/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 *
 * Copyright (©) 2017,2018 Marc Alexander Lehmann / the Deliantra team
 * Copyright (©) 2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * Copyright (©) 2001 Mark Wedel & Crossfire Development Team
 * Copyright (©) 1992 Frank Tore Johansen
 *
 * 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>
 */

/*  The onion room generator:
Onion rooms are like this:

char **map_gen_onion(int xsize, int ysize, int option, int layers);

like this:
regular			      random
centered, linear onion        bottom/right centered, nonlinear

#########################     #########################
#                       #     #                       #
# ########  ##########  #     #   #####################
# #                  #  #     #   #                   #
# # ######  ######## #  #     #   #                   #
# # #              # #  #     #   #   ######## ########
# # # ####  ###### # #  #     #   #   #               #
# # # #          # # #  #     #   #   #               #
# # # ############ # #  #     #   #   #  ########### ##
# # #              # #  #     #   #   #  #            #
# # ################ #  #     #   #   #  #    #########
# #                  #  #     #       #  #    #       #
# ####################  #     #   #   #  #            #
#                       #     #   #   #  #    #       #
#########################     #########################

*/


#include <global.h>
#include <rmg.h>
#include <rproto.h>

static void centered_onion (char **maze, int xsize, int ysize, int option, int layers);
static void bottom_centered_onion (char **maze, int xsize, int ysize, int option, int layers);
static void bottom_right_centered_onion (char **maze, int xsize, int ysize, int option, int layers);

static void draw_onion (char **maze, float *xlocations, float *ylocations, int layers);
static void make_doors (char **maze, float *xlocations, float *ylocations, int layers, int options);

void
map_gen_onion (layout &maze, int option, int layers)
{
  int xsize = maze.w;
  int ysize = maze.h;

  maze.clear ();

  /* pick some random options if option = 0 */
  if (option == 0)
    {
      switch (rmg_rndm (3))
        {
          case 0:
            option |= RMOPT_CENTERED;
            break;
          case 1:
            option |= RMOPT_BOTTOM_C;
            break;
          case 2:
            option |= RMOPT_BOTTOM_R;
            break;
        }

      if (rmg_rndm (2)) option |= RMOPT_LINEAR;
      if (rmg_rndm (2)) option |= RMOPT_IRR_SPACE;
    }

  /* write the outer walls, if appropriate. */
  if (!(option & RMOPT_WALL_OFF))
    maze.border ();

  if (option & RMOPT_WALLS_ONLY)
    return;

  /* pick off the mutually exclusive options */
  if (option & RMOPT_BOTTOM_R)
    bottom_right_centered_onion (maze, xsize, ysize, option, layers);
  else if (option & RMOPT_BOTTOM_C)
    bottom_centered_onion (maze, xsize, ysize, option, layers);
  else if (option & RMOPT_CENTERED)
    centered_onion (maze, xsize, ysize, option, layers);
}

static void
centered_onion (char **maze, int xsize, int ysize, int option, int layers)
{
  int i, maxlayers;

  maxlayers = (min (xsize, ysize) - 2) / 5;

  if (!maxlayers)
    return;                     /* map too small to onionize */

  if (layers > maxlayers)
    layers = maxlayers;

  if (layers == 0)
    layers = rmg_rndm (maxlayers) + 1;

  float *xlocations = salloc0<float> (2 * layers);
  float *ylocations = salloc0<float> (2 * layers);

  /* place all the walls */
  if (option & RMOPT_IRR_SPACE) /* randomly spaced */
    {
      int x_spaces_available, y_spaces_available;

      /* the "extra" spaces available for spacing between layers */
      x_spaces_available = (xsize - 2) - 6 * layers + 1;
      y_spaces_available = (ysize - 2) - 6 * layers + 1;

