// 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

#ifndef QTEXTENGINE_P_H

#define QTEXTENGINE_P_H

//

//  W A R N I N G

//  -------------

//

// This file is not part of the Qt API.  It exists for the convenience

// of other Qt classes.  This header file may change from version to

// version without notice, or even be removed.

//

// We mean it.

//

#include <QtGui/private/qtguiglobal_p.h>

#include "QtGui/qpaintengine.h"

#include "QtGui/qtextcursor.h"

#include "QtGui/qtextobject.h"

#include "QtGui/qtextoption.h"

#include "QtGui/qtextlayout.h"

#include "QtCore/qlist.h"

#include "QtCore/qnamespace.h"

#include "QtCore/qset.h"

#include <QtCore/qspan.h>

#include "QtCore/qstring.h"

#include "QtCore/qvarlengtharray.h"

#include "private/qfixed_p.h"

#include "private/qfont_p.h"

#include "private/qtextformat_p.h"

#include "private/qunicodetools_p.h"

#ifndef QT_BUILD_COMPAT_LIB

#include "private/qtextdocument_p.h"

#endif

#include <stdlib.h>

#include <vector>

QT_BEGIN_NAMESPACE

class QFontPrivate;

class QFontEngine;

class QString;

class QPainter;

class QAbstractTextDocumentLayout;

typedef quint32 glyph_t;

// this uses the same coordinate system as Qt, but a different one to freetype.

// * y is usually negative, and is equal to the ascent.

// * negative yoff means the following stuff is drawn higher up.

// the characters bounding rect is given by QRect(x,y,width,height), its advance by

// xoo and yoff

struct Q_GUI_EXPORT glyph_metrics_t

{

    inline glyph_metrics_t()

        : x(100000),  y(100000) {}

    inline glyph_metrics_t(QFixed _x, QFixed _y, QFixed _width, QFixed _height, QFixed _xoff, QFixed _yoff)

        : x(_x),

          y(_y),

          width(_width),

          height(_height),

          xoff(_xoff),

          yoff(_yoff)

        {}

    QFixed x;

    QFixed y;

    QFixed width;

    QFixed height;

    QFixed xoff;

    QFixed yoff;

    glyph_metrics_t transformed(const QTransform &xform) const;

    inline bool isValid() const {return x != 100000 && y != 100000;}

    inline QFixed leftBearing() const

    {

        if (!isValid())

            return QFixed();

        return x;

    }

    inline QFixed rightBearing() const

    {

        if (!isValid())

            return QFixed();

        return xoff - x - width;

    }

};

Q_DECLARE_TYPEINFO(glyph_metrics_t, Q_PRIMITIVE_TYPE);

struct Q_AUTOTEST_EXPORT QScriptAnalysis

{

    enum Flags {

        None = 0,

        Lowercase = 1,

        Uppercase = 2,

        SmallCaps = 3,

        LineOrParagraphSeparator = 4,

        Space = 5,

        SpaceTabOrObject = Space,

        Nbsp = 6,

        Tab = 7,

        TabOrObject = Tab,

        Object = 8

    };

    enum BidiFlags {

        BidiBN = 1,

        BidiMaybeResetToParagraphLevel = 2,

        BidiResetToParagraphLevel = 4,

        BidiMirrored = 8

    };

    unsigned short script    : 8;

    unsigned short flags     : 4;

    unsigned short bidiFlags : 4;

    unsigned short bidiLevel : 8;  // Unicode Bidi algorithm embedding level (0-125)

    QChar::Direction bidiDirection : 8; // used when running the bidi algorithm

    inline bool operator == (const QScriptAnalysis &other) const {

        return script == other.script && bidiLevel == other.bidiLevel && flags == other.flags;

    }

};

Q_DECLARE_TYPEINFO(QScriptAnalysis, Q_PRIMITIVE_TYPE);

struct QGlyphJustification

{

    inline QGlyphJustification()

        : type(0), nKashidas(0), space_18d6(0)

