//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.3
// 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
//----------------------------------------------------------------------------
//
// Line dash generator
//
//----------------------------------------------------------------------------

public class agg_vcgen_dash {
  //enum max_dashes_e
  final static public int max_dashes = 32;

  //enum status_e  values arbitrarily chosen
  final static public int initial = 1;
  final static public int ready = 2;
  final static public int polyline = 3;
  final static public int stop = 4;

  //typedef vertex_sequence<vertex_dist, 6> vertex_storage;

  //vcgen_dash(const vcgen_dash&);
  //const vcgen_dash& operator = (const vcgen_dash&);

  private float m_dashes[] = new float[max_dashes];
  private float m_total_dash_len;
  private int m_num_dashes;  // un
  private float m_dash_start;
  private float m_shorten;
  private float m_curr_dash_start;
  private unsigned m_curr_dash;
  private float m_curr_rest;
  private vertex_dist m_v1;
  private vertex_dist m_v2;

  private vertex_storage m_src_vertices;
  private unsigned m_closed;
  private status_e m_status;
  private unsigned m_src_vertex;


  public agg_vcgen_dash() {
    m_total_dash_len = 0;
    m_num_dashes = 0;
    m_dash_start = 0;
    m_shorten = 0;
    m_curr_dash_start = 0;
    m_curr_dash = 0;
    m_src_vertices = new vertex_storage();
    m_closed(0);
    m_status(initial);
    m_src_vertex(0);
  }


  public void remove_all_dashes() {
    m_total_dash_len = 0;
    m_num_dashes = 0;
    m_curr_dash_start = 0;
    m_curr_dash = 0;
  }


  public void add_dash(float dash_len, float gap_len) {
    if (m_num_dashes < max_dashes) {
      m_total_dash_len += dash_len + gap_len;
      m_dashes[m_num_dashes++] = dash_len;
      m_dashes[m_num_dashes++] = gap_len;
    }
  }


  public void dash_start(float ds) {
    m_dash_start = ds;
    calc_dash_start(Math.abs(ds));
  }


  private void calc_dash_start(float ds) {
    m_curr_dash = 0;
    m_curr_dash_start = 0.0;
    while (ds > 0.0f) {
      if(ds > m_dashes[m_curr_dash]) {
        ds -= m_dashes[m_curr_dash];
        ++m_curr_dash;
        m_curr_dash_start = 0.0;
        if (m_curr_dash >= m_num_dashes) m_curr_dash = 0;
      } else {
        m_curr_dash_start = ds;
        ds = 0.0f;
      }
    }
  }


  public void remove_all() {
    m_status = initial;
    m_src_vertices.remove_all();
    m_closed = 0;
  }


  public void shorten(float s) {
    m_shorten = s;
  }


  public float shorten() {
    return m_shorten;
  }


  public void add_vertex(float x, float y, int cmd) {  // un
    m_status = initial;
    if (agg_basics.is_move_to(cmd)) {
      m_src_vertices.modify_last(vertex_dist(x, y));
    } else {
      if (is_vertex(cmd)) {
        m_src_vertices.add(vertex_dist(x, y));
      } else {
        m_closed = get_close_flag(cmd);
      }
    }
  }


  //void rewind(unsigned path_id);  // ??

  public void rewind() {
    if (m_status == initial) {
      m_src_vertices.close(m_closed != 0);
      shorten_path(m_src_vertices, m_shorten, m_closed);
    }
    m_status = ready;
    m_src_vertex = 0;
  }


  public int vertex(double x[], double y[], int offset) {  // un
    int cmd = path_cmd_move_to;  // un
    while (!agg_basics.is_stop(cmd)) {
      switch (m_status) {
      case initial:
        rewind(0);

      case ready:
        if(m_num_dashes < 2 || m_src_vertices.size() < 2) {
          cmd = path_cmd_stop;
          break;
        }
        m_status = polyline;
        m_src_vertex = 1;
        m_v1 = &m_src_vertices[0];
        m_v2 = &m_src_vertices[1];
        m_curr_rest = m_v1->dist;
        *x = m_v1->x;
        *y = m_v1->y;
        if (m_dash_start >= 0.0) calc_dash_start(m_dash_start);
        return path_cmd_move_to;

      case polyline: {
        float dash_rest = m_dashes[m_curr_dash] - m_curr_dash_start;

        int cmd = (m_curr_dash & 1) ? path_cmd_move_to : path_cmd_line_to;

        if(m_curr_rest > dash_rest) {
          m_curr_rest -= dash_rest;
          ++m_curr_dash;
          if(m_curr_dash >= m_num_dashes) m_curr_dash = 0;
          m_curr_dash_start = 0.0;
          x[offset] = m_v2->x - (m_v2->x - m_v1->x) * m_curr_rest / m_v1->dist;
          y[offset] = m_v2->y - (m_v2->y - m_v1->y) * m_curr_rest / m_v1->dist;
        } else {
          m_curr_dash_start += m_curr_rest;
          x[offset] = m_v2->x;
          y[offset] = m_v2->y;
          ++m_src_vertex;
          m_v1 = m_v2;
          m_curr_rest = m_v1->dist;
          if (m_closed) {
            if(m_src_vertex > m_src_vertices.size()) {
              m_status = stop;
            } else {
              m_v2 = &m_src_vertices[(m_src_vertex >= m_src_vertices.size()) ?
                                     0 : m_src_vertex];
            }
          } else {
            if (m_src_vertex >= m_src_vertices.size()) {
              m_status = stop;
            } else {
              m_v2 = &m_src_vertices[m_src_vertex];
            }
          }
        }
        return cmd;
      }
        break;

      case stop:
        cmd = path_cmd_stop;
        break;
      }
    }
    return path_cmd_stop;
  }
}