/**
 * Patchboard for a Enigma.
 */
public class PatchBoard implements EnigmaComponent {
    /**
     * Permutation for the patchboard.
     */
    private int[] permu;

    /**
     * Inverse permutation for the patchboard.
     */
    private int[] invPermu;

    /**
     * Constructor for the patchboard.
     * @param permu permutation
     */
    PatchBoard(final int[] permu) {
        this.permu = permu;
        this.invPermu = calcInvPermu(permu);
    }

    /**
     * {@inheritDoc}
     */
    public final int encode(final int i) {
        return permu[i];
    }

    /**
     * {@inheritDoc}
     */
    public final int decode(final int i) {
        return invPermu[i];
    }

    /**
     * {@inheritDoc}
     */
    public final void tick() {   
    }
    /**
     * Calculates the inverese permutation.
     * @param permu permutation
     * @return <code>inverse permutation</code>
     */
    private int[] calcInvPermu(final int[] permu) {
        int[] array = new int[permu.length];
        for (int i = 0; i < permu.length; i++) {
            for (int k = 0; k < permu.length; k++) {
               if (i == permu[k]) {
                    array[i] = k;
                }
            }
        }
        return array;
    }
}