//  $Id: path.cpp 2986 2007-08-17 16:20:09Z grumbel $
//
//  Pingus - A free Lemmings clone
//  Copyright (C) 2002 Ingo Ruhnke <grumbel@gmx.de>
//
//  This program is free software; you can redistribute it and/or
//  modify it under the terms of the GNU General Public License
//  as published by the Free Software Foundation; either version 2
//  of the License, or (at your option) any later version.
//
//  This program 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 General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

#include <iostream>
#include <algorithm>
#include <assert.h>
#include "path.hpp"

namespace WorldMapNS {

Path::Path()
  : path_length_valid (false)
{
}

std::vector<Vector3f >::size_type
Path::size()
{
  return vec.size();
}

float
Path::length()
{
  if (path_length_valid)
    {
      return path_length;
    }
  else
    {
      path_length = calc_length ();
      path_length_valid = true;
      return path_length;
    }
}

float
Path::calc_length()
{
  if (vec.empty())
    {
      return 0.0f;
    }
  else
    {
      float length = 0;
      Vec::iterator prev = vec.begin();
      for(Vec::iterator next = prev + 1; next != vec.end(); ++next)
        {
          length += Vector3f ::distance2d(*prev, *next);
          prev = next;
        }
      return length;
    }
}

Vector3f 
Path::at(float vec_position)
{
  assert(!vec.empty());

  Path::iterator current = vec.begin ();
  Path::iterator next    = vec.begin () + 1;

  float comp_length = 0.0f;
  while (next != vec.end())
    {
      float length = Vector3f::distance2d(*current, *next);

      // The pingu is between current and next
      if (comp_length + length > vec_position)
        {
          float perc = (vec_position - comp_length) // length to walk from current node
            / length;

          return Vector3f::interpolate(*current, *next, perc);
        }

      comp_length += length;

      ++current;
      ++next;
    }
  return vec.back();
}

void
Path::reverse()
{
  std::reverse(vec.begin (), vec.end ());
}

} // namespace WorldMapNS

/* EOF */