<?php
namespace taskman;

function gamectl_check_lock()
{
  global $GAME_ROOT;

  //let's check if are already in a locked environment
  if(getenv("GAMECTL_IN_LOCK"))
    return;

  $is_nix = DIRECTORY_SEPARATOR === '/';

  $is_process_alive = $is_nix ?  
    function($pid) : bool
    {
      return !empty(trim(exec("lsof -p $pid")));
    }
    :
    function($pid) : bool
    {
      $output = shell_exec("tasklist /FI \"PID eq $pid\" 2>NUL");
      return strpos($output, "$pid") !== false;
    };

  $lock = $GAME_ROOT . '/gamectl.lock';
  $last_pid = null;

  while(file_exists($lock))
  {
    $pid = '0';
    try
    {
      $pid = file_get_contents($lock);
    }
    catch(\Exception $e) {}

    if($last_pid !== $pid)
    {
      echo "gamectl is locked by process ($pid). Waiting...\n";
      $last_pid = $pid;
    }

    if(!$is_process_alive($pid))
    {
      echo "Seems gamectl process ($pid) is gone but lock still exists, proceeding..\n";
      break;
    }

    sleep(1);
  }

  register_shutdown_function('taskman\\gamectl_unlock');

  //for spawned child processes
  putenv("GAMECTL_IN_LOCK=1");

  file_put_contents($lock, getmypid(), LOCK_EX);
}

function gamectl_unlock()
{
  global $GAME_ROOT;

  $lock = $GAME_ROOT . '/gamectl.lock';
  if(file_exists($lock))
    unlink($lock);
}