/*
 * Code to fill the dungeon with objects.
 */

#include "obj.h"
#include "vars.h"
#include "dice.h"
#include "vault.h"
#include "pline.h"
#include "structs.h"
#include "objtypes.h"
#include "obj-ring.h"
#include "digdungeon.h"
#include "obj-weapon.h"
#include "obj-armour.h"

#include "filldungeon.h"

static RANDCHOICE choose_type[]
 = { { 30, OC_SCROLL },
     { 30, OC_POTION },
     { 5, OC_WAND },
     { 10, OC_WEAPON },
     { 10, OC_ARMOUR },
     { 4, OC_RING } };

static RANDCHOICE choose_scroll[]
 = { { 4, OBJ_SCROLL_OF_CHARGING },
     { 5, OBJ_SCROLL_OF_ENCHANT_ITEM },
     { 8, OBJ_SCROLL_OF_HOLD_OTHERS },
     { 15, OBJ_SCROLL_OF_IDENTIFY },
     { 3, OBJ_SCROLL_OF_INVULNERABILITY },
     { 10, OBJ_SCROLL_OF_LOCATE_MONSTERS },
     { 10, OBJ_SCROLL_OF_LOCATE_OBJECTS },
     { 5, OBJ_SCROLL_OF_MAGIC_MAPPING },
     { 4, OBJ_SCROLL_OF_PHASING },
     { 6, OBJ_SCROLL_OF_TELEPORTATION },
     { 9, OBJ_SCROLL_OF_REMOVE_CURSE },
     { 10, OBJ_SCROLL_OF_SUMMON_MONSTER },
     { 10, OBJ_SCROLL_OF_EXPLOSION } };

static RANDCHOICE choose_potion[]
 = { { 15, OBJ_POTION_OF_AMNESIA },
     { 10, OBJ_POTION_OF_CLAIRVOYANCE },
     { 15, OBJ_POTION_OF_CONFUSION },
     { 5, OBJ_POTION_OF_EXTRA_HEALING },
     { 9, OBJ_POTION_OF_FIRE_RESISTANCE },
     { 7, OBJ_POTION_OF_GAIN_STRENGTH },
     { 6, OBJ_POTION_OF_GIANT_STRENGTH },
     { 10, OBJ_POTION_OF_HEALING },
     { 5, OBJ_POTION_OF_HEROISM },
     { 10, OBJ_POTION_OF_INFRAVISION },
     { 5, OBJ_POTION_OF_INVISIBILITY },
     { 9, OBJ_POTION_OF_LEVITATION },
     { 8, OBJ_POTION_OF_MEMORY },
     { 10, OBJ_POTION_OF_PERCEPTION },
     { 8, OBJ_POTION_OF_RESTORATION },
     { 10, OBJ_POTION_OF_SEE_INVISIBLE },
     { 15, OBJ_POTION_OF_SLEEP },
     { 5, OBJ_POTION_OF_SPEED },
     { 8, OBJ_POTION_OF_WATER_BREATHING } };

static RANDCHOICE choose_wand[]
 = { { 10, OBJ_WAND_OF_CANCELLATION },
     { 10, OBJ_WAND_OF_DARKNESS },
     { 3, OBJ_WAND_OF_DEATH },
     { 7, OBJ_WAND_OF_DIGGING },
     { 6, OBJ_WAND_OF_DISINTEGRATION },
     { 10, OBJ_WAND_OF_FIRE_BALL },
     { 10, OBJ_WAND_OF_FIRE_BOLT },
     { 10, OBJ_WAND_OF_ICE_BOLT },
     { 10, OBJ_WAND_OF_LIGHTNING },
     { 10, OBJ_WAND_OF_MAGIC_MISSILE },
     { 15, OBJ_WAND_OF_MAKE_INVISIBLE },
     { 4, OBJ_WAND_OF_POLYMORPH },
     { 10, OBJ_WAND_OF_STRIKING },
     { 10, OBJ_WAND_OF_TELEPORTATION },
     { 5, OBJ_WAND_OF_UNDEAD_TURNING },
     { 3, OBJ_WAND_OF_WISHING } };

