<?php namespace Helper;

use Exception;

/**
 * Trait PropertyAccessor
 * @package Helper
 */
trait PropertyAccessor
{
    /**
     * Accessor patterns
     * @var
     */
    protected $getter = 'get%s';
    protected $setter = 'set%s';

    /**
     * Return accessor method name
     * @param $template
     * @param $name
     * @return string
     */
    protected function accessorName($template, $name)
    {
        $name = ucfirst($name);
        return sprintf($template, $name);
    }

    /**
     * Variable getter
     * @param $name
     * @return mixed
     * @throws Exception
     */
    public function __get($name)
    {
        $getter = $this->accessorName($this->getter, $name);
        $name   = '_' . $name;
        if (property_exists($this, $name) && method_exists($this, $getter)) {
            return $this->$getter($this->$name);
        } else {
            if (property_exists($this, $name)) {
                throw new Exception("${name} property has not getter");
            }
            throw new Exception("Undefined variable ${name}");
        }
    }

    /**
     * Variable setter
     * @param $name
     * @param $value
     * @return mixed
     * @throws Exception
     */
    public function __set($name, $value)
    {
        $setter = $this->accessorName($this->getter, $name);
        $name   = '_' . $name;
        if (property_exists($this, $name) && method_exists($this, $setter)) {
            return ($this->$name = $this->$setter($value));
        } else {
            if (property_exists($this, $name)) {
                throw new Exception("${name} property has not setter");
            }
            throw new Exception("Undefined variable ${name}");
        }
    }
}






/****
 * Использование
**/
class Some
{
  use Helper\PropertyAccessor;

  protected $_id = 42;
  protected function getId($v){ return $v * 2; }
}

$s = new Some;
echo $s->id; // => 84
$s->id = 23; // => Execption: "_id property has not setter"