/*
   Copyright (c) 2002 Craig Drummond <craig@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#include "kxftconfig.h"
#ifdef HAVE_FONTCONFIG

#include <stdarg.h>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <sys/stat.h>

#include <QRegExp>
#include <QFile>
#include <QDir>
#include <QtGui/qx11info_x11.h>
#include <QByteArray>

#include <KLocale>
#include <kde_file.h>
#include <KGlobal>
#include <KStandardDirs>
#include <KDebug>

#include <fontconfig/fontconfig.h>

using namespace std;

static int point2Pixel(double point)
{
    return (int)(((point*QX11Info::appDpiY())/72.0)+0.5);
}

static int pixel2Point(double pixel)
{
    return (int)(((pixel*72.0)/(double)QX11Info::appDpiY())+0.5);
}

static bool equal(double d1, double d2)
{
    return (fabs(d1 - d2) < 0.0001);
}

static QString dirSyntax(const QString &d)
{
    if(!d.isNull())
    {
        QString ds(d);

        ds.replace("//", "/");

        int slashPos=ds.lastIndexOf('/');

        if(slashPos!=(((int)ds.length())-1))
            ds.append('/');

        return ds;
    }

    return d;
}

static bool check(const QString &path, unsigned int fmt, bool checkW=false)
{
    KDE_struct_stat info;
    QByteArray        pathC(QFile::encodeName(path));

    return 0==KDE_lstat(pathC, &info) && (info.st_mode&S_IFMT)==fmt &&
           (!checkW || 0==::access(pathC, W_OK));
}

inline bool fExists(const QString &p)
{
    return check(p, S_IFREG, false);
}

inline bool dWritable(const QString &p)
{
    return check(p, S_IFDIR, true);
}

static QString getDir(const QString &f)
{
    QString d(f);

    int slashPos=d.lastIndexOf('/');

    if(-1!=slashPos)
        d.remove(slashPos+1, d.length());

    return dirSyntax(d);
}

static time_t getTimeStamp(const QString &item)
{
    KDE_struct_stat info;

    return !item.isNull() && 0==KDE_lstat(QFile::encodeName(item), &info) ? info.st_mtime : 0;
}

//
// Obtain location of config file to use.
QString getConfigFile()
{
    FcStrList   *list=FcConfigGetConfigFiles(FcConfigGetCurrent());
    QStringList files;
    FcChar8     *file;
    QString     home(dirSyntax(QDir::homePath()));

    while((file=FcStrListNext(list)))
    {
        QString f((const char *)file);

        if(fExists(f) && 0==f.indexOf(home))
            files.append(f);
    }
    FcStrListDone(list);

    //
    // Go through list of files, looking for the preferred one...
    if(files.count())
    {
        QStringList::const_iterator it(files.begin()),
                                    end(files.end());

        for(; it!=end; ++it)
            if(-1!=(*it).indexOf(QRegExp("/\\.?fonts\\.conf$")))
                return *it;
        return files.front();  // Just return the 1st one...
    }
    else // Hmmm... no known files?
    {
        if(FcGetVersion() >= 21000)
        {
            QString targetPath(KGlobal::dirs()->localxdgconfdir()+"fontconfig");
            QDir target(targetPath);
            if(!target.exists())
                target.mkpath(targetPath);
            return targetPath+"/fonts.conf";
        }
        else
            return home+"/.fonts.conf";
    }
}

static QString getEntry(QDomElement element, const char *type, unsigned int numAttributes, ...)
{
    if(numAttributes==element.attributes().length())
    {
        va_list      args;
        unsigned int arg;
        bool         ok=true;

        va_start(args, numAttributes);

        for(arg=0; arg<numAttributes && ok; ++arg)
        {
            const char *attr=va_arg(args, const char *);
            const char *val =va_arg(args, const char *);

            if(!attr || !val || val!=element.attribute(attr))
                ok=false;
        }

        va_end(args);

        if(ok)
        {
            QDomNode n=element.firstChild();

            if(!n.isNull())
            {
                QDomElement e = n.toElement();

                if(!e.isNull() && type==e.tagName())
                    return e.text();
            }
        }
    }

