// Copyright (C) 2019 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

// Qt-Security score:critical reason:data-parser

#include "qtextmarkdownimporter_p.h"

#include "qtextdocumentfragment_p.h"

#include <QLoggingCategory>

#if QT_CONFIG(regularexpression)

#include <QRegularExpression>

#include <QRegularExpressionMatchIterator>

#endif

#include <QTextCursor>

#include <QTextDocument>

#include <QTextDocumentFragment>

#include <QTextList>

#include <QTextTable>

#if QT_CONFIG(system_textmarkdownreader)

#include <md4c.h>

#else

#include "../../3rdparty/md4c/md4c.h"

#endif

QT_BEGIN_NAMESPACE

using namespace Qt::StringLiterals;

Q_STATIC_LOGGING_CATEGORY(lcMD, "qt.text.markdown")

static const QChar qtmi_Newline = u'\n';

static const QChar qtmi_Space = u' ';

static constexpr auto lfMarkerString() noexcept { return "---\n"_L1; }

static constexpr auto crlfMarkerString() noexcept { return "---\r\n"_L1; }

// TODO maybe eliminate the margins after all views recognize BlockQuoteLevel, CSS can format it, etc.

static const int qtmi_BlockQuoteIndent =

        40; // pixels, same as in QTextHtmlParserNode::initializeProperties

static_assert(int(QTextMarkdownImporter::FeatureCollapseWhitespace) == MD_FLAG_COLLAPSEWHITESPACE);

static_assert(int(QTextMarkdownImporter::FeaturePermissiveATXHeaders) == MD_FLAG_PERMISSIVEATXHEADERS);

static_assert(int(QTextMarkdownImporter::FeaturePermissiveURLAutoLinks) == MD_FLAG_PERMISSIVEURLAUTOLINKS);

static_assert(int(QTextMarkdownImporter::FeaturePermissiveMailAutoLinks) == MD_FLAG_PERMISSIVEEMAILAUTOLINKS);

static_assert(int(QTextMarkdownImporter::FeatureNoIndentedCodeBlocks) == MD_FLAG_NOINDENTEDCODEBLOCKS);

static_assert(int(QTextMarkdownImporter::FeatureNoHTMLBlocks) == MD_FLAG_NOHTMLBLOCKS);

static_assert(int(QTextMarkdownImporter::FeatureNoHTMLSpans) == MD_FLAG_NOHTMLSPANS);

static_assert(int(QTextMarkdownImporter::FeatureTables) == MD_FLAG_TABLES);

static_assert(int(QTextMarkdownImporter::FeatureStrikeThrough) == MD_FLAG_STRIKETHROUGH);

static_assert(int(QTextMarkdownImporter::FeatureUnderline) == MD_FLAG_UNDERLINE);

static_assert(int(QTextMarkdownImporter::FeaturePermissiveWWWAutoLinks) == MD_FLAG_PERMISSIVEWWWAUTOLINKS);

static_assert(int(QTextMarkdownImporter::FeaturePermissiveAutoLinks) == MD_FLAG_PERMISSIVEAUTOLINKS);

static_assert(int(QTextMarkdownImporter::FeatureTasklists) == MD_FLAG_TASKLISTS);

static_assert(int(QTextMarkdownImporter::FeatureNoHTML) == MD_FLAG_NOHTML);

static_assert(int(QTextMarkdownImporter::DialectCommonMark) == MD_DIALECT_COMMONMARK);

static_assert(int(QTextMarkdownImporter::DialectGitHub) ==

              (MD_DIALECT_GITHUB | MD_FLAG_UNDERLINE | QTextMarkdownImporter::FeatureFrontMatter));

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

// MD4C callback function wrappers

static int CbEnterBlock(MD_BLOCKTYPE type, void *detail, void *userdata)

{

    QTextMarkdownImporter *mdi = static_cast<QTextMarkdownImporter *>(userdata);

    return mdi->cbEnterBlock(int(type), detail);

}

static int CbLeaveBlock(MD_BLOCKTYPE type, void *detail, void *userdata)

{

    QTextMarkdownImporter *mdi = static_cast<QTextMarkdownImporter *>(userdata);

    return mdi->cbLeaveBlock(int(type), detail);

}

static int CbEnterSpan(MD_SPANTYPE type, void *detail, void *userdata)

