// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qshortcutmap_p.h"
#include "private/qobject_p.h"
#include "qkeysequence.h"
#include "qdebug.h"
#include "qevent.h"
#include "qlist.h"
#include "qguiapplication.h"
#include "qwindow.h"
#include <private/qkeymapper_p.h>
#include <QtCore/qloggingcategory.h>
#include <QtCore/qscopeguard.h>

#include <algorithm>

QT_BEGIN_NAMESPACE

Q_LOGGING_CATEGORY(lcShortcutMap, "qt.gui.shortcutmap")

/* \internal
    Entry data for QShortcutMap
    Contains:
        Keysequence for entry
        Pointer to parent owning the sequence
*/

struct QShortcutEntry
{
    QShortcutEntry()
        : keySequence(0), context(Qt::WindowShortcut), enabled(false), autorepeat(1), id(0), owner(nullptr), contextMatcher(nullptr)
    {}

    QShortcutEntry(const QKeySequence &k)
        : keySequence(k), context(Qt::WindowShortcut), enabled(false), autorepeat(1), id(0), owner(nullptr), contextMatcher(nullptr)
    {}

    QShortcutEntry(QObject *o, const QKeySequence &k, Qt::ShortcutContext c, int i, bool a, QShortcutMap::ContextMatcher m)
        : keySequence(k), context(c), enabled(true), autorepeat(a), id(i), owner(o), contextMatcher(m)
    {}

    bool correctContext() const { return contextMatcher(owner, context); }

    bool operator<(const QShortcutEntry &f) const
    { return keySequence < f.keySequence; }

    QKeySequence keySequence;
    Qt::ShortcutContext context;
    bool enabled : 1;
    bool autorepeat : 1;
    signed int id;
    QObject *owner;
    QShortcutMap::ContextMatcher contextMatcher;
};
Q_DECLARE_TYPEINFO(QShortcutEntry, Q_RELOCATABLE_TYPE);

#ifdef Dump_QShortcutMap
/*! \internal
    QDebug operator<< for easy debug output of the shortcut entries.
*/
static QDebug &operator<<(QDebug &dbg, const QShortcutEntry *se)
{
    QDebugStateSaver saver(dbg);
    if (!se)
        return dbg << "QShortcutEntry(0x0)";
    dbg.nospace()
        << "QShortcutEntry(" << se->keyseq
        << "), id(" << se->id << "), enabled(" << se->enabled << "), autorepeat(" << se->autorepeat
        << "), owner(" << se->owner << ')';
    return dbg;
}
#endif // Dump_QShortcutMap

/* \internal
    Private data for QShortcutMap
*/
class QShortcutMapPrivate
{
    Q_DECLARE_PUBLIC(QShortcutMap)

public:
    QShortcutMapPrivate(QShortcutMap* parent)
        : q_ptr(parent), currentId(0), ambigCount(0), currentState(QKeySequence::NoMatch)
    {
        identicals.reserve(10);
        currentSequences.reserve(10);
    }
    QShortcutMap *q_ptr;                        // Private's parent

    QList<QShortcutEntry> shortcuts;            // All shortcuts!

    int currentId;                              // Global shortcut ID number
    int ambigCount;                             // Index of last enabled ambiguous dispatch
    QKeySequence::SequenceMatch currentState;
    QList<QKeySequence> currentSequences;       // Sequence for the current state
    QList<QKeySequence> newEntries;
    QKeySequence prevSequence;                  // Sequence for the previous identical match
    QList<const QShortcutEntry*> identicals;    // Last identical matches
};


/*! \internal
    QShortcutMap constructor.
*/
QShortcutMap::QShortcutMap()
    : d_ptr(new QShortcutMapPrivate(this))
{
    resetState();
}