    {}

    enum JustificationType {

        JustifyNone,

        JustifySpace,

        JustifyKashida

    };

    uint type :2;

    uint nKashidas : 6; // more do not make sense...

    uint space_18d6 : 24;

};

Q_DECLARE_TYPEINFO(QGlyphJustification, Q_PRIMITIVE_TYPE);

struct QGlyphAttributes {

    uchar clusterStart  : 1;

    uchar dontPrint     : 1;

    uchar justification : 4;

    uchar reserved      : 2;

};

static_assert(sizeof(QGlyphAttributes) == 1);

Q_DECLARE_TYPEINFO(QGlyphAttributes, Q_PRIMITIVE_TYPE);

struct QGlyphLayout

{

    static constexpr qsizetype SpaceNeeded = sizeof(glyph_t) + sizeof(QFixed) + sizeof(QFixedPoint)

            + sizeof(QGlyphAttributes) + sizeof(QGlyphJustification);

    // init to 0 not needed, done when shaping

    QFixedPoint *offsets; // 8 bytes per element

    glyph_t *glyphs; // 4 bytes per element

    QFixed *advances; // 4 bytes per element

    QGlyphJustification *justifications; // 4 bytes per element

    QGlyphAttributes *attributes; // 1 byte per element

    int numGlyphs;

    inline QGlyphLayout() : numGlyphs(0) {}

    inline explicit QGlyphLayout(char *address, int totalGlyphs)

    {

        offsets = reinterpret_cast<QFixedPoint *>(address);

        qsizetype offset = totalGlyphs * sizeof(QFixedPoint);

        glyphs = reinterpret_cast<glyph_t *>(address + offset);

        offset += totalGlyphs * sizeof(glyph_t);

        advances = reinterpret_cast<QFixed *>(address + offset);

        offset += totalGlyphs * sizeof(QFixed);

        justifications = reinterpret_cast<QGlyphJustification *>(address + offset);

        offset += totalGlyphs * sizeof(QGlyphJustification);

        attributes = reinterpret_cast<QGlyphAttributes *>(address + offset);

        numGlyphs = totalGlyphs;

    }

    inline QGlyphLayout mid(int position, int n = -1) const {

        QGlyphLayout copy = *this;

        copy.glyphs += position;

        copy.advances += position;

        copy.offsets += position;

        copy.justifications += position;

        copy.attributes += position;

        if (n == -1)

            copy.numGlyphs -= position;

        else

            copy.numGlyphs = n;

        return copy;

    }

    inline QFixed effectiveAdvance(int item) const

    { return (advances[item] + QFixed::fromFixed(justifications[item].space_18d6)) * !attributes[item].dontPrint; }

    inline void clear(int first = 0, int last = -1) {

        if (last == -1)

            last = numGlyphs;

        if (first == 0 && last == numGlyphs

            && reinterpret_cast<char *>(offsets + numGlyphs) == reinterpret_cast<char *>(glyphs)) {

            memset(static_cast<void *>(offsets), 0, qsizetype(numGlyphs) * SpaceNeeded);

        } else {

            const int num = last - first;

            memset(static_cast<void *>(offsets + first), 0, num * sizeof(QFixedPoint));

            memset(glyphs + first, 0, num * sizeof(glyph_t));

            memset(static_cast<void *>(advances + first), 0, num * sizeof(QFixed));

            memset(static_cast<void *>(justifications + first), 0, num * sizeof(QGlyphJustification));

            memset(attributes + first, 0, num * sizeof(QGlyphAttributes));

        }

    }

    inline char *data() {

        return reinterpret_cast<char *>(offsets);

    }

    void copy(QGlyphLayout *other);

    void grow(char *address, int totalGlyphs);

};

class QVarLengthGlyphLayoutArray : private QVarLengthArray<void *>, public QGlyphLayout

{

private:

    typedef QVarLengthArray<void *> Array;

public:

    QVarLengthGlyphLayoutArray(int totalGlyphs)

        : Array((totalGlyphs * SpaceNeeded) / sizeof(void *) + 1)

        , QGlyphLayout(reinterpret_cast<char *>(Array::data()), totalGlyphs)

