/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the tools applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL-EXCEPT$
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** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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****************************************************************************/

#include <qfileinfo.h>
#include <qregexp.h>
#include <qdebug.h>

#include "quoter.h"

QT_BEGIN_NAMESPACE

QHash<QString,QString> Quoter::commentHash;

static void replaceMultipleNewlines(QString &s)
{
    const int n = s.size();
    bool slurping = false;
    int j = -1;
    const QChar newLine = QLatin1Char('\n');
    QChar *d = s.data();
    for (int i = 0; i != n; ++i) {
        const QChar c = d[i];
        bool hit = (c == newLine);
        if (slurping && hit)
            continue;
        d[++j] = c;
        slurping = hit;
    }
    s.resize(++j);
}

// This is equivalent to  line.split( QRegExp("\n(?!\n|$)") ) but much faster
QStringList Quoter::splitLines(const QString &line)
{
    QStringList result;
    int i = line.size();
    while (true) {
        int j = i - 1;
        while (j >= 0 && line.at(j) == QLatin1Char('\n'))
            --j;
        while (j >= 0 && line.at(j) != QLatin1Char('\n'))
            --j;
        result.prepend(line.mid(j + 1, i - j - 1));
        if (j < 0)
            break;
        i = j;
    }
    return result;
}

/*
  Transforms 'int x = 3 + 4' into 'int x=3+4'. A white space is kept
  between 'int' and 'x' because it is meaningful in C++.
*/
static void trimWhiteSpace( QString& str )
{
    enum { Normal, MetAlnum, MetSpace } state = Normal;
    const int n = str.length();

    int j = -1;
    QChar *d = str.data();
    for ( int i = 0; i != n; ++i ) {
        const QChar c = d[i];
        if ( c.isLetterOrNumber() ) {
            if ( state == Normal ) {
                state = MetAlnum;
            } else {
                if ( state == MetSpace )
                    str[++j] = c;
                state = Normal;
            }
            str[++j] = c;
        } else if ( c.isSpace() ) {
            if ( state == MetAlnum )
                state = MetSpace;
        } else {
            state = Normal;
            str[++j] = c;
        }
    }
    str.resize(++j);
}

Quoter::Quoter()
    : silent( false )
{
    /* We're going to hard code these delimiters:
        * C++, Qt, Qt Script, Java:
          //! [<id>]
        * .pro, .py files:
          #! [<id>]
        * .html, .qrc, .ui, .xq, .xml .dita files:
          <!-- [<id>] -->
    */
    if (!commentHash.size()) {
        commentHash["pro"] = "#!";
        commentHash["py"] = "#!";
        commentHash["html"] = "<!--";
        commentHash["qrc"] = "<!--";
        commentHash["ui"] = "<!--";
        commentHash["xml"] = "<!--";
        commentHash["dita"] = "<!--";
        commentHash["xq"] = "<!--";
    }
}

void Quoter::reset()
{
    silent = false;
    plainLines.clear();
    markedLines.clear();
    codeLocation = Location::null;
}

void Quoter::quoteFromFile( const QString& userFriendlyFilePath,
                            const QString& plainCode,
                            const QString& markedCode )
{
    silent = false;

    /*
      Split the source code into logical lines. Empty lines are
      treated specially. Before:

   p->alpha();
   p->beta();

   p->gamma();


   p->delta();

      After:

   p->alpha();
   p->beta();\n
   p->gamma();\n\n
   p->delta();

      Newlines are preserved because they affect codeLocation.
    */
    codeLocation = Location( userFriendlyFilePath );

    plainLines = splitLines(plainCode);
    markedLines = splitLines(markedCode);
    if (markedLines.count() != plainLines.count()) {
        codeLocation.warning(tr("Something is wrong with qdoc's handling of marked code"));
        markedLines = plainLines;
    }

    /*
      Squeeze blanks (cat -s).
    */
    QStringList::Iterator m = markedLines.begin();
    while ( m != markedLines.end() ) {
        replaceMultipleNewlines( *m );
        ++m;
    }
    codeLocation.start();
}

QString Quoter::quoteLine( const Location& docLocation, const QString& command,
                           const QString& pattern )
{
    if ( plainLines.isEmpty() ) {
        failedAtEnd( docLocation, command );
        return QString();
    }

    if ( pattern.isEmpty() ) {
        docLocation.warning( tr("Missing pattern after '\\%1'").arg(command) );
        return QString();
    }

    if ( match(docLocation, pattern, plainLines.first()) )
        return getLine();

    if ( !silent ) {
        docLocation.warning( tr("Command '\\%1' failed").arg(command) );
        codeLocation.warning( tr("Pattern '%1' didn't match here")
                              .arg(pattern) );
        silent = true;
    }
    return QString();
}

