/* Emacs style mode select   -*- C++ -*-
 *-----------------------------------------------------------------------------
 *
 *
 *  PrBoom a Doom port merged with LxDoom and LSDLDoom
 *  based on BOOM, a modified and improved DOOM engine
 *  Copyright (C) 1999 by
 *  id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
 *  Copyright (C) 1999-2000 by
 *  Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
 *
 *  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.
 *
 * DESCRIPTION:
 *   Ceiling aninmation (lowering, crushing, raising)
 *
 *-----------------------------------------------------------------------------*/

#include "doomstat.h"
#include "r_main.h"
#include "p_spec.h"
#include "p_tick.h"
#include "s_sound.h"
#include "sounds.h"
#include "z_zone.h"
#include "doomdef.h"
#define PU_LEVSPEC  51      // a special thinker in a level
#include "rockmacros.h"

// the list of ceilings moving currently, including crushers
ceilinglist_t *activeceilings;

/////////////////////////////////////////////////////////////////
//
// Ceiling action routine and linedef type handler
//
/////////////////////////////////////////////////////////////////

//
// T_MoveCeiling
//
// Action routine that moves ceilings. Called once per tick.
//
// Passed a ceiling_t structure that contains all the info about the move.
// see P_SPEC.H for fields. No return.
//
// jff 02/08/98 all cases with labels beginning with gen added to support
// generalized line type behaviors.
//
void T_MoveCeiling (ceiling_t* ceiling)
{
   result_e  res;

   switch(ceiling->direction)
   {
   case 0:
      // If ceiling in stasis, do nothing
      break;

   case 1:
      // Ceiling is moving up
      res = T_MovePlane
            (
               ceiling->sector,
               ceiling->speed,
               ceiling->topheight,
               false,
               1,
               ceiling->direction
            );

      // if not a silent crusher, make moving sound
      if (!(leveltime&7))
      {
         switch(ceiling->type)
         {
         case silentCrushAndRaise:
         case genSilentCrusher:
            break;
         default:
            S_StartSound((mobj_t *)&ceiling->sector->soundorg,sfx_stnmov);
            break;
         }
      }

      // handle reaching destination height
      if (res == pastdest)
      {
         switch(ceiling->type)
         {
            // plain movers are just removed
         case raiseToHighest:
         case genCeiling:
            P_RemoveActiveCeiling(ceiling);
            break;

            // movers with texture change, change the texture then get removed
         case genCeilingChgT:
         case genCeilingChg0:
            ceiling->sector->special = ceiling->newspecial;
            //jff 3/14/98 transfer old special field as well
            ceiling->sector->oldspecial = ceiling->oldspecial;
         case genCeilingChg:
            ceiling->sector->ceilingpic = ceiling->texture;
            P_RemoveActiveCeiling(ceiling);
            break;

            // crushers reverse direction at the top
         case silentCrushAndRaise:
            S_StartSound((mobj_t *)&ceiling->sector->soundorg,sfx_pstop);
            /* fallthrough */
         case genSilentCrusher:
         case genCrusher:
         case fastCrushAndRaise:
         case crushAndRaise:
            ceiling->direction = -1;
            break;

         default:
            break;
         }
      }
      break;

   case -1:
      // Ceiling moving down
      res = T_MovePlane
            (
               ceiling->sector,
               ceiling->speed,
               ceiling->bottomheight,
               ceiling->crush,
               1,
               ceiling->direction
            );

      // if not silent crusher type make moving sound
      if (!(leveltime&7))
      {
         switch(ceiling->type)
         {
         case silentCrushAndRaise:
         case genSilentCrusher:
            break;
         default:
            S_StartSound((mobj_t *)&ceiling->sector->soundorg,sfx_stnmov);
         }
      }

      // handle reaching destination height
      if (res == pastdest)
      {
         switch(ceiling->type)
         {
            // 02/09/98 jff change slow crushers' speed back to normal
            // start back up
         case genSilentCrusher:
         case genCrusher:
            if (ceiling->oldspeed<CEILSPEED*3)
               ceiling->speed = ceiling->oldspeed;
            ceiling->direction = 1; //jff 2/22/98 make it go back up!
            break;