      /* pick an initial random pitch */
      for (i = 0; i < 2 * layers; i++)
        {
          float xpitch = 2, ypitch = 2;

          if (x_spaces_available > 0)
            xpitch = 2 + (rmg_rndm (x_spaces_available) + rmg_rndm (x_spaces_available) + rmg_rndm (x_spaces_available)) / 3;

          if (y_spaces_available > 0)
            ypitch = 2 + (rmg_rndm (y_spaces_available) + rmg_rndm (y_spaces_available) + rmg_rndm (y_spaces_available)) / 3;

          xlocations[i] = ((i > 0) ? xlocations[i - 1] : 0) + xpitch;
          ylocations[i] = ((i > 0) ? ylocations[i - 1] : 0) + ypitch;
          x_spaces_available -= (int) (xpitch - 2);
          y_spaces_available -= (int) (ypitch - 2);
        }

    }

  if (!(option & RMOPT_IRR_SPACE))
    {                           /* evenly spaced */
      float xpitch, ypitch;     /* pitch of the onion layers */

      xpitch = (xsize - 2.0) / (2.0 * layers + 1);
      ypitch = (ysize - 2.0) / (2.0 * layers + 1);

      xlocations[0] = xpitch;
      ylocations[0] = ypitch;

      for (i = 1; i < 2 * layers; i++)
        {
          xlocations[i] = xlocations[i - 1] + xpitch;
          ylocations[i] = ylocations[i - 1] + ypitch;
        }
    }

  /* draw all the onion boxes.  */
  draw_onion (maze, xlocations, ylocations, layers);
  make_doors (maze, xlocations, ylocations, layers, option);

  sfree (xlocations, 2 * layers);
  sfree (ylocations, 2 * layers);
}

static void
bottom_centered_onion (char **maze, int xsize, int ysize, int option, int layers)
{
  int i, maxlayers;

  maxlayers = (min (xsize, ysize) - 2) / 5;

  if (!maxlayers)
    return;                     /* map too small to onionize */

  if (layers > maxlayers)
    layers = maxlayers;

  if (layers == 0)
    layers = rmg_rndm (maxlayers) + 1;

  float *xlocations = salloc0<float> (2 * layers);
  float *ylocations = salloc0<float> (2 * layers);

  /* place all the walls */
  if (option & RMOPT_IRR_SPACE) /* randomly spaced */
    {
      int x_spaces_available, y_spaces_available;

      /* the "extra" spaces available for spacing between layers */
      x_spaces_available = (xsize - 2) - 6 * layers + 1;
      y_spaces_available = (ysize - 2) - 3 * layers + 1;

      /* pick an initial random pitch */
      for (i = 0; i < 2 * layers; i++)
        {
          float xpitch = 2, ypitch = 2;

          if (x_spaces_available > 0)
            xpitch = 2 + (rmg_rndm (x_spaces_available) + rmg_rndm (x_spaces_available) + rmg_rndm (x_spaces_available)) / 3;

          if (y_spaces_available > 0)
            ypitch = 2 + (rmg_rndm (y_spaces_available) + rmg_rndm (y_spaces_available) + rmg_rndm (y_spaces_available)) / 3;

          xlocations[i] = ((i > 0) ? xlocations[i - 1] : 0) + xpitch;

          if (i < layers)
            ylocations[i] = ((i > 0) ? ylocations[i - 1] : 0) + ypitch;
          else
            ylocations[i] = ysize - 1;

          x_spaces_available -= (int) (xpitch - 2);
          y_spaces_available -= (int) (ypitch - 2);
        }
    }

  if (!(option & RMOPT_IRR_SPACE))
    {                           /* evenly spaced */
      float xpitch, ypitch;     /* pitch of the onion layers */

      xpitch = (xsize - 2.0) / (2.0 * layers + 1);
      ypitch = (ysize - 2.0) / (layers + 1);

      xlocations[0] = xpitch;
      ylocations[0] = ypitch;

      for (i = 1; i < 2 * layers; i++)
        {
          xlocations[i] = xlocations[i - 1] + xpitch;

          if (i < layers)
            ylocations[i] = ylocations[i - 1] + ypitch;
          else
            ylocations[i] = ysize - 1;
        }
    }