static RANDCHOICE choose_ring[]
 = { { 15, OBJ_RING_OF_FIRE_RESISTANCE },
     { 10, OBJ_RING_OF_PROTECTION },
     { 7, OBJ_RING_OF_REGENERATION },
     { 15, OBJ_RING_OF_SEE_INVISIBLE },
     { 4, OBJ_RING_OF_SLOW_DIGESTION },
     { 10, OBJ_RING_OF_STEALTH },
     { 10, OBJ_RING_OF_TELEPORT_CONTROL },
     { 7, OBJ_RING_OF_VAMPIRIC_REGENERATION },
     { 10, OBJ_RING_OF_WATER_BREATHING } };

static RANDCHOICE choose_weapon[]
 = { { 3, OBJ_DAGGER },
     { 4, OBJ_CLUB },
     { 2, OBJ_MACE },
     { 1, OBJ_FLAIL },
     { 1, OBJ_MORNINGSTAR },
     { 1, OBJ_SHORT_SWORD },
     { 1, OBJ_LONG_SWORD },
     { 1, OBJ_TWO_HANDED_SWORD } };

static RANDCHOICE choose_armour[]
 = { { 4, OBJ_LEATHER_ARMOUR },
     { 3, OBJ_STUDDED_LEATHER_ARMOUR },
     { 2, OBJ_RING_MAIL },
     { 1, OBJ_SCALE_MAIL },
     { 1, OBJ_CHAIN_MAIL },
     { 1, OBJ_BANDED_MAIL },
     { 1, OBJ_SPLINT_MAIL },
     { 1, OBJ_PLATE_MAIL } };

/*
 * Location test function for placing the Crown.
 */
static int ckcrown(LOC *lc)
{
 return(!(lc->flags & LF_NOCROWN) && ckavoid(lc));
}

OBJ *obj_gen(int type)
{
 OBJ *o;

 o = obj_make(type);
 switch (objtypes[type].class)
  { case OC_SCROLL:
    case OC_POTION:
    case OC_WAND:
       break;
    case OC_RING:
       // Ring plusses/curses are handled in new_ring()
       break;
    case OC_WEAPON:
	{ int plush;
	  int plusd;
	  int sign;
	  plush = 0;
	  plusd = 0;
	  if (onein(3))
	   { sign = rnd(2) ? 1 : -1;
	     do if (rnd(2)) plush += sign * roll("2d10-1"); else plusd += sign * roll("2d10-1"); while (rnd(2));
	   }
	  weapon_set_plusses(o,plush,plusd);
	  (*objtypes[type].ops->setcursed)(o,sign<0);
	}
       break;
    case OC_ARMOUR:
	{ int plus;
	  int sign;
	  plus = 0;
	  if (onein(3))
	   { sign = rnd(2) ? 1 : -1;
	     do plus += sign * roll("2d10-1"); while (rnd(2));
	   }
	  armour_set_plusses(o,plus);
	  (*objtypes[type].ops->setcursed)(o,sign<0);
	}
       break;
  }
 return(o);
}

/*
 * Generate a random object and place it on a dungeon level, given by
 *  level number.
 */
static void random_object_on_level(int ln)
{
 int class;
 int type;
 OBJ *o;

 class = RANDCHOOSE(choose_type);
 switch (class)
  { case OC_SCROLL:
       type = RANDCHOOSE(choose_scroll);
       break;
    case OC_POTION:
       type = RANDCHOOSE(choose_potion);
       break;
    case OC_WAND:
       type = RANDCHOOSE(choose_wand);
       break;
    case OC_WEAPON:
       type = RANDCHOOSE(choose_weapon);
       break;
    case OC_ARMOUR:
       type = RANDCHOOSE(choose_armour);
       break;
    case OC_RING:
       type = RANDCHOOSE(choose_ring);
       break;
    default:
       panic("impossible object class");
       break;
  }
 o = obj_gen(type);
 add_obj_to_inv(o,&randomloc(&levels[ln],&ckroutine)->objs);
}