/*! \internal
    QShortcutMap destructor.
*/
QShortcutMap::~QShortcutMap()
{
}

/*! \internal
    Adds a shortcut to the global map.
    Returns the id of the newly added shortcut.
*/
int QShortcutMap::addShortcut(QObject *owner, const QKeySequence &keySequence, Qt::ShortcutContext context, ContextMatcher matcher)
{
    Q_ASSERT_X(owner, "QShortcutMap::addShortcut", "All shortcuts need an owner");
    Q_ASSERT_X(!keySequence.isEmpty(), "QShortcutMap::addShortcut", "Cannot add keyless shortcuts to map");
    Q_D(QShortcutMap);

    QShortcutEntry newEntry(owner, keySequence, context, --(d->currentId), true, matcher);
    const auto it = std::upper_bound(d->shortcuts.begin(), d->shortcuts.end(), newEntry);
    d->shortcuts.insert(it, newEntry); // Insert sorted
    qCDebug(lcShortcutMap).nospace()
        << "QShortcutMap::addShortcut(" << owner << ", "
        << keySequence << ", " << context << ") added shortcut with ID " << d->currentId;
    return d->currentId;
}

/*! \internal
    Removes a shortcut from the global map.
    If \a owner is \nullptr, all entries in the map with the key sequence specified
    is removed. If \a key is null, all sequences for \a owner is removed from
    the map. If \a id is 0, any identical \a key sequences owned by \a owner
    are removed.
    Returns the number of sequences removed from the map.
*/

int QShortcutMap::removeShortcut(int id, QObject *owner, const QKeySequence &keySequence)
{
    Q_D(QShortcutMap);
    int itemsRemoved = 0;
    bool allOwners = (owner == nullptr);
    bool allKeys = keySequence.isEmpty();
    bool allIds = id == 0;

    auto debug = qScopeGuard([&](){
        qCDebug(lcShortcutMap).nospace()
            << "QShortcutMap::removeShortcut(" << id << ", " << owner << ", "
            << keySequence << ") removed " << itemsRemoved << " shortcuts(s)";
    });

    // Special case, remove everything
    if (allOwners && allKeys && allIds) {
        itemsRemoved = d->shortcuts.size();
        d->shortcuts.clear();
        return itemsRemoved;
    }

    int i = d->shortcuts.size()-1;
    while (i>=0)
    {
        const QShortcutEntry &entry = d->shortcuts.at(i);
        int entryId = entry.id;
        if ((allOwners || entry.owner == owner)
            && (allIds || entry.id == id)
            && (allKeys || entry.keySequence == keySequence)) {
            d->shortcuts.removeAt(i);
            ++itemsRemoved;
        }
        if (id == entryId)
            return itemsRemoved;
        --i;
    }
    return itemsRemoved;
}

/*! \internal
    Changes the enable state of a shortcut to \a enable.
    If \a owner is \nullptr, all entries in the map with the key sequence specified
    is removed. If \a key is null, all sequences for \a owner is removed from
    the map. If \a id is 0, any identical \a key sequences owned by \a owner
    are changed.
    Returns the number of sequences which are matched in the map.
*/
int QShortcutMap::setShortcutEnabled(bool enable, int id, QObject *owner, const QKeySequence &keySequence)
{
    Q_D(QShortcutMap);
    int itemsChanged = 0;
    bool allOwners = (owner == nullptr);
    bool allKeys = keySequence.isEmpty();
    bool allIds = id == 0;

    int i = d->shortcuts.size()-1;
    while (i>=0)
    {
        QShortcutEntry entry = d->shortcuts.at(i);
        if ((allOwners || entry.owner == owner)
            && (allIds || entry.id == id)
            && (allKeys || entry.keySequence == keySequence)) {
            d->shortcuts[i].enabled = enable;
            ++itemsChanged;
        }
        if (id == entry.id)
            return itemsChanged;
        --i;
    }
    qCDebug(lcShortcutMap).nospace()
        << "QShortcutMap::setShortcutEnabled(" << enable << ", " << id << ", "
        << owner << ", " << keySequence << ") = " << itemsChanged;
    return itemsChanged;
}

