<?php
class Employee{

	private $id;
	private $firstName;
	private $lastName;
	private $salary;

	const MONTHS = 12;

	public function __construct($id, $firstName, $lastName, $salary)
	{
		$this->id = $id;
		$this->firstName = $firstName;
		$this->lastName = $lastName;
		$this->setSalary($salary);
	}

	public function getId()
	{
		return $this->id;
	}

	public function getFirstName()
	{
		return $this->firstName;
	}

	public function getLastName()
	{
		return $this->lastName;
	}

	public function getSalary()
	{
		return $this->salary;
	}

	public function setSalary($salary)
	{
		if($salary <= 0){
            throw new InvalidArgumentException('Salary must be greater then zero');
        }
		$this->salary = $salary;
	}

	public function getName()
	{
		return $this->firstName . ' '. $this->lastName;
	}

	public function getAnnualSalary()
	{
		return $this->salary * MONTHS;
	}

	public function raiseSalary($percent)
	{
		if($percent <= 0){
            throw new InvalidArgumentException('Percent must be greater then zero');
        }
		$this->salary += $this->salary * $percent / 100;
		return $this->salary;
	}

	public function __toString()
    {
        return sprintf('Employee[id=%d,name=%s,salary=%d]', $this->id,$this->getName(),$this->salary);
    }
}