{

    QTextMarkdownImporter *mdi = static_cast<QTextMarkdownImporter *>(userdata);

    return mdi->cbEnterSpan(int(type), detail);

}

static int CbLeaveSpan(MD_SPANTYPE type, void *detail, void *userdata)

{

    QTextMarkdownImporter *mdi = static_cast<QTextMarkdownImporter *>(userdata);

    return mdi->cbLeaveSpan(int(type), detail);

}

static int CbText(MD_TEXTTYPE type, const MD_CHAR *text, MD_SIZE size, void *userdata)

{

    QTextMarkdownImporter *mdi = static_cast<QTextMarkdownImporter *>(userdata);

    return mdi->cbText(int(type), text, size);

}

static void CbDebugLog(const char *msg, void *userdata)

{

    Q_UNUSED(userdata);

    qCDebug(lcMD) << msg;

}

// MD4C callback function wrappers

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

static Qt::Alignment MdAlignment(MD_ALIGN a, Qt::Alignment defaultAlignment = Qt::AlignLeft | Qt::AlignVCenter)

{

    switch (a) {

    case MD_ALIGN_LEFT:

        return Qt::AlignLeft | Qt::AlignVCenter;

    case MD_ALIGN_CENTER:

        return Qt::AlignHCenter | Qt::AlignVCenter;

    case MD_ALIGN_RIGHT:

        return Qt::AlignRight | Qt::AlignVCenter;

    default: // including MD_ALIGN_DEFAULT

        return defaultAlignment;

    }

}

QTextMarkdownImporter::QTextMarkdownImporter(QTextDocument *doc, QTextMarkdownImporter::Features features)

  : m_cursor(doc)

  , m_monoFont(QFontDatabase::systemFont(QFontDatabase::FixedFont))

  , m_features(features)

{

}

QTextMarkdownImporter::QTextMarkdownImporter(QTextDocument *doc, QTextDocument::MarkdownFeatures features)

  : QTextMarkdownImporter(doc, static_cast<QTextMarkdownImporter::Features>(int(features)))

{

}

/*! \internal

    Split any Front Matter from the Markdown document \a md.

    Returns a pair of QStringViews: if \a md begins with qualifying Front Matter

    (according to the specification at https://jekyllrb.com/docs/front-matter/ ),

    put it into the \c frontMatter view, omitting both markers; and put the remaining

    Markdown into \c rest. If no Front Matter is found, return all of \a md in \c rest.

*/

static auto splitFrontMatter(QStringView md)

{

    struct R {

        QStringView frontMatter, rest;

        explicit operator bool() const noexcept { return !frontMatter.isEmpty(); }

    };

    const auto NotFound = R{{}, md};

    /*  Front Matter must start with '---\n' or '---\r\n' on the very first line,

        and Front Matter must end with another such line.

        If that is not the case, we return NotFound: then the whole document is

        to be passed on to the Markdown parser, in which '---\n' is interpreted

        as a "thematic break" (like <hr/> in HTML). */

    QLatin1StringView marker;

    if (md.startsWith(lfMarkerString()))

        marker = lfMarkerString();

    else if (md.startsWith(crlfMarkerString()))

        marker = crlfMarkerString();

    else

        return NotFound;

    const auto frontMatterStart = marker.size();

    const auto endMarkerPos = md.indexOf(marker, frontMatterStart);

    if (endMarkerPos < 0 || md[endMarkerPos - 1] != QChar::LineFeed)

        return NotFound;

    Q_ASSERT(frontMatterStart < md.size());

    Q_ASSERT(endMarkerPos < md.size());

    const auto frontMatter = md.sliced(frontMatterStart, endMarkerPos - frontMatterStart);

    return R{frontMatter, md.sliced(endMarkerPos + marker.size())};

}

void QTextMarkdownImporter::import(const QString &markdown)

{

    MD_PARSER callbacks = {

        0, // abi_version

        unsigned(m_features),

        &CbEnterBlock,

        &CbLeaveBlock,

        &CbEnterSpan,

        &CbLeaveSpan,

        &CbText,

        &CbDebugLog,

        nullptr // syntax

    };

    QTextDocument *doc = m_cursor.document();

    const auto defaultFont = doc->defaultFont();

    m_paragraphMargin = defaultFont.pointSize() * 2 / 3;

    doc->clear();

    if (defaultFont.pointSize() != -1)

        m_monoFont.setPointSize(defaultFont.pointSize());

    else

        m_monoFont.setPixelSize(defaultFont.pixelSize());

    qCDebug(lcMD) << "default font" << defaultFont << "mono font" << m_monoFont;

