package ch.fhnw.kry;

import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;

class SPNTest {

    @Test
    void k() {
        var spn = new SPN();

        final int key = 0xFFFFFFFF;
        assertEquals(0xFFFF, spn.k(key, 0));
        assertEquals(0xFFFF, spn.k(key, 1));
        assertEquals(0xFFFF, spn.k(key, 2));
    }

    @Test
    void substitution() {
        var spn = new SPN();

        //given
        int x = 0xEF45;
        int r = 0x051C;

        //when
        int y = spn.substitution(x, SPN.SBOX_REVERSE);

        // then
        assertEquals(r, y);

        // System.out.print(Integer.toHexString(spn.substitution(x)));
    }

    @Test
    void swapBits() {
        var spn = new SPN();

        // given 
        int x = 0xA;
        int r = 0xC;

        // when
        int y = spn.swapBits(x, 13, 14);
        int yy = spn.swapBits(x, 14, 13);
        int yyy = spn.swapBits(x, 14, 14);

        // then
        assertEquals(r, y);
        assertEquals(r, yy);
        assertEquals(x, yyy);

        assertEquals(0x100A, spn.swapBits(0x80A, 3, 4));
    }

    @Test
    void permutation() {
        var spn = new SPN();

        int x = spn.permutation(0xEF45);
        assertEquals(0xCFC5, x);
    }

    @Test
    void blockEncryptionDecryption() {
        var spn = new SPN();

        int x = 0x128F;
        int key = 0x11288C00;
        int y = 0xAEB4;

        assertEquals(y, spn.encryptBlock(key, x));
        assertEquals(x, spn.decryptBlock(key, y));
    }
}