/**
 * Allows you to easily keep track of rows of items as either odd or even.
 * Each time you check (using the "which" method) the counter increments so that
 * the next time you check the state will have changed.
 *
 * Jonathan Spalink
 * Dec. 2009
 */
class OddEven
{
    private $counter;
    private $odd;
    private $even;
   
    const ODD = "odd";
    const EVEN = "even";
    /**
     * Constructor method to create a new OddEven counter
     *
     * @param String $odd  The value to return when the counter is Odd
     * @param String $even The value to return when the counter is Even
     */
    public function __construct($odd=self::ODD, $even=self::EVEN)
    {
        $this->counter = 1;
        $this->odd = $odd;
        $this->even = $even;
    }

    /**
     * Increase the counter by 1 and return the old value
     *
     * @return Int The value of the counter before it is incremented
     */
    public function increment()
    {
        return $this->counter++;
    }

    /**
     * Resets the counter
     *
     * @param Int $initial The value at which to start the counter
     */
    public function reset($initial=1)
    {
        $this->counter = $initial;
    }

    /**
     * Runs an interation of the counter and returns whether its Odd or Even.
     * This also increments the counter by 1.
     *
     * @return String Odd or Even?
     */
    public function which()
    {
        $now = $this->increment();
        return ($now % 2 ? $this->odd : $this->even);
    }

    /**
     * Static invocation of the OddEven class to simply check a number without
     * futher complications.  If you don't pass in $odd or $even then the class
     * defaults are used.
     *
     * @param  int   $number The number to check
     * @param  mixed $odd    Value to return if number is odd
     * @param  mixed $even   Value to return if number is even
     * @return mixed $odd or $even
     */
    static public function OddOrEven($number, $odd=self::ODD, $even=self::EVEN)
    {
        return ($number % 2 ? $odd : $even);
    }

}