    return QString();
}

static KXftConfig::SubPixel::Type strToType(const char *str)
{
    if(0==strcmp(str, "rgb"))
        return KXftConfig::SubPixel::Rgb;
    else if(0==strcmp(str, "bgr"))
        return KXftConfig::SubPixel::Bgr;
    else if(0==strcmp(str, "vrgb"))
        return KXftConfig::SubPixel::Vrgb;
    else if(0==strcmp(str, "vbgr"))
        return KXftConfig::SubPixel::Vbgr;
    else
        return KXftConfig::SubPixel::None;
}

static KXftConfig::Hint::Style strToStyle(const char *str)
{
    if(0==strcmp(str, "hintslight"))
        return KXftConfig::Hint::Slight;
    else if(0==strcmp(str, "hintmedium"))
        return KXftConfig::Hint::Medium;
    else if(0==strcmp(str, "hintfull"))
        return KXftConfig::Hint::Full;
    else
        return KXftConfig::Hint::None;
}

KXftConfig::KXftConfig()
          : m_doc("fontconfig")
          , m_file(getConfigFile())
{
    kDebug() << "Using fontconfig file:" << m_file;
    m_antiAliasing = aliasingEnabled();
    reset();
}

KXftConfig::~KXftConfig()
{
}

bool KXftConfig::reset()
{
    bool ok=false;

    m_madeChanges=false;
    m_hint.reset();
    m_hinting.reset();
    m_excludeRange.reset();
    m_excludePixelRange.reset();
    m_subPixel.reset();

    QFile f(m_file);

    if(f.open(QIODevice::ReadOnly))
    {
        m_time=getTimeStamp(m_file);
        ok=true;
        m_doc.clear();

        if(m_doc.setContent(&f))
            readContents();
        f.close();
    }
    else
        ok=!fExists(m_file) && dWritable(getDir(m_file));

    if(m_doc.documentElement().isNull())
        m_doc.appendChild(m_doc.createElement("fontconfig"));

    if(ok)
    {
        //
        // Check exclude range values - i.e. size and pixel size...
        // If "size" range is set, ensure "pixelsize" matches...
        if(!equal(0, m_excludeRange.from) || !equal(0, m_excludeRange.to))
        {
            double pFrom=(double)point2Pixel(m_excludeRange.from),
                   pTo=(double)point2Pixel(m_excludeRange.to);

            if(!equal(pFrom, m_excludePixelRange.from) || !equal(pTo, m_excludePixelRange.to))
            {
                m_excludePixelRange.from=pFrom;
                m_excludePixelRange.to=pTo;
                m_madeChanges=true;
                apply();
            }
        }
        else if(!equal(0, m_excludePixelRange.from) || !equal(0, m_excludePixelRange.to))   
        {
            // "pixelsize" set, but not "size" !!!
            m_excludeRange.from=(int)pixel2Point(m_excludePixelRange.from);
            m_excludeRange.to=(int)pixel2Point(m_excludePixelRange.to);
            m_madeChanges=true;
            apply();
        }
    }

    return ok;
}

bool KXftConfig::apply()
{
    bool ok=true;

    if(m_madeChanges)
    {
        //
        // Check if file has been written since we last read it. If it has, then re-read and add any
        // of our changes...
        if(fExists(m_file) && getTimeStamp(m_file)!=m_time)
        {
            KXftConfig newConfig;

            newConfig.setExcludeRange(m_excludeRange.from, m_excludeRange.to);
            newConfig.setSubPixelType(m_subPixel.type);
            newConfig.setHintStyle(m_hint.style);
            newConfig.setAntiAliasing(m_antiAliasing.set);

            ok=newConfig.changed() ? newConfig.apply() : true;
            if(ok)
                reset();
            else
                m_time=getTimeStamp(m_file);
        }
        else
        {
            // Ensure these are always equal...
            m_excludePixelRange.from=(int)point2Pixel(m_excludeRange.from);
            m_excludePixelRange.to=(int)point2Pixel(m_excludeRange.to);