QString Quoter::quoteSnippet(const Location &docLocation, const QString &identifier)
{
    QString comment = commentForCode();
    QString delimiter = comment + QString(" [%1]").arg(identifier);
    QString t;
    int indent = 0;

    while (!plainLines.isEmpty()) {
        if (match(docLocation, delimiter, plainLines.first())) {
            QString startLine = getLine();
            while (indent < startLine.length() && startLine[indent] == QLatin1Char(' '))
                indent++;
            break;
        }
        getLine();
    }
    while (!plainLines.isEmpty()) {
        QString line = plainLines.first();
        if (match(docLocation, delimiter, line)) {
            QString lastLine = getLine(indent);
            int dIndex = lastLine.indexOf(delimiter);
            if (dIndex > 0) {
                // The delimiter might be preceded on the line by other
                // delimeters, so look for the first comment on the line.
                QString leading = lastLine.left(dIndex);
                dIndex = leading.indexOf(comment);
                if (dIndex != -1)
                    leading = leading.left(dIndex);
                if (leading.endsWith(QLatin1String("<@comment>")))
                    leading.chop(10);
                if (!leading.trimmed().isEmpty())
                    t += leading;
            }
            return t;
        }

        t += removeSpecialLines(line, comment, indent);
    }
    failedAtEnd(docLocation, QString("snippet (%1)").arg(delimiter));
    return t;
}

QString Quoter::quoteTo( const Location& docLocation, const QString& command,
                         const QString& pattern )
{
    QString t;
    QString comment = commentForCode();

    if ( pattern.isEmpty() ) {
        while ( !plainLines.isEmpty() ) {
            QString line = plainLines.first();
            t += removeSpecialLines(line, comment);
        }
    } else {
        while ( !plainLines.isEmpty() ) {
            if ( match(docLocation, pattern, plainLines.first()) ) {
                return t;
            }
            t += getLine();
        }
        failedAtEnd( docLocation, command );
    }
    return t;
}

QString Quoter::quoteUntil( const Location& docLocation, const QString& command,
                            const QString& pattern )
{
    QString t = quoteTo( docLocation, command, pattern );
    t += getLine();
    return t;
}

QString Quoter::getLine(int unindent)
{
    if ( plainLines.isEmpty() )
        return QString();

    plainLines.removeFirst();

    QString t = markedLines.takeFirst();
    int i = 0;
    while (i < unindent && i < t.length() && t[i] == QLatin1Char(' '))
        i++;

    t = t.mid(i);
    t += QLatin1Char('\n');
    codeLocation.advanceLines( t.count( QLatin1Char('\n') ) );
    return t;
}

bool Quoter::match( const Location& docLocation, const QString& pattern0,
                    const QString& line )
{
    QString str = line;
    while ( str.endsWith(QLatin1Char('\n')) )
        str.truncate( str.length() - 1 );

    QString pattern = pattern0;
    if ( pattern.startsWith(QLatin1Char('/'))
         && pattern.endsWith(QLatin1Char('/'))
         && pattern.length() > 2 ) {
        QRegExp rx( pattern.mid(1, pattern.length() - 2) );
        if ( !silent && !rx.isValid() ) {
            docLocation.warning( tr("Invalid regular expression '%1'")
                                 .arg(rx.pattern()) );
            silent = true;
        }
        return str.indexOf( rx ) != -1;
    }
    trimWhiteSpace(str);
    trimWhiteSpace(pattern);
    return str.indexOf(pattern) != -1;
}

void Quoter::failedAtEnd( const Location& docLocation, const QString& command )
{
    if (!silent && !command.isEmpty()) {
        if ( codeLocation.filePath().isEmpty() ) {
            docLocation.warning( tr("Unexpected '\\%1'").arg(command) );
        } else {
            docLocation.warning( tr("Command '\\%1' failed at end of file '%2'")
                                 .arg(command).arg(codeLocation.filePath()) );
        }
        silent = true;
    }
}

QString Quoter::commentForCode() const
{
    QString suffix = QFileInfo(codeLocation.fileName()).suffix();
    return commentHash.value(suffix, "//!");
}

QString Quoter::removeSpecialLines(const QString &line, const QString &comment, int unindent)
{
    QString t;

    // Remove special macros to support Qt namespacing.
    QString trimmed = line.trimmed();
    if (trimmed.startsWith("QT_BEGIN_NAMESPACE")) {
        getLine();
    } else if (trimmed.startsWith("QT_END_NAMESPACE")) {
        getLine();
        t += QLatin1Char('\n');
    } else if (!trimmed.startsWith(comment)) {
        // Ordinary code
        t += getLine(unindent);
    } else {
        // Comments
        if (line.contains(QLatin1Char('\n')))
            t += QLatin1Char('\n');
        getLine();
    }
    return t;
}

QT_END_NAMESPACE