let versionInfo = null;

const Crc16Tab = [0, 4129, 8258, 12387, 16516, 20645, 24774, 28903, 33032, 37161, 41290, 45419, 49548, 53677, 57806, 61935, 4657, 528, 12915, 8786, 21173, 17044, 29431, 25302, 37689, 33560, 45947, 41818, 54205, 50076, 62463, 58334, 9314, 13379, 1056, 5121, 25830, 29895, 17572, 21637, 42346, 46411, 34088, 38153, 58862, 62927, 50604, 54669, 13907, 9842, 5649, 1584, 30423, 26358, 22165, 18100, 46939, 42874, 38681, 34616, 63455, 59390, 55197, 51132, 18628, 22757, 26758, 30887, 2112, 6241, 10242, 14371, 51660, 55789, 59790, 63919, 35144, 39273, 43274, 47403, 23285, 19156, 31415, 27286, 6769, 2640, 14899, 10770, 56317, 52188, 64447, 60318, 39801, 35672, 47931, 43802, 27814, 31879, 19684, 23749, 11298, 15363, 3168, 7233, 60846, 64911, 52716, 56781, 44330, 48395, 36200, 40265, 32407, 28342, 24277, 20212, 15891, 11826, 7761, 3696, 65439, 61374, 57309, 53244, 48923, 44858, 40793, 36728, 37256, 33193, 45514, 41451, 53516, 49453, 61774, 57711, 4224, 161, 12482, 8419, 20484, 16421, 28742, 24679, 33721, 37784, 41979, 46042, 49981, 54044, 58239, 62302, 689, 4752, 8947, 13010, 16949, 21012, 25207, 29270, 46570, 42443, 38312, 34185, 62830, 58703, 54572, 50445, 13538, 9411, 5280, 1153, 29798, 25671, 21540, 17413, 42971, 47098, 34713, 38840, 59231, 63358, 50973, 55100, 9939, 14066, 1681, 5808, 26199, 30326, 17941, 22068, 55628, 51565, 63758, 59695, 39368, 35305, 47498, 43435, 22596, 18533, 30726, 26663, 6336, 2273, 14466, 10403, 52093, 56156, 60223, 64286, 35833, 39896, 43963, 48026, 19061, 23124, 27191, 31254, 2801, 6864, 10931, 14994, 64814, 60687, 56684, 52557, 48554, 44427, 40424, 36297, 31782, 27655, 23652, 19525, 15522, 11395, 7392, 3265, 61215, 65342, 53085, 57212, 44955, 49082, 36825, 40952, 28183, 32310, 20053, 24180, 11923, 16050, 3793, 7920];

function crc16_ccitt(data) {
    var i2, out;
    i2 = 0;

    for (var i3 = 0, _pj_a = data.length; i3 < _pj_a; i3 += 1) {
        out = Crc16Tab[(i2 >> 8 ^ data[i3]) & 255];
        i2 = out ^ i2 << 8;
    }

    return 65535 & i2;
}

function crc16_ccitt_le(data) {
    var crc;
    crc = crc16_ccitt(data);
    return new Uint8Array([crc & 255, crc >> 8]);
}

function firmware_xor(fwcontent) {
    const XOR_ARRAY = new Uint8Array([
        0x47, 0x22, 0xc0, 0x52, 0x5d, 0x57, 0x48, 0x94, 0xb1, 0x60, 0x60, 0xdb, 0x6f, 0xe3, 0x4c, 0x7c,
        0xd8, 0x4a, 0xd6, 0x8b, 0x30, 0xec, 0x25, 0xe0, 0x4c, 0xd9, 0x00, 0x7f, 0xbf, 0xe3, 0x54, 0x05,
        0xe9, 0x3a, 0x97, 0x6b, 0xb0, 0x6e, 0x0c, 0xfb, 0xb1, 0x1a, 0xe2, 0xc9, 0xc1, 0x56, 0x47, 0xe9,
        0xba, 0xf1, 0x42, 0xb6, 0x67, 0x5f, 0x0f, 0x96, 0xf7, 0xc9, 0x3c, 0x84, 0x1b, 0x26, 0xe1, 0x4e,
        0x3b, 0x6f, 0x66, 0xe6, 0xa0, 0x6a, 0xb0, 0xbf, 0xc6, 0xa5, 0x70, 0x3a, 0xba, 0x18, 0x9e, 0x27,
        0x1a, 0x53, 0x5b, 0x71, 0xb1, 0x94, 0x1e, 0x18, 0xf2, 0xd6, 0x81, 0x02, 0x22, 0xfd, 0x5a, 0x28,
        0x91, 0xdb, 0xba, 0x5d, 0x64, 0xc6, 0xfe, 0x86, 0x83, 0x9c, 0x50, 0x1c, 0x73, 0x03, 0x11, 0xd6,
        0xaf, 0x30, 0xf4, 0x2c, 0x77, 0xb2, 0x7d, 0xbb, 0x3f, 0x29, 0x28, 0x57, 0x22, 0xd6, 0x92, 0x8b
    ]);
    const XOR_LEN = XOR_ARRAY.length;

    for (let i = 0; i < fwcontent.length; i += 1) {
        fwcontent[i] ^= XOR_ARRAY[i % XOR_LEN];
    }

    return fwcontent;
}


function unpack(encoded_firmware) {

    if (crc16_ccitt_le(encoded_firmware.slice(0, -2)).toString() === encoded_firmware.slice(-2).toString()) {
        log("CRC check passed...");
    } else {
        log("WARNING: CRC CHECK FAILED! FIRMWARE NOT VALID!\nMake sure to choose a flashable bin file. ");
    }

    const decoded_firmware = firmware_xor(encoded_firmware.slice(0, -2));
    const versionInfoOffset = 0x2000;
    const versionInfoLength = 16;
    const resultLength = decoded_firmware.length - versionInfoLength;
    const result = new Uint8Array(resultLength);

    result.set(decoded_firmware.subarray(0, versionInfoOffset));
    result.set(decoded_firmware.subarray(versionInfoOffset + versionInfoLength), versionInfoOffset);

    versionInfo = decoded_firmware.subarray(versionInfoOffset, versionInfoOffset + versionInfoLength);

    return result;
}

function pack(decoded_firmware) {
    const versionInfoOffset = 0x2000;
    const versionInfoLength = 16;

    const result = new Uint8Array(versionInfoLength + decoded_firmware.length);
    result.set(decoded_firmware.subarray(0, versionInfoOffset));
    result.set(versionInfo, versionInfoOffset);
    result.set(decoded_firmware.subarray(versionInfoOffset), versionInfoOffset + versionInfoLength);

    const firmware_with_version_encoded = firmware_xor(result);
    const crc = crc16_ccitt_le(firmware_with_version_encoded);

    const packed_firmware = new Uint8Array(firmware_with_version_encoded.length + crc.length);
    packed_firmware.set(firmware_with_version_encoded, 0);
    packed_firmware.set(crc, firmware_with_version_encoded.length);

    return packed_firmware;
}