            FcAtomic *atomic=FcAtomicCreate((const unsigned char *)(QFile::encodeName(m_file).data()));

            ok=false;
            if(atomic)
            {
                if(FcAtomicLock(atomic))
                {
                    FILE *f=fopen((char *)FcAtomicNewFile(atomic), "w");

                    if(f)
                    {
                        applySubPixelType();
                        applyHintStyle();
                        applyAntiAliasing();
                        applyExcludeRange(false);
                        applyExcludeRange(true);

                        //
                        // Check document syntax...
                        static const char qtXmlHeader[]   = "<?xml version = '1.0'?>";
                        static const char xmlHeader[]     = "<?xml version=\"1.0\"?>";
                        static const char qtDocTypeLine[] = "<!DOCTYPE fontconfig>";
                        static const char docTypeLine[]   = "<!DOCTYPE fontconfig SYSTEM "
                                                            "\"fonts.dtd\">";

                        QString str(m_doc.toString());
                        int     idx;

                        if(0!=str.indexOf("<?xml"))
                            str.insert(0, xmlHeader);
                        else if(0==str.indexOf(qtXmlHeader))
                            str.replace(0, strlen(qtXmlHeader), xmlHeader);

                        if(-1!=(idx=str.indexOf(qtDocTypeLine)))
                            str.replace(idx, strlen(qtDocTypeLine), docTypeLine);

                        //
                        // Write to file...
                        fputs(str.toUtf8(), f);
                        fclose(f);

                        if(FcAtomicReplaceOrig(atomic))
                        {
                            ok=true;
                            reset(); // Re-read contents..
                        }
                        else
                            FcAtomicDeleteNew(atomic);
                    }
                    FcAtomicUnlock(atomic);
                }
                FcAtomicDestroy(atomic);
            }
        }
    }

    return ok;
}

bool KXftConfig::getSubPixelType(SubPixel::Type &type)
{
    type=m_subPixel.type;
    return SubPixel::None!=m_subPixel.type;
}

void KXftConfig::setSubPixelType(SubPixel::Type type)
{
    if(type!=m_subPixel.type)
    {
        m_subPixel.type=type;
        m_madeChanges=true;
    }
}

bool KXftConfig::getHintStyle(Hint::Style &style)
{
    if(Hint::NotSet!=m_hint.style && !m_hint.toBeRemoved)
    {
        style=m_hint.style;
        return true;
    }
    else
        return false;
}

void KXftConfig::setHintStyle(Hint::Style style)
{
    if((Hint::NotSet==style && Hint::NotSet!=m_hint.style && !m_hint.toBeRemoved) ||
       (Hint::NotSet!=style && (style!=m_hint.style || m_hint.toBeRemoved)) )
    {
        m_hint.toBeRemoved=(Hint::NotSet==style);
        m_hint.style=style;
        m_madeChanges=true;
    }

    if(Hint::NotSet!=style)
        setHinting(Hint::None!=m_hint.style);
}

void KXftConfig::setHinting(bool set)
{
    if(set!=m_hinting.set)
    {
        m_hinting.set=set;
        m_madeChanges=true;
    }
}

bool KXftConfig::getExcludeRange(double &from, double &to)
{
    if(!equal(0, m_excludeRange.from) || !equal(0,m_excludeRange.to))
    {
        from=m_excludeRange.from;
        to=m_excludeRange.to;
        return true;
    }
    else
        return false;
}


void KXftConfig::setExcludeRange(double from, double to)
{
    double f=from<to ? from : to,
           t=from<to ? to   : from;

    if(!equal(f, m_excludeRange.from) || !equal(t,m_excludeRange.to))
    {
        m_excludeRange.from=f;
        m_excludeRange.to=t;
        m_madeChanges=true;
    }
}

QString KXftConfig::description(SubPixel::Type t)
{
    switch(t)
    {
        default:
        case SubPixel::None:
            return i18nc("no subpixel rendering", "None");
        case SubPixel::Rgb:
            return i18n("RGB");
        case SubPixel::Bgr:
            return i18n("BGR");
        case SubPixel::Vrgb:
            return i18n("Vertical RGB");
        case SubPixel::Vbgr:
            return i18n("Vertical BGR");
    }
}

const char * KXftConfig::toStr(SubPixel::Type t)
{
    switch(t)
    {
        default:
        case SubPixel::None:
            return "none";
        case SubPixel::Rgb:
            return "rgb";
        case SubPixel::Bgr:
            return "bgr";
        case SubPixel::Vrgb:
            return "vrgb";
        case SubPixel::Vbgr:
            return "vbgr";
    }
}