/*! \internal
    Changes the auto repeat state of a shortcut to \a enable.
    If \a owner is \nullptr, all entries in the map with the key sequence specified
    is removed. If \a key is null, all sequences for \a owner is removed from
    the map. If \a id is 0, any identical \a key sequences owned by \a owner
    are changed.
    Returns the number of sequences which are matched in the map.
*/
int QShortcutMap::setShortcutAutoRepeat(bool on, int id, QObject *owner, const QKeySequence &keySequence)
{
    Q_D(QShortcutMap);
    int itemsChanged = 0;
    bool allOwners = (owner == nullptr);
    bool allKeys = keySequence.isEmpty();
    bool allIds = id == 0;

    int i = d->shortcuts.size()-1;
    while (i>=0)
    {
        QShortcutEntry entry = d->shortcuts.at(i);
        if ((allOwners || entry.owner == owner)
            && (allIds || entry.id == id)
            && (allKeys || entry.keySequence == keySequence)) {
                d->shortcuts[i].autorepeat = on;
                ++itemsChanged;
        }
        if (id == entry.id)
            return itemsChanged;
        --i;
    }
    qCDebug(lcShortcutMap).nospace()
        << "QShortcutMap::setShortcutAutoRepeat(" << on << ", " << id << ", "
        << owner << ", " << keySequence << ") = " << itemsChanged;
    return itemsChanged;
}

/*! \internal
    Resets the state of the statemachine to NoMatch
*/
void QShortcutMap::resetState()
{
    Q_D(QShortcutMap);
    d->currentState = QKeySequence::NoMatch;
    clearSequence(d->currentSequences);
}

/*! \internal
    Returns the current state of the statemachine
*/
QKeySequence::SequenceMatch QShortcutMap::state()
{
    Q_D(QShortcutMap);
    return d->currentState;
}

/*! \internal
    Uses nextState(QKeyEvent) to check for a grabbed shortcut.

    If so, it is dispatched using dispatchEvent().

    Returns true if a shortcut handled the event.

    \sa nextState, dispatchEvent
*/
bool QShortcutMap::tryShortcut(QKeyEvent *e)
{
    Q_D(QShortcutMap);

    if (e->key() == Qt::Key_unknown)
        return false;

    QKeySequence::SequenceMatch previousState = state();

    switch (nextState(e)) {
    case QKeySequence::NoMatch:
        // In the case of going from a partial match to no match we handled the
        // event, since we already stated that we did for the partial match. But
        // in the normal case of directly going to no match we say we didn't.
        return previousState == QKeySequence::PartialMatch;
    case QKeySequence::PartialMatch:
        // For a partial match we don't know yet if we will handle the shortcut
        // but we need to say we did, so that we get the follow-up key-presses.
        return true;
    case QKeySequence::ExactMatch: {
        // Save number of identical matches before dispatching
        // to keep QShortcutMap and tryShortcut reentrant.
        const int identicalMatches = d->identicals.size();
        resetState();
        dispatchEvent(e);
        // If there are no identicals we've only found disabled shortcuts, and
        // shouldn't say that we handled the event.
        return identicalMatches > 0;
    }
    }
    Q_UNREACHABLE_RETURN(false);
}

/*! \internal
    Returns the next state of the statemachine
    If return value is SequenceMatch::ExactMatch, then a call to matches()
    will return a QObjects* list of all matching objects for the last matching
    sequence.
*/
QKeySequence::SequenceMatch QShortcutMap::nextState(QKeyEvent *e)
{
    Q_D(QShortcutMap);
    // Modifiers can NOT be shortcuts...
    if (e->key() >= Qt::Key_Shift &&
        e->key() <= Qt::Key_ScrollLock)
        return d->currentState;

    QKeySequence::SequenceMatch result = QKeySequence::NoMatch;

    // We start fresh each time..
    d->identicals.clear();

    result = find(e);
    if (result == QKeySequence::NoMatch && (e->modifiers() & Qt::KeypadModifier)) {
        // Try to find a match without keypad modifier
        result = find(e, Qt::KeypadModifier);
    }
    if (result == QKeySequence::NoMatch && e->modifiers() & Qt::ShiftModifier) {
        // If Shift + Key_Backtab, also try Shift + Qt::Key_Tab
        if (e->key() == Qt::Key_Backtab) {
            QKeyEvent pe = QKeyEvent(e->type(), Qt::Key_Tab, e->modifiers(), e->text());
            result = find(&pe);
        }
    }

