/*
 * 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>

Layout::Layout (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;
}

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

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

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

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

void Layout::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::fill_rand (int percent)
{
  percent = lerp (percent, 0, 100, 0, 256);

  for (int x = w - 1; --x > 0; )
    for (int y = h - 1; --y > 0; )
      col [x][y] = rmg_rndm (256) > percent ? 0 : '#';
}

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

// erode by cellular automata
void
Layout::erode_1_2 (int c1, int c2, int repeat)
{
  Layout neu (w, h);

  while (repeat--)
    {
      for (int x = 0; x < w; ++x)
        {
          coroapi::cede_to_tick ();

          for (int y = 0; y < h; ++y)
            {
              int n1 = 0, n2 = 0;

              // a 5x5 area, dx, dy, distance (1 == <= 1, 0 <= 2)
              static I8 dds[][3] = {
                               { -2, -1, 0 }, { -2,  0, 0 }, { -2,  1, 0 },
                { -1, -2, 0 }, { -1, -1, 1 }, { -1,  0, 1 }, { -1,  1, 1 }, { -1,  2, 0 },
                {  0, -2, 0 }, {  0, -1, 1 }, {  0,  0, 1 }, {  0,  1, 1 }, {  0,  2, 0 },
                {  1, -2, 0 }, {  1, -1, 1 }, {  1,  0, 1 }, {  1,  1, 1 }, {  1,  2, 0 },
                               {  2, -1, 0 }, {  2,  0, 0 }, {  2,  1, 0 },
              };

              for (int i = array_length (dds); i--; )
                {
                  int nx = x + dds [i][0];
                  int ny = y + dds [i][1];

                  if (!IN_RANGE_EXC (nx, 0, w) || !IN_RANGE_EXC (ny, 0, h) || !col [nx][ny])
                    {
                      n1 += dds [i][2];
                      n2++;
                    }
                }

              neu [x][y] = n1 >= c1 || n2 <= c2 ? '#' : 0;
            }
        }

      swap (neu);
    }
}

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

void
Layout::print ()
{
  for (int y = 0; y < h; y++)
    {
      for (int x = 0; x < w; x++)
        {
          U8 c = (U8)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 noinline void
push_flood_fill (Layout &dist, pointlist &seeds, int x, int y)
{
  if (dist [x][y])
    return;

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

  int y0 = y;

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

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

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

static inline void
make_tunnel (Layout &dist, pointlist &seeds, int x, int y, U8 d)
{
  for (;;)
    {
      if (x >               1 && U8 (dist [x - 1][y]) < d && dist [x - 1][y] > 1)
        --x;
      else if (x < dist.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 < dist.h - 2 && U8 (dist [x][y + 1]) < d && dist [x][y + 1] > 1)
        ++y;
      else
        break;

      d = dist [x][y];
      dist [x][y] = 1;
      seeds.push (point (x, y));
    }
}

static void inline
maybe_push (Layout &dist, pointlist &seeds, int x, int y, U8 d)
{
  char &D = dist [x][y];

  if (U8 (D) > d) // if wall and higher distance, lower distance
    D = d;
  else if (D) // otherwise, if it's no room, this space is uninteresting
    return;

  seeds.push (point (x, y));
}

static void
isolation_remover (Layout &maze, bool dirty)
{
  Layout dist (maze.w, maze.h);

  // dist contains
  // 0 == invisited rooms
  // 1 == visited rooms
  // 2+ shortest distance to random near room

  // phase 1, initialise dist array, find seed
  int cnt = 0;
  int x, y;

  for (int i = 0; i < maze.w; ++i)
    for (int j = 0; j < maze.h; ++j)
      {
        if (maze [i][j] == '#')
          dist [i][j] = U8 (255);
        else
          {
            dist [i][j] = 0;
            if (!rmg_rndm (++cnt))
              x = i, y = j;
          }
      }

  if (!cnt)
    return;

  fixed_stack<point> seeds (maze.w * maze.h * 5);

  // found first free space - picking the first one gives
  // us a slight bias for tunnels, but usually you won't
  // notice that in-game
  seeds.push (point (x, y));

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

  while (seeds.size)
    {
      coroapi::cede_to_tick ();

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

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

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

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

          if (dirty)
            push_flood_fill (dist, seeds, x, y);
        }
      else
        {
          // nothing here, continue to expand
          U8 d = U8 (dist [x][y]) + 1;

          if (x < dist.w - 1) maybe_push (dist, seeds, x + 1, y, d);
          if (x >          0) maybe_push (dist, seeds, x - 1, y, d);
          if (y < dist.h - 1) maybe_push (dist, seeds, x, y + 1, d);
          if (y >          0) maybe_push (dist, seeds, x, y - 1, d);
        }
    }

  // now copy the tunnels over
  for (int x = 0; x < maze.w; ++x)
    for (int y = 0; y < maze.h; ++y)
      if (maze [x][y] == '#' && dist [x][y] == 1)
        maze [x][y] = 0;
}

void
Layout::isolation_remover (bool dirty)
{
  ::isolation_remover (*this, dirty);
}

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

// inspired mostly by http://www.jimrandomh.org/misc/caves.txt
void
Layout::gen_cave (int subtype)
{
  switch (subtype)
    {
      // a rough cave
      case 0:
        fill_rand (rmg_rndm (80, 95));
        break;

      // corridors
      case 1:
        fill_rand (rmg_rndm (5, 40));
        erode_1_2 (5,  2, 10);
        erode_1_2 (5, -1, 10);
        erode_1_2 (5,  2, 1);
        break;

      // somewhat open, roundish
      case 2:
        fill_rand (45);
        erode_1_2 (5,  0, 5);
        erode_1_2 (5, 1, 1);
        break;

      // wide open, some room-like structures
      case 3:
        fill_rand (45);
        erode_1_2 (5,  2, 4);
        erode_1_2 (5, -1, 3);
        break;
    }

  border ();
  isolation_remover ();
}

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

    for(int i=1;i<10;i)
      {
        maze.fill_rand (97);
        maze.border ();
        maze.isolation_remover ();
        maze.print ();
      }

    exit (1);
  }
} demo;
#endif