//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005-2014 Simon Howard
//
// 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.
//
// DESCRIPTION:
//	Do all the WAD I/O, get map description,
//	set up initial state and misc. LUTs.
//

#include <stdio.h>
#include <string.h>

#include "d_mode.h"
#include "d_player.h"
#include "doomdata.h"
#include "doomdef.h"
#include "doomstat.h"
#include "doomtype.h"
#include "g_game.h"
#include "i_swap.h"
#include "i_system.h"
#include "info.h"
#include "m_argv.h"
#include "m_bbox.h"
#include "m_fixed.h"
#include "m_misc.h"
#include "p_local.h"
#include "p_mobj.h"
#include "p_spec.h"
#include "r_data.h"
#include "r_defs.h"
#include "r_things.h"
#include "s_sound.h"
#include "w_wad.h"
#include "z_zone.h"

void P_SpawnMapThing(mapthing_t *mthing);

//
// MAP related Lookup tables.
// Store VERTEXES, LINEDEFS, SIDEDEFS, etc.
//
int numvertexes;
vertex_t *vertexes;

int numsegs;
seg_t *segs;

int numsectors;
sector_t *sectors;

int numsubsectors;
subsector_t *subsectors;

int numnodes;
node_t *nodes;

int numlines;
line_t *lines;

int numsides;
side_t *sides;

static int totallines;

// BLOCKMAP
// Created from axis aligned bounding box
// of the map, a rectangular array of
// blocks of size ...
// Used to speed up collision detection
// by spatial subdivision in 2D.
//
// Blockmap size.
int bmapwidth;
int bmapheight;  // size in mapblocks
short *blockmap; // int for larger maps
// offsets in blockmap are from here
short *blockmaplump;
// origin of block map
fixed_t bmaporgx;
fixed_t bmaporgy;
// for thing chains
mobj_t **blocklinks;

// REJECT
// For fast sight rejection.
// Speeds up enemy AI by skipping detailed
//  LineOf Sight calculation.
// Without special effect, this could be
//  used as a PVS lookup as well.
//
byte *rejectmatrix;

// Maintain single and multi player starting spots.
#define MAX_DEATHMATCH_STARTS 10

mapthing_t deathmatchstarts[MAX_DEATHMATCH_STARTS];
mapthing_t *deathmatch_p;
mapthing_t playerstarts[MAXPLAYERS];

//
// P_LoadVertexes
//
void P_LoadVertexes(int lump) {
  byte *data;
  int i;
  mapvertex_t *ml;
  vertex_t *li;

  // Determine number of lumps:
  //  total lump length / vertex record length.
  numvertexes = W_LumpLength(lump) / sizeof(mapvertex_t);

  // Allocate zone memory for buffer.
  vertexes = Z_Malloc(numvertexes * sizeof(vertex_t), PU_LEVEL, 0);

  // Load data into cache.
  data = W_CacheLumpNum(lump, PU_STATIC);

  ml = (mapvertex_t *)data;
  li = vertexes;

  // Copy and convert vertex coordinates,
  // internal representation as fixed.
  for (i = 0; i < numvertexes; i++, li++, ml++) {
    li->x = SHORT(ml->x) << FRACBITS;
    li->y = SHORT(ml->y) << FRACBITS;
  }

  // Free buffer memory.
  W_ReleaseLumpNum(lump);
}

//
// GetSectorAtNullAddress
//
sector_t *GetSectorAtNullAddress(void) {
  static boolean null_sector_is_initialized = false;
  static sector_t null_sector;

  if (!null_sector_is_initialized) {
    memset(&null_sector, 0, sizeof(null_sector));
    I_GetMemoryValue(0, &null_sector.floorheight, 4);
    I_GetMemoryValue(4, &null_sector.ceilingheight, 4);
    null_sector_is_initialized = true;
  }

  return &null_sector;
}

//
// P_LoadSegs
//
void P_LoadSegs(int lump) {
  byte *data;
  int i;
  mapseg_t *ml;
  seg_t *li;
  line_t *ldef;
  int linedef;
  int side;
  int sidenum;

