/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2005,2006,2007,2008 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * Copyright (©) 2001,2007 Mark Wedel & Crossfire Development Team
 * Copyright (©) 1992,2007 Frank Tore Johansen
 * 
 * Deliantra 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 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 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>
 */

/* peterm@langmuir.eecs.berkeley.edu:  this function generates a random
snake-type layout.

input:  xsize, ysize;
output:  a char** array with # and . for closed and open respectively.

a char value of 0 represents a blank space:  a '#' is
a wall.

*/

#include <global.h>

#include "random_map.h"
#include "rproto.h"

/* These are some helper functions which help with
   manipulating a centered onion and turning it into
   a square spiral */

/* this starts from within a centered onion layer (or between two layers),
   and looks up until it finds a wall, and then looks right until it
   finds a vertical wall, i.e., the corner.  It sets cx and cy to that.
   it also starts from cx and cy. */

void
find_top_left_corner (char **maze, int *cx, int *cy)
{
  --(*cy);

  /* find the top wall. */
  while (maze[*cx][*cy] == 0)
    --(*cy);

  /* proceed right until a corner is detected */
  while (maze[*cx][*cy + 1] == 0)
    ++(*cx);

  /* cx and cy should now be the top-right corner of the onion layer */
}

void
make_square_spiral_layout (Maze maze, int options)
{
  int i, j;
  int cx, cy;
  int tx, ty;

  /* generate and allocate a doorless, centered onion */
  map_gen_onion (maze, RMOPT_CENTERED | RMOPT_NO_DOORS, 0);

  int xsize = maze->w;
  int ysize = maze->h;

  /* find the layout center.  */
  cx = 0;
  cy = 0;
  for (i = 0; i < xsize; i++)
    for (j = 0; j < ysize; j++)
      if (maze[i][j] == 'C')
        {
          cx = i;
          cy = j;
        }

  tx = cx;
  ty = cy;
  for (;;)
    {
      find_top_left_corner (maze, &tx, &ty);

      if (ty < 2 || tx < 2 || tx > xsize - 2 || ty > ysize - 2)
        break;

      make_wall (maze, tx, ty - 1, 1);  /* make a vertical wall with a door */

      maze[tx][ty - 1] = '#';   /* convert the door that make_wall puts here to a wall */
      maze[tx - 1][ty] = 'D';   /* make a doorway out of this layer */

      /* walk left until we find the top-left corner */
      while ((tx > 2) && maze[tx - 1, ty])
        tx--;

      make_wall (maze, tx - 1, ty, 0);  /* make a horizontal wall with a door */

      /* walk down until we find the bottom-left corner */
      while (((ty + 1) < ysize) && maze[tx][ty + 1])
        ty++;

      make_wall (maze, tx, ty + 1, 1);  /* make a vertical wall with a door */

      /* walk rightuntil we find the bottom-right corner */
      while (((tx + 1) < xsize) && maze[tx + 1][ty])
        tx++;

      make_wall (maze, tx + 1, ty, 0);  /* make a horizontal wall with a door */
      tx++;                     /* set up for next layer. */
    }

  /* place the exits.  */

  if (rndm (2))
    {
      maze[cx][cy] = '>';
      maze[xsize - 2][1] = '<';
    }
  else
    {
      maze[cx][cy] = '<';
      maze[xsize - 2][1] = '>';
    }
}