// SPDX-FileCopyrightText: 2009 Manjeet Dahiya <manjeetdahiya@gmail.com>
// SPDX-FileCopyrightText: 2010 Jeremy Lainé <jeremy.laine@m4x.org>
//
// SPDX-License-Identifier: LGPL-2.1-or-later

#include "QXmppUtils.h"

#include "QXmppNonza.h"
#include "QXmppUtils_p.h"

#include "Algorithms.h"
#include "StringLiterals.h"
#include "XmlWriter.h"

#include <QBuffer>
#include <QByteArray>
#include <QCryptographicHash>
#include <QDateTime>
#include <QDebug>
#include <QDomElement>
#include <QRandomGenerator>
#include <QRegularExpression>
#include <QStringList>
#include <QUrl>
#include <QUuid>
#include <QXmlStreamWriter>

using namespace QXmpp::Private;

// adapted from public domain source by Ross Williams and Eric Durbin
// FIXME : is this valid for big-endian machines?
static quint32 crctable[256] = {
    0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL,
    0x076DC419L, 0x706AF48FL, 0xE963A535L, 0x9E6495A3L,
    0x0EDB8832L, 0x79DCB8A4L, 0xE0D5E91EL, 0x97D2D988L,
    0x09B64C2BL, 0x7EB17CBDL, 0xE7B82D07L, 0x90BF1D91L,
    0x1DB71064L, 0x6AB020F2L, 0xF3B97148L, 0x84BE41DEL,
    0x1ADAD47DL, 0x6DDDE4EBL, 0xF4D4B551L, 0x83D385C7L,
    0x136C9856L, 0x646BA8C0L, 0xFD62F97AL, 0x8A65C9ECL,
    0x14015C4FL, 0x63066CD9L, 0xFA0F3D63L, 0x8D080DF5L,
    0x3B6E20C8L, 0x4C69105EL, 0xD56041E4L, 0xA2677172L,
    0x3C03E4D1L, 0x4B04D447L, 0xD20D85FDL, 0xA50AB56BL,
    0x35B5A8FAL, 0x42B2986CL, 0xDBBBC9D6L, 0xACBCF940L,
    0x32D86CE3L, 0x45DF5C75L, 0xDCD60DCFL, 0xABD13D59L,
    0x26D930ACL, 0x51DE003AL, 0xC8D75180L, 0xBFD06116L,
    0x21B4F4B5L, 0x56B3C423L, 0xCFBA9599L, 0xB8BDA50FL,
    0x2802B89EL, 0x5F058808L, 0xC60CD9B2L, 0xB10BE924L,
    0x2F6F7C87L, 0x58684C11L, 0xC1611DABL, 0xB6662D3DL,
    0x76DC4190L, 0x01DB7106L, 0x98D220BCL, 0xEFD5102AL,
    0x71B18589L, 0x06B6B51FL, 0x9FBFE4A5L, 0xE8B8D433L,
    0x7807C9A2L, 0x0F00F934L, 0x9609A88EL, 0xE10E9818L,
    0x7F6A0DBBL, 0x086D3D2DL, 0x91646C97L, 0xE6635C01L,
    0x6B6B51F4L, 0x1C6C6162L, 0x856530D8L, 0xF262004EL,
    0x6C0695EDL, 0x1B01A57BL, 0x8208F4C1L, 0xF50FC457L,
    0x65B0D9C6L, 0x12B7E950L, 0x8BBEB8EAL, 0xFCB9887CL,
    0x62DD1DDFL, 0x15DA2D49L, 0x8CD37CF3L, 0xFBD44C65L,
    0x4DB26158L, 0x3AB551CEL, 0xA3BC0074L, 0xD4BB30E2L,
    0x4ADFA541L, 0x3DD895D7L, 0xA4D1C46DL, 0xD3D6F4FBL,
    0x4369E96AL, 0x346ED9FCL, 0xAD678846L, 0xDA60B8D0L,
    0x44042D73L, 0x33031DE5L, 0xAA0A4C5FL, 0xDD0D7CC9L,
    0x5005713CL, 0x270241AAL, 0xBE0B1010L, 0xC90C2086L,
    0x5768B525L, 0x206F85B3L, 0xB966D409L, 0xCE61E49FL,
    0x5EDEF90EL, 0x29D9C998L, 0xB0D09822L, 0xC7D7A8B4L,
    0x59B33D17L, 0x2EB40D81L, 0xB7BD5C3BL, 0xC0BA6CADL,
    0xEDB88320L, 0x9ABFB3B6L, 0x03B6E20CL, 0x74B1D29AL,
    0xEAD54739L, 0x9DD277AFL, 0x04DB2615L, 0x73DC1683L,
    0xE3630B12L, 0x94643B84L, 0x0D6D6A3EL, 0x7A6A5AA8L,
    0xE40ECF0BL, 0x9309FF9DL, 0x0A00AE27L, 0x7D079EB1L,
    0xF00F9344L, 0x8708A3D2L, 0x1E01F268L, 0x6906C2FEL,
    0xF762575DL, 0x806567CBL, 0x196C3671L, 0x6E6B06E7L,
    0xFED41B76L, 0x89D32BE0L, 0x10DA7A5AL, 0x67DD4ACCL,
    0xF9B9DF6FL, 0x8EBEEFF9L, 0x17B7BE43L, 0x60B08ED5L,
    0xD6D6A3E8L, 0xA1D1937EL, 0x38D8C2C4L, 0x4FDFF252L,
    0xD1BB67F1L, 0xA6BC5767L, 0x3FB506DDL, 0x48B2364BL,
    0xD80D2BDAL, 0xAF0A1B4CL, 0x36034AF6L, 0x41047A60L,
    0xDF60EFC3L, 0xA867DF55L, 0x316E8EEFL, 0x4669BE79L,
    0xCB61B38CL, 0xBC66831AL, 0x256FD2A0L, 0x5268E236L,
    0xCC0C7795L, 0xBB0B4703L, 0x220216B9L, 0x5505262FL,
    0xC5BA3BBEL, 0xB2BD0B28L, 0x2BB45A92L, 0x5CB36A04L,
    0xC2D7FFA7L, 0xB5D0CF31L, 0x2CD99E8BL, 0x5BDEAE1DL,
    0x9B64C2B0L, 0xEC63F226L, 0x756AA39CL, 0x026D930AL,
    0x9C0906A9L, 0xEB0E363FL, 0x72076785L, 0x05005713L,
    0x95BF4A82L, 0xE2B87A14L, 0x7BB12BAEL, 0x0CB61B38L,
    0x92D28E9BL, 0xE5D5BE0DL, 0x7CDCEFB7L, 0x0BDBDF21L,
    0x86D3D2D4L, 0xF1D4E242L, 0x68DDB3F8L, 0x1FDA836EL,
    0x81BE16CDL, 0xF6B9265BL, 0x6FB077E1L, 0x18B74777L,
    0x88085AE6L, 0xFF0F6A70L, 0x66063BCAL, 0x11010B5CL,
    0x8F659EFFL, 0xF862AE69L, 0x616BFFD3L, 0x166CCF45L,
    0xA00AE278L, 0xD70DD2EEL, 0x4E048354L, 0x3903B3C2L,
    0xA7672661L, 0xD06016F7L, 0x4969474DL, 0x3E6E77DBL,
    0xAED16A4AL, 0xD9D65ADCL, 0x40DF0B66L, 0x37D83BF0L,
    0xA9BCAE53L, 0xDEBB9EC5L, 0x47B2CF7FL, 0x30B5FFE9L,
    0xBDBDF21CL, 0xCABAC28AL, 0x53B39330L, 0x24B4A3A6L,
    0xBAD03605L, 0xCDD70693L, 0x54DE5729L, 0x23D967BFL,
    0xB3667A2EL, 0xC4614AB8L, 0x5D681B02L, 0x2A6F2B94L,
    0xB40BBE37L, 0xC30C8EA1L, 0x5A05DF1BL, 0x2D02EF8DL
};