    {

        memset(Array::data(), 0, Array::size() * sizeof(void *));

    }

    void resize(int totalGlyphs)

    {

        Array::resize((totalGlyphs * SpaceNeeded) / sizeof(void *) + 1);

        *((QGlyphLayout *)this) = QGlyphLayout(reinterpret_cast<char *>(Array::data()), totalGlyphs);

        memset(Array::data(), 0, Array::size() * sizeof(void *));

    }

};

template <int N> struct QGlyphLayoutArray : public QGlyphLayout

{

public:

    QGlyphLayoutArray()

        : QGlyphLayout(reinterpret_cast<char *>(buffer), N)

    {

        memset(buffer, 0, sizeof(buffer));

    }

private:

    void *buffer[(N * SpaceNeeded) / sizeof(void *) + 1];

};

struct QScriptItem;

/// Internal QTextItem

class QTextItemInt : public QTextItem

{

public:

    inline QTextItemInt() = default;

    QTextItemInt(const QScriptItem &si, QFont *font, const QTextCharFormat &format = QTextCharFormat());

    QTextItemInt(const QGlyphLayout &g, QFont *font, const QChar *chars, int numChars, QFontEngine *fe,

                 const QTextCharFormat &format = QTextCharFormat());

    /// copy the structure items, adjusting the glyphs arrays to the right subarrays.

    /// the width of the returned QTextItemInt is not adjusted, for speed reasons

    QTextItemInt midItem(QFontEngine *fontEngine, int firstGlyphIndex, int numGlyphs) const;

    void initWithScriptItem(const QScriptItem &si);

    QFixed descent;

    QFixed ascent;

    QFixed width;

    RenderFlags flags;

    bool justified = false;

    QTextCharFormat::UnderlineStyle underlineStyle = QTextCharFormat::NoUnderline;

    const QTextCharFormat charFormat;

    int num_chars = 0;

    const QChar *chars = nullptr;

    const unsigned short *logClusters = nullptr;

    const QFont *f = nullptr;

    QGlyphLayout glyphs;

    QFontEngine *fontEngine = nullptr;

};

struct QScriptItem

{

    constexpr QScriptItem(int p, QScriptAnalysis a) noexcept

        : position(p), analysis(a),

          num_glyphs(0), descent(-1), ascent(-1), leading(-1), width(-1),

          glyph_data_offset(0) {}

    int position;

    QScriptAnalysis analysis;

    unsigned short num_glyphs;

    QFixed descent;

    QFixed ascent;

    QFixed leading;

    QFixed width;

    int glyph_data_offset;

    constexpr QFixed height() const noexcept { return ascent + descent; }

private:

    friend class QList<QScriptItem>;

    QScriptItem() {} // for QList, don't use

};

Q_DECLARE_TYPEINFO(QScriptItem, Q_PRIMITIVE_TYPE);

typedef QList<QScriptItem> QScriptItemArray;

struct Q_AUTOTEST_EXPORT QScriptLine

{

    // created and filled in QTextLine::layout_helper

    QScriptLine()

        : from(0), trailingSpaces(0), length(0),

        justified(0), gridfitted(0),

        hasTrailingSpaces(0), leadingIncluded(0) {}

    QFixed descent;

    QFixed ascent;

    QFixed leading;

    QFixed x;

    QFixed y;

    QFixed width;

    QFixed textWidth;

    QFixed textAdvance;

    int from;

    unsigned short trailingSpaces;

    signed int length : 28;

    mutable uint justified : 1;

    mutable uint gridfitted : 1;

    uint hasTrailingSpaces : 1;

    uint leadingIncluded : 1;

    QFixed height() const { return ascent + descent

                            + (leadingIncluded?  qMax(QFixed(),leading) : QFixed()); }

    QFixed base() const { return ascent; }

    void setDefaultHeight(QTextEngine *eng);

    void operator+=(const QScriptLine &other);

};

Q_DECLARE_TYPEINFO(QScriptLine, Q_PRIMITIVE_TYPE);

inline void QScriptLine::operator+=(const QScriptLine &other)