    QStringView md = markdown;

    if (m_features.testFlag(QTextMarkdownImporter::FeatureFrontMatter)) {

        if (const auto split = splitFrontMatter(md)) {

            doc->setMetaInformation(QTextDocument::FrontMatter, split.frontMatter.toString());

            qCDebug(lcMD) << "extracted FrontMatter: size" << split.frontMatter.size();

            md = split.rest;

        }

    }

    const auto mdUtf8 = md.toUtf8();

    m_cursor.beginEditBlock();

    md_parse(mdUtf8.constData(), MD_SIZE(mdUtf8.size()), &callbacks, this);

    m_cursor.endEditBlock();

}

int QTextMarkdownImporter::cbEnterBlock(int blockType, void *det)

{

    m_blockType = blockType;

    switch (blockType) {

    case MD_BLOCK_P:

        if (!m_listStack.isEmpty())

            qCDebug(lcMD, m_listItem ? "P of LI at level %d"  : "P continuation inside LI at level %d", int(m_listStack.size()));

        else

            qCDebug(lcMD, "P");

        m_needsInsertBlock = true;

        break;

    case MD_BLOCK_QUOTE:

        ++m_blockQuoteDepth;

        qCDebug(lcMD, "QUOTE level %d", m_blockQuoteDepth);

        break;

    case MD_BLOCK_CODE: {

        MD_BLOCK_CODE_DETAIL *detail = static_cast<MD_BLOCK_CODE_DETAIL *>(det);

        m_codeBlock = true;

        m_blockCodeLanguage = QLatin1StringView(detail->lang.text, int(detail->lang.size));

        m_blockCodeFence = detail->fence_char;

        QString info = QLatin1StringView(detail->info.text, int(detail->info.size));

        m_needsInsertBlock = true;

        if (m_blockQuoteDepth)

            qCDebug(lcMD, "CODE lang '%s' info '%s' fenced with '%c' inside QUOTE %d", qPrintable(m_blockCodeLanguage), qPrintable(info), m_blockCodeFence, m_blockQuoteDepth);

        else

            qCDebug(lcMD, "CODE lang '%s' info '%s' fenced with '%c'", qPrintable(m_blockCodeLanguage), qPrintable(info), m_blockCodeFence);

    } break;

    case MD_BLOCK_H: {

        MD_BLOCK_H_DETAIL *detail = static_cast<MD_BLOCK_H_DETAIL *>(det);

        QTextBlockFormat blockFmt;

        QTextCharFormat charFmt;

        int sizeAdjustment = 4 - int(detail->level); // H1 to H6: +3 to -2

        charFmt.setProperty(QTextFormat::FontSizeAdjustment, sizeAdjustment);

        charFmt.setFontWeight(QFont::Bold);

        blockFmt.setHeadingLevel(int(detail->level));

        m_needsInsertBlock = false;

        if (m_cursor.document()->isEmpty()) {

            m_cursor.setBlockFormat(blockFmt);

            m_cursor.setCharFormat(charFmt);

        } else {

            m_cursor.insertBlock(blockFmt, charFmt);

        }

        qCDebug(lcMD, "H%d", detail->level);

    } break;

    case MD_BLOCK_LI: {

        m_needsInsertBlock = true;

        m_listItem = true;

        MD_BLOCK_LI_DETAIL *detail = static_cast<MD_BLOCK_LI_DETAIL *>(det);

        m_markerType = detail->is_task ?

                    (detail->task_mark == ' ' ? QTextBlockFormat::MarkerType::Unchecked : QTextBlockFormat::MarkerType::Checked) :

                    QTextBlockFormat::MarkerType::NoMarker;

        qCDebug(lcMD) << "LI";

    } break;

    case MD_BLOCK_UL: {

        if (m_needsInsertList) // list nested in an empty list

            m_listStack.push(m_cursor.insertList(m_listFormat));

        else

            m_needsInsertList = true;

