grf {
 grfid : "ZUU0";
 name : string(STR_GRF_NAME);
 desc : string(STR_GRF_DESCRIPTION);
 version: 1;
 min_compatible_version: 1;
}

/* Behaviour:
 *   Industry is constructed with 'storage 0' set to 512, which means 100%.
 *   GS sets 'storage 0' via command.
 *   Actual production modifier is: (1 + storage0/256) / 3
 *     storage0 = 0   ->  33%
 *     storage0 = 256 ->  66%
 *     storage0 = 512 -> 100%
 *     storage0 = 1024 -> 166%
 *   Special value:
 *     Adding 0x10000 to storage0 announces closure and closes the industry next month.
 */

produce (primary_produce,
  0, 0, 0,
  production_rate_1 * (LOAD_PERM(0) & 0xFFFF) / 256,
  production_rate_2 * (LOAD_PERM(0) & 0xFFFF) / 256,
);

switch (FEAT_INDUSTRIES, SELF, monthly_check), [
  LOAD_PERM(0) >> 16
]) {
  1: return CB_RESULT_IND_PROD_CLOSE;
  0: return CB_RESULT_IND_PROD_NO_CHANGE;
}

switch (FEAT_INDUSTRIES, SELF, switch_prod_change, [
  STORE_PERM(extra_callback_info1, 0),
  extra_callback_info1
]) {
  return CB_RESULT_IND_PROD_CLOSE;
}

switch (FEAT_INDUSTRIES, SELF, init_industry, [
  STORE_PERM(512, 0),
  extra_callback_info1
]) {
  return 16;
}

item (FEAT_INDUSTRIES, item_industry_coal_mine) {
 property {
  substitute: 00; // coal mine
  override: 00;
  prod_multiplier: [5, 0]
 }
 graphics {
  build_prod_change: init_industry;
  random_prod_change: switch_prod_change;
  monthly_prod_change: monthly_check;
  produce_256_ticks: primary_produce;
 }
}