{

    leading= qMax(leading + ascent, other.leading + other.ascent) - qMax(ascent, other.ascent);

    descent = qMax(descent, other.descent);

    ascent = qMax(ascent, other.ascent);

    textWidth += other.textWidth;

    length += other.length;

}

typedef QList<QScriptLine> QScriptLineArray;

class QFontPrivate;

class QTextFormatCollection;

class Q_GUI_EXPORT QTextEngine {

public:

    enum LayoutState {

        LayoutEmpty,

        InLayout,

        LayoutFailed

    };

    struct Q_GUI_EXPORT LayoutData {

        LayoutData(const QString &str, void **stack_memory, qsizetype mem_size);

        LayoutData();

        ~LayoutData();

        mutable QScriptItemArray items;

        qsizetype allocated;

        qsizetype available_glyphs;

        void **memory;

        unsigned short *logClustersPtr;

        QGlyphLayout glyphLayout;

        mutable int used;

        uint hasBidi : 1;

        uint layoutState : 2;

        uint memory_on_stack : 1;

        uint haveCharAttributes : 1;

        QFixed currentMaxWidth;

        QString string;

        bool reallocate(int totalGlyphs);

    };

    struct ItemDecoration {

        ItemDecoration() { } // for QList, don't use

        ItemDecoration(qreal x1, qreal x2, qreal y, const QPen &pen):

            x1(x1), x2(x2), y(y), pen(pen) {}

        qreal x1;

        qreal x2;

        qreal y;

        QPen pen;

    };

    typedef QList<ItemDecoration> ItemDecorationList;

    QTextEngine();

    QTextEngine(const QString &str, const QFont &f);

    ~QTextEngine();

    enum Mode {

        WidthOnly = 0x07

    };

    void invalidate();

    void clearLineData();

    void validate() const;

    void itemize() const;

    bool isRightToLeft() const;

    static void bidiReorder(int numRuns, const quint8 *levels, int *visualOrder);

    const QCharAttributes *attributes() const;

    void shape(int item) const;

    void justify(const QScriptLine &si);

    QFixed alignLine(const QScriptLine &line);

    QFixed width(int charFrom, int numChars) const;

    glyph_metrics_t boundingBox(int from,  int len) const;

    glyph_metrics_t tightBoundingBox(int from,  int len) const;

    int length(int item) const {

        const QScriptItem &si = layoutData->items[item];

        int from = si.position;

        item++;

        return (item < layoutData->items.size() ? layoutData->items[item].position : layoutData->string.size()) - from;

    }

    int length(const QScriptItem *si) const {

        int end;

        if (si + 1 < layoutData->items.constData()+ layoutData->items.size())

            end = (si+1)->position;

        else

            end = layoutData->string.size();

        return end - si->position;

    }

    QFontEngine *fontEngine(const QScriptItem &si, QFixed *ascent = nullptr, QFixed *descent = nullptr, QFixed *leading = nullptr) const;

    QFont font(const QScriptItem &si) const;

    inline QFont font() const { return fnt; }

    /**

     * Returns a pointer to an array of log clusters, offset at the script item.

     * Each item in the array is a unsigned short.  For each character in the original string there is an entry in the table

     * so there is a one to one correlation in indexes between the original text and the index in the logcluster.

     * The value of each item is the position in the glyphs array. Multiple similar pointers in the logclusters array imply

     * that one glyph is used for more than one character.

     * \sa glyphs()

     */

    inline unsigned short *logClusters(const QScriptItem *si) const

        { return layoutData->logClustersPtr+si->position; }

    /**

     * Returns an array of QGlyphLayout items, offset at the script item.

     * Each item in the array matches one glyph in the text, storing the advance, position etc.

     * The returned item's length equals to the number of available glyphs. This may be more

     * than what was actually shaped.

     * \sa logClusters()

     */

    inline QGlyphLayout availableGlyphs(const QScriptItem *si) const {

        return layoutData->glyphLayout.mid(si->glyph_data_offset);

    }

    /**

     * Returns an array of QGlyphLayout items, offset at the script item.

