<?php
namespace Lazy;

class Lazy
{

    /**
     * @var callable
     */
    private $callable;

    /**
     * @var Context
     */
    private $context;

    /**
     * @var bool
     */
    private $cacheable = true;

    /**
     * @var mixed
     */
    private $cache;

    /**
     * @param callable $callable
     * @param Context|null $context
     */
    public function __construct(callable $callable, Context $context = null)
    {
        $this->callable = $callable;

        if ($context === null) {
            $context = new Context();
        }

        $this->context = $context;
    }

    /**
     * @return mixed
     */
    private function invoke()
    {
        $this->context->lazy($this);

        if (!$this->cache || !$this->cacheable) {
            $callable = $this->callable;
            $this->cache = $callable($this->context);
        }

        return $this->cache;
    }

    /**
     * @return string
     */
    public function __toString()
    {
        return (string)$this->invoke();
    }

    /**
     * @param $property
     * @return mixed
     */
    public function __get($property)
    {
        return $this->invoke()->{$property};
    }

    /**
     * @param $property
     * @param $value
     * @return mixed
     */
    public  function __set($property, $value)
    {
        return $this->invoke()->{$property} = $value;
    }

    /**
     * @param $method
     * @param $arguments
     * @return mixed
     */
    public function __call($method, $arguments)
    {
        return call_user_func_array([$this->invoke(), $method], $arguments);
    }

    /**
     * @return mixed
     */
    public function __invoke()
    {
        return $this->invoke();
    }

    public function disableCache()
    {
        $this->cacheable = false;
    }
}