<?php
	namespace App\DI;

	use Closure;
	use App\DI\ServiceProviderInterface;
	//use olifant\exceptions\AppException;

	class Container implements \ArrayAccess
	{
		protected $aliases   = [];
		protected $freezed   = [];
		protected $instances = [];
		protected $shared    = [];

		public function set($key, $entity)
		{
			if (null === $key) {
				throw new Appexception('Key cannot be null');
			}

			$this->instances[$key] = $entity;
		}

		public function singleton($key, $entity)
		{
			$this->shared[$key] = $entity;
		}

		public function has($key)
		{
			$key = $this->resolveAlias($key);

			return (
				isset($this->instances[$key]) or
				isset($this->shared[$key])
			);
		}

		public function alias($alias, $key)
		{
			$this->aliases[$alias] = $key;

			return $this;
		}

		protected function resolveAlias($key)
		{
			if (isset($this->aliases[$key])) {
				return $this->aliases[$key];
			}

			return $key;
		}

		public function extend($key, \Closure $callable)
		{
			$store = $this->get($key);

			$closure = function ($container) use($callable, $store) {
				return $callable($store->get($container), $container);
			};

			$this->set($key, $closure, $store->isShared());

			return $this;
		}

		public function fork($key, $newkey)
		{

		}

		public function get($key)
		{
			$key = $this->resolveAlias($key);

			if(isset($this->instances[$key])){
				if($this->instances[$key] instanceof Closure)
					return call_user_func_array(
						$this->instances[$key],
						array($this)
					);

				return $this->instances[$key];
			}

			if(isset($this->shared[$key])){
				if($this->shared[$key] instanceof Closure)
					$this->shared[$key] = call_user_func_array(
						$this->shared[$key],
						array($this)
					);

				return $this->shared[$key];
			}
		}

		public function offsetSet($offset, $value)
		{
			$this->set($offset,$value);
		}

		public function offsetExists($offset)
		{
			return $this->has($offset);
		}

		public function offsetGet($offset)
		{
			return $this->get($offset);
		}

		public function offsetUnset($offset)
		{
			//$offset = $this->resolveAlias($offset);

			unset(
				$this->instances[$offset],
				$this->shared[$offset]
			);
    	}

    	public function keys()
    	{
    		return array_unique(
    			array_merge(
    				array_keys($this->instances),
    				array_keys($this->shared),
    				array_keys($this->aliases)
    			)
    		);
    	}

    	public function register(ServiceProviderInterface $provider)
    	{
    		$provider->register($this);

    		return $this;
    	}
	}
?>