     * Each item in the array matches one glyph in the text, storing the advance, position etc.

     * The returned item's length equals to the number of shaped glyphs.

     * \sa logClusters()

     */

    inline QGlyphLayout shapedGlyphs(const QScriptItem *si) const {

        return layoutData->glyphLayout.mid(si->glyph_data_offset, si->num_glyphs);

    }

    inline bool ensureSpace(int nGlyphs) const {

        if (layoutData->glyphLayout.numGlyphs - layoutData->used < nGlyphs)

            return layoutData->reallocate((((layoutData->used + nGlyphs)*3/2 + 15) >> 4) << 4);

        return true;

    }

    void freeMemory();

    int findItem(int strPos, int firstItem = 0) const;

    inline QTextFormatCollection *formatCollection() const {

        if (QTextDocumentPrivate::get(block) != nullptr)

            return const_cast<QTextFormatCollection *>(QTextDocumentPrivate::get(block)->formatCollection());

        return specialData ? specialData->formatCollection.data() : nullptr;

    }

    QTextCharFormat format(const QScriptItem *si) const;

    inline QAbstractTextDocumentLayout *docLayout() const {

        Q_ASSERT(QTextDocumentPrivate::get(block) != nullptr);

        return QTextDocumentPrivate::get(block)->document()->documentLayout();

    }

    int formatIndex(const QScriptItem *si) const;

    /// returns the width of tab at index (in the tabs array) with the tab-start at position x

    QFixed calculateTabWidth(int index, QFixed x) const;

    mutable QScriptLineArray lines;

private:

    struct FontEngineCache {

        FontEngineCache();

        mutable QFontEngine *prevFontEngine;

        mutable QFontEngine *prevScaledFontEngine;

        mutable int prevScript;

        mutable int prevPosition;

        mutable int prevLength;

        inline void reset() {

            prevFontEngine = nullptr;

            prevScaledFontEngine = nullptr;

            prevScript = -1;

            prevPosition = -1;

            prevLength = -1;

        }

    };

    mutable FontEngineCache feCache;

public:

    QString text;

    mutable QFont fnt;

#ifndef QT_NO_RAWFONT

    QRawFont rawFont;

#endif

    QTextBlock block;

    QTextOption option;

    QFixed minWidth;

    QFixed maxWidth;

    QPointF position;

    uint ignoreBidi : 1;

    uint cacheGlyphs : 1;

    uint stackEngine : 1;

    uint forceJustification : 1;

    uint visualMovement : 1;

    uint delayDecorations: 1;

#ifndef QT_NO_RAWFONT

    uint useRawFont : 1;

#endif

    mutable LayoutData *layoutData;

    ItemDecorationList underlineList;

    ItemDecorationList strikeOutList;

    ItemDecorationList overlineList;

    inline bool visualCursorMovement() const

    { return visualMovement || (QTextDocumentPrivate::get(block) != nullptr && QTextDocumentPrivate::get(block)->defaultCursorMoveStyle == Qt::VisualMoveStyle); }

    inline int preeditAreaPosition() const { return specialData ? specialData->preeditPosition : -1; }

    inline QString preeditAreaText() const { return specialData ? specialData->preeditText : QString(); }

    void setPreeditArea(int position, const QString &text);

    inline bool hasFormats() const

    { return QTextDocumentPrivate::get(block) != nullptr || (specialData && !specialData->formats.isEmpty()); }

    inline QList<QTextLayout::FormatRange> formats() const

    {

        return specialData ? specialData->formats : QList<QTextLayout::FormatRange>();

    }

    void setFormats(const QList<QTextLayout::FormatRange> &formats);

private:

    static void init(QTextEngine *e);

    struct SpecialData {

        int preeditPosition;

        QString preeditText;

        QList<QTextLayout::FormatRange> formats;

        QList<QTextCharFormat> resolvedFormats;

        // only used when no QTextDocumentPrivate is available

        QScopedPointer<QTextFormatCollection> formatCollection;

    };