        MD_BLOCK_UL_DETAIL *detail = static_cast<MD_BLOCK_UL_DETAIL *>(det);

        m_listFormat = QTextListFormat();

        m_listFormat.setIndent(m_listStack.size() + 1);

        switch (detail->mark) {

        case '*':

            m_listFormat.setStyle(QTextListFormat::ListCircle);

            break;

        case '+':

            m_listFormat.setStyle(QTextListFormat::ListSquare);

            break;

        default: // including '-'

            m_listFormat.setStyle(QTextListFormat::ListDisc);

            break;

        }

        qCDebug(lcMD, "UL %c level %d", detail->mark, int(m_listStack.size()) + 1);

    } break;

    case MD_BLOCK_OL: {

        if (m_needsInsertList) // list nested in an empty list

            m_listStack.push(m_cursor.insertList(m_listFormat));

        else

            m_needsInsertList = true;

        MD_BLOCK_OL_DETAIL *detail = static_cast<MD_BLOCK_OL_DETAIL *>(det);

        m_listFormat = QTextListFormat();

        m_listFormat.setIndent(m_listStack.size() + 1);

        m_listFormat.setNumberSuffix(QChar::fromLatin1(detail->mark_delimiter));

        m_listFormat.setStyle(QTextListFormat::ListDecimal);

        m_listFormat.setStart(detail->start);

        qCDebug(lcMD, "OL xx%d level %d start %d", detail->mark_delimiter, int(m_listStack.size()) + 1, detail->start);

    } break;

    case MD_BLOCK_TD: {

        MD_BLOCK_TD_DETAIL *detail = static_cast<MD_BLOCK_TD_DETAIL *>(det);

        ++m_tableCol;

        // absolute movement (and storage of m_tableCol) shouldn't be necessary, but

        // movePosition(QTextCursor::NextCell) doesn't work

        QTextTableCell cell = m_currentTable->cellAt(m_tableRowCount - 1, m_tableCol);

        if (!cell.isValid()) {

            qWarning("malformed table in Markdown input");

            return 1;

        }

        m_cursor = cell.firstCursorPosition();

        QTextBlockFormat blockFmt = m_cursor.blockFormat();

        blockFmt.setAlignment(MdAlignment(detail->align));

        m_cursor.setBlockFormat(blockFmt);

        qCDebug(lcMD) << "TD; align" << detail->align << MdAlignment(detail->align) << "col" << m_tableCol;

    } break;

    case MD_BLOCK_TH: {

        ++m_tableColumnCount;

        ++m_tableCol;

        if (m_currentTable->columns() < m_tableColumnCount)

            m_currentTable->appendColumns(1);

        auto cell = m_currentTable->cellAt(m_tableRowCount - 1, m_tableCol);

        if (!cell.isValid()) {

            qWarning("malformed table in Markdown input");

            return 1;

        }

        auto fmt = cell.format();

        fmt.setFontWeight(QFont::Bold);

        cell.setFormat(fmt);

    } break;

    case MD_BLOCK_TR: {

        ++m_tableRowCount;

        m_nonEmptyTableCells.clear();

        if (m_currentTable->rows() < m_tableRowCount)

            m_currentTable->appendRows(1);

        m_tableCol = -1;

        qCDebug(lcMD) << "TR" << m_currentTable->rows();

    } break;

    case MD_BLOCK_TABLE:

        m_tableColumnCount = 0;

        m_tableRowCount = 0;

        m_currentTable = m_cursor.insertTable(1, 1); // we don't know the dimensions yet

        break;

    case MD_BLOCK_HR: {

        qCDebug(lcMD, "HR");

        QTextBlockFormat blockFmt;

        blockFmt.setProperty(QTextFormat::BlockTrailingHorizontalRulerWidth, 1);

        m_cursor.insertBlock(blockFmt, QTextCharFormat());

    } break;

    default:

        break; // nothing to do for now

    }

    return 0; // no error

}

int QTextMarkdownImporter::cbLeaveBlock(int blockType, void *detail)

{

    Q_UNUSED(detail);

    switch (blockType) {

    case MD_BLOCK_P:

        m_listItem = false;

        break;

    case MD_BLOCK_UL:

    case MD_BLOCK_OL:

        if (Q_UNLIKELY(m_needsInsertList))

            m_listStack.push(m_cursor.createList(m_listFormat));

        if (Q_UNLIKELY(m_listStack.isEmpty())) {

            qCWarning(lcMD, "list ended unexpectedly");

        } else {

            qCDebug(lcMD, "list at level %d ended", int(m_listStack.size()));

            m_listStack.pop();

