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#include <qglobal.h>

#if QT_CONFIG(topleveldomain)

#include "qplatformdefs.h"
#include "qurl.h"
#include "private/qurltlds_p.h"
#include "private/qtldurl_p.h"
#include "QtCore/qstring.h"
#include "QtCore/qvector.h"

QT_BEGIN_NAMESPACE

enum TLDMatchType {
    ExactMatch,
    SuffixMatch,
    ExceptionMatch,
};

// Scan the auto-generated table of TLDs for an entry. For more details
// see comments in file:  util/corelib/qurl-generateTLDs/main.cpp
static bool containsTLDEntry(QStringView entry, TLDMatchType match)
{
    const QStringView matchSymbols[] = {
        u"",
        u"*",
        u"!",
    };
    const auto symbol = matchSymbols[match];
    const int index = qt_hash(entry, qt_hash(symbol)) % tldCount;

    // select the right chunk from the big table
    short chunk = 0;
    uint chunkIndex = tldIndices[index], offset = 0;

    // The offset in the big string, of the group that our entry hashes into.
    const auto tldGroupOffset = tldIndices[index];

    // It should always be inside all chunks' total size.
    Q_ASSERT(tldGroupOffset < tldChunks[tldChunkCount - 1]);
    // All offsets are stored in non-decreasing order.
    // This check is within bounds as tldIndices has length tldCount+1.
    Q_ASSERT(tldGroupOffset <= tldIndices[index + 1]);
    // The last extra entry in tldIndices
    // should be equal to the total of all chunks' lengths.
    Q_ASSERT(tldIndices[tldCount] == tldChunks[tldChunkCount - 1]);

    // Find which chunk contains the tldGroupOffset
    while (tldGroupOffset >= tldChunks[chunk]) {
        chunk++;
        // We can not go above the number of chunks we have, since all our
        // indices are less than the total chunks' size (see asserts above).
        Q_ASSERT(chunk < tldChunkCount);
    }
    if (chunk > 0) {
        chunkIndex -= tldChunks[chunk - 1];
        offset += tldChunks[chunk - 1];
    }

    // check all the entries from the given offset
    while (chunkIndex < tldIndices[index+1] - offset) {
        const auto utf8 = tldData[chunk] + chunkIndex;
        if ((symbol.isEmpty() || QLatin1Char(*utf8) == symbol) && entry == QString::fromUtf8(utf8 + symbol.size()))
            return true;
        chunkIndex += qstrlen(utf8) + 1; // +1 for the ending \0
    }
    return false;
}

/*!
    \internal

    Return the top-level-domain per Qt's copy of the Mozilla public suffix list of
    \a domain.
*/

Q_CORE_EXPORT QString qTopLevelDomain(const QString &domain)
{
    const QString domainLower = domain.toLower();
    QVector<QStringRef> sections = domainLower.splitRef(QLatin1Char('.'), Qt::SkipEmptyParts);
    if (sections.isEmpty())
        return QString();

    QString level, tld;
    for (int j = sections.count() - 1; j >= 0; --j) {
        level.prepend(QLatin1Char('.') + sections.at(j));
        if (qIsEffectiveTLD(level.rightRef(level.size() - 1)))
            tld = level;
    }
    return tld;
}

/*!
    \internal

    Return true if \a domain is a top-level-domain per Qt's copy of the Mozilla public suffix list.
*/

Q_CORE_EXPORT bool qIsEffectiveTLD(const QStringRef &domain)
{
    // for domain 'foo.bar.com':
    // 1. return if TLD table contains 'foo.bar.com'
    // 2. else if table contains '*.bar.com',
    // 3. test that table does not contain '!foo.bar.com'

    if (containsTLDEntry(domain, ExactMatch)) // 1
        return true;

    const int dot = domain.indexOf(QLatin1Char('.'));
    if (dot < 0) // Actual TLD: may be effective if the subject of a wildcard rule:
        return containsTLDEntry(QString(QLatin1Char('.') + domain), SuffixMatch);
    if (containsTLDEntry(domain.mid(dot), SuffixMatch))   // 2
        return !containsTLDEntry(domain, ExceptionMatch); // 3
    return false;
}

QT_END_NAMESPACE

#endif
