<?php
 
use Closure;
use Exception;
use ReflectionClass;
 
class Container
{
    private $dependencies;
    private $result = [];
 
    public function __construct($dependencies = [])
    {
        $this->dependencies = $dependencies;
    }
 
    public function set($key, $value)
    {
        if (array_key_exists($key, $this->result)) {
            unset($this->result[$key]);
        }
 
        $this->dependencies[$key] = $value;
 
        return $this;
    }
 
    public function has($key)
    {
        return array_key_exists($key, $this->dependencies) || class_exists($key);
    }
 
    public function get($key)
    {
        if (array_key_exists($key, $this->result)) {
            return $this->result[$key];
        }
 
        if (!array_key_exists($key, $this->dependencies)) {
 
            if (class_exists($key)) {
                $reflectionClass = new ReflectionClass($key);
                $args = [];
 
                if ($constructor = $reflectionClass->getConstructor()) {
 
                    foreach ($constructor->getParameters() as $parameter) {
 
                        if ($parameter->getType()->isBuiltin()) {
 
                            if (!$parameter->isDefaultValueAvailable()) {
                                throw new Exception("Не указано значение по умолчанию параметра: $parameter->name");
                            }
 
                            $args[] = $parameter->getDefaultValue();
                        } else {
                            $args[] = $this->get($parameter->getType()->getName());
                        }
                    }
                }
 
                return $this->result[$key] = $reflectionClass->newInstanceArgs($args);
            }
 
            throw new Exception("Не найдена зависимость: $key");
        }
 
        $dependency = $this->dependencies[$key];
 
        if ($dependency instanceof Closure) {
            $this->result[$key] = $dependency($this);
        } else {
            $this->result[$key] = $dependency;
        }
 
        return $this->result[$key];
    }
}