/****************************************************************************
 **
 ** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the doxygen2qthelp project on Trolltech Labs.
 **
 ** This file may be used under the terms of the GNU General Public
 ** License version 2.0 or 3.0 as published by the Free Software Foundation
 ** and appearing in the file LICENSE.GPL included in the packaging of
 ** this file.  Please review the following information to ensure GNU
 ** General Public Licensing requirements will be met:
 ** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
 ** http://www.gnu.org/copyleft/gpl.html.
 **
 ** If you are unsure which license is appropriate for your use, please
 ** contact the sales department at qt-sales@nokia.com.
 **
 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 **
 ****************************************************************************/

#include "simplehtmlparser_p.h"
#include "simplehtmlreceiver_p.h"

#include <QtCore/QtAlgorithms>
#include <QtCore/QStringList>

QT_BEGIN_NAMESPACE

// see also tst_qtextdocumentfragment.cpp
#define MAX_ENTITY 258
static const struct QTextHtmlEntity
{
    const char *name;
    quint16 code;
} entities[MAX_ENTITY]= {
    { "AElig", 0x00c6 },
    { "AMP", 38 },
    { "Aacute", 0x00c1 },
    { "Acirc", 0x00c2 },
    { "Agrave", 0x00c0 },
    { "Alpha", 0x0391 },
    { "Aring", 0x00c5 },
    { "Atilde", 0x00c3 },
    { "Auml", 0x00c4 },
    { "Beta", 0x0392 },
    { "Ccedil", 0x00c7 },
    { "Chi", 0x03a7 },
    { "Dagger", 0x2021 },
    { "Delta", 0x0394 },
    { "ETH", 0x00d0 },
    { "Eacute", 0x00c9 },
    { "Ecirc", 0x00ca },
    { "Egrave", 0x00c8 },
    { "Epsilon", 0x0395 },
    { "Eta", 0x0397 },
    { "Euml", 0x00cb },
    { "GT", 62 },
    { "Gamma", 0x0393 },
    { "Iacute", 0x00cd },
    { "Icirc", 0x00ce },
    { "Igrave", 0x00cc },
    { "Iota", 0x0399 },
    { "Iuml", 0x00cf },
    { "Kappa", 0x039a },
    { "LT", 60 },
    { "Lambda", 0x039b },
    { "Mu", 0x039c },
    { "Ntilde", 0x00d1 },
    { "Nu", 0x039d },
    { "OElig", 0x0152 },
    { "Oacute", 0x00d3 },
    { "Ocirc", 0x00d4 },
    { "Ograve", 0x00d2 },
    { "Omega", 0x03a9 },
    { "Omicron", 0x039f },
    { "Oslash", 0x00d8 },
    { "Otilde", 0x00d5 },
    { "Ouml", 0x00d6 },
    { "Phi", 0x03a6 },
    { "Pi", 0x03a0 },
    { "Prime", 0x2033 },
    { "Psi", 0x03a8 },
    { "QUOT", 34 },
    { "Rho", 0x03a1 },
    { "Scaron", 0x0160 },
    { "Sigma", 0x03a3 },
    { "THORN", 0x00de },
    { "Tau", 0x03a4 },
    { "Theta", 0x0398 },
    { "Uacute", 0x00da },
    { "Ucirc", 0x00db },
    { "Ugrave", 0x00d9 },
    { "Upsilon", 0x03a5 },
    { "Uuml", 0x00dc },
    { "Xi", 0x039e },
    { "Yacute", 0x00dd },
    { "Yuml", 0x0178 },
    { "Zeta", 0x0396 },
    { "aacute", 0x00e1 },
    { "acirc", 0x00e2 },
    { "acute", 0x00b4 },
    { "aelig", 0x00e6 },
    { "agrave", 0x00e0 },
    { "alefsym", 0x2135 },
    { "alpha", 0x03b1 },
    { "amp", 38 },
    { "and", 0x22a5 },
    { "ang", 0x2220 },
    { "apos", 0x0027 },
    { "aring", 0x00e5 },
    { "asymp", 0x2248 },
    { "atilde", 0x00e3 },
    { "auml", 0x00e4 },
    { "bdquo", 0x201e },
    { "beta", 0x03b2 },
    { "brvbar", 0x00a6 },
    { "bull", 0x2022 },
    { "cap", 0x2229 },
    { "ccedil", 0x00e7 },
    { "cedil", 0x00b8 },
    { "cent", 0x00a2 },
    { "chi", 0x03c7 },
    { "circ", 0x02c6 },
    { "clubs", 0x2663 },
    { "cong", 0x2245 },
    { "copy", 0x00a9 },
    { "crarr", 0x21b5 },
    { "cup", 0x222a },
    { "curren", 0x00a4 },
    { "dArr", 0x21d3 },
    { "dagger", 0x2020 },
    { "darr", 0x2193 },
    { "deg", 0x00b0 },
    { "delta", 0x03b4 },
    { "diams", 0x2666 },
    { "divide", 0x00f7 },
    { "eacute", 0x00e9 },
    { "ecirc", 0x00ea },
    { "egrave", 0x00e8 },