            // make platform stop at bottom of all crusher strokes
            // except generalized ones, reset speed, start back up
         case silentCrushAndRaise:
            S_StartSound((mobj_t *)&ceiling->sector->soundorg,sfx_pstop);
            /* fallthrough */
         case crushAndRaise:
            ceiling->speed = CEILSPEED;
            /* fallthrough */
         case fastCrushAndRaise:
            ceiling->direction = 1;
            break;

            // in the case of ceiling mover/changer, change the texture
            // then remove the active ceiling
         case genCeilingChgT:
         case genCeilingChg0:
            ceiling->sector->special = ceiling->newspecial;
            //jff add to fix bug in special transfers from changes
            ceiling->sector->oldspecial = ceiling->oldspecial;
         case genCeilingChg:
            ceiling->sector->ceilingpic = ceiling->texture;
            P_RemoveActiveCeiling(ceiling);
            break;

            // all other case, just remove the active ceiling
         case lowerAndCrush:
         case lowerToFloor:
         case lowerToLowest:
         case lowerToMaxFloor:
         case genCeiling:
            P_RemoveActiveCeiling(ceiling);
            break;

         default:
            break;
         }
      }
      else // ( res != pastdest )
      {
         // handle the crusher encountering an obstacle
         if (res == crushed)
         {
            switch(ceiling->type)
            {
               //jff 02/08/98 slow down slow crushers on obstacle
            case genCrusher:
            case genSilentCrusher:
               if (ceiling->oldspeed < CEILSPEED*3)
                  ceiling->speed = CEILSPEED / 8;
               break;
            case silentCrushAndRaise:
            case crushAndRaise:
            case lowerAndCrush:
               ceiling->speed = CEILSPEED / 8;
               break;

            default:
               break;
            }
         }
      }
      break;
   }
}


//
// EV_DoCeiling
//
// Move a ceiling up/down or start a crusher
//
// Passed the linedef activating the function and the type of function desired
// returns true if a thinker started
//
int EV_DoCeiling
( line_t* line,
  ceiling_e type )
{
   int   secnum;
   int   rtn;
   sector_t* sec;
   ceiling_t*  ceiling;

   secnum = -1;
   rtn = 0;

   // Reactivate in-stasis ceilings...for certain types.
   // This restarts a crusher after it has been stopped
   switch(type)
   {
   case fastCrushAndRaise:
   case silentCrushAndRaise:
   case crushAndRaise:
      //jff 4/5/98 return if activated
      rtn = P_ActivateInStasisCeiling(line);
   default:
      break;
   }

   // affects all sectors with the same tag as the linedef
   while ((secnum = P_FindSectorFromLineTag(line,secnum)) >= 0)
   {
      sec = &sectors[secnum];

      // if ceiling already moving, don't start a second function on it
      if (P_SectorActive(ceiling_special,sec))  //jff 2/22/98
         continue;

      // create a new ceiling thinker
      rtn = 1;
      ceiling = Z_Malloc (sizeof(*ceiling), PU_LEVSPEC, 0);
      P_AddThinker (&ceiling->thinker);
      sec->ceilingdata = ceiling;               //jff 2/22/98
      ceiling->thinker.function = T_MoveCeiling;
      ceiling->sector = sec;
      ceiling->crush = false;

      // setup ceiling structure according to type of function
      switch(type)
      {
      case fastCrushAndRaise:
         ceiling->crush = true;
         ceiling->topheight = sec->ceilingheight;
         ceiling->bottomheight = sec->floorheight + (8*FRACUNIT);
         ceiling->direction = -1;
         ceiling->speed = CEILSPEED * 2;
         break;

      case silentCrushAndRaise:
      case crushAndRaise:
         ceiling->crush = true;
         ceiling->topheight = sec->ceilingheight;
      case lowerAndCrush:
      case lowerToFloor:
         ceiling->bottomheight = sec->floorheight;
         if (type != lowerToFloor)
            ceiling->bottomheight += 8*FRACUNIT;
         ceiling->direction = -1;
         ceiling->speed = CEILSPEED;
         break;