QString KXftConfig::description(Hint::Style s)
{
    switch(s)
    {
        default:
        case Hint::Medium:
            return i18nc("medium hinting", "Medium");
        case Hint::NotSet:
            return "";
        case Hint::None:
            return i18nc("no hinting", "None");
        case Hint::Slight:
            return i18nc("slight hinting", "Slight");
        case Hint::Full:
            return i18nc("full hinting", "Full");
    }
}

const char * KXftConfig::toStr(Hint::Style s)
{
    switch(s)
    {
        default:
        case Hint::Medium:
            return "hintmedium";
        case Hint::None:
            return "hintnone";
        case Hint::Slight:
            return "hintslight";
        case Hint::Full:
            return "hintfull";
    }
}

void KXftConfig::readContents()
{
    QDomNode n = m_doc.documentElement().firstChild();

    while(!n.isNull())
    {
        QDomElement e = n.toElement();

        if(!e.isNull())
        {
            if("match"==e.tagName())
            {
                QString str;

                switch(e.childNodes().count())
                {
                    case 1:
                        if("font"==e.attribute("target"))
                        {
                            QDomElement ene=e.firstChild().toElement();

                            if(!ene.isNull() && "edit"==ene.tagName())
                            {
                                if(!(str=getEntry(ene, "const", 2, "name", "rgba", "mode",
                                                  "assign")).isNull())
                                {
                                    m_subPixel.node=n;
                                    m_subPixel.type=strToType(str.toLatin1());
                                }
                                else if(!(str=getEntry(ene, "const", 2, "name", "hintstyle", "mode",
                                                       "assign")).isNull())
                                {
                                    m_hint.node=n;
                                    m_hint.style=strToStyle(str.toLatin1());
                                }
                                else if(!(str=getEntry(ene, "bool", 2, "name", "hinting", "mode",
                                                       "assign")).isNull())
                                {
                                    m_hinting.node=n;
                                    m_hinting.set=str.toLower()!="false";
                                }
                                else if(!(str=getEntry(ene, "bool", 2, "name", "antialias", "mode",
                                                       "assign")).isNull())
                                {
                                    m_antiAliasing.node=n;
                                    m_antiAliasing.set=str.toLower()!="false";
                                }
                            }
                        }
                        break;
                    case 3: // CPD: Is target "font" or "pattern" ????
                        if("font"==e.attribute("target"))
                        {
                            bool     foundFalse=false;
                            QDomNode en=e.firstChild();
                            QString  family;
                            double   from=-1.0,
                                     to=-1.0,
                                     pixelFrom=-1.0,
                                     pixelTo=-1.0;

                            while(!en.isNull())
                            {
                                QDomElement ene=en.toElement();

                                if(!ene.isNull())
                                {
                                    if("test"==ene.tagName())
                                    {
                                        // kcmfonts used to write incorrectly more or less instead of
                                        // more_eq and less_eq, so read both,
                                        // first the old (wrong) one then the right one
                                        if(!(str=getEntry(ene, "double", 3, "qual", "any", "name",
                                                          "size", "compare", "more")).isNull())
                                            from=str.toDouble();
                                        if(!(str=getEntry(ene, "double", 3, "qual", "any", "name",
                                                          "size", "compare", "more_eq")).isNull())
                                            from=str.toDouble();
                                        if(!(str=getEntry(ene, "double", 3, "qual", "any", "name",
                                                          "size", "compare", "less")).isNull())
                                            to=str.toDouble();
                                        if(!(str=getEntry(ene, "double", 3, "qual", "any", "name",
                                                          "size", "compare", "less_eq")).isNull())
                                            to=str.toDouble();
                                        if(!(str=getEntry(ene, "double", 3, "qual", "any", "name",
                                                          "pixelsize", "compare", "more")).isNull())
                                            pixelFrom=str.toDouble();
                                        if(!(str=getEntry(ene, "double", 3, "qual", "any", "name",
                                                          "pixelsize", "compare",
                                                          "more_eq")).isNull())
                                            pixelFrom=str.toDouble();
                                        if(!(str=getEntry(ene, "double", 3, "qual", "any", "name",
                                                          "pixelsize", "compare", "less")).isNull())
                                            pixelTo=str.toDouble();
                                        if(!(str=getEntry(ene, "double", 3, "qual", "any", "name",
                                                          "pixelsize", "compare",
                                                          "less_eq")).isNull())
                                            pixelTo=str.toDouble();
                                    }
                                    else if("edit"==ene.tagName() &&
                                            "false"==getEntry(ene, "bool", 2, "name", "antialias",
                                                              "mode", "assign"))
                                        foundFalse=true;
                                }

