<?php

if (class_exists('ParagonIE_Sodium_Core32_HSalsa20', false)) {
    return;
}

/**
 * Class ParagonIE_Sodium_Core32_HSalsa20
 */
abstract class ParagonIE_Sodium_Core32_HSalsa20 extends ParagonIE_Sodium_Core32_Salsa20 {

    /**
     * Calculate an hsalsa20 hash of a single block
     *
     * HSalsa20 doesn't have a counter and will never be used for more than
     * one block (used to derive a subkey for xsalsa20).
     *
     * @internal You should not use this directly from another application
     *
     * @param string $in
     * @param string $k
     * @param string|null $c
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
    public static function hsalsa20($in, $k, $c = null) {
        /**
         * @var ParagonIE_Sodium_Core32_Int32 $x0
         * @var ParagonIE_Sodium_Core32_Int32 $x1
         * @var ParagonIE_Sodium_Core32_Int32 $x2
         * @var ParagonIE_Sodium_Core32_Int32 $x3
         * @var ParagonIE_Sodium_Core32_Int32 $x4
         * @var ParagonIE_Sodium_Core32_Int32 $x5
         * @var ParagonIE_Sodium_Core32_Int32 $x6
         * @var ParagonIE_Sodium_Core32_Int32 $x7
         * @var ParagonIE_Sodium_Core32_Int32 $x8
         * @var ParagonIE_Sodium_Core32_Int32 $x9
         * @var ParagonIE_Sodium_Core32_Int32 $x10
         * @var ParagonIE_Sodium_Core32_Int32 $x11
         * @var ParagonIE_Sodium_Core32_Int32 $x12
         * @var ParagonIE_Sodium_Core32_Int32 $x13
         * @var ParagonIE_Sodium_Core32_Int32 $x14
         * @var ParagonIE_Sodium_Core32_Int32 $x15
         * @var ParagonIE_Sodium_Core32_Int32 $j0
         * @var ParagonIE_Sodium_Core32_Int32 $j1
         * @var ParagonIE_Sodium_Core32_Int32 $j2
         * @var ParagonIE_Sodium_Core32_Int32 $j3
         * @var ParagonIE_Sodium_Core32_Int32 $j4
         * @var ParagonIE_Sodium_Core32_Int32 $j5
         * @var ParagonIE_Sodium_Core32_Int32 $j6
         * @var ParagonIE_Sodium_Core32_Int32 $j7
         * @var ParagonIE_Sodium_Core32_Int32 $j8
         * @var ParagonIE_Sodium_Core32_Int32 $j9
         * @var ParagonIE_Sodium_Core32_Int32 $j10
         * @var ParagonIE_Sodium_Core32_Int32 $j11
         * @var ParagonIE_Sodium_Core32_Int32 $j12
         * @var ParagonIE_Sodium_Core32_Int32 $j13
         * @var ParagonIE_Sodium_Core32_Int32 $j14
         * @var ParagonIE_Sodium_Core32_Int32 $j15
         */
        if (self::strlen($k) < 32) {
            throw new RangeException('Key must be 32 bytes long');
        }
        if ($c === null) {
            $x0 = new ParagonIE_Sodium_Core32_Int32(array(0x6170, 0x7865));
            $x5 = new ParagonIE_Sodium_Core32_Int32(array(0x3320, 0x646e));
            $x10 = new ParagonIE_Sodium_Core32_Int32(array(0x7962, 0x2d32));
            $x15 = new ParagonIE_Sodium_Core32_Int32(array(0x6b20, 0x6574));
        } else {
            $x0 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 0, 4));
            $x5 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 4, 4));
            $x10 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 8, 4));
            $x15 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 12, 4));
        }
        $x1 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($k, 0, 4));
        $x2 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($k, 4, 4));
        $x3 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($k, 8, 4));
        $x4 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($k, 12, 4));
        $x6 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 0, 4));
        $x7 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 4, 4));
        $x8 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 8, 4));
        $x9 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 12, 4));
        $x11 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($k, 16, 4));
        $x12 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($k, 20, 4));
        $x13 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($k, 24, 4));
        $x14 = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($k, 28, 4));

        for ($i = self::ROUNDS; $i > 0; $i -= 2) {
            $x4 = $x4->xorInt32($x0->addInt32($x12)->rotateLeft(7));
            $x8 = $x8->xorInt32($x4->addInt32($x0)->rotateLeft(9));
            $x12 = $x12->xorInt32($x8->addInt32($x4)->rotateLeft(13));
            $x0 = $x0->xorInt32($x12->addInt32($x8)->rotateLeft(18));

            $x9 = $x9->xorInt32($x5->addInt32($x1)->rotateLeft(7));
            $x13 = $x13->xorInt32($x9->addInt32($x5)->rotateLeft(9));
            $x1 = $x1->xorInt32($x13->addInt32($x9)->rotateLeft(13));
            $x5 = $x5->xorInt32($x1->addInt32($x13)->rotateLeft(18));

            $x14 = $x14->xorInt32($x10->addInt32($x6)->rotateLeft(7));
            $x2 = $x2->xorInt32($x14->addInt32($x10)->rotateLeft(9));
            $x6 = $x6->xorInt32($x2->addInt32($x14)->rotateLeft(13));
            $x10 = $x10->xorInt32($x6->addInt32($x2)->rotateLeft(18));

            $x3 = $x3->xorInt32($x15->addInt32($x11)->rotateLeft(7));
            $x7 = $x7->xorInt32($x3->addInt32($x15)->rotateLeft(9));
            $x11 = $x11->xorInt32($x7->addInt32($x3)->rotateLeft(13));
            $x15 = $x15->xorInt32($x11->addInt32($x7)->rotateLeft(18));

            $x1 = $x1->xorInt32($x0->addInt32($x3)->rotateLeft(7));
            $x2 = $x2->xorInt32($x1->addInt32($x0)->rotateLeft(9));
            $x3 = $x3->xorInt32($x2->addInt32($x1)->rotateLeft(13));
            $x0 = $x0->xorInt32($x3->addInt32($x2)->rotateLeft(18));

            $x6 = $x6->xorInt32($x5->addInt32($x4)->rotateLeft(7));
            $x7 = $x7->xorInt32($x6->addInt32($x5)->rotateLeft(9));
            $x4 = $x4->xorInt32($x7->addInt32($x6)->rotateLeft(13));
            $x5 = $x5->xorInt32($x4->addInt32($x7)->rotateLeft(18));

            $x11 = $x11->xorInt32($x10->addInt32($x9)->rotateLeft(7));
            $x8 = $x8->xorInt32($x11->addInt32($x10)->rotateLeft(9));
            $x9 = $x9->xorInt32($x8->addInt32($x11)->rotateLeft(13));
            $x10 = $x10->xorInt32($x9->addInt32($x8)->rotateLeft(18));

            $x12 = $x12->xorInt32($x15->addInt32($x14)->rotateLeft(7));
            $x13 = $x13->xorInt32($x12->addInt32($x15)->rotateLeft(9));
            $x14 = $x14->xorInt32($x13->addInt32($x12)->rotateLeft(13));
            $x15 = $x15->xorInt32($x14->addInt32($x13)->rotateLeft(18));
        }

        return $x0->toReverseString() .
                $x5->toReverseString() .
                $x10->toReverseString() .
                $x15->toReverseString() .
                $x6->toReverseString() .
                $x7->toReverseString() .
                $x8->toReverseString() .
                $x9->toReverseString();
    }

}
