/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2009 Robert Osfield
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * 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
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSGDB_XML_PARSER
#define OSGDB_XML_PARSER 1

#include <osgDB/Registry>

namespace osgDB {

// forward declare
class XmlNode;

/** read an Xml file, find the file in Options DataFilePathList.*/
extern OSGDB_EXPORT XmlNode* readXmlFile(const std::string& filename,const Options* options);

/** read an Xml file, find the file in osgDB::Registry's eaderWriter::Options DataFilePathList.*/
inline XmlNode* readXmlFile(const std::string& filename)
{
    return readXmlFile(filename, osgDB::Registry::instance()->getOptions());
}

/** read an Xml from from an istream.*/
extern OSGDB_EXPORT XmlNode* readXmlStream(std::istream& fin);

extern OSGDB_EXPORT std::string trimEnclosingSpaces(const std::string& str);

/** XmlNode class for very basic reading and writing of xml files.*/
class OSGDB_EXPORT XmlNode : public osg::Referenced
{
    public:

        XmlNode();

        enum NodeType
        {
            UNASSIGNED,
            ATOM,
            NODE,
            GROUP,
            ROOT,
            COMMENT,
            INFORMATION
        };

        typedef std::map< std::string, std::string > Properties;
        typedef std::vector< osg::ref_ptr<XmlNode> >  Children;

        NodeType        type;
        std::string     name;
        std::string     contents;
        Properties      properties;
        Children        children;

        std::string getTrimmedContents() const { return trimEnclosingSpaces(contents); }

    public:

        class OSGDB_EXPORT ControlMap
        {
            public:
                ControlMap();

                typedef std::map< std::string, int > ControlToCharacterMap;
                typedef std::map< int, std::string> CharacterToControlMap;

                void addControlToCharacter(const std::string& control, int c);

                ControlToCharacterMap _controlToCharacterMap;
                CharacterToControlMap _characterToControlMap;

            private:

                void setUpControlMappings();

        };

        class OSGDB_EXPORT Input : public ControlMap
        {
            public:

                Input();
                Input(const Input&);

                ~Input();

                typedef std::string::size_type size_type;

                void open(const std::string& filename);
                void attach(std::istream& istream);

                void readAllDataIntoBuffer();

                operator bool () const { return _currentPos<_buffer.size(); }

                size_type currentPosition() const { return _currentPos; }

                int get() { if (_currentPos<_buffer.size()) return static_cast<unsigned char>(_buffer[_currentPos++]); else return -1; }

                int operator [] (size_type i) const { if ((_currentPos+i)<_buffer.size()) return static_cast<unsigned char>(_buffer[_currentPos+i]); else return -1; }

                void operator ++ () { if (_currentPos<_buffer.size()) ++_currentPos; }

                void operator += (size_type n) { if ((_currentPos+n)<_buffer.size()) _currentPos+=n; else _currentPos = _buffer.size(); }

                void skipWhiteSpace();

                std::string substr(size_type pos, size_type n=std::string::npos) { return (_currentPos<_buffer.size()) ? _buffer.substr(_currentPos+pos,n) : std::string(); }

                size_type find(const std::string& str)
                {
                    if (_currentPos<_buffer.size())
                    {
                        size_type pos = _buffer.find(str, _currentPos);
                        if (pos==std::string::npos) return std::string::npos;
                        else return pos-_currentPos;
                    } else return std::string::npos;
                }

                bool match(const std::string& str) { return (_currentPos<_buffer.size()) ? _buffer.compare(_currentPos, str.size(), str)==0 : false; }

                enum Encoding
                {
                    ENCODING_ASCII,
                    ENCODING_UTF8
                };

                void setEncoding(Encoding encoding) { _encoding = encoding; }
                Encoding getEncoding() const { return _encoding; }

                inline void copyCharacterToString(std::string& str)
                {
                    if (_currentPos>=_buffer.size()) return;
                    switch (_encoding)
                    {
                        case(ENCODING_UTF8) :
                        {
                            int char0 = static_cast<unsigned char>(_buffer[_currentPos]); ++_currentPos;
                            str.push_back(char0);

                            if (char0 < 0x80 || _currentPos>=_buffer.size()) break; // 1-byte character

                            str.push_back(_buffer[_currentPos]); ++_currentPos;
                            if (char0<0xe0 || _currentPos<_buffer.size()) break; // 2-byte character

                            str.push_back(_buffer[_currentPos]); ++_currentPos;
                            if (char0<0xf0 || _currentPos>=_buffer.size()) break; // 3-byte character

                            str.push_back(_buffer[_currentPos]); ++_currentPos;
                            if (char0<0xf8 || _currentPos>=_buffer.size()) break; // 4-byte character

                            if (_currentPos>=_buffer.size()) break;
                            str.push_back(_buffer[_currentPos]); ++_currentPos;  // 5-byte character?

                            break;
                        }
                        case(ENCODING_ASCII) :
                        default:
                            str.push_back(_buffer[_currentPos]);
                            ++_currentPos;
                            return;
                    }
                }

            private:

                size_type       _currentPos;

                std::ifstream   _fin;
                std::string     _buffer;
                Encoding        _encoding;

        };

        bool read(Input& input);
        bool write(std::ostream& fout, const std::string& indent = "") const;

        bool write(const ControlMap& controlMap, std::ostream& fout, const std::string& indent = "") const;
        bool writeString(const ControlMap& controlMap, std::ostream& fout, const std::string& str) const;

    protected:

        bool writeChildren(const ControlMap& controlMap, std::ostream& fout, const std::string& indent) const;
        bool writeProperties(const ControlMap& controlMap, std::ostream& fout) const;

        bool readAndReplaceControl(std::string& in_contents, Input& input) const;
};

}
#endif