/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/

#ifndef MAPNIK_CONFIG_HELPERS_INCLUDED
#define MAPNIK_CONFIG_HELPERS_INCLUDED

#include <mapnik/enumeration.hpp>
#include <mapnik/config_error.hpp>
#include <mapnik/color_factory.hpp>

#include <boost/property_tree/ptree.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/optional.hpp>

#include <iostream>
#include <sstream>

namespace mapnik {

    template <typename T>
    T get(const boost::property_tree::ptree & node, const std::string & name, bool is_attribute,
            const T & default_value);
    template <typename T>
    T get(const boost::property_tree::ptree & node, const std::string & name, bool is_attribute);
    template <typename T>
    T get_own(const boost::property_tree::ptree & node, const std::string & name);
    template <typename T>
    boost::optional<T> get_optional(const boost::property_tree::ptree & node, const std::string & name,
                                    bool is_attribute);

    template <typename T>
    boost::optional<T> get_opt_attr( const boost::property_tree::ptree & node,
                                      const std::string & name)
    {
        return get_optional<T>( node, name, true);
    }

    template <typename T>
    boost::optional<T> get_opt_child( const boost::property_tree::ptree & node,
                                      const std::string & name)
    {
        return get_optional<T>( node, name, false);
    }

    template <typename T>
    T get_attr( const boost::property_tree::ptree & node, const std::string & name,
                const T & default_value )
    {
        return get<T>( node, name, true, default_value);
    }

    template <typename T>
    T get_attr( const boost::property_tree::ptree & node, const std::string & name )
    {
        return get<T>( node, name, true );
    }

    template <typename T>
    T get_css( const boost::property_tree::ptree & node, const std::string & name )
    {
        return get_own<T>( node, std::string("CSS parameter '") + name + "'");
    }

    /** Stream input operator for Color values */
    template <typename charT, typename traits>
    std::basic_istream<charT, traits> &
    operator >> ( std::basic_istream<charT, traits> & s, mapnik::Color & c )
    {
        std::string word;
        s >> word;
        if ( s ) 
        {
            try
            {
                c = mapnik::color_factory::from_string( word.c_str() );
            }
            catch (...) 
            {
                s.setstate( std::ios::failbit );    
            }
        }
        return s;
    }

    template <typename charT, typename traits>
    std::basic_ostream<charT, traits> &
    operator << ( std::basic_ostream<charT, traits> & s, const mapnik::Color & c )
    {
        std::string hex_string( c.to_hex_string() );
        s << hex_string;
        return s;
    }

    /** Helper for class bool */
    class boolean {
        public:
            boolean() {}
            boolean(bool b) : b_(b) {}
            boolean(const boolean & b) : b_(b.b_) {}

            operator bool() const 
            {
                return b_;
            }
            boolean & operator = (const boolean & other)
            {
                b_ = other.b_;
                return * this;
            }
            boolean & operator = (bool other)
            {
                b_ = other;
                return * this;
            }
        private:
            bool b_;
    };

    /** Special stream input operator for boolean values */
    template <typename charT, typename traits>
    std::basic_istream<charT, traits> &
    operator >> ( std::basic_istream<charT, traits> & s, boolean & b )
    {
        std::string word;
        s >> word;
        if ( s ) 
        {
            if ( word == "true" || word == "yes" || word == "on" || 
                 word == "1")
            {
                b = true;
            }
            else if ( word == "false" || word == "no" || word == "off" ||
                      word == "0")
            {
                b = false;
            }
            else
            {
                s.setstate( std::ios::failbit );    
            }
        }
        return s;
    }

    template <typename charT, typename traits>
    std::basic_ostream<charT, traits> &
    operator << ( std::basic_ostream<charT, traits> & s, const boolean & b )
    {
        s << ( b ? "true" : "false" );
        return s;
    }

    template <typename T>
    void set_attr(boost::property_tree::ptree & pt, const std::string & name, const T & v)
    {
        pt.put("<xmlattr>." + name, v);
    }

    /*
    template <>
    void set_attr<bool>(boost::property_tree::ptree & pt, const std::string & name, const bool & v)
    {
        pt.put("<xmlattr>." + name, boolean(v));
    }
    */

    class boolean;

    template <typename T>
    void set_css(boost::property_tree::ptree & pt, const std::string & name, const T & v)
    {
        boost::property_tree::ptree & css_node = pt.push_back(
            boost::property_tree::ptree::value_type("CssParameter", 
            boost::property_tree::ptree()))->second;
        css_node.put("<xmlattr>.name", name );
        css_node.put_own( v );
    }

    template <typename T>
    struct name_trait
    {
        static std::string name()
        {
            return "<unknown>";
        }
        // missing name_trait for type ...
        // if you get here you are probably using a new type
        // in the XML file. Just add a name trait for the new
        // type below.
        BOOST_STATIC_ASSERT( sizeof(T) == 0 );
    };

