/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2010 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * 
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 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 Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

#include <global.h>
#include <random_map.h>

LayoutData::LayoutData (int w, int h)
: w(w), h(h)
{
  int size = (sizeof (char *) + sizeof (char) * h) * w;

  col = (char **)salloc<char> (size);

  char *data = (char *)(col + w);

  for (int x = w; x--; )
    col [x] = data + x * h;
}

LayoutData::~LayoutData ()
{
  int size = (sizeof (char *) + sizeof (char) * h) * w;

  sfree ((char *)col, size);
}

void
LayoutData::fill (char fill)
{
  memset (col [0], fill, w * h);
}

void
LayoutData::rect (int x1, int y1, int x2, int y2, char fill)
{
  for (; x1 < x2; ++x1)
    memset (col [x1] + y1, fill, y2 - y1);
}

void LayoutData::border (char fill)
{
  for (int i = 0; i < w; i++) col [i][0] = col [i][h - 1] = fill;
  for (int j = 0; j < h; j++) col [0][j] = col [w - 1][j] = fill;
}

/////////////////////////////////////////////////////////////////////////////

void
Layout::print ()
{
  for (int y = 0; y < ptr->h; y++)
    {
      for (int x = 0; x < ptr->w; x++)
        {
          U8 c = (U8)ptr->col[x][y];

          if (!c)
            c = ' ';
          else if (c < 10)
            c += '0';
          else if (c < 32)
            c += 'a' - 10;

          putc ((char)c, stdout);
        }

      putc ('\n', stdout);
    }

  putc ('\n', stdout);
}

/////////////////////////////////////////////////////////////////////////////
// isolation remover - ensures single connected area

typedef fixed_stack<point> pointlist;

static void
room (Layout &layout, int xc, int yc)
{
  layout->rect (xc - 2, yc - 2, xc + 3, yc + 3, 0);
}

static noinline void
push_flood_fill (Layout maze, Layout dist, pointlist &seeds, int x, int y)
{
  if (maze [x][y])
    return;

  while (y > 0 && !maze [x][y - 1])
    --y;

  int y0 = y;

  while (y < maze->h && !maze [x][y])
    {
      seeds.push (point (x, y));

      maze [x][y] = 1;
      dist [x][y] = 1;
      ++y;
    }

  while (--y >= y0)
    {
      if (x >           0) push_flood_fill (maze, dist, seeds, x - 1, y);
      if (x < maze->w - 1) push_flood_fill (maze, dist, seeds, x + 1, y);
    }
}

static inline void
make_tunnel (Layout maze, Layout dist, pointlist &seeds, int x, int y, U8 d)
{
  for (;;)
    {
      seeds.push (point (x, y));

      maze [x][y] = 1;
      dist [x][y] = 1;

      if (x >                1 && U8 (dist [x - 1][y]) < d && dist [x - 1][y] > 1)
        --x;
      else if (x < maze->w - 2 && U8 (dist [x + 1][y]) < d && dist [x + 1][y] > 1)
        ++x;
      else if (y >           1 && U8 (dist [x][y - 1]) < d && dist [x][y - 1] > 1)
        --y;
      else if (y < maze->h - 2 && U8 (dist [x][y + 1]) < d && dist [x][y + 1] > 1)
        ++y;
      else
        break;

      d = dist [x][y];
    }
}

static void
isolation_remover (Layout maze, bool dirty)
{
  Layout dist (maze->w, maze->h);

  dist->fill (255);

  fixed_stack<point> seeds (maze->w * maze->h * 4);

  // phase 1, find seed
  for (int x = 1; x < maze->w; ++x)
    for (int y = 1; y < maze->h; ++y)
      if (!maze [x][y])
        {
          seeds.push (point (x, y));

          // phase 2, while we have seeds, if
          // seed is empty, floodfill, else grow

          while (seeds.size)
            {
              point p = seeds.remove (rmg_rndm (seeds.size));

              x = p.x;
              y = p.y;

              if (!maze [x][y])
                {
                  // found new isolated area, make tunnel?
                  if (!dirty)
                    push_flood_fill (maze, dist, seeds, x, y);

                  make_tunnel (maze, dist, seeds, x, y, 255);

                  if (dirty)
                    push_flood_fill (maze, dist, seeds, x, y);
                }
              else
                {
                  U8 d = U8 (dist [x][y]) + 1;

                  if (x < maze->w - 1 && U8 (dist [x + 1][y]) > d)
                    {
                      dist [x + 1][y] = d;
                      seeds.push (point (x + 1, y));
                    }

                  if (x > 0           && U8 (dist [x - 1][y]) > d)
                    {
                      dist [x - 1][y] = d;
                      seeds.push (point (x - 1, y));
                    }

                  if (y < maze->h - 1 && U8 (dist [x][y + 1]) > d)
                    {
                      dist [x][y + 1] = d;
                      seeds.push (point (x, y + 1));
                    }

                  if (y > 0           && U8 (dist [x][y - 1]) > d)
                    {
                      dist [x][y - 1] = d;
                      seeds.push (point (x, y - 1));
                    }
                }
            }

          goto success;
        }

success:
  dist.free ();

  // we mark free but visited floors as 1, undo this here
  for (int x = 0; x < maze->w; ++x)
    for (int y = 0; y < maze->h; ++y)
      if (maze [x][y] == 1)
        maze [x][y] = 0;
}

void
LayoutData::isolation_remover (bool dirty)
{
  Layout maze;
  maze.ptr = this;
  ::isolation_remover (maze, dirty);
}

#if 0
static struct demo
{
  demo ()
  {
    Layout maze (40, 25);
    rmg_rndm.seed (time (0));

    for (int p = 80; p < 100; p += 1) {
    maze->fill ('#');

#if 1
    for (int x = 1; x < maze->w - 1; ++x)
      for (int y = 1; y < maze->h - 1; ++y)
        maze [x][y] = rmg_rndm(100) < p ? '#' : 0;
#else
    room (maze,  5, 5);
    room (maze, 30,20);
    room (maze, 10,20);
    room (maze, 20,10);
#endif

    isolation_remover (maze, 1);
    maze.print ();
    }

#if 0
    for(int i=1;i<10;i)
      {
        maze_gen (maze, 1);
        maze.print ();
      }
#endif
    exit (1);
  }
} demo;
#endif