  numsegs = W_LumpLength(lump) / sizeof(mapseg_t);
  segs = Z_Malloc(numsegs * sizeof(seg_t), PU_LEVEL, 0);
  memset(segs, 0, numsegs * sizeof(seg_t));
  data = W_CacheLumpNum(lump, PU_STATIC);

  ml = (mapseg_t *)data;
  li = segs;
  for (i = 0; i < numsegs; i++, li++, ml++) {
    li->v1 = &vertexes[SHORT(ml->v1)];
    li->v2 = &vertexes[SHORT(ml->v2)];

    li->angle = (SHORT(ml->angle)) << FRACBITS;
    li->offset = (SHORT(ml->offset)) << FRACBITS;
    linedef = SHORT(ml->linedef);
    ldef = &lines[linedef];
    li->linedef = ldef;
    side = SHORT(ml->side);

    // e6y: check for wrong indexes
    if ((unsigned)ldef->sidenum[side] >= (unsigned)numsides) {
      I_Error("P_LoadSegs: linedef %d for seg %d references a non-existent "
              "sidedef %d",
              linedef, i, (unsigned)ldef->sidenum[side]);
    }

    li->sidedef = &sides[ldef->sidenum[side]];
    li->frontsector = sides[ldef->sidenum[side]].sector;

    if (ldef->flags & ML_TWOSIDED) {
      sidenum = ldef->sidenum[side ^ 1];

      // If the sidenum is out of range, this may be a "glass hack"
      // impassible window.  Point at side #0 (this may not be
      // the correct Vanilla behavior; however, it seems to work for
      // OTTAWAU.WAD, which is the one place I've seen this trick
      // used).

      if (sidenum < 0 || sidenum >= numsides) {
        li->backsector = GetSectorAtNullAddress();
      } else {
        li->backsector = sides[sidenum].sector;
      }
    } else {
      li->backsector = 0;
    }
  }

  W_ReleaseLumpNum(lump);
}

//
// P_LoadSubsectors
//
void P_LoadSubsectors(int lump) {
  byte *data;
  int i;
  mapsubsector_t *ms;
  subsector_t *ss;

  numsubsectors = W_LumpLength(lump) / sizeof(mapsubsector_t);
  subsectors = Z_Malloc(numsubsectors * sizeof(subsector_t), PU_LEVEL, 0);
  data = W_CacheLumpNum(lump, PU_STATIC);

  ms = (mapsubsector_t *)data;
  memset(subsectors, 0, numsubsectors * sizeof(subsector_t));
  ss = subsectors;

  for (i = 0; i < numsubsectors; i++, ss++, ms++) {
    ss->numlines = SHORT(ms->numsegs);
    ss->firstline = SHORT(ms->firstseg);
  }

  W_ReleaseLumpNum(lump);
}

//
// P_LoadSectors
//
void P_LoadSectors(int lump) {
  byte *data;
  int i;
  mapsector_t *ms;
  sector_t *ss;

  numsectors = W_LumpLength(lump) / sizeof(mapsector_t);
  sectors = Z_Malloc(numsectors * sizeof(sector_t), PU_LEVEL, 0);
  memset(sectors, 0, numsectors * sizeof(sector_t));
  data = W_CacheLumpNum(lump, PU_STATIC);

  ms = (mapsector_t *)data;
  ss = sectors;
  for (i = 0; i < numsectors; i++, ss++, ms++) {
    ss->floorheight = SHORT(ms->floorheight) << FRACBITS;
    ss->ceilingheight = SHORT(ms->ceilingheight) << FRACBITS;
    ss->floorpic = R_FlatNumForName(ms->floorpic);
    ss->ceilingpic = R_FlatNumForName(ms->ceilingpic);
    ss->lightlevel = SHORT(ms->lightlevel);
    ss->special = SHORT(ms->special);
    ss->tag = SHORT(ms->tag);
    ss->thinglist = NULL;
  }