        }

        break;

    case MD_BLOCK_TR: {

        // https://github.com/mity/md4c/issues/29

        // MD4C doesn't tell us explicitly which cells are merged, so merge empty cells

        // with previous non-empty ones

        int mergeEnd = -1;

        int mergeBegin = -1;

        for (int col = m_tableCol; col >= 0; --col) {

            if (m_nonEmptyTableCells.contains(col)) {

                if (mergeEnd >= 0 && mergeBegin >= 0) {

                    qCDebug(lcMD) << "merging cells" << mergeBegin << "to" << mergeEnd << "inclusive, on row" << m_currentTable->rows() - 1;

                    m_currentTable->mergeCells(m_currentTable->rows() - 1, mergeBegin - 1, 1, mergeEnd - mergeBegin + 2);

                }

                mergeEnd = -1;

                mergeBegin = -1;

            } else {

                if (mergeEnd < 0)

                    mergeEnd = col;

                else

                    mergeBegin = col;

            }

        }

    } break;

    case MD_BLOCK_QUOTE: {

        qCDebug(lcMD, "QUOTE level %d ended", m_blockQuoteDepth);

        --m_blockQuoteDepth;

        m_needsInsertBlock = true;

    } break;

    case MD_BLOCK_TABLE:

        qCDebug(lcMD) << "table ended with" << m_currentTable->columns() << "cols and" << m_currentTable->rows() << "rows";

        m_currentTable = nullptr;

        m_cursor.movePosition(QTextCursor::End);

        break;

    case MD_BLOCK_LI:

        qCDebug(lcMD, "LI at level %d ended", int(m_listStack.size()));

        m_listItem = false;

        break;

    case MD_BLOCK_CODE: {

        m_codeBlock = false;

        m_blockCodeLanguage.clear();

        m_blockCodeFence = 0;

        if (m_blockQuoteDepth)

            qCDebug(lcMD, "CODE ended inside QUOTE %d", m_blockQuoteDepth);

        else

            qCDebug(lcMD, "CODE ended");

        m_needsInsertBlock = true;

    } break;

    case MD_BLOCK_H:

        m_cursor.setCharFormat(QTextCharFormat());

        break;

    default:

        break;

    }

    return 0; // no error

}

int QTextMarkdownImporter::cbEnterSpan(int spanType, void *det)

{

    QTextCharFormat charFmt;

    if (!m_spanFormatStack.isEmpty())

        charFmt = m_spanFormatStack.top();

    switch (spanType) {

    case MD_SPAN_EM:

        charFmt.setFontItalic(true);

        break;

    case MD_SPAN_STRONG:

        charFmt.setFontWeight(QFont::Bold);

        break;

    case MD_SPAN_U:

        charFmt.setFontUnderline(true);

        break;

    case MD_SPAN_A: {

        MD_SPAN_A_DETAIL *detail = static_cast<MD_SPAN_A_DETAIL *>(det);

        QString url = QString::fromUtf8(detail->href.text, int(detail->href.size));

        QString title = QString::fromUtf8(detail->title.text, int(detail->title.size));

        charFmt.setAnchor(true);

        charFmt.setAnchorHref(url);

        if (!title.isEmpty())

            charFmt.setToolTip(title);

        charFmt.setForeground(m_palette.link());

        qCDebug(lcMD) << "anchor" << url << title;

        } break;

    case MD_SPAN_IMG: {

        m_imageSpan = true;

        m_imageFormat = QTextImageFormat();

        MD_SPAN_IMG_DETAIL *detail = static_cast<MD_SPAN_IMG_DETAIL *>(det);

        m_imageFormat.setName(QString::fromUtf8(detail->src.text, int(detail->src.size)));

        m_imageFormat.setProperty(QTextFormat::ImageTitle, QString::fromUtf8(detail->title.text, int(detail->title.size)));

        break;

    }

    case MD_SPAN_CODE:

        charFmt.setFont(m_monoFont);

        charFmt.setFontFixedPitch(true);

        break;

    case MD_SPAN_DEL:

        charFmt.setFontStrikeOut(true);

        break;

    }

    m_spanFormatStack.push(charFmt);

    qCDebug(lcMD) << spanType << "setCharFormat" << charFmt.font().family()

                  << charFmt.fontWeight() << (charFmt.fontItalic() ? "italic" : "")