                                en=en.nextSibling();
                            }

                            if((from>=0 || to>=0) && foundFalse)
                            {
                                m_excludeRange.from=from < to ? from : to;
                                m_excludeRange.to  =from < to ? to   : from;
                                m_excludeRange.node=n;
                            }
                            else if((pixelFrom>=0 || pixelTo>=0) && foundFalse)
                            {
                                m_excludePixelRange.from=pixelFrom < pixelTo ? pixelFrom : pixelTo;
                                m_excludePixelRange.to  =pixelFrom < pixelTo ? pixelTo   : pixelFrom;
                                m_excludePixelRange.node=n;
                            }
                        }
                        break;
                    default:
                        break;
                }
            }
        }
        n=n.nextSibling();
    }
}

void KXftConfig::applySubPixelType()
{
    QDomElement matchNode = m_doc.createElement("match"),
                typeNode  = m_doc.createElement("const"),
                editNode  = m_doc.createElement("edit");
    QDomText    typeText  = m_doc.createTextNode(toStr(m_subPixel.type));

    matchNode.setAttribute("target", "font");
    editNode.setAttribute("mode", "assign");
    editNode.setAttribute("name", "rgba");
    editNode.appendChild(typeNode);
    typeNode.appendChild(typeText);
    matchNode.appendChild(editNode);
    if(m_subPixel.node.isNull())
        m_doc.documentElement().appendChild(matchNode);
    else
        m_doc.documentElement().replaceChild(matchNode, m_subPixel.node);
    m_subPixel.node=matchNode;
}

void KXftConfig::applyHintStyle()
{
    applyHinting();

    if(Hint::NotSet==m_hint.style || m_hint.toBeRemoved)
    {
        if(!m_hint.node.isNull())
        {
            m_doc.documentElement().removeChild(m_hint.node);
            m_hint.node.clear();
        }
    }
    else
    {
        QDomElement matchNode = m_doc.createElement("match"),
                    typeNode  = m_doc.createElement("const"),
                    editNode  = m_doc.createElement("edit");
        QDomText    typeText  = m_doc.createTextNode(toStr(m_hint.style));

        matchNode.setAttribute("target", "font");
        editNode.setAttribute("mode", "assign");
        editNode.setAttribute("name", "hintstyle");
        editNode.appendChild(typeNode);
        typeNode.appendChild(typeText);
        matchNode.appendChild(editNode);
        if(m_hint.node.isNull())
            m_doc.documentElement().appendChild(matchNode);
        else
            m_doc.documentElement().replaceChild(matchNode, m_hint.node);
        m_hint.node=matchNode;
    }
}

void KXftConfig::applyHinting()
{
    QDomElement matchNode = m_doc.createElement("match"),
                typeNode  = m_doc.createElement("bool"),
                editNode  = m_doc.createElement("edit");
    QDomText    typeText  = m_doc.createTextNode(m_hinting.set ? "true" : "false");

    matchNode.setAttribute("target", "font");
    editNode.setAttribute("mode", "assign");
    editNode.setAttribute("name", "hinting");
    editNode.appendChild(typeNode);
    typeNode.appendChild(typeText);
    matchNode.appendChild(editNode);
    if(m_hinting.node.isNull())
        m_doc.documentElement().appendChild(matchNode);
    else
        m_doc.documentElement().replaceChild(matchNode, m_hinting.node);
    m_hinting.node=matchNode;
}

void KXftConfig::applyExcludeRange(bool pixel)
{
    Exclude &range=pixel ? m_excludePixelRange : m_excludeRange;

    if(equal(range.from, 0) && equal(range.to, 0))
    {
        if(!range.node.isNull())
        {
            m_doc.documentElement().removeChild(range.node);
            range.node.clear();
        }
    }
    else
    {
        QString     fromString,
                    toString;

        fromString.setNum(range.from);
        toString.setNum(range.to);