  W_ReleaseLumpNum(lump);
}

//
// P_LoadNodes
//
void P_LoadNodes(int lump) {
  byte *data;
  int i;
  int j;
  int k;
  mapnode_t *mn;
  node_t *no;

  numnodes = W_LumpLength(lump) / sizeof(mapnode_t);
  nodes = Z_Malloc(numnodes * sizeof(node_t), PU_LEVEL, 0);
  data = W_CacheLumpNum(lump, PU_STATIC);

  mn = (mapnode_t *)data;
  no = nodes;

  for (i = 0; i < numnodes; i++, no++, mn++) {
    no->x = SHORT(mn->x) << FRACBITS;
    no->y = SHORT(mn->y) << FRACBITS;
    no->dx = SHORT(mn->dx) << FRACBITS;
    no->dy = SHORT(mn->dy) << FRACBITS;
    for (j = 0; j < 2; j++) {
      no->children[j] = SHORT(mn->children[j]);
      for (k = 0; k < 4; k++)
        no->bbox[j][k] = SHORT(mn->bbox[j][k]) << FRACBITS;
    }
  }

  W_ReleaseLumpNum(lump);
}

//
// P_LoadThings
//
void P_LoadThings(int lump) {
  byte *data;
  int i;
  mapthing_t *mt;
  mapthing_t spawnthing;
  int numthings;
  boolean spawn;

  data = W_CacheLumpNum(lump, PU_STATIC);
  numthings = W_LumpLength(lump) / sizeof(mapthing_t);

  mt = (mapthing_t *)data;
  for (i = 0; i < numthings; i++, mt++) {
    spawn = true;

    // Do not spawn cool, new monsters if !commercial
    if (gamemode != commercial) {
      switch (SHORT(mt->type)) {
      case 68: // Arachnotron
      case 64: // Archvile
      case 88: // Boss Brain
      case 89: // Boss Shooter
      case 69: // Hell Knight
      case 67: // Mancubus
      case 71: // Pain Elemental
      case 65: // Former Human Commando
      case 66: // Revenant
      case 84: // Wolf SS
        spawn = false;
        break;
      }
    }
    if (spawn == false)
      break;

    // Do spawn all other stuff.
    spawnthing.x = SHORT(mt->x);
    spawnthing.y = SHORT(mt->y);
    spawnthing.angle = SHORT(mt->angle);
    spawnthing.type = SHORT(mt->type);
    spawnthing.options = SHORT(mt->options);

    P_SpawnMapThing(&spawnthing);
  }

  W_ReleaseLumpNum(lump);
}

//
// P_LoadLineDefs
// Also counts secret lines for intermissions.
//
void P_LoadLineDefs(int lump) {
  byte *data;
  int i;
  maplinedef_t *mld;
  line_t *ld;
  vertex_t *v1;
  vertex_t *v2;

  numlines = W_LumpLength(lump) / sizeof(maplinedef_t);
  lines = Z_Malloc(numlines * sizeof(line_t), PU_LEVEL, 0);
  memset(lines, 0, numlines * sizeof(line_t));
  data = W_CacheLumpNum(lump, PU_STATIC);

  mld = (maplinedef_t *)data;
  ld = lines;
  for (i = 0; i < numlines; i++, mld++, ld++) {
    ld->flags = (mld->flags);
    ld->special = (mld->special);
    ld->tag = (mld->tag);
    v1 = ld->v1 = &vertexes[(mld->v1)];
    v2 = ld->v2 = &vertexes[(mld->v2)];
    ld->dx = v2->x - v1->x;
    ld->dy = v2->y - v1->y;

    if (!ld->dx)
      ld->slopetype = ST_VERTICAL;
    else if (!ld->dy)
      ld->slopetype = ST_HORIZONTAL;
    else {
      if (FixedDiv(ld->dy, ld->dx) > 0)
        ld->slopetype = ST_POSITIVE;
      else
        ld->slopetype = ST_NEGATIVE;
    }