    { "empty", 0x2205 },
    { "emsp", 0x2003 },
    { "ensp", 0x2002 },
    { "epsilon", 0x03b5 },
    { "equiv", 0x2261 },
    { "eta", 0x03b7 },
    { "eth", 0x00f0 },
    { "euml", 0x00eb },
    { "euro", 0x20ac },
    { "exist", 0x2203 },
    { "fnof", 0x0192 },
    { "forall", 0x2200 },
    { "frac12", 0x00bd },
    { "frac14", 0x00bc },
    { "frac34", 0x00be },
    { "frasl", 0x2044 },
    { "gamma", 0x03b3 },
    { "ge", 0x2265 },
    { "gt", 62 },
    { "hArr", 0x21d4 },
    { "harr", 0x2194 },
    { "hearts", 0x2665 },
    { "hellip", 0x2026 },
    { "iacute", 0x00ed },
    { "icirc", 0x00ee },
    { "iexcl", 0x00a1 },
    { "igrave", 0x00ec },
    { "image", 0x2111 },
    { "infin", 0x221e },
    { "int", 0x222b },
    { "iota", 0x03b9 },
    { "iquest", 0x00bf },
    { "isin", 0x2208 },
    { "iuml", 0x00ef },
    { "kappa", 0x03ba },
    { "lArr", 0x21d0 },
    { "lambda", 0x03bb },
    { "lang", 0x2329 },
    { "laquo", 0x00ab },
    { "larr", 0x2190 },
    { "lceil", 0x2308 },
    { "ldquo", 0x201c },
    { "le", 0x2264 },
    { "lfloor", 0x230a },
    { "lowast", 0x2217 },
    { "loz", 0x25ca },
    { "lrm", 0x200e },
    { "lsaquo", 0x2039 },
    { "lsquo", 0x2018 },
    { "lt", 60 },
    { "macr", 0x00af },
    { "mdash", 0x2014 },
    { "micro", 0x00b5 },
    { "middot", 0x00b7 },
    { "minus", 0x2212 },
    { "mu", 0x03bc },
    { "nabla", 0x2207 },
    { "nbsp", 0x00a0 },
    { "ndash", 0x2013 },
    { "ne", 0x2260 },
    { "ni", 0x220b },
    { "not", 0x00ac },
    { "notin", 0x2209 },
    { "nsub", 0x2284 },
    { "ntilde", 0x00f1 },
    { "nu", 0x03bd },
    { "oacute", 0x00f3 },
    { "ocirc", 0x00f4 },
    { "oelig", 0x0153 },
    { "ograve", 0x00f2 },
    { "oline", 0x203e },
    { "omega", 0x03c9 },
    { "omicron", 0x03bf },
    { "oplus", 0x2295 },
    { "or", 0x22a6 },
    { "ordf", 0x00aa },
    { "ordm", 0x00ba },
    { "oslash", 0x00f8 },
    { "otilde", 0x00f5 },
    { "otimes", 0x2297 },
    { "ouml", 0x00f6 },
    { "para", 0x00b6 },
    { "part", 0x2202 },
    { "percnt", 0x0025 },
    { "permil", 0x2030 },
    { "perp", 0x22a5 },
    { "phi", 0x03c6 },
    { "pi", 0x03c0 },
    { "piv", 0x03d6 },
    { "plusmn", 0x00b1 },
    { "pound", 0x00a3 },
    { "prime", 0x2032 },
    { "prod", 0x220f },
    { "prop", 0x221d },
    { "psi", 0x03c8 },
    { "quot", 34 },
    { "rArr", 0x21d2 },
    { "radic", 0x221a },
    { "rang", 0x232a },
    { "raquo", 0x00bb },
    { "rarr", 0x2192 },
    { "rceil", 0x2309 },
    { "rdquo", 0x201d },
    { "real", 0x211c },
    { "reg", 0x00ae },
    { "rfloor", 0x230b },
    { "rho", 0x03c1 },
    { "rlm", 0x200f },
    { "rsaquo", 0x203a },
    { "rsquo", 0x2019 },
    { "sbquo", 0x201a },
    { "scaron", 0x0161 },
    { "sdot", 0x22c5 },
    { "sect", 0x00a7 },
    { "shy", 0x00ad },
    { "sigma", 0x03c3 },
    { "sigmaf", 0x03c2 },
    { "sim", 0x223c },
    { "spades", 0x2660 },
    { "sub", 0x2282 },
    { "sube", 0x2286 },
    { "sum", 0x2211 },
    { "sup", 0x2283 },
    { "sup1", 0x00b9 },
    { "sup2", 0x00b2 },
    { "sup3", 0x00b3 },
    { "supe", 0x2287 },
    { "szlig", 0x00df },
    { "tau", 0x03c4 },
    { "there4", 0x2234 },
    { "theta", 0x03b8 },
    { "thetasym", 0x03d1 },
    { "thinsp", 0x2009 },
    { "thorn", 0x00fe },
    { "tilde", 0x02dc },
    { "times", 0x00d7 },
    { "trade", 0x2122 },
    { "uArr", 0x21d1 },
    { "uacute", 0x00fa },
    { "uarr", 0x2191 },
    { "ucirc", 0x00fb },
    { "ugrave", 0x00f9 },
    { "uml", 0x00a8 },
    { "upsih", 0x03d2 },
    { "upsilon", 0x03c5 },
    { "uuml", 0x00fc },
    { "weierp", 0x2118 },
    { "xi", 0x03be },
    { "yacute", 0x00fd },
    { "yen", 0x00a5 },
    { "yuml", 0x00ff },
    { "zeta", 0x03b6 },
    { "zwj", 0x200d },
    { "zwnj", 0x200c }
};