                  << charFmt.foreground().color().name();

    m_cursor.setCharFormat(charFmt);

    return 0; // no error

}

int QTextMarkdownImporter::cbLeaveSpan(int spanType, void *detail)

{

    Q_UNUSED(detail);

    QTextCharFormat charFmt;

    if (!m_spanFormatStack.isEmpty()) {

        m_spanFormatStack.pop();

        if (!m_spanFormatStack.isEmpty())

            charFmt = m_spanFormatStack.top();

    }

    m_cursor.setCharFormat(charFmt);

    qCDebug(lcMD) << spanType << "setCharFormat" << charFmt.font().family()

                  << charFmt.fontWeight() << (charFmt.fontItalic() ? "italic" : "")

                  << charFmt.foreground().color().name();

    if (spanType == int(MD_SPAN_IMG))

        m_imageSpan = false;

    return 0; // no error

}

int QTextMarkdownImporter::cbText(int textType, const char *text, unsigned size)

{

    if (m_needsInsertBlock)

        insertBlock();

#if QT_CONFIG(regularexpression)

    static const QRegularExpression openingBracket(QStringLiteral("<[a-zA-Z]"));

    static const QRegularExpression closingBracket(QStringLiteral("(/>|</)"));

#endif

    QString s = QString::fromUtf8(text, int(size));

    switch (textType) {

    case MD_TEXT_NORMAL:

#if QT_CONFIG(regularexpression)

        if (m_htmlTagDepth) {

            m_htmlAccumulator += s;

            s = QString();

        }

#endif

        break;

    case MD_TEXT_NULLCHAR:

        s = QString(QChar(u'\xFFFD')); // CommonMark-required replacement for null

        break;

    case MD_TEXT_BR:

        s = QString(qtmi_Newline);

        break;

    case MD_TEXT_SOFTBR:

        s = QString(qtmi_Space);

        break;

    case MD_TEXT_CODE:

        // We'll see MD_SPAN_CODE too, which will set the char format, and that's enough.

        break;

#if QT_CONFIG(texthtmlparser)

    case MD_TEXT_ENTITY:

        if (m_htmlTagDepth)

            m_htmlAccumulator += s;

        else

            m_cursor.insertHtml(s);

        s = QString();

        break;

#endif

    case MD_TEXT_HTML:

        // count how many tags are opened and how many are closed

#if QT_CONFIG(regularexpression) && QT_CONFIG(texthtmlparser)

        {

            QRegularExpressionMatchIterator i = openingBracket.globalMatch(s);

            while (i.hasNext()) {

                ++m_htmlTagDepth;

                i.next();

            }

            i = closingBracket.globalMatch(s);

            while (i.hasNext()) {

                --m_htmlTagDepth;

                i.next();

            }

        }

        m_htmlAccumulator += s;

        if (!m_htmlTagDepth) { // all open tags are now closed

            qCDebug(lcMD) << "HTML" << m_htmlAccumulator;

            m_cursor.insertHtml(m_htmlAccumulator);

            if (m_spanFormatStack.isEmpty())

                m_cursor.setCharFormat(QTextCharFormat());

            else

                m_cursor.setCharFormat(m_spanFormatStack.top());

            m_htmlAccumulator = QString();

        }

#endif

        s = QString();

        break;

    }

    switch (m_blockType) {

    case MD_BLOCK_TD:

        m_nonEmptyTableCells.append(m_tableCol);

        break;

    case MD_BLOCK_CODE:

        if (s == qtmi_Newline) {

            // defer a blank line until we see something else in the code block,

            // to avoid ending every code block with a gratuitous blank line

            m_needsInsertBlock = true;

            s = QString();

        }

        break;

    default:

        break;

    }

    if (m_imageSpan) {

        // TODO we don't yet support alt text with formatting, because of the cases where m_cursor

        // already inserted the text above.  Rather need to accumulate it in case we need it here.

        m_imageFormat.setProperty(QTextFormat::ImageAltText, s);

        qCDebug(lcMD) << "image" << m_imageFormat.name()

                      << "title" << m_imageFormat.stringProperty(QTextFormat::ImageTitle)

                      << "alt" << s << "relative to" << m_cursor.document()->baseUrl();

        m_cursor.insertImage(m_imageFormat);

        return 0; // no error

    }

    if (!s.isEmpty())

        m_cursor.insertText(s);

    if (m_cursor.currentList()) {

        // The list item will indent the list item's text, so we don't need indentation on the block.