/*
 * Create a trap on a given level.
 *
 * Note that this doesn't check that the location doesn't already have
 *  a trap.  See the comment on filldungeon for discussion.
 */
static void create_trap(LEVEL *lv)
{
 LOC *l;

 l = randomloc(lv,&ckroutine);
 l->trap = TRAP_KIND_ARROW;
}

/*
 * Fill the dungeon with objects.  This means:
 *
 * - Blank maps.  We create one per level of the main dungeon.  With
 *  the maps created in the player's inventory, this is enough to map
 *  the whole dungeon.
 *
 * - The Crown of Yendor.
 *
 * - Scarabs of the elemental planes, on the bottom four levels of the
 *  dungeon, with a chance of a duplicate.
 *
 * - Gold scattered around.
 *
 * - Various objects.
 *
 * - Traps.  See below.
 *
 * The initial player OBJ_LEATHER_ARMOUR and OBJ_DAGGER are not done
 *  here; those are created as part of creating the player-avatar
 *  monster, over in mon-@-you.c.
 *
 * We create an average of two traps per level, with a bias for
 *  creating them deeper in the dungeon; we want an expected count of
 *  one trap on level 1, increasing linearly up to an expected count of
 *  three traps on the deepest level.  We could create a fixed number
 *  of traps, with only the levels they are on varying, but that would
 *  be too predictable ("okay, I've found all but two of the traps in
 *  this dungeon, so....").  Instead, we do a loop like
 *  "while (chance) create trap" for each level, with the chance
 *  computed based on level number to get the desired expected number
 *  of traps for each level.  For probability p in the while(), the
 *  expected number of traps is 0*(1-p) + 1*p*(1-p) + 2*p*p*(1-p) +
 *  3*p*p*p*(1-p) + ...; if we let this number be E, then it can be
 *  written as E = ((1 - p) * 0) + (p * (1 + E)): chance 1-p of none,
 *  plus chance p of 1 plus another E more.  Solving, p = E / (1 + E).
 *  If E were always an integer, we could express this as simply
 *  !onein(E) in the while(), but E is not an integer for most levels.
 *
 * Because create_trap() doesn't check that the location it chooses
 *  doesn't already have a trap, there is a reduction in the expected
 *  number of traps per level due to the second and later traps
 *  potentially picking the same cell as an earlier trap.  We don't do
 *  anything to alleviate this; the reduction is slight enough I don't
 *  think it's worth doing anything about.
 */
void filldungeon(void)
{
 int ln;
 LOC *lc;
 OBJ *g;
 int scarabs[4];
 int i;
 int j;
 int t;
 char dr[16];
 double e;
 double p;

 // Maps and gold in the main dungeon
 for (ln=DUNGEON_LEVELS-1;ln>=0;ln--)
  { add_obj_to_inv(obj_make(OBJ_MAP),&randomloc(&levels[ln],&ckroutine)->objs);
    sprintf(&dr[0],"%dd10",levels[ln].levelno);
    for (i=roll("2d6-1");i>0;i--)
     { g = obj_make(OBJ_GOLD);
       g->number = roll(&dr[0]);
       add_obj_to_inv(g,&randomloc(&levels[ln],&ckroutine)->objs);
     }
  }
 // Gold in vaults
 fillvaults();
 // The Crown of Yendor
 avoidloc = gate_hell;
 lc = randomloc(&levels[L_HELL],&ckcrown);
 add_obj_to_inv(obj_make(OBJ_CROWN),&lc->objs);
 // The scarabs
 scarabs[0] = OBJ_SCARAB_OF_EARTH;
 scarabs[1] = OBJ_SCARAB_OF_AIR;
 scarabs[2] = OBJ_SCARAB_OF_FIRE;
 scarabs[3] = OBJ_SCARAB_OF_WATER;
 for (i=4-1;i>=0;i--)
  { j = rnd(4);
    t = scarabs[i];
    scarabs[i] = scarabs[j];
    scarabs[j] = t;
  }
 for (i=4-1;i>=0;i--)
  { add_obj_to_inv(obj_make(scarabs[i]),&randomloc(&levels[DUNGEON_LEVELS-1-i],&ckroutine)->objs);
  }
 // Possible duplicate scarab
 if (! rnd(5))
  { add_obj_to_inv(obj_make(scarabs[1+rnd(3)]),&randomloc(&levels[DUNGEON_LEVELS-4+rnd(2)],&ckroutine)->objs);
  }
 // Various other objects
 for (ln=DUNGEON_LEVELS-1;ln>=0;ln--)
  { for (j=roll("d4+d3+d2");j>0;j--) random_object_on_level(ln);
    while (! rnd(2)) random_object_on_level(ln);
  }
 for (ln=DUNGEON_LEVELS-1;ln>=0;ln--)
  { e = ((2.0 * ln) / (DUNGEON_LEVELS - 1)) + 1;
    p = e / (1 + e);
    while (frnd() < p)
     { create_trap(&levels[ln]);
     }
  }
}