static bool operator<(const QString &entityStr, const QTextHtmlEntity &entity)
{
    return entityStr < QLatin1String(entity.name);
}

static bool operator<(const QTextHtmlEntity &entity, const QString &entityStr)
{
    return QLatin1String(entity.name) < entityStr;
}

static QChar resolveEntity(const QString &entity)
{
    const QTextHtmlEntity *start = &entities[0];
    const QTextHtmlEntity *end = &entities[MAX_ENTITY];
    const QTextHtmlEntity *e = qBinaryFind(start, end, entity);
    if (e == end)
        return QChar();
    return e->code;
}

static const uint windowsLatin1ExtendedCharacters[0xA0 - 0x80] = {
    0x20ac, // 0x80
    0x0081, // 0x81 direct mapping
    0x201a, // 0x82
    0x0192, // 0x83
    0x201e, // 0x84
    0x2026, // 0x85
    0x2020, // 0x86
    0x2021, // 0x87
    0x02C6, // 0x88
    0x2030, // 0x89
    0x0160, // 0x8A
    0x2039, // 0x8B
    0x0152, // 0x8C
    0x008D, // 0x8D direct mapping
    0x017D, // 0x8E
    0x008F, // 0x8F directmapping
    0x0090, // 0x90 directmapping
    0x2018, // 0x91
    0x2019, // 0x92
    0x201C, // 0x93
    0X201D, // 0x94
    0x2022, // 0x95
    0x2013, // 0x96
    0x2014, // 0x97
    0x02DC, // 0x98
    0x2122, // 0x99
    0x0161, // 0x9A
    0x203A, // 0x9B
    0x0153, // 0x9C
    0x009D, // 0x9D direct mapping
    0x017E, // 0x9E
    0x0178  // 0x9F
};

void SimpleHtmlParser::parse(const QString &text, SimpleHtmlReceiver *receiver)
{
    m_receiver = receiver;
    txt = text;
    pos = 0;
    len = txt.length();
    parse();
    Q_ASSERT(m_receiver != NULL);
    m_receiver->onStop();
    //dumpHtml();
}

void SimpleHtmlParser::eatSpace()
{
    while (pos < len && txt.at(pos).isSpace() && txt.at(pos)
            != QChar::ParagraphSeparator) {
        pos++;
    }
}

void SimpleHtmlParser::parse()
{
    QString buffer;
    while (pos < len) {
        QChar c = txt.at(pos++);
        if (c == QLatin1Char('<')) {
            if (!buffer.isEmpty()) {
                Q_ASSERT(m_receiver != NULL);
                m_receiver->onTextChunk(buffer);
                buffer.clear();
            }
            parseTag();
        } else if (c == QLatin1Char('&')) {
            buffer += parseEntity();
        } else {
            buffer += c;
        }
    }

    if (!buffer.isEmpty()) {
        Q_ASSERT(m_receiver != NULL);
        m_receiver->onTextChunk(buffer);
        buffer.clear();
    }
}

// parses a tag after "<"
void SimpleHtmlParser::parseTag()
{
    eatSpace();

    // handle comments and other exclamation mark declarations
    if (hasPrefix(QLatin1Char('!'))) {
        parseExclamationTag();
        return;
    }

    // if close tag just close
    if (hasPrefix(QLatin1Char('/'))) {
        parseCloseTag();
        return;
    }

    // parse tag name
    const QString tagName = parseWord().toLower();