    // Does the new state require us to clean up?
    if (result == QKeySequence::NoMatch)
        clearSequence(d->currentSequences);
    d->currentState = result;

    qCDebug(lcShortcutMap).nospace() << "QShortcutMap::nextState(" << e << ") = " << result;
    return result;
}


/*! \internal
    Determines if an enabled shortcut has a matching key sequence.
*/
bool QShortcutMap::hasShortcutForKeySequence(const QKeySequence &seq) const
{
    Q_D(const QShortcutMap);
    QShortcutEntry entry(seq); // needed for searching
    const auto itEnd = d->shortcuts.cend();
    auto it = std::lower_bound(d->shortcuts.cbegin(), itEnd, entry);

    for (;it != itEnd; ++it) {
        if (entry.keySequence.matches(it->keySequence) == QKeySequence::ExactMatch
                && (*it).correctContext() && (*it).enabled) {
            return true;
        }
    }

    //end of the loop: we didn't find anything
    return false;
}

/*! \internal
    Returns the next state of the statemachine, based
    on the new key event \a e.
    Matches are appended to the list of identicals,
    which can be access through matches().
    \sa matches
*/
QKeySequence::SequenceMatch QShortcutMap::find(QKeyEvent *e, int ignoredModifiers)
{
    Q_D(QShortcutMap);
    if (!d->shortcuts.size())
        return QKeySequence::NoMatch;

    createNewSequences(e, d->newEntries, ignoredModifiers);
    qCDebug(lcShortcutMap) << "Possible input sequences:" << d->newEntries;

    // Should never happen
    if (d->newEntries == d->currentSequences) {
        Q_ASSERT_X(e->key() != Qt::Key_unknown || e->text().size(),
                   "QShortcutMap::find", "New sequence to find identical to previous");
        return QKeySequence::NoMatch;
    }

    // Looking for new identicals, scrap old
    d->identicals.clear();

    bool partialFound = false;
    bool identicalDisabledFound = false;
    QList<QKeySequence> okEntries;
    QKeySequence::SequenceMatch result = QKeySequence::NoMatch;
    for (int i = d->newEntries.size()-1; i >= 0 ; --i) {
        QShortcutEntry entry(d->newEntries.at(i)); // needed for searching
        qCDebug(lcShortcutMap) << "Looking for shortcuts matching" << entry.keySequence;

        QKeySequence::SequenceMatch bestMatchForEntry = QKeySequence::NoMatch;

        const auto itEnd = d->shortcuts.constEnd();
        auto it = std::lower_bound(d->shortcuts.constBegin(), itEnd, entry);
        for (; it != itEnd; ++it) {
            QKeySequence::SequenceMatch match = entry.keySequence.matches(it->keySequence);
            qCDebug(lcShortcutMap) << " -" << match << "for shortcut" << it->keySequence;

            // If we got a valid match, there might still be more keys to check against,
            // but if we get no match, we know that there are no more possible matches.
            if (match == QKeySequence::NoMatch)
                break;

            bestMatchForEntry = qMax(bestMatchForEntry, match);

            if ((*it).correctContext()) {
                if (match == QKeySequence::ExactMatch) {
                    if ((*it).enabled)
                        d->identicals.append(&*it);
                    else
                        identicalDisabledFound = true;
                } else if (match == QKeySequence::PartialMatch) {
                    // We don't need partials, if we have identicals
                    if (d->identicals.size())
                        break;
                    // We only care about enabled partials, so we don't consume
                    // key events when all partials are disabled!
                    partialFound |= (*it).enabled;
                }
            } else {
                qCDebug(lcShortcutMap) << "  - But context was not correct";
            }
        }