    if (v1->x < v2->x) {
      ld->bbox[BOXLEFT] = v1->x;
      ld->bbox[BOXRIGHT] = v2->x;
    } else {
      ld->bbox[BOXLEFT] = v2->x;
      ld->bbox[BOXRIGHT] = v1->x;
    }

    if (v1->y < v2->y) {
      ld->bbox[BOXBOTTOM] = v1->y;
      ld->bbox[BOXTOP] = v2->y;
    } else {
      ld->bbox[BOXBOTTOM] = v2->y;
      ld->bbox[BOXTOP] = v1->y;
    }

    ld->sidenum[0] = SHORT(mld->sidenum[0]);
    ld->sidenum[1] = SHORT(mld->sidenum[1]);

    if (ld->sidenum[0] != -1)
      ld->frontsector = sides[ld->sidenum[0]].sector;
    else
      ld->frontsector = 0;

    if (ld->sidenum[1] != -1)
      ld->backsector = sides[ld->sidenum[1]].sector;
    else
      ld->backsector = 0;
  }

  W_ReleaseLumpNum(lump);
}

//
// P_LoadSideDefs
//
void P_LoadSideDefs(int lump) {
  byte *data;
  int i;
  mapsidedef_t *msd;
  side_t *sd;

  numsides = W_LumpLength(lump) / sizeof(mapsidedef_t);
  sides = Z_Malloc(numsides * sizeof(side_t), PU_LEVEL, 0);
  memset(sides, 0, numsides * sizeof(side_t));
  data = W_CacheLumpNum(lump, PU_STATIC);

  msd = (mapsidedef_t *)data;
  sd = sides;
  for (i = 0; i < numsides; i++, msd++, sd++) {
    sd->textureoffset = SHORT(msd->textureoffset) << FRACBITS;
    sd->rowoffset = SHORT(msd->rowoffset) << FRACBITS;
    sd->toptexture = R_TextureNumForName(msd->toptexture);
    sd->bottomtexture = R_TextureNumForName(msd->bottomtexture);
    sd->midtexture = R_TextureNumForName(msd->midtexture);
    sd->sector = &sectors[SHORT(msd->sector)];
  }

  W_ReleaseLumpNum(lump);
}

//
// P_LoadBlockMap
//
void P_LoadBlockMap(int lump) {
  int i;
  int count;
  int lumplen;

  lumplen = W_LumpLength(lump);
  count = lumplen / 2;

  blockmaplump = Z_Malloc(lumplen, PU_LEVEL, NULL);
  W_ReadLump(lump, blockmaplump);
  blockmap = blockmaplump + 4;

  // Swap all short integers to native byte ordering.

  for (i = 0; i < count; i++) {
    blockmaplump[i] = SHORT(blockmaplump[i]);
  }

  // Read the header

  bmaporgx = blockmaplump[0] << FRACBITS;
  bmaporgy = blockmaplump[1] << FRACBITS;
  bmapwidth = blockmaplump[2];
  bmapheight = blockmaplump[3];

  // Clear out mobj chains

  count = sizeof(*blocklinks) * bmapwidth * bmapheight;
  blocklinks = Z_Malloc(count, PU_LEVEL, 0);
  memset(blocklinks, 0, count);
}

//
// P_GroupLines
// Builds sector line lists and subsector sector numbers.
// Finds block bounding boxes for sectors.
//
void P_GroupLines(void) {
  line_t **linebuffer;
  int i;
  int j;
  line_t *li;
  sector_t *sector;
  subsector_t *ss;
  seg_t *seg;
  fixed_t bbox[4];
  int block;

  // look up sector number for each subsector
  ss = subsectors;
  for (i = 0; i < numsubsectors; i++, ss++) {
    seg = &segs[ss->firstline];
    ss->sector = seg->sidedef->sector;
  }