    // _need_ at least one space after the tag name,
    // otherwise there can't be attributes
    QStringList attributes;
    if (pos < len && txt.at(pos).isSpace()) {
        attributes = parseAttributes();
    }

    Q_ASSERT(m_receiver != NULL);
    m_receiver->onTagOpen(tagName, attributes);

    // finish tag
    bool tagClosed = false;
    while (pos < len && txt.at(pos) != QLatin1Char('>')) {
        if (txt.at(pos) == QLatin1Char('/'))
            tagClosed = true;

        pos++;
    }
    pos++;
}

// parses a tag beginning with "/"
void SimpleHtmlParser::parseCloseTag()
{
    ++pos;
    const QString tagName = parseWord().toLower().trimmed();
    Q_ASSERT(m_receiver != NULL);
    m_receiver->onTagClose(tagName);

    while (pos < len) {
        QChar c = txt.at(pos++);
        if (c == QLatin1Char('>'))
            break;
    }
}

// parses a tag beginning with "!"
void SimpleHtmlParser::parseExclamationTag()
{
    ++pos;
    if (hasPrefix(QLatin1Char('-'),1) && hasPrefix(QLatin1Char('-'),2)) {
        pos += 3;
        // eat comments
        int end = txt.indexOf(QLatin1String("-->"), pos);
        pos = (end >= 0 ? end + 3 : len);
    } else {
        // eat internal tags
        while (pos < len) {
            QChar c = txt.at(pos++);
            if (c == QLatin1Char('>'))
                break;
        }
    }
}

// parses an entity after "&", and returns it
QString SimpleHtmlParser::parseEntity()
{
    int recover = pos;
    QString entity;
    while (pos < len) {
        QChar c = txt.at(pos++);
        if (c.isSpace() || pos - recover > 9) {
            goto error;
        }
        if (c == QLatin1Char(';'))
            break;
        entity += c;
    }
    {
        QChar resolved = resolveEntity(entity);
        if (!resolved.isNull())
            return QString(resolved);
    }
    if (entity.length() > 1 && entity.at(0) == QLatin1Char('#')) {
        entity.remove(0, 1); // removing leading #

        int base = 10;
        bool ok = false;

        if (entity.at(0).toLower() == QLatin1Char('x')) { // hex entity?
            entity.remove(0, 1);
            base = 16;
        }

        uint uc = entity.toUInt(&ok, base);
        if (ok) {
            if (uc >= 0x80 && uc < 0x80
                    + (sizeof(windowsLatin1ExtendedCharacters)
                    /sizeof(windowsLatin1ExtendedCharacters[0])))
                uc = windowsLatin1ExtendedCharacters[uc - 0x80];
            QString str;
            if (uc > 0xffff) {
                // surrogate pair
                uc -= 0x10000;
                ushort high = uc/0x400 + 0xd800;
                ushort low = uc%0x400 + 0xdc00;
                str.append(QChar(high));
                str.append(QChar(low));
            } else {
                str.append(QChar(uc));
            }
            return str;
        }
    }
error:
    pos = recover;
    return QLatin1String("&");
}

// parses one word, possibly quoted, and returns it
QString SimpleHtmlParser::parseWord()
{
    QString word;
    if (hasPrefix(QLatin1Char('\"'))) { // double quotes
        ++pos;
        while (pos < len) {
            QChar c = txt.at(pos++);
            if (c == QLatin1Char('\"'))
                break;
            else if (c == QLatin1Char('&'))
                word += parseEntity();
            else
                word += c;
        }
    } else if (hasPrefix(QLatin1Char('\''))) { // single quotes
        ++pos;
        while (pos < len) {
            QChar c = txt.at(pos++);
            if (c == QLatin1Char('\''))
                break;
            else
                word += c;
        }
    } else { // normal text
        while (pos < len) {
            QChar c = txt.at(pos++);
            if (c == QLatin1Char('>')
                || (c == QLatin1Char('/') && hasPrefix(QLatin1Char('>'), 1))
                || c == QLatin1Char('<')
                || c == QLatin1Char('=')
                || c.isSpace()) {
                --pos;
                break;
            }
            if (c == QLatin1Char('&'))
                word += parseEntity();
            else
                word += c;
        }
    }
    return word;
}

QStringList SimpleHtmlParser::parseAttributes()
{
    QStringList attrs;

    while (pos < len) {
        eatSpace();
        if (hasPrefix(QLatin1Char('>')) || hasPrefix(QLatin1Char('/')))
            break;
        QString key = parseWord().toLower();
        QString value = QLatin1String("1");
        if (key.size() == 0)
            break;
        eatSpace();
        if (hasPrefix(QLatin1Char('='))){
            pos++;
            eatSpace();
            value = parseWord();
        }
        if (value.size() == 0)
            continue;
        attrs << key << value;
    }

    return attrs;
}

QT_END_NAMESPACE