        QTextBlockFormat bfmt = m_cursor.blockFormat();

        bfmt.setIndent(0);

        m_cursor.setBlockFormat(bfmt);

    }

    if (lcMD().isEnabled(QtDebugMsg)) {

        QTextBlockFormat bfmt = m_cursor.blockFormat();

        QString debugInfo;

        if (m_cursor.currentList())

            debugInfo = "in list at depth "_L1 + QString::number(m_cursor.currentList()->format().indent());

        if (bfmt.hasProperty(QTextFormat::BlockQuoteLevel))

            debugInfo += "in blockquote at depth "_L1 +

                    QString::number(bfmt.intProperty(QTextFormat::BlockQuoteLevel));

        if (bfmt.hasProperty(QTextFormat::BlockCodeLanguage))

            debugInfo += "in a code block"_L1;

        qCDebug(lcMD) << textType << "in block" << m_blockType << s << qPrintable(debugInfo)

                      << "bindent" << bfmt.indent() << "tindent" << bfmt.textIndent()

                      << "margins" << bfmt.leftMargin() << bfmt.topMargin() << bfmt.bottomMargin() << bfmt.rightMargin();

    }

    return 0; // no error

}

/*!

    Insert a new block based on stored state.

    m_cursor cannot store the state for the _next_ block ahead of time, because

    m_cursor.setBlockFormat() controls the format of the block that the cursor

    is already in; so cbLeaveBlock() cannot call setBlockFormat() without

    altering the block that was just added. Therefore cbLeaveBlock() and the

    following cbEnterBlock() set variables to remember what formatting should

    come next, and insertBlock() is called just before the actual text

    insertion, to create a new block with the right formatting.

*/

void QTextMarkdownImporter::insertBlock()

{

    QTextCharFormat charFormat;

    if (!m_spanFormatStack.isEmpty())

        charFormat = m_spanFormatStack.top();

    QTextBlockFormat blockFormat;

    if (!m_listStack.isEmpty() && !m_needsInsertList && m_listItem) {

        QTextList *list = m_listStack.top();

        if (list)

            blockFormat = list->item(list->count() - 1).blockFormat();

        else

            qWarning() << "attempted to insert into a list that no longer exists";

    }

    if (m_blockQuoteDepth) {

        blockFormat.setProperty(QTextFormat::BlockQuoteLevel, m_blockQuoteDepth);

        blockFormat.setLeftMargin(qtmi_BlockQuoteIndent * m_blockQuoteDepth);

        blockFormat.setRightMargin(qtmi_BlockQuoteIndent);

    }

    if (m_codeBlock) {

        blockFormat.setProperty(QTextFormat::BlockCodeLanguage, m_blockCodeLanguage);

        if (m_blockCodeFence) {

            blockFormat.setNonBreakableLines(true);

            blockFormat.setProperty(QTextFormat::BlockCodeFence, QString(QLatin1Char(m_blockCodeFence)));

        }

        charFormat.setFont(m_monoFont);

    } else {

        blockFormat.setTopMargin(m_paragraphMargin);

        blockFormat.setBottomMargin(m_paragraphMargin);

    }

    if (m_markerType == QTextBlockFormat::MarkerType::NoMarker)

        blockFormat.clearProperty(QTextFormat::BlockMarker);

    else

        blockFormat.setMarker(m_markerType);

    if (!m_listStack.isEmpty())

        blockFormat.setIndent(m_listStack.size());

    if (m_cursor.document()->isEmpty()) {

        m_cursor.setBlockFormat(blockFormat);

        m_cursor.setCharFormat(charFormat);

    } else if (m_listItem) {

        m_cursor.insertBlock(blockFormat, QTextCharFormat());

        m_cursor.setCharFormat(charFormat);

    } else {

        m_cursor.insertBlock(blockFormat, charFormat);

    }

    if (m_needsInsertList) {

        m_listStack.push(m_cursor.createList(m_listFormat));

    } else if (!m_listStack.isEmpty() && m_listItem && m_listStack.top()) {

        m_listStack.top()->add(m_cursor.block());

    }

    m_needsInsertList = false;

    m_needsInsertBlock = false;

}

QT_END_NAMESPACE