//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
//          mcseemagg@yahoo.com
//          http://www.antigrain.com
//----------------------------------------------------------------------------

#ifndef AGG_CONV_ADAPTOR_VCGEN_INCLUDED
#define AGG_CONV_ADAPTOR_VCGEN_INCLUDED

#include "agg_basics.h"

namespace agg
{
    //------------------------------------------------------------null_markers
    struct null_markers
    {
        void remove_all() {}
        void add_vertex(double, double, unsigned) {}
        void prepare_src() {}

        void rewind(unsigned) {}
        unsigned vertex(double*, double*)
        {
            return path_cmd_stop;
        }
    };

    //------------------------------------------------------conv_adaptor_vcgen
    template <class VertexSource, class Generator, class Markers = null_markers>
    class conv_adaptor_vcgen
    {
        enum status
        {
            initial,
            accumulate,
            generate
        };

    public:
        explicit conv_adaptor_vcgen(VertexSource& source):
            m_source(&source),
            m_status(initial)
        {
        }
        void attach(VertexSource& source)
        {
            m_source = &source;
        }

        Generator& generator()
        {
            return m_generator;
        }
        const Generator& generator() const
        {
            return m_generator;
        }

        Markers& markers()
        {
            return m_markers;
        }
        const Markers& markers() const
        {
            return m_markers;
        }

        void rewind(unsigned path_id)
        {
            m_source->rewind(path_id);
            m_status = initial;
        }

        unsigned vertex(double* x, double* y);

    private:
        // Prohibit copying
        conv_adaptor_vcgen(
            const conv_adaptor_vcgen<VertexSource, Generator, Markers>&);
        const conv_adaptor_vcgen<VertexSource, Generator, Markers>& operator=(
            const conv_adaptor_vcgen<VertexSource, Generator, Markers>&);

        VertexSource* m_source;
        Generator m_generator;
        Markers m_markers;
        status m_status;
        unsigned m_last_cmd;
        double m_start_x;
        double m_start_y;
    };

    //------------------------------------------------------------------------
    template <class VertexSource, class Generator, class Markers>
    unsigned conv_adaptor_vcgen<VertexSource, Generator, Markers>::vertex(
        double* x, double* y)
    {
        unsigned cmd = path_cmd_stop;
        bool done = false;
        while (!done)
        {
            switch (m_status)
            {
                case initial:
                    m_markers.remove_all();
                    m_last_cmd = m_source->vertex(&m_start_x, &m_start_y);
                    m_status = accumulate;

                case accumulate:
                    if (is_stop(m_last_cmd))
                        return path_cmd_stop;

                    m_generator.remove_all();
                    m_generator.add_vertex(
                        m_start_x, m_start_y, path_cmd_move_to);
                    m_markers.add_vertex(
                        m_start_x, m_start_y, path_cmd_move_to);

                    for (;;)
                    {
                        cmd = m_source->vertex(x, y);
                        if (is_vertex(cmd))
                        {
                            m_last_cmd = cmd;
                            if (is_move_to(cmd))
                            {
                                m_start_x = *x;
                                m_start_y = *y;
                                break;
                            }
                            m_generator.add_vertex(*x, *y, cmd);
                            m_markers.add_vertex(*x, *y, path_cmd_line_to);
                        }
                        else
                        {
                            if (is_stop(cmd))
                            {
                                m_last_cmd = path_cmd_stop;
                                break;
                            }
                            if (is_end_poly(cmd))
                            {
                                m_generator.add_vertex(*x, *y, cmd);
                                break;
                            }
                        }
                    }
                    m_generator.rewind(0);
                    m_status = generate;

                case generate:
                    cmd = m_generator.vertex(x, y);
                    if (is_stop(cmd))
                    {
                        m_status = accumulate;
                        break;
                    }
                    done = true;
                    break;
            }
        }
        return cmd;
    }

}

#endif