        // If the type of match improves (ergo, NoMatch->Partial, or Partial->Exact), clear the
        // previous list. If this match is equal or better than the last match, append to the list
        if (bestMatchForEntry > result) {
            okEntries.clear();
            qCDebug(lcShortcutMap) << "Found better match (" << d->newEntries << "), clearing key sequence list";
        }
        if (bestMatchForEntry && bestMatchForEntry >= result) {
            okEntries << d->newEntries.at(i);
            qCDebug(lcShortcutMap) << "Added ok key sequence" << d->newEntries;
        }
    }

    if (d->identicals.size()) {
        result = QKeySequence::ExactMatch;
    } else if (partialFound) {
        result = QKeySequence::PartialMatch;
    } else if (identicalDisabledFound) {
        result = QKeySequence::ExactMatch;
    } else {
        clearSequence(d->currentSequences);
        result = QKeySequence::NoMatch;
    }
    if (result != QKeySequence::NoMatch)
        d->currentSequences = okEntries;
    qCDebug(lcShortcutMap) << "Returning shortcut match == " << result;
    return result;
}

/*! \internal
    Clears \a seq to an empty QKeySequence.
    Same as doing (the slower)
    \snippet code/src_gui_kernel_qshortcutmap.cpp 0
*/
void QShortcutMap::clearSequence(QList<QKeySequence> &ksl)
{
    ksl.clear();
    d_func()->newEntries.clear();
}

/*! \internal
    Alters \a seq to the new sequence state, based on the
    current sequence state, and the new key event \a e.
*/
void QShortcutMap::createNewSequences(QKeyEvent *e, QList<QKeySequence> &ksl, int ignoredModifiers)
{
    Q_D(QShortcutMap);
    QList<QKeyCombination> possibleKeys = QKeyMapper::possibleKeys(e);
    qCDebug(lcShortcutMap) << "Creating new sequences for" << e
        << "with ignoredModifiers=" << Qt::KeyboardModifiers(ignoredModifiers);
    int pkTotal = possibleKeys.size();
    if (!pkTotal)
        return;

    int ssActual = d->currentSequences.size();
    int ssTotal = qMax(1, ssActual);
    // Resize to possible permutations of the current sequence(s).
    ksl.resize(pkTotal * ssTotal);

    int index = ssActual ? d->currentSequences.at(0).count() : 0;
    for (int pkNum = 0; pkNum < pkTotal; ++pkNum) {
        for (int ssNum = 0; ssNum < ssTotal; ++ssNum) {
            int i = (pkNum * ssTotal) + ssNum;
            QKeySequence &curKsl = ksl[i];
            if (ssActual) {
                const QKeySequence &curSeq = d->currentSequences.at(ssNum);
                curKsl.setKey(curSeq[0], 0);
                curKsl.setKey(curSeq[1], 1);
                curKsl.setKey(curSeq[2], 2);
                curKsl.setKey(curSeq[3], 3);
            } else {
                curKsl.setKey(QKeyCombination::fromCombined(0), 0);
                curKsl.setKey(QKeyCombination::fromCombined(0), 1);
                curKsl.setKey(QKeyCombination::fromCombined(0), 2);
                curKsl.setKey(QKeyCombination::fromCombined(0), 3);
            }
            const int key = possibleKeys.at(pkNum).toCombined();
            curKsl.setKey(QKeyCombination::fromCombined(key & ~ignoredModifiers), index);
        }
    }
}

/*! \internal
    Converts keyboard button states into modifier states
*/
int QShortcutMap::translateModifiers(Qt::KeyboardModifiers modifiers)
{
    int result = 0;
    if (modifiers & Qt::ShiftModifier)
        result |= Qt::SHIFT;
    if (modifiers & Qt::ControlModifier)
        result |= Qt::CTRL;
    if (modifiers & Qt::MetaModifier)
        result |= Qt::META;
    if (modifiers & Qt::AltModifier)
        result |= Qt::ALT;
    return result;
}

/*! \internal
    Returns the list of QShortcutEntry's matching the last Identical state.
*/
QList<const QShortcutEntry*> QShortcutMap::matches() const
{
    Q_D(const QShortcutMap);
    return d->identicals;
}