        QDomElement matchNode    = m_doc.createElement("match"),
                    fromTestNode = m_doc.createElement("test"),
                    fromNode     = m_doc.createElement("double"),
                    toTestNode   = m_doc.createElement("test"),
                    toNode       = m_doc.createElement("double"),
                    editNode     = m_doc.createElement("edit"),
                    boolNode     = m_doc.createElement("bool");
        QDomText    fromText     = m_doc.createTextNode(fromString),
                    toText       = m_doc.createTextNode(toString),
                    boolText     = m_doc.createTextNode("false");

        matchNode.setAttribute("target", "font");   // CPD: Is target "font" or "pattern" ????
        fromTestNode.setAttribute("qual", "any");
        fromTestNode.setAttribute("name", pixel ? "pixelsize" : "size");
        fromTestNode.setAttribute("compare", "more_eq");
        fromTestNode.appendChild(fromNode);
        fromNode.appendChild(fromText);
        toTestNode.setAttribute("qual", "any");
        toTestNode.setAttribute("name", pixel ? "pixelsize" : "size");
        toTestNode.setAttribute("compare", "less_eq");
        toTestNode.appendChild(toNode);
        toNode.appendChild(toText);
        editNode.setAttribute("mode", "assign");
        editNode.setAttribute("name", "antialias");
        editNode.appendChild(boolNode);
        boolNode.appendChild(boolText);
        matchNode.appendChild(fromTestNode);
        matchNode.appendChild(toTestNode);
        matchNode.appendChild(editNode);

        if(!m_antiAliasing.node.isNull())
            m_doc.documentElement().removeChild(range.node);
        m_doc.documentElement().appendChild(matchNode);
        range.node=matchNode;
    }
}

bool KXftConfig::getAntiAliasing() const
{
    return m_antiAliasing.set;
}

void KXftConfig::setAntiAliasing( bool set )
{
    if(set!=m_antiAliasing.set)
    {
        m_antiAliasing.set = set;
        m_madeChanges = true;
    }
}

void KXftConfig::applyAntiAliasing()
{
    QDomElement matchNode = m_doc.createElement("match"),
                typeNode  = m_doc.createElement("bool"),
                editNode  = m_doc.createElement("edit");
    QDomText    typeText  = m_doc.createTextNode(m_antiAliasing.set ? "true" : "false");

    matchNode.setAttribute("target", "font");
    editNode.setAttribute("mode", "assign");
    editNode.setAttribute("name", "antialias");
    editNode.appendChild(typeNode);
    typeNode.appendChild(typeText);
    matchNode.appendChild(editNode);
    if(!m_antiAliasing.node.isNull())
        m_doc.documentElement().removeChild(m_antiAliasing.node);
    m_doc.documentElement().appendChild(matchNode);
    m_antiAliasing.node=matchNode;
}

// KXftConfig only parses one config file, user's .fonts.conf usually.
// If that one doesn't exist, then KXftConfig doesn't know if antialiasing
// is enabled or not. So try to find out the default value from the default font.
// Maybe there's a better way *shrug*.
bool KXftConfig::aliasingEnabled()
{
    FcPattern *pattern = FcPatternCreate();
    FcConfigSubstitute(0, pattern, FcMatchPattern);
    FcDefaultSubstitute(pattern);
    FcResult result;
    FcPattern *f = FcFontMatch( 0, pattern, &result );
    FcBool antialiased = FcTrue;
    FcPatternGetBool( f, FC_ANTIALIAS, 0, &antialiased );
    FcPatternDestroy( f );
    FcPatternDestroy( pattern );
    return antialiased == FcTrue;
}

#endif