    SpecialData *specialData;

    void indexFormats();

    void resolveFormats() const;

public:

    bool atWordSeparator(int position) const;

    QString elidedText(Qt::TextElideMode mode, QFixed width, int flags = 0, int from = 0, int count = -1) const;

    void shapeLine(const QScriptLine &line);

    QFixed leadingSpaceWidth(const QScriptLine &line);

    QFixed offsetInLigature(const QScriptItem *si, int pos, int max, int glyph_pos);

    int positionInLigature(const QScriptItem *si, int end, QFixed x, QFixed edge, int glyph_pos, bool cursorOnCharacter);

    int previousLogicalPosition(int oldPos) const;

    int nextLogicalPosition(int oldPos) const;

    int lineNumberForTextPosition(int pos);

    int positionAfterVisualMovement(int oldPos, QTextCursor::MoveOperation op);

    std::vector<int> insertionPointsForLine(int lineNum);

    void resetFontEngineCache();

    void enableDelayDecorations(bool enable = true) { delayDecorations = enable; }

    void addUnderline(QPainter *painter, const QLineF &line);

    void addStrikeOut(QPainter *painter, const QLineF &line);

    void addOverline(QPainter *painter, const QLineF &line);

    void drawDecorations(QPainter *painter);

    void clearDecorations();

    void adjustUnderlines();

private:

    void addItemDecoration(QPainter *painter, const QLineF &line, ItemDecorationList *decorationList);

    void adjustUnderlines(ItemDecorationList::iterator start,

                          ItemDecorationList::iterator end,

                          qreal underlinePos, qreal penWidth);

    void drawItemDecorationList(QPainter *painter, const ItemDecorationList &decorationList);

    void setBoundary(int strPos) const;

    void addRequiredBoundaries() const;

    void shapeText(int item) const;

#if QT_CONFIG(harfbuzz)

    int shapeTextWithHarfbuzzNG(const QScriptItem &si, const ushort *string, int stringBaseIndex,

                                int stringLength, int itemLength, QFontEngine *fontEngine,

                                QSpan<uint> itemBoundaries, bool kerningEnabled,

                                bool hasLetterSpacing,

                                const QMap<QFont::Tag, quint32> &features) const;

#endif

    int endOfLine(int lineNum);

    int beginningOfLine(int lineNum);

    int getClusterLength(unsigned short *logClusters, const QCharAttributes *attributes, int from, int to, int glyph_pos, int *start);

};

class Q_GUI_EXPORT QStackTextEngine : public QTextEngine {

public:

    enum { MemSize = 256*40/sizeof(void *) };

    QStackTextEngine(const QString &string, const QFont &f);

    LayoutData _layoutData;

    void *_memory[MemSize];

};

Q_DECLARE_TYPEINFO(QTextEngine::ItemDecoration, Q_RELOCATABLE_TYPE);

struct QTextLineItemIterator

{

    QTextLineItemIterator(QTextEngine *eng, int lineNum, const QPointF &pos = QPointF(),

                          const QTextLayout::FormatRange *_selection = nullptr);

    inline bool atEnd() const { return logicalItem >= nItems - 1; }

    inline bool atBeginning() const { return logicalItem <= 0; }

    QScriptItem &next();

    bool getSelectionBounds(QFixed *selectionX, QFixed *selectionWidth) const;

    inline bool isOutsideSelection() const {

        QFixed tmp1, tmp2;

        return !getSelectionBounds(&tmp1, &tmp2);

    }

    QTextEngine *eng;

    QFixed x;

    const QScriptLine &line;

    QScriptItem *si;

    const int lineNum;

    const int lineEnd;

    const int firstItem;

    const int lastItem;

    const int nItems;

    int logicalItem;

    int item;

    int itemLength;

    int glyphsStart;

    int glyphsEnd;

    int itemStart;

    int itemEnd;

    QFixed itemWidth;

    QVarLengthArray<int> visualOrder;

    const QTextLayout::FormatRange *selection;

};

QT_END_NAMESPACE

#endif // QTEXTENGINE_P_H