require 'socket'
require 'sys/proctable'

LAUNCH_TIMEOUT = 2
SHUTDOWN_TIMEOUT = 2

class OSRMLauncher
  def initialize &block
    Dir.chdir TEST_FOLDER do
      begin
        launch
        yield
      ensure
        shutdown
      end
    end
  end

  private
  
  def launch
    Timeout.timeout(LAUNCH_TIMEOUT) do
      osrm_up
      wait_for_connection
    end
  rescue Timeout::Error
    raise "*** Launching osrm-routed timed out."
  end
  
  def shutdown
    Timeout.timeout(SHUTDOWN_TIMEOUT) do
      osrm_down
    end
  rescue Timeout::Error
    kill
    raise "*** Shutting down osrm-routed timed out."
  end
  
  
  def osrm_up?
    if @pipe
      begin
        Process.getpgid @pipe.pid
        true
      rescue Errno::ESRCH
        false
      end
    else
      false
    end
  end

  def osrm_up
    return if osrm_up?
    #exec avoids popen running osrm-routed inside a shell
    #if the cmd is run inside a shell, popen returns the pid for the shell, and if we try to kill it,
    #the child process is orphaned, and we can't terminate it.
    @pipe = IO.popen('exec ../osrm-routed 1>>osrm-routed.log 2>>osrm-routed.log')
  end

  def osrm_down
    if @pipe
      Process.kill 'TERM', @pipe.pid
      wait_for_shutdown
    end
  end

  def kill
    if @pipe
      Process.kill 'KILL', @pipe.pid
    end
  end

  def wait_for_connection
    while true
      begin
        socket = TCPSocket.new('localhost', OSRM_PORT)
        return
      rescue Errno::ECONNREFUSED
        sleep 0.1
      end
    end
  end

  def wait_for_shutdown
    while osrm_up?
      sleep 0.1
    end
  end
end