<?
/**
 * This class represents the Plugboard of an Enigma.
 *
 * The initial setup looks like this:
 * <pre>
 * ABCDEFGHIJKLMNOPQRSTUVWXYZ
 * ||||||||||||||||||||||||||
 * ABCDEFGHIJKLMNOPQRSTUVWXYZ
 * </pre>
 * However, unlike rotor and reflector, the wiring can be changed by the operator.
 * This is done by plugging 2 letters, e.: 'D' and 'F' results in:
 * <pre>
 * ABCDEFGHIJKLMNOPQRSTUVWXYZ
 * ||||||||||||||||||||||||||
 * ABCFEDGHIJKLMNOPQRSTUVWXYZ
 * </pre>
 * unplugging 1 of the 2 letters leads back to original state
 *
 * @author David Kargl <hide@address.com>
 * @version 1.0
 * @package Enigma
 * @subpackage Core
 */
class EnigmaPlugboard {

	/**
    * The wiring of the plugboard.
    *
    * Pins always have to be connected in pairs, that means, if 'D' on side A
    * connects to 'H' on side B, 'H' on side A has to connect to 'D' on side B
    * @var EnigmaWiring
    */
	private $wiring = null;

    /**
     * Constructor creates a new Wiring and connects the pins in pairs.
     * @uses enigma_p2l
     * @uses EnigmaWiring
     * @uses ENIGMA_ALPHABET_SIZE
     */
	public function __construct() {
		for($idx=0; $idx<ENIGMA_ALPHABET_SIZE;$idx++) $wiring.= enigma_p2l($idx);
		$this->wiring = new EnigmaWiring($wiring);
	}

    /**
     * Send a letter through the wiring.
     * Because pins are connected in pairs, there is no difference if
     * processLetter1stPass() or processLetter2ndPass() is used.
     * @param integer letter to process
     * @return integer resulting letter
     */
	public function processLetter($letter) {
		return $this->wiring->processLetter1stPass($letter);
	}

    /**
     * Connect 2 letters.
     * @param integer letter 1 to connect
     * @param integer letter 2 to connect
     * @return void
     */
	public function plugLetters($letter1, $letter2) {
		$this->wiring->connect($letter1, $letter2);
		$this->wiring->connect($letter2, $letter1);
	}

    /**
     * Disconnect 2 letters.
     * Because letters are connected in pairs, we only need to know one of them.
     * @param integer 1 of the 2 letters to disconnect
     * @return void
     */
	public function unplugLetters($letter) {
		$temp = $this->wiring->connectsTo($letter);
		$this->wiring->connect($letter, $letter);
		$this->wiring->connect($temp, $temp);
	}

}
?>