb, line 15
def start(socket, executable)
  path = preload_gem(executable)
  server = create_socket(socket) # do this last, it signals we are ready

  loop do
    return unless IO.select([server], nil, nil, TIMEOUT)

    # execute the gems binary in a fork
    _, status = Process.wait2(fork do
      File.write("#{socket}.pid", Process.pid) # uncovered
      replace_env server # uncovered
      load path # uncovered
    end)

    # send back exit status
    File.write("#{socket}.status", status.exitstatus || 127)
  end
ensure
  # signal that this program is done so ruby-sli-daemon.sh restarts it
  File.unlink socket if File.exist?(socket)
end

# File lib/ruby_cli_daemon.rb, line 92
def create_socket(socket)
  FileUtils.mkdir_p(File.dirname(socket))
  UNIXServer.new(socket)
end

# File lib/ruby_cli_daemon.rb, line 59
def find_gem_spec(executable)
  spec = Gem::Specification.detect { |s| s.executables.include?(executable) }
  [spec.name, spec.bin_file(executable)] if spec # need something we can send out from fork
end

# File lib/ruby_cli_daemon.rb, line 64
def fork_with_return
  read, write = IO.pipe
  Process.wait(fork do
    read.close
    begin
      Marshal.dump(yield, write)
    rescue StandardError => e
      Marshal.dump(e, write)
    end
  end)
  write.close
  result = Marshal.load(read)
  result.is_a?(StandardError) ? raise(result) : result
end

# File lib/ruby_cli_daemon.rb, line 41
def preload_gem(executable)
  name, path = fork_with_return do
    require "bundler/setup"
    find_gem_spec(executable)
  end

  if name
    require "bundler/setup"
  else
    name, path = find_gem_spec(executable)
    raise "No gem with executable #{executable} found" unless name
  end

  require name
  GC.start # https://bugs.ruby-lang.org/issues/15878
  path
end

# File lib/ruby_cli_daemon.rb, line 79
def replace_env(server)
  connection = server.accept
  begin
    STDOUT.reopen connection.recv_io
    STDERR.reopen connection.recv_io
    STDIN.reopen connection.recv_io
    ARGV.replace connection.gets.shellsplit
    ENV.replace Hash[connection.read.split("--RCD--").map { |s| s.split(/ /, 2) }]
  ensure
    connection.close # not sure if this is necessary
  end
end