/* vi: set ts=2:
 +-------------------+  Christian Schlittchen <corwin@amber.kn-bremen.de>
 |                   |  Enno Rehling <enno@eressea.de>
 | Eressea PBEM host |  Katja Zedel <katze@felidae.kn-bremen.de>
 | (c) 1998 - 2003   |  Henning Peters <faroul@beyond.kn-bremen.de>
 |                   |  Ingo Wilken <Ingo.Wilken@informatik.uni-oldenburg.de>
 +-------------------+  Stefan Reich <reich@halbling.de>

 This program may not be used, modified or distributed
 without prior permission by the authors of Eressea.
*/

#include <platform.h>
#include <kernel/config.h>
#include "resources.h"

/* kernel includes */
#include "build.h"
#include "item.h"
#include "region.h"
#include "terrain.h"

#include <util/rand.h>
#include <util/rng.h>

#include <stdlib.h>
#include <assert.h>
#include <string.h>

static double
ResourceFactor(void)
{
  static double value = -1.0;
  if (value<0) {
    const char * str = get_param(global.parameters, "resource.factor");
    value = str?atof(str):1.0;
  }
  return value;
}

void
update_resources(region * r)
{
  struct rawmaterial * res = r->resources;
  while (res) {
    if (res->type->update) res->type->update(res, r);
    res = res->next;
  }
}

extern int dice_rand(const char *s);

static void
update_resource(struct rawmaterial * res, double modifier)
{
  double amount = 1 + (res->level-res->startlevel) * res->divisor/100.0;
  amount = ResourceFactor() * res->base * amount * modifier;
  if (amount<1.0) res->amount = 1;
  else res->amount = (int)amount;
  assert(res->amount>0);
}

void
add_resource(region * r, int level, int base, int divisor, const resource_type * rtype)
{
  struct rawmaterial * rm = calloc(sizeof(struct rawmaterial), 1);

  rm->next = r->resources;
  r->resources = rm;
  rm->level      = level;
  rm->startlevel = level;
  rm->base       = base;
  rm->divisor    = divisor;
  rm->flags      = 0;
  rm->type       = rmt_get(rtype);
  update_resource(rm, 1.0);
  rm->type->terraform(rm, r);
}

void
terraform_resources(region * r)
{
  int i;
  const terrain_type * terrain = r->terrain;

  if (terrain->production==NULL) return;
  for (i=0;terrain->production[i].type; ++i) {
    rawmaterial *rm;
    const terrain_production * production = terrain->production+i;
    const resource_type * rtype = production->type;

    for (rm=r->resources; rm; rm=rm->next) {
      if (rm->type->rtype == rtype) break;
    }
    if (rm) continue;
    
    if (chance(production->chance)) {
      add_resource(r, dice_rand(production->startlevel), dice_rand(production->base), dice_rand(production->divisor), production->type);
    }
  }
}

static void
terraform_default(struct rawmaterial * res, const region * r)
{
#define SHIFT 70
	double modifier = 1.0 + ((rng_int() % (SHIFT*2+1)) - SHIFT) * ((rng_int() % (SHIFT*2+1)) - SHIFT) / 10000.0;
	res->amount = (int)(res->amount*modifier); /* random adjustment, +/- 91% */
	if (res->amount<1) res->amount=1;
	unused(r);
}

#ifdef RANDOM_CHANGE
static void
resource_random_change(int *pvalue, boolean used)
{
	int split = 5;
	int rnd = rng_int()%100;

	if (pvalue==0 || rnd %10 >= 10) return;
	if (used) split = 4;
	/* if a resource was mined this round, there is a 6% probability
	 * of a decline and a 4% probability of a raise. */
	/* if it wasn't mined this round, there is an equal probability
	 * of 5% for a decline or a raise. */
	if(rnd < split) {
		(*pvalue)++;
	} else {
		(*pvalue)--;
	}
	if ((*pvalue) < 0) (*pvalue) = 0;
}
#endif

static int
visible_default(const rawmaterial *res, int skilllevel)
/* resources are visible, if skill equals minimum skill to mine them
 * plus current level of difficulty */
{
	const struct item_type * itype = res->type->rtype->itype;
	if (res->level<=1 && res->level + itype->construction->minskill <= skilllevel+1) {
		assert (res->amount>0);
		return res->amount;
	} else if (res->level + itype->construction->minskill <= skilllevel+2) {
		assert (res->amount>0);
		return res->amount;
	}
	return -1;
}

static void 
use_default(rawmaterial *res, const region * r, int amount)
{
  assert(res->amount>0 && amount>=0 && amount <= res->amount);
  res->amount-=amount;
  while (res->amount==0) {
    double modifier = 1.0 + ((rng_int() % (SHIFT*2+1)) - SHIFT) * ((rng_int() % (SHIFT*2+1)) - SHIFT) / 10000.0;
    int i;

    for (i=0;r->terrain->production[i].type;++i) {
      if (res->type->rtype == r->terrain->production[i].type) break;
    }

    ++res->level;
    update_resource(res, modifier);
  }
}

struct rawmaterial *
rm_get(region * r, const struct resource_type * rtype)
{
	struct rawmaterial * rm = r->resources;
	while (rm && rm->type->rtype!=rtype) rm = rm->next;
	return rm;
}

struct rawmaterial_type * rawmaterialtypes = 0;

struct rawmaterial_type * 
rmt_find(const char * str)
{
	rawmaterial_type * rmt = rawmaterialtypes;
	while (rmt && strcmp(rmt->name, str)!=0) rmt = rmt->next;
	return rmt;
}

struct rawmaterial_type * 
rmt_get(const struct resource_type * rtype)
{
  rawmaterial_type * rmt = rawmaterialtypes;
  while (rmt && rmt->rtype!=rtype) rmt = rmt->next;
  return rmt;
}

struct rawmaterial_type * 
rmt_create(const struct resource_type * rtype, const char * name)
{
  rawmaterial_type * rmtype = malloc(sizeof(rawmaterial_type));
  rmtype->name = strdup(name);
  rmtype->rtype = rtype;
  rmtype->terraform = terraform_default;
  rmtype->update = NULL;
  rmtype->use = use_default;
  rmtype->visible = visible_default;
  rmtype->next = rawmaterialtypes;
  rawmaterialtypes = rmtype;
  return rmtype;
}