  /* draw all the onion boxes.  */

  draw_onion (maze, xlocations, ylocations, layers);
  make_doors (maze, xlocations, ylocations, layers, option);

  sfree (xlocations, 2 * layers);
  sfree (ylocations, 2 * layers);
}

/*  draw_boxes: draws the lines in the maze defining the onion layers */
static void
draw_onion (char **maze, float *xlocations, float *ylocations, int layers)
{
  int i, j, l;

  for (l = 0; l < layers; l++)
    {
      int x1, x2, y1, y2;

      /* horizontal segments */
      y1 = (int) ylocations[l];
      y2 = (int) ylocations[2 * layers - l - 1];
      for (i = (int) xlocations[l]; i <= (int) xlocations[2 * layers - l - 1]; i++)
        {
          maze[i][y1] = '#';
          maze[i][y2] = '#';
        }

      /* vertical segments */
      x1 = (int) xlocations[l];
      x2 = (int) xlocations[2 * layers - l - 1];
      for (j = (int) ylocations[l]; j <= (int) ylocations[2 * layers - l - 1]; j++)
        {
          maze[x1][j] = '#';
          maze[x2][j] = '#';
        }

    }
}

static void
make_doors (char **maze, float *xlocations, float *ylocations, int layers, int options)
{
  int freedoms;                 /* number of different walls on which we could place a door */
  int which_wall;               /* left, 1, top, 2, right, 3, bottom 4 */
  int l, x1 = 0, x2, y1 = 0, y2;

  freedoms = 4;                 /* centered */

  if (options & RMOPT_BOTTOM_C)
    freedoms = 3;

  if (options & RMOPT_BOTTOM_R)
    freedoms = 2;

  if (layers <= 0)
    return;

  /* pick which wall will have a door. */
  which_wall = rmg_rndm (freedoms) + 1;
  for (l = 0; l < layers; l++)
    {
      if (options & RMOPT_LINEAR)
        {                       /* linear door placement. */
          switch (which_wall)
            {
              case 1:
                {               /* left hand wall */
                  x1 = (int) xlocations[l];
                  y1 = (int) ((ylocations[l] + ylocations[2 * layers - l - 1]) / 2);
                  break;
                }
              case 2:
                {               /* top wall placement */
                  x1 = (int) ((xlocations[l] + xlocations[2 * layers - l - 1]) / 2);
                  y1 = (int) ylocations[l];
                  break;
                }
              case 3:
                {               /* right wall placement */
                  x1 = (int) xlocations[2 * layers - l - 1];
                  y1 = (int) ((ylocations[l] + ylocations[2 * layers - l - 1]) / 2);
                  break;
                }
              case 4:
                {               /* bottom wall placement */
                  x1 = (int) ((xlocations[l] + xlocations[2 * layers - l - 1]) / 2);
                  y1 = (int) ylocations[2 * layers - l - 1];
                  break;
                }
            }
        }
      else
        {                       /* random door placement. */
          which_wall = rmg_rndm (freedoms) + 1;
          switch (which_wall)
            {
              case 1:
                {               /* left hand wall */
                  x1 = (int) xlocations[l];
                  y2 = (int) (ylocations[2 * layers - l - 1] - ylocations[l] - 1);
                  if (y2 > 0)
                    y1 = (int) (ylocations[l] + rmg_rndm (y2) + 1);
                  else
                    y1 = (int) (ylocations[l] + 1);
                  break;
                }
              case 2:
                {               /* top wall placement */
                  x2 = (int) ((-xlocations[l] + xlocations[2 * layers - l - 1])) - 1;
                  if (x2 > 0)
                    x1 = (int) (xlocations[l] + rmg_rndm (x2) + 1);
                  else
                    x1 = (int) (xlocations[l] + 1);
                  y1 = (int) ylocations[l];
                  break;
                }
              case 3:
                {               /* right wall placement */
                  x1 = (int) xlocations[2 * layers - l - 1];
                  y2 = (int) ((-ylocations[l] + ylocations[2 * layers - l - 1])) - 1;
                  if (y2 > 0)
                    y1 = (int) (ylocations[l] + rmg_rndm (y2) + 1);
                  else
                    y1 = (int) (ylocations[l] + 1);