      case raiseToHighest:
         ceiling->topheight = P_FindHighestCeilingSurrounding(sec);
         ceiling->direction = 1;
         ceiling->speed = CEILSPEED;
         break;

      case lowerToLowest:
         ceiling->bottomheight = P_FindLowestCeilingSurrounding(sec);
         ceiling->direction = -1;
         ceiling->speed = CEILSPEED;
         break;

      case lowerToMaxFloor:
         ceiling->bottomheight = P_FindHighestFloorSurrounding(sec);
         ceiling->direction = -1;
         ceiling->speed = CEILSPEED;
         break;

      default:
         break;
      }

      // add the ceiling to the active list
      ceiling->tag = sec->tag;
      ceiling->type = type;
      P_AddActiveCeiling(ceiling);
   }
   return rtn;
}

//////////////////////////////////////////////////////////////////////
//
// Active ceiling list primitives
//
/////////////////////////////////////////////////////////////////////

// jff 2/22/98 - modified Lee's plat code to work for ceilings
//
// The following were all rewritten by Lee Killough
// to use the new structure which places no limits
// on active ceilings. It also avoids spending as much
// time searching for active ceilings. Previously a
// fixed-size array was used, with NULL indicating
// empty entries, while now a doubly-linked list
// is used.

//
// P_ActivateInStasisCeiling()
//
// Reactivates all stopped crushers with the right tag
//
// Passed the line reactivating the crusher
// Returns true if a ceiling reactivated
//
//jff 4/5/98 return if activated
int P_ActivateInStasisCeiling(line_t *line)
{
   ceilinglist_t *cl;
   int rtn=0;

   for (cl=activeceilings; cl; cl=cl->next)
   {
      ceiling_t *ceiling = cl->ceiling;
      if (ceiling->tag == line->tag && ceiling->direction == 0)
      {
         ceiling->direction = ceiling->olddirection;
         ceiling->thinker.function = T_MoveCeiling;
         //jff 4/5/98 return if activated
         rtn=1;
      }
   }
   return rtn;
}

//
// EV_CeilingCrushStop()
//
// Stops all active ceilings with the right tag
//
// Passed the linedef stopping the ceilings
// Returns true if a ceiling put in stasis
//
int EV_CeilingCrushStop(line_t* line)
{
   int rtn=0;

   ceilinglist_t *cl;
   for (cl=activeceilings; cl; cl=cl->next)
   {
      ceiling_t *ceiling = cl->ceiling;
      if (ceiling->direction != 0 && ceiling->tag == line->tag)
      {
         ceiling->olddirection = ceiling->direction;
         ceiling->direction = 0;
         ceiling->thinker.function = NULL;
         rtn=1;
      }
   }
   return rtn;
}

//
// P_AddActiveCeiling()
//
// Adds a ceiling to the head of the list of active ceilings
//
// Passed the ceiling motion structure
// Returns nothing
//
void P_AddActiveCeiling(ceiling_t* ceiling)
{
   ceilinglist_t *list = malloc(sizeof *list);
   list->ceiling = ceiling;
   ceiling->list = list;
   if ((list->next = activeceilings))
      list->next->prev = &list->next;
   list->prev = &activeceilings;
   activeceilings = list;
}

//
// P_RemoveActiveCeiling()
//
// Removes a ceiling from the list of active ceilings
//
// Passed the ceiling motion structure
// Returns nothing
//
void P_RemoveActiveCeiling(ceiling_t* ceiling)
{
   ceilinglist_t *list = ceiling->list;
   ceiling->sector->ceilingdata = NULL;  //jff 2/22/98
   P_RemoveThinker(&ceiling->thinker);
   if ((*list->prev = list->next))
      list->next->prev = list->prev;
   free(list);
}

//
// P_RemoveAllActiveCeilings()
//
// Removes all ceilings from the active ceiling list
//
// Passed nothing, returns nothing
//
void P_RemoveAllActiveCeilings(void)
{
   while (activeceilings)
   {
      ceilinglist_t *next = activeceilings->next;
      free(activeceilings);
      activeceilings = next;
   }
}