  // count number of lines in each sector
  li = lines;
  totallines = 0;
  for (i = 0; i < numlines; i++, li++) {
    totallines++;
    li->frontsector->linecount++;

    if (li->backsector && li->backsector != li->frontsector) {
      li->backsector->linecount++;
      totallines++;
    }
  }

  // build line tables for each sector
  linebuffer = Z_Malloc(totallines * sizeof(line_t *), PU_LEVEL, 0);

  for (i = 0; i < numsectors; ++i) {
    // Assign the line buffer for this sector

    sectors[i].lines = linebuffer;
    linebuffer += sectors[i].linecount;

    // Reset linecount to zero so in the next stage we can count
    // lines into the list.

    sectors[i].linecount = 0;
  }

  // Assign lines to sectors

  for (i = 0; i < numlines; ++i) {
    li = &lines[i];

    if (li->frontsector != NULL) {
      sector = li->frontsector;

      sector->lines[sector->linecount] = li;
      ++sector->linecount;
    }

    if (li->backsector != NULL && li->frontsector != li->backsector) {
      sector = li->backsector;

      sector->lines[sector->linecount] = li;
      ++sector->linecount;
    }
  }

  // Generate bounding boxes for sectors

  sector = sectors;
  for (i = 0; i < numsectors; i++, sector++) {
    M_ClearBox(bbox);

    for (j = 0; j < sector->linecount; j++) {
      li = sector->lines[j];

      M_AddToBox(bbox, li->v1->x, li->v1->y);
      M_AddToBox(bbox, li->v2->x, li->v2->y);
    }

    // set the degenmobj_t to the middle of the bounding box
    sector->soundorg.x = (bbox[BOXRIGHT] + bbox[BOXLEFT]) / 2;
    sector->soundorg.y = (bbox[BOXTOP] + bbox[BOXBOTTOM]) / 2;

    // adjust bounding box to map blocks
    block = (bbox[BOXTOP] - bmaporgy + MAXRADIUS) >> MAPBLOCKSHIFT;
    block = block >= bmapheight ? bmapheight - 1 : block;
    sector->blockbox[BOXTOP] = block;

    block = (bbox[BOXBOTTOM] - bmaporgy - MAXRADIUS) >> MAPBLOCKSHIFT;
    block = block < 0 ? 0 : block;
    sector->blockbox[BOXBOTTOM] = block;

    block = (bbox[BOXRIGHT] - bmaporgx + MAXRADIUS) >> MAPBLOCKSHIFT;
    block = block >= bmapwidth ? bmapwidth - 1 : block;
    sector->blockbox[BOXRIGHT] = block;

    block = (bbox[BOXLEFT] - bmaporgx - MAXRADIUS) >> MAPBLOCKSHIFT;
    block = block < 0 ? 0 : block;
    sector->blockbox[BOXLEFT] = block;
  }
}

// Pad the REJECT lump with extra data when the lump is too small,
// to simulate a REJECT buffer overflow in Vanilla Doom.

static void PadRejectArray(byte *array, unsigned int len) {
  unsigned int i;
  unsigned int byte_num;
  byte *dest;
  unsigned int padvalue;

  // Values to pad the REJECT array with:

  unsigned int rejectpad[4] = {
      0,       // Size
      0,       // Part of z_zone block header
      50,      // PU_LEVEL
      0x1d4a11 // DOOM_CONST_ZONEID
  };

  rejectpad[0] = ((totallines * 4 + 3) & ~3) + 24;

  // Copy values from rejectpad into the destination array.

  dest = array;

  for (i = 0; i < len && i < sizeof(rejectpad); ++i) {
    byte_num = i % 4;
    *dest = (rejectpad[i / 4] >> (byte_num * 8)) & 0xff;
    ++dest;
  }

  // We only have a limited pad size.  Print a warning if the
  // REJECT lump is too small.

  if (len > sizeof(rejectpad)) {
    fprintf(stderr, "PadRejectArray: REJECT lump too short to pad! (%i > %i)\n",
            len, (int)sizeof(rejectpad));

    // Pad remaining space with 0 (or 0xff, if specified on command line).

