<?php

namespace ModulesGarden\Servers\KerioEmail\Core\CommandLine;

use ModulesGarden\Servers\KerioEmail\Core\Models\Commands;

/**
 * We need that for calculating interval between operations and for killing process for PHP < 7.1
 * Don't remove it!
 */
declare(ticks = 1);

/**
 * Class Hypervisor
 * @package ModulesGarden\Servers\KerioEmail\Core\CommandLine
 * @todo - clean up!
 */
class Hypervisor
{
    /**
     * command name
     * @var null
     */
    protected $name     = null;

    /**
     * command params
     * @var null
     */
    protected $params   = null;

    /**
     * @var int
     */
    protected $counter  = 0;

    /**
     * @var \ModulesGarden\Servers\KerioEmail\Core\Models\Commands
     */
    protected $entity   = null;

    protected $tickTime = 1;

    /**
     * @var int
     */
    protected $sleepInterval    =   5;

    /**
     * Hypervisor constructor.
     * @param $name
     * @param $params
     */
    public function __construct($name, $params)
    {
        $this->name     = $name;
        $this->params   = $params;
    }

    /**
     * Lock script
     * @return $this
     * @throws \Exception
     */
    public function lock()
    {
        if($this->isActive())
        {
            throw new \Exception('Cannot create lock. Command already running');
        }

        $this->registerTickHandler();
        $this->registerSignalHandler();

        $this->getEntity()->setRunning();

        return $this;
    }

    /**
     * Unlock script
     * @return $this
     */
    public function unlock()
    {
        $this->getEntity()
            ->setStopped()
            ->clearAction();

        return $this;
    }

    /**
     * Update information about running command
     * @return $this
     */
    public function ping()
    {
        $this->getEntity()
            ->ping();

        return $this;
    }

    /**
     * @param $interval
     * @return $this
     */
    public function sleep($interval)
    {
        $this->getEntity()
            ->setSleeping();

        /**
         * We need run tick function during sleep, so we run many sleep function in loop
         */
        $counter    = 0;
        while($counter < $interval)
        {
            if($interval <= $this->sleepInterval)
            {
                $time   = $interval;
            }
            else
            {
                $time   = $this->sleepInterval;
            }


            $counter    += $time;

            sleep($time);
        }


        $this->getEntity()
            ->setRunning();

        return $this;
    }

    public function shouldBeStopped()
    {
        return $this->getEntity()
                    ->shouldBeStopped();
    }

    /**
     * @return bool
     * @throws \Exception
     */
    public function checkIfRunning()
    {
        if(!$this->isRunning())
        {
            throw new \Exception('Script is not running');
        }

        return true;
    }

    /**
     * @return bool
     */
    public function isStopped()
    {
        $this->getEntity()
            ->shouldBeStopped();
    }

    /**
     * Returns true if command is running or sleeping
     * @return bool
     */
    public function isActive()
    {
        $entity = $this->getEntity();
        $diff   = time() - $entity->updated_at->timestamp;

        if($entity->isSleeping() && $diff <= $this->sleepInterval)
        {
            return true;
        }

        if($entity->isRunning() && $entity->updated_at->timestamp + $this->tickTime > time())
        {
            return true;
        }

        return false;
    }

    /**
     * @param bool $force
     * @return ModulesGarden\Servers\KerioEmail\Core\Models\Commands|Commands
     */
    protected function getEntity($force = false)
    {
        if($this->entity && $force === false)
        {
            return $this->entity;
        }

        $this->entity = Commands::where('name', $this->name)->first();

        if(!$this->entity)
        {
            $this->entity        = new Commands();
            $this->entity->name  = $this->name;
            $this->entity->uuid  = uniqid();
            $this->entity->save();
        }

        return $this->entity;
    }

    /**
     *
     */
    protected function registerTickHandler()
    {
        $tick   = new Tick(function(){
            $this->ping();
        }, 10);
        $tick->start();
    }

    /**
     * Mark process as stopped and exit. This function will be called when you press ctrl c from console
     */
    protected function registerSignalHandler()
    {
        if(!function_exists('pcntl_signal'))
        {
            return;
        }

        //works from PHP 7.1
        if(function_exists('pcntl_async_signals'))
        {
            pcntl_async_signals(true);
        }

        $exit = function(){
            $this->getEntity()->setStopped();
            exit;
        };

        pcntl_signal(SIGINT,  $exit);
        pcntl_signal(SIGHUP, $exit);
        pcntl_signal(SIGUSR1, $exit);
    }
}