                  break;
                }
              case 4:
                {               /* bottom wall placement */
                  x2 = (int) ((-xlocations[l] + xlocations[2 * layers - l - 1])) - 1;
                  if (x2 > 0)
                    x1 = (int) (xlocations[l] + rmg_rndm (x2) + 1);
                  else
                    x1 = (int) (xlocations[l] + 1);
                  y1 = (int) ylocations[2 * layers - l - 1];
                  break;
                }

            }
        }

      if (options & RMOPT_NO_DOORS)
        maze[x1][y1] = '#';     /* no door. */
      else
        maze[x1][y1] = 'D';     /* write the door */

    }
  /* mark the center of the maze with a C */
  l = layers - 1;
  x1 = (int) (xlocations[l] + xlocations[2 * layers - l - 1]) / 2;
  y1 = (int) (ylocations[l] + ylocations[2 * layers - l - 1]) / 2;

  maze[x1][y1] = 'C';
}

static void
bottom_right_centered_onion (char **maze, int xsize, int ysize, int option, int layers)
{
  int i, maxlayers;

  maxlayers = (min (xsize, ysize) - 2) / 5;

  if (!maxlayers)
    return;                     /* map too small to onionize */

  if (layers > maxlayers)
    layers = maxlayers;

  if (layers == 0)
    layers = rmg_rndm (maxlayers) + 1;

  float *xlocations = salloc0<float> (2 * layers);
  float *ylocations = salloc0<float> (2 * layers);

  /* place all the walls */
  if (option & RMOPT_IRR_SPACE) /* randomly spaced */
    {
      int x_spaces_available, y_spaces_available;

      /* the "extra" spaces available for spacing between layers */
      x_spaces_available = (xsize - 2) - 3 * layers + 1;
      y_spaces_available = (ysize - 2) - 3 * layers + 1;


      /* pick an initial random pitch */
      for (i = 0; i < 2 * layers; i++)
        {
          float xpitch = 2, ypitch = 2;

          if (x_spaces_available > 0)
            xpitch = 2 + (rmg_rndm (x_spaces_available) + rmg_rndm (x_spaces_available) + rmg_rndm (x_spaces_available)) / 3;

          if (y_spaces_available > 0)
            ypitch = 2 + (rmg_rndm (y_spaces_available) + rmg_rndm (y_spaces_available) + rmg_rndm (y_spaces_available)) / 3;

          if (i < layers)
            xlocations[i] = ((i > 0) ? xlocations[i - 1] : 0) + xpitch;
          else
            xlocations[i] = xsize - 1;

          if (i < layers)
            ylocations[i] = ((i > 0) ? ylocations[i - 1] : 0) + ypitch;
          else
            ylocations[i] = ysize - 1;

          x_spaces_available -= (int) (xpitch - 2);
          y_spaces_available -= (int) (ypitch - 2);
        }
    }

  if (!(option & RMOPT_IRR_SPACE))
    {                           /* evenly spaced */
      float xpitch, ypitch;     /* pitch of the onion layers */

      xpitch = (xsize - 2.0) / (2.0 * layers + 1);
      ypitch = (ysize - 2.0) / (layers + 1);

      xlocations[0] = xpitch;
      ylocations[0] = ypitch;

      for (i = 1; i < 2 * layers; i++)
        {
          if (i < layers)
            xlocations[i] = xlocations[i - 1] + xpitch;
          else
            xlocations[i] = xsize - 1;

          if (i < layers)
            ylocations[i] = ylocations[i - 1] + ypitch;
          else
            ylocations[i] = ysize - 1;
        }
    }

  /* draw all the onion boxes.  */

  draw_onion (maze, xlocations, ylocations, layers);
  make_doors (maze, xlocations, ylocations, layers, option);

  sfree (xlocations, 2 * layers);
  sfree (ylocations, 2 * layers);
}