<?php

if (!extension_loaded('pthreads')) {
    class Worker extends Thread
    {
        public function collect(Closure $collector = null)
        {
            foreach ($this->gc as $idx => $collectable) {
                if ($collector) {
                    if ($collector($collectable)) {
                        unset($this->gc[$idx]);
                    }
                } else {
                    if ($this->collector($collectable)) {
                        unset($this->gc[$idx]);
                    }
                }
            }

            return count($this->gc) + count($this->stack);
        }

        public function collector(Collectable $collectable)
        {
            return $collectable->isGarbage();
        }

        public function shutdown()
        {
            return $this->join();
        }

        public function isShutdown()
        {
            return $this->isJoined();
        }

        public function getStacked()
        {
            return count($this->stack);
        }

        public function unstack()
        {
            return array_shift($this->stack);
        }

        public function stack(Threaded $collectable)
        {
            $this->stack[] = $collectable;
            if ($this->isStarted()) {
                $this->runCollectable(count($this->stack) - 1, $collectable);
            }
        }

        public function run()
        {
            foreach ($this->stack as $idx => $collectable) {
                $this
                    ->runCollectable($idx, $collectable);
            }
        }

        private function runCollectable($idx, Collectable $collectable)
        {
            $collectable->worker = $this;
            if (!isset($collectable->state)) {
                $collectable->state = 0;
            }
            $collectable->state |= THREAD::RUNNING;
            $collectable->run();
            $collectable->state &= ~THREAD::RUNNING;
            $this->gc[] = $collectable;
            unset($this->stack[$idx]);
        }

        private $stack = [];
        private $gc = [];
    }
}