barbarian.c

Go to the documentation of this file.

/***********************************************************************
 Freeciv - Copyright (C) 2003 - A Kjeldberg, L Gregersen, P Unold
   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, 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.
***********************************************************************/
 
/***********************************************************************
  Functions for creating barbarians in huts, land and sea
  Started by Jerzy Klek <jekl@altavista.net>
  with more ideas from Falk Hueffner
***********************************************************************/
 
#ifdef HAVE_CONFIG_H
#include <fc_config.h>
#endif
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
/* utility */
#include "fcintl.h"
#include "log.h"
#include "rand.h"
#include "support.h"
 
/* common */
#include "effects.h"
#include "events.h"
#include "game.h"
#include "government.h"
#include "map.h"
#include "movement.h"
#include "nation.h"
#include "research.h"
#include "tech.h"
#include "terrain.h"
#include "unitlist.h"
 
/* server */
#include "aiiface.h"
#include "citytools.h"
#include "diplhand.h"
#include "gamehand.h"
#include "maphand.h"
#include "notify.h"
#include "plrhand.h"
#include "srv_main.h"
#include "stdinhand.h"
#include "techtools.h"
#include "unithand.h"
#include "unittools.h"
 
/* server/advisors */
#include "advdata.h"
 
/* ai */
#include "difficulty.h"
 
#include "barbarian.h"
 
#define BARBARIAN_INITIAL_VISION_RADIUS 3
#define BARBARIAN_INITIAL_VISION_RADIUS_SQ 9
 
/**********************************************************************/
bool is_land_barbarian(struct player *pplayer)
{
  return (pplayer->ai_common.barbarian_type == LAND_BARBARIAN
          || pplayer->ai_common.barbarian_type == LAND_AND_SEA_BARBARIAN);
}
 
/**********************************************************************/
bool is_sea_barbarian(struct player *pplayer)
{
  return (pplayer->ai_common.barbarian_type == SEA_BARBARIAN
          || pplayer->ai_common.barbarian_type == LAND_AND_SEA_BARBARIAN);
}
 
/**********************************************************************/
struct player *create_barbarian_player(enum barbarian_type type)
{
  struct player *barbarians;
  struct nation_type *nation = NULL;
  struct research *presearch;
 
  players_iterate(old_barbs) {
    if ((type == LAND_BARBARIAN && is_land_barbarian(old_barbs))
        || (type == SEA_BARBARIAN && is_sea_barbarian(old_barbs))) {
      if (!old_barbs->is_alive) {
        old_barbs->economic.gold = 0;
        old_barbs->is_alive = TRUE;
        player_status_reset(old_barbs);
 
        /* Free old name so pick_random_player_name() can select it again.
         * This is needed in case ruleset defines just one leader for
         * barbarian nation. */
        old_barbs->name[0] = '\0';
        server_player_set_name(old_barbs,
            pick_random_player_name(nation_of_player(old_barbs)));
        sz_strlcpy(old_barbs->username, _(ANON_USER_NAME));
        old_barbs->unassigned_user = TRUE;
        /* I need to make them to forget the map, I think */
        whole_map_iterate(&(wld.map), ptile) {
          map_clear_known(ptile, old_barbs);
        } whole_map_iterate_end;
      }
      old_barbs->economic.gold += 100;  /* New leader, new money */
 
      return old_barbs;
    }
  } players_iterate_end;
 
  /* Make a new player, or not */
  barbarians = server_create_player(-1, default_ai_type_name(), NULL, FALSE);
  if (barbarians == NULL) {
    return NULL;
  }
  /* Freeciv-web depends on AI-status being set already before server_player_init() */
  set_as_ai(barbarians);
  server_player_init(barbarians, TRUE, TRUE);
 
  if (type == LAND_BARBARIAN || type == SEA_BARBARIAN) {
    /* Try LAND_AND_SEA *FIRST*, so that we don't end up
     * with one of the Land/Sea barbarians created first and
     * then LAND_AND_SEA created instead of the second. */
    nation = pick_a_nation(NULL, FALSE, FALSE, LAND_AND_SEA_BARBARIAN);
    if (nation != NULL) {
      type = LAND_AND_SEA_BARBARIAN;
    }
  }
 
  if (nation == NULL) {
    nation = pick_a_nation(NULL, FALSE, FALSE, type);
  }
 
  /* Ruleset loading time checks should guarantee that there always is
     suitable nation available */
  fc_assert(nation != NULL);
 
  player_nation_defaults(barbarians, nation, TRUE);
  if (game_was_started()) {
    /* Find a color for the new player. */
    assign_player_colors();
  }
 
  server.nbarbarians++;
 
  sz_strlcpy(barbarians->username, _(ANON_USER_NAME));
  barbarians->unassigned_user = TRUE;
  barbarians->is_connected = FALSE;
  barbarians->government = init_government_of_nation(nation);
  fc_assert(barbarians->revolution_finishes < 0);
  BV_CLR(barbarians->flags, PLRF_FIRST_CITY);
  barbarians->economic.gold = 100;
 
  barbarians->phase_done = TRUE;
 