QAtomicInt QXmpp::Private::globalStanzaIdCounter = 0;

///
/// Parses a date-time from a string according to \xep{0082, XMPP Date and Time Profiles}.
///
/// Takes QStringView since QXmpp 1.8.
///
QDateTime QXmppUtils::datetimeFromString(QStringView str)
{
    // Qt::ISODate parses milliseconds, but doesn't output them
    return QDateTime::fromString(toString60(str), Qt::ISODate).toUTC();
}

///
/// Serializes a date-time to a string according to \xep{0082, XMPP Date and Time Profiles}.
///
QString QXmppUtils::datetimeToString(const QDateTime &dt)
{
    if (!dt.isValid()) {
        return {};
    }
    if (dt.time().msec()) {
        return dt.toUTC().toString(Qt::ISODateWithMs);
    }
    return dt.toUTC().toString(Qt::ISODate);
}

///
/// Parses a timezone offset (in seconds) from a string according to
/// \xep{0082}: XMPP Date and Time Profiles.
///
int QXmppUtils::timezoneOffsetFromString(const QString &str)
{
    static const QRegularExpression timezoneRegex(u"(Z|([+-])([0-9]{2}):([0-9]{2}))"_s);

    const auto match = timezoneRegex.match(str);
    if (!match.hasMatch()) {
        return 0;
    }