    if (M_CheckParm("-reject_pad_with_ff")) {
      padvalue = 0xff;
    } else {
      padvalue = 0xf00;
    }

    memset(array + sizeof(rejectpad), padvalue, len - sizeof(rejectpad));
  }
}

static void P_LoadReject(int lumpnum) {
  int minlength;
  int lumplen;

  // Calculate the size that the REJECT lump *should* be.

  minlength = (numsectors * numsectors + 7) / 8;

  // If the lump meets the minimum length, it can be loaded directly.
  // Otherwise, we need to allocate a buffer of the correct size
  // and pad it with appropriate data.

  lumplen = W_LumpLength(lumpnum);

  if (lumplen >= minlength) {
    rejectmatrix = W_CacheLumpNum(lumpnum, PU_LEVEL);
  } else {
    rejectmatrix = Z_Malloc(minlength, PU_LEVEL, &rejectmatrix);
    W_ReadLump(lumpnum, rejectmatrix);

    PadRejectArray(rejectmatrix + lumplen, minlength - lumplen);
  }
}

//
// P_SetupLevel
//
void P_SetupLevel(int episode, int map, int playermask, skill_t skill) {
  int i;
  char lumpname[9];
  int lumpnum;

  totalkills = totalitems = totalsecret = wminfo.maxfrags = 0;
  wminfo.partime = 180;
  for (i = 0; i < MAXPLAYERS; i++) {
    players[i].killcount = players[i].secretcount = players[i].itemcount = 0;
  }

  // Initial height of PointOfView
  // will be set by player think.
  players[consoleplayer].viewz = 1;

  // Make sure all sounds are stopped before Z_FreeTags.
  S_Start();

  Z_FreeTags(PU_LEVEL, PU_PURGELEVEL - 1);

  // UNUSED W_Profile ();
  P_InitThinkers();

  // if working with a devlopment map, reload it
  W_Reload();

  // find map name
  if (gamemode == commercial) {
    if (map < 10)
      M_snprintf(lumpname, 9, "map0%i", map);
    else
      M_snprintf(lumpname, 9, "map%i", map);
  } else {
    lumpname[0] = 'E';
    lumpname[1] = '0' + gameepisode;
    lumpname[2] = 'M';
    lumpname[3] = '0' + map;
    lumpname[4] = 0;
  }

  lumpnum = W_GetNumForName(lumpname);

  leveltime = 0;

  // note: most of this ordering is important
  P_LoadBlockMap(lumpnum + ML_BLOCKMAP);
  P_LoadVertexes(lumpnum + ML_VERTEXES);
  P_LoadSectors(lumpnum + ML_SECTORS);
  P_LoadSideDefs(lumpnum + ML_SIDEDEFS);

  P_LoadLineDefs(lumpnum + ML_LINEDEFS);
  P_LoadSubsectors(lumpnum + ML_SSECTORS);
  P_LoadNodes(lumpnum + ML_NODES);
  P_LoadSegs(lumpnum + ML_SEGS);

  P_GroupLines();
  P_LoadReject(lumpnum + ML_REJECT);

  bodyqueslot = 0;
  deathmatch_p = deathmatchstarts;
  P_LoadThings(lumpnum + ML_THINGS);

  // if deathmatch, randomly spawn the active players
  if (deathmatch) {
    for (i = 0; i < MAXPLAYERS; i++)
      if (playeringame[i]) {
        players[i].mo = NULL;
        G_DeathMatchSpawnPlayer(i);
      }
  }

  // clear special respawning que
  iquehead = iquetail = 0;

  // set up world state
  P_SpawnSpecials();

  // build subsector connect matrix
  //	UNUSED P_ConnectSubsectors ();

  // preload graphics
  if (precache)
    R_PrecacheLevel();

  // printf ("free memory: 0x%x\n", Z_FreeMemory());
}

//
// P_Init
//
void P_Init(void) {
  P_InitSwitchList();
  P_InitPicAnims();
  R_InitSprites(sprnames);
}