  /* Do the AI */
  barbarians->ai_common.barbarian_type = type;
  set_ai_level_directer(barbarians, game.info.skill_level);
 
  presearch = research_get(barbarians);
  init_tech(presearch, TRUE);
  give_initial_techs(presearch, 0);
 
  /* Ensure that we are at war with everyone else */
  barbarian_initial_wars(barbarians);
 
  CALL_PLR_AI_FUNC(gained_control, barbarians, barbarians);
 
  log_verbose("Created barbarian %s, player %d", player_name(barbarians),
              player_number(barbarians));
  notify_player(NULL, NULL, E_UPRISING, ftc_server,
                _("%s gain a leader by the name %s. Dangerous "
                  "times may lie ahead."),
                nation_plural_for_player(barbarians),
                player_name(barbarians));
 
  send_player_all_c(barbarians, NULL);
  /* Send research info after player info, else the client will complain
   * about invalid team. */
  send_research_info(presearch, NULL);
 
  return barbarians;
}
 
/**********************************************************************/
static void init_dir_checked_status(bool *checked,
                                    enum terrain_class *terrainc,
                                    enum terrain_class tclass)
{
  int dir;
 
  for (dir = 0; dir < 8; dir++) {
    if (terrainc[dir] == tclass) {
      checked[dir] = FALSE;
    } else {
      checked[dir] = TRUE;
    }
  }
}
 
/**********************************************************************/
static int random_unchecked_direction(int possibilities, const bool *checked)
{
  int j = -1;
  int i;
 
  int num = fc_rand(possibilities);
  for (i = 0; i <= num; i++) {
    j++;
    while (checked[j]) {
      j++;
      fc_assert(j < 8);
    }
  }
 
  return j;
}
 
/**********************************************************************/
static void unit_move_pay(struct unit *punit, struct tile *pdesttile)
{
  int move_cost = map_move_cost_unit(&(wld.map), punit, pdesttile);
 
  unit_move(punit, pdesttile, move_cost,
            /* Don't override "Transport Embark" */
            NULL, FALSE,
            /* Don't override "Conquer City" */
            FALSE,
            /* Don't override "Conquer Extras" */
            FALSE,
            /* Don't override "Enter Hut" */
            FALSE,
            /* Don't override "Frighten Hut" */
            FALSE);
}
 
/**********************************************************************/
bool unleash_barbarians(struct tile *ptile)
{
  struct player *barbarians;
  int unit_cnt;
  int i;
  bool alive = TRUE;     /* explorer survived */
  enum terrain_class terrainc[8];
  struct tile *dir_tiles[8];
  int land_tiles = 0;
  int ocean_tiles = 0;
  bool checked[8];
  int checked_count;
  int dir;
  bool barbarian_stays = FALSE;
  const struct civ_map *nmap = &(wld.map);
 
  /* FIXME: When there is no L_BARBARIAN unit,
   *        but L_BARBARIAN_TECH is already available,
   *        we should unleash those.
   *        Doesn't affect any ruleset I'm aware of. */
  if (BARBS_DISABLED == game.server.barbarianrate
      || game.info.turn < game.server.onsetbarbarian
      || num_role_units(L_BARBARIAN) == 0) {
    unit_list_iterate_safe((ptile)->units, punit) {
      wipe_unit(punit, ULR_BARB_UNLEASH, NULL);
    } unit_list_iterate_safe_end;
    return FALSE;
  }
 
  barbarians = create_barbarian_player(LAND_BARBARIAN);
  if (!barbarians) {
    return FALSE;
  }
 
  adv_data_phase_init(barbarians, TRUE);
  CALL_PLR_AI_FUNC(phase_begin, barbarians, barbarians, TRUE);
 
  unit_cnt = 3 + fc_rand(4);
  for (i = 0; i < unit_cnt; i++) {
    struct unit_type *punittype
      = find_a_unit_type(L_BARBARIAN, L