class Spring::Client::Run

def boot_server
  env.socket_path.unlink if env.socket_path.exist?
  pid = fork {
    require "spring/server"
    Spring::Server.boot
  }
  until env.socket_path.exist?
    _, status = Process.waitpid2(pid, Process::WNOHANG)
    exit status.exitstatus if status
    sleep 0.1
  end
end

def call
  boot_server unless env.server_running?
  verify_server_version
  application, client = UNIXSocket.pair
  connect_to_application(client)
  run_command(client, application)
rescue Errno::ECONNRESET
  exit 1
ensure
  server.close if @server
end

def connect_to_application(client)
  server.send_io client
  send_json server, "args" => args, "default_rails_env" => default_rails_env
  server.gets or raise CommandNotFound
end

def default_rails_env
  ENV['RAILS_ENV'] || ENV['RACK_ENV'] || 'development'
end

def forward_signal(sig, pid)
  Process.kill(sig, -Process.getpgid(pid))
rescue Errno::ESRCH
  # If the application process is gone, then don't block the
  # signal on this process.
  trap(sig, 'DEFAULT')
  Process.kill(sig, Process.pid)
end

def forward_signals(pid)
  FORWARDED_SIGNALS.each do |sig|
    trap(sig) { forward_signal sig, pid }
  end
end

def log(message)
  env.log "[client] #{message}"
end

def run_command(client, application)
  log "sending command"
  application.send_io STDOUT
  application.send_io STDERR
  application.send_io STDIN
  send_json application, "args" => args, "env" => ENV.to_hash
  pid = server.gets
  pid = pid.chomp if pid
  # We must not close the client socket until we are sure that the application has
  # received the FD. Otherwise the FD can end up getting closed while it's in the server
  # socket buffer on OS X. This doesn't happen on Linux.
  client.close
  if pid && !pid.empty?
    log "got pid: #{pid}"
    forward_signals(pid.to_i)
    status = application.read.to_i
    log "got exit status #{status}"
    exit status
  else
    log "got no pid"
    exit 1
  end
ensure
  application.close
end

def send_json(socket, data)
  data = JSON.dump(data)
  socket.puts  data.bytesize
  socket.write data
end

def server
  @server ||= UNIXSocket.open(env.socket_name)
end

def verify_server_version
  server_version = server.gets.chomp
  if server_version != env.version
    $stderr.puts <<-ERROR
is a version mismatch between the spring client and the server.
ould restart the server and make sure to use the same version.
: #{env.version}, SERVER: #{server_version}
    exit 1
  end
end