/*! \internal
    Dispatches QShortcutEvents to widgets who grabbed the matched key sequence.
*/
void QShortcutMap::dispatchEvent(QKeyEvent *e)
{
    Q_D(QShortcutMap);
    if (!d->identicals.size())
        return;

    const QKeySequence &curKey = d->identicals.at(0)->keySequence;
    if (d->prevSequence != curKey) {
        d->ambigCount = 0;
        d->prevSequence = curKey;
    }
    // Find next
    const QShortcutEntry *current = nullptr, *next = nullptr;
    int i = 0, enabledShortcuts = 0;
    QList<const QShortcutEntry*> ambiguousShortcuts;
    while(i < d->identicals.size()) {
        current = d->identicals.at(i);
        if (current->enabled || !next){
            ++enabledShortcuts;
            if (lcShortcutMap().isDebugEnabled())
                ambiguousShortcuts.append(current);
            if (enabledShortcuts > d->ambigCount + 1)
                break;
            next = current;
        }
        ++i;
    }
    d->ambigCount = (d->identicals.size() == i ? 0 : d->ambigCount + 1);
    // Don't trigger shortcut if we're autorepeating and the shortcut is
    // grabbed with not accepting autorepeats.
    if (!next || (e->isAutoRepeat() && !next->autorepeat))
        return;
    // Dispatch next enabled
    if (lcShortcutMap().isDebugEnabled()) {
        if (ambiguousShortcuts.size() > 1) {
            qCDebug(lcShortcutMap) << "The following shortcuts are about to be activated ambiguously:";
            for (const QShortcutEntry *entry : std::as_const(ambiguousShortcuts))
                qCDebug(lcShortcutMap).nospace() << "- " << entry->keySequence << " (belonging to " << entry->owner << ")";
        }

        qCDebug(lcShortcutMap).nospace()
            << "QShortcutMap::dispatchEvent(): Sending QShortcutEvent(\""
            << next->keySequence.toString() << "\", " << next->id << ", "
            << static_cast<bool>(enabledShortcuts>1) << ") to object(" << next->owner << ')';
    }
    QShortcutEvent se(next->keySequence, next->id, enabledShortcuts > 1);
    QCoreApplication::sendEvent(const_cast<QObject *>(next->owner), &se);
}

QList<QKeySequence> QShortcutMap::keySequences(bool getAll) const
{
    Q_D(const QShortcutMap);
    QList<QKeySequence> keys;
    for (auto sequence : d->shortcuts) {
        bool addSequence = false;
        if (sequence.enabled) {
            if (getAll || sequence.context == Qt::ApplicationShortcut ||
                sequence.owner == QGuiApplication::focusObject()) {
                addSequence = true;
            } else {
                QObject *possibleWindow = sequence.owner;
                while (possibleWindow) {
                    if (qobject_cast<QWindow *>(possibleWindow))
                        break;
                    possibleWindow = possibleWindow->parent();
                }
                if (possibleWindow == QGuiApplication::focusWindow()) {
                    if (sequence.context == Qt::WindowShortcut) {
                        addSequence = true;
                    } else if (sequence.context == Qt::WidgetWithChildrenShortcut) {
                        QObject *possibleWidget = QGuiApplication::focusObject();
                        while (possibleWidget->parent()) {
                            possibleWidget = possibleWidget->parent();
                            if (possibleWidget == sequence.owner) {
                                addSequence = true;
                                break;
                            }
                        }
                    }
                }
            }
            if (addSequence)
                keys << sequence.keySequence;
        }
    }
    return keys;

}

/* \internal
    QShortcutMap dump function, only available when DEBUG_QSHORTCUTMAP is
    defined.
*/
#if defined(Dump_QShortcutMap)
void QShortcutMap::dumpMap() const
{
    Q_D(const QShortcutMap);
    for (int i = 0; i < d->shortcuts.size(); ++i)
        qDebug().nospace() << &(d->shortcuts.at(i));
}
#endif

QT_END_NAMESPACE