    // No offset from UTC
    if (match.captured(1) == QChar(u'Z')) {
        return 0;
    }

    // Calculate offset
    const int offset = match.captured(3).toInt() * 3600 +
        match.captured(4).toInt() * 60;

    if (match.captured(2) == QChar(u'-')) {
        return -offset;
    }
    return offset;
}

///
/// Serializes a timezone offset (in seconds) to a string according to
/// \xep{0082, XMPP Date and Time Profiles}.
///
QString QXmppUtils::timezoneOffsetToString(int secs)
{
    if (!secs) {
        return u"Z"_s;
    }

    const QTime tzoTime = QTime(0, 0, 0).addSecs(qAbs(secs));
    return (secs < 0 ? u"-"_s : u"+"_s) + tzoTime.toString(u"hh:mm"_s);
}

/// Returns the domain for the given \a jid.
QString QXmppUtils::jidToDomain(const QString &jid)
{
    return jidToBareJid(jid).split(u"@"_s).last();
}

/// Returns the resource for the given \a jid.
QString QXmppUtils::jidToResource(const QString &jid)
{
    const int pos = jid.indexOf(u'/');
    if (pos < 0) {
        return QString();
    }
    return jid.mid(pos + 1);
}

/// Returns the user for the given \a jid.
QString QXmppUtils::jidToUser(const QString &jid)
{
    const int pos = jid.indexOf(u'@');
    if (pos < 0) {
        return QString();
    }
    return jid.left(pos);
}

/// Returns the bare jid (i.e. without resource) for the given \a jid.
QString QXmppUtils::jidToBareJid(const QString &jid)
{
    const int pos = jid.indexOf(u'/');
    if (pos < 0) {
        return jid;
    }
    return jid.left(pos);
}

/// Calculates the CRC32 checksum for the given input.
quint32 QXmppUtils::generateCrc32(const QByteArray &in)
{
    quint32 result = 0xffffffff;
    for (char n : in) {
        result = (result >> 8) ^ (crctable[(result & 0xff) ^ (quint8)n]);
    }
    return result ^= 0xffffffff;
}

static QByteArray generateHmac(QCryptographicHash::Algorithm algorithm, const QByteArray &key, const QByteArray &text)
{
    QCryptographicHash hasher(algorithm);

    const int B = 64;
    QByteArray kpad = key + QByteArray(B - key.size(), 0);

    QByteArray ba;
    for (int i = 0; i < B; ++i) {
        ba += kpad[i] ^ 0x5c;
    }

    QByteArray tmp;
    for (int i = 0; i < B; ++i) {
        tmp += kpad[i] ^ 0x36;
    }
    hasher.addData(tmp);
    hasher.addData(text);
    ba += hasher.result();

    hasher.reset();
    hasher.addData(ba);
    return hasher.result();
}

/// Generates the MD5 HMAC for the given \a key and \a text.

QByteArray QXmppUtils::generateHmacMd5(const QByteArray &key, const QByteArray &text)
{
    return generateHmac(QCryptographicHash::Md5, key, text);
}

/// Generates the SHA1 HMAC for the given \a key and \a text.

QByteArray QXmppUtils::generateHmacSha1(const QByteArray &key, const QByteArray &text)
{
    return generateHmac(QCryptographicHash::Sha1, key, text);
}

/// Generates a random integer x between 0 and N-1.
///
/// \param N

int QXmppUtils::generateRandomInteger(int N)
{
    Q_ASSERT(N > 0 && N <= RAND_MAX);
    int val;
    while (N <= (val = QRandomGenerator::global()->generate() / (RAND_MAX / N))) {
    }
    return val;
}

/// Returns a random byte array of the specified size.
///
/// \param length

QByteArray QXmppUtils::generateRandomBytes(int length)
{
    QByteArray bytes(length, 'm');
    for (int i = 0; i < length; ++i) {
        bytes[i] = (char)generateRandomInteger(256);
    }
    return bytes;
}

///
/// Creates a new stanza id in the UUID format.
///
/// \since QXmpp 1.3
///
QString QXmppUtils::generateStanzaUuid()
{
    return QUuid::createUuid().toString(QUuid::WithoutBraces);
}

///
/// Returns a random alphanumerical string of the specified size.
///
/// Since QXmpp 1.3 this will generate a UUID, if the specified \p length is 36
/// which is also the new default value. The returned string is still 36
/// characters long, but will contain dashes (as specified in the UUID format).
///
/// \note It is recommended to use UUIDs for cases where IDs must be unique and
/// are possibly stored permanently. This can be done using
/// QXmppUtils::generateStanzaUuid(). However, since that function is only
/// available since QXmpp 1.3, you may also want to continue to use this
/// function because of compatibility reasons.
///
/// \param length
///
QString QXmppUtils::generateStanzaHash(int length)
{
    if (length == 36) {
        return QXmppUtils::generateStanzaUuid();
    }

    const QString somechars = u"1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"_s;
    const int N = somechars.size();
    QString hashResult;
    for (int idx = 0; idx < length; ++idx) {
        hashResult += somechars[generateRandomInteger(N)];
    }
    return hashResult;
}

std::tuple<QString, QString> QXmpp::Private::elementXmlTag(const QDomElement &el)
{
    return { el.tagName(), el.namespaceURI() };
}

std::tuple<QString, QString> QXmpp::Private::iqPayloadXmlTag(const QDomElement &el)
{
    if (el.tagName() == u"iq") {
        return elementXmlTag(el.firstChildElement());
    }
    return { {}, {} };
}

///
/// Generates a new sequential stanza id. The ID is locally unique, not globally unique (see
/// QXmppUtils::generateStanzaUuid()).
///
/// This is used for all QXmppStanzas automatically.
///
/// \since QXmpp 1.11
///
QString QXmpp::generateSequentialStanzaId()
{
    ++globalStanzaIdCounter;
    return u"qx" + QString::number(globalStanzaIdCounter);
}

/// \cond
std::optional<QByteArray> QXmpp::Private::parseBase64(const QString &text)
{
    if (auto result = QByteArray::fromBase64Encoding(text.toUtf8())) {
        return *result;
    }
    return {};
}

template<typename T>
concept SupportedNumber =
    std::same_as<T, int8_t> || std::same_as<T, uint8_t> ||
    std::same_as<T, int16_t> || std::same_as<T, uint16_t> ||
    std::same_as<T, int32_t> || std::same_as<T, uint32_t> ||
    std::same_as<T, int64_t> || std::same_as<T, uint64_t> ||
    std::same_as<T, float> || std::same_as<T, double>;

template<typename Int>
Int stringToInt(QStringView str, bool *ok)
{
    static_assert(SupportedNumber<Int>, "invalid integer type");

    if constexpr (std::is_same_v<Int, int8_t>) {
        auto result = str.toShort(ok);
        if (*ok && result <= std::numeric_limits<int8_t>::max() && result >= std::numeric_limits<int8_t>::min()) {
            return Int(result);
        }
        *ok = false;
        return 0;
    } else if constexpr (std::is_same_v<Int, uint8_t>) {
        auto result = str.toUShort(ok);
        if (*ok && result <= std::numeric_limits<int8_t>::max()) {
            return Int(result);
        }
        *ok = false;
        return 0;
    } else if constexpr (std::is_same_v<Int, int16_t>) {
        return str.toShort(ok);
    } else if constexpr (std::is_same_v<Int, uint16_t>) {
        return str.toUShort(ok);
    } else if constexpr (std::is_same_v<Int, int32_t>) {
        return str.toInt(ok);
    } else if constexpr (std::is_same_v<Int, uint32_t>) {
        return str.toUInt(ok);
    } else if constexpr (std::is_same_v<Int, int64_t>) {
        return str.toLongLong(ok);
    } else if constexpr (std::is_same_v<Int, uint64_t>) {
        return str.toULongLong(ok);
    } else if constexpr (std::is_same_v<Int, double>) {
        return str.toDouble(ok);
    } else if constexpr (std::is_same_v<Int, float>) {
        return str.toFloat(ok);
    }
}

template<typename Int>
std::optional<Int> QXmpp::Private::parseInt(QStringView str)
{
    bool ok = false;
    if (auto result = stringToInt<Int>(str, &ok); ok) {
        return result;
    }
    return {};
}

template std::optional<int8_t> QXmpp::Private::parseInt<int8_t>(QStringView);
template std::optional<uint8_t> QXmpp::Private::parseInt<uint8_t>(QStringView);
template std::optional<int16_t> QXmpp::Private::parseInt<int16_t>(QStringView);
template std::optional<uint16_t> QXmpp::Private::parseInt<uint16_t>(QStringView);
template std::optional<int32_t> QXmpp::Private::parseInt<int32_t>(QStringView);
template std::optional<uint32_t> QXmpp::Private::parseInt<uint32_t>(QStringView);
template std::optional<int64_t> QXmpp::Private::parseInt<int64_t>(QStringView);
template std::optional<uint64_t> QXmpp::Private::parseInt<uint64_t>(QStringView);

std::optional<double> QXmpp::Private::parseDouble(QStringView str)
{
    return parseInt<double>(str);
}

std::optional<float> QXmpp::Private::parseFloat(QStringView str)
{
    return parseInt<float>(str);
}

std::optional<bool> QXmpp::Private::parseBoolean(const QString &str)
{
    if (str == u"1" || str == u"true") {
        return true;
    }
    if (str == u"0" || str == u"false") {
        return false;
    }
    return {};
}

QString QXmpp::Private::serializeBoolean(bool value)
{
    return value ? QStringLiteral("true") : QStringLiteral("false");
}

QDomElement QXmpp::Private::firstChildElement(const QDomElement &el, QStringView tagName, QStringView xmlNs)
{
    for (auto child = el.firstChild(); !child.isNull(); child = child.nextSibling()) {
        if (child.isElement() && (xmlNs.isEmpty() || child.namespaceURI() == xmlNs)) {
            auto elt = child.toElement();
            if (tagName.isEmpty() || elt.tagName() == tagName) {
                return elt;
            }
        }
    }
    return {};
}

QDomElement QXmpp::Private::nextSiblingElement(const QDomElement &el, QStringView tagName, QStringView xmlNs)
{
    for (auto sib = el.nextSibling(); !sib.isNull(); sib = sib.nextSibling()) {
        if (sib.isElement() && (xmlNs.isEmpty() || sib.namespaceURI() == xmlNs)) {
            auto elt = sib.toElement();
            if (tagName.isEmpty() || elt.tagName() == tagName) {
                return elt;
            }
        }
    }
    return {};
}

QByteArray QXmpp::Private::serializeXmlWriter(std::function<void(XmlWriter &)> toXml)
{
    QByteArray data;
    QXmlStreamWriter xmlStream(&data);
    XmlWriter writer(&xmlStream);
    toXml(writer);
    return data;
}

QByteArray QXmpp::Private::serializeQXmlStream(std::function<void(QXmlStreamWriter *)> toXml)
{
    QByteArray data;
    QXmlStreamWriter xmlStream(&data);
    toXml(&xmlStream);
    return data;
}

//
// Generates a random count of random bytes.
//
// \param minimumByteCount minimum count of bytes to generate
// \param maximumByteCount maximum count of bytes to generate
//
// \return the generated bytes
//
QByteArray QXmpp::Private::generateRandomBytes(size_t minimumByteCount, size_t maximumByteCount)
{
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
    const auto byteCount = QRandomGenerator::system()->bounded(quint64(minimumByteCount), quint64(maximumByteCount));
#else
    // Qt 5 only supports 32 bit integer!
    const auto byteCount = QRandomGenerator::system()->bounded(quint32(minimumByteCount), quint32(maximumByteCount));
#endif
    QByteArray bytes;
    bytes.resize(byteCount);
    generateRandomBytes(reinterpret_cast<uint8_t *>(bytes.data()), byteCount);

    return bytes;
}

//
// Generates random bytes.
//
// \param bytes generated bytes
// \param byteCount count of bytes to generate
//
void QXmpp::Private::generateRandomBytes(uint8_t *bytes, size_t byteCount)
{
    // QRandomGenerator does not provide a random generation of single bytes. Thus, this approach
    // fills an array with unsigned integers until no additional integer fits into the array. If
    // byteCount is no multiple of intSize, the remaining bytes need to be filled separately.
    constexpr auto intSize = sizeof(uint32_t);
    auto intCount = byteCount / intSize;

    auto *randomGenerator = QRandomGenerator::system();

    // Fill the space with intCount unsigned integers.
    if (intCount) {
        randomGenerator->fillRange(reinterpret_cast<uint32_t *>(bytes), intCount);
    }

    // Fill the remaining space with single bytes.
    for (size_t i = byteCount - byteCount % intSize; i < byteCount; i++) {
        bytes[i] = randomGenerator->bounded(std::numeric_limits<uint8_t>::max() + 1);
    }
}

float QXmpp::Private::calculateProgress(qint64 transferred, qint64 total)
{
    if (total > 0) {
        if (transferred > total) {
            return 1;
        }
        return float(transferred) / total;
    }

    return 0;
}

std::pair<QString, int> QXmpp::Private::parseHostAddress(const QString &address)
{
    QUrl url(u"//" + address);
    if (url.isValid() && !url.host().isEmpty()) {
        return { url.host(), url.port() };
    }
    return { {}, -1 };
}
/// \endcond