#define DEFINE_NAME_TRAIT_WITH_NAME( type, type_name ) \
    template <> \
    struct name_trait<type> \
    { \
        static std::string name() { return std::string("type ") + type_name; } \
    };

#define DEFINE_NAME_TRAIT( type ) \
    DEFINE_NAME_TRAIT_WITH_NAME( type, #type );

    DEFINE_NAME_TRAIT( double );
    DEFINE_NAME_TRAIT( float );
    DEFINE_NAME_TRAIT( unsigned );
    DEFINE_NAME_TRAIT( boolean );
    DEFINE_NAME_TRAIT_WITH_NAME( int, "integer" );
    DEFINE_NAME_TRAIT_WITH_NAME( std::string, "string" );
    DEFINE_NAME_TRAIT_WITH_NAME( Color, "color" );

    template <typename ENUM, int MAX>
    struct name_trait< mapnik::enumeration<ENUM, MAX> >
    {
        typedef enumeration<ENUM, MAX> Enum;

        static std::string name()
        {
            std::string value_list("one of [");
            for (unsigned i = 0; i < Enum::MAX; ++i)
            {
                value_list += Enum::get_string( i );
                if ( i + 1 < Enum::MAX ) value_list += ", ";
            }
            value_list += "]";
            
            return value_list;
        }
    };

    template <typename T>
    T get(const boost::property_tree::ptree & node, const std::string & name, bool is_attribute,
          const T & default_value)
    {
        boost::optional<std::string> str;
        if (is_attribute)
        {
            str = node.get_optional<std::string>( std::string("<xmlattr>.") + name );
        }
        else
        {
            str = node.get_optional<std::string>(name );
        }

        if ( str ) {
            try
            {
                return boost::lexical_cast<T>( * str );
            }
            catch (const boost::bad_lexical_cast & )
            {
                throw config_error(string("Failed to parse ") +
                        (is_attribute ? "attribute" : "child node") + " '" +
                        name + "'. Expected " + name_trait<T>::name() +
                        " but got '" + *str + "'");
            }
        } else {
            return default_value;
        }
    }

    template <typename T>
    T get(const boost::property_tree::ptree & node, const std::string & name, bool is_attribute)
    {
        boost::optional<std::string> str;
        if (is_attribute)
        {
            str = node.get_optional<std::string>( std::string("<xmlattr>.") + name);
        }
        else
        {
            str = node.get_optional<std::string>(name);
        }

        if ( ! str ) {
            throw config_error(string("Required ") +
                    (is_attribute ? "attribute " : "child node ") +
                    "'" + name + "' is missing");
        }
        try
        {
            return boost::lexical_cast<T>( *str );
        }
        catch (const boost::bad_lexical_cast & )
        {
            throw config_error(string("Failed to parse ") +
                    (is_attribute ? "attribute" : "child node") + " '" +
                    name + "'. Expected " + name_trait<T>::name() +
                    " but got '" + *str + "'");
        }
    }

    template <typename T>
    T get_own(const boost::property_tree::ptree & node, const std::string & name)
    {
        try
        {
            return node.get_own<T>();
        }
        catch (...)
        {
            throw config_error(string("Failed to parse ") +
                    name + ". Expected " + name_trait<T>::name() +
                    " but got '" + node.data() + "'");
        }
    }

    template <typename T>
    boost::optional<T> get_optional(const boost::property_tree::ptree & node, const std::string & name,
                                    bool is_attribute)
    {
        boost::optional<std::string> str;
        if (is_attribute)
        {
            str = node.get_optional<std::string>( std::string("<xmlattr>.") + name);
        }
        else
        {
            str = node.get_optional<std::string>(name);
        }

        boost::optional<T> result;
        if ( str ) {
            try
            {
                result = boost::lexical_cast<T>( *str );
            }
            catch (const boost::bad_lexical_cast &)
            {
                throw config_error(string("Failed to parse ") +
                        (is_attribute ? "attribute" : "child node") + " '" +
                        name + "'. Expected " + name_trait<T>::name() +
                        " but got '" + *str + "'");
            }
            
        }
        return result;
    }
} // end of namespace mapnik

#endif // MAPNIK_CONFIG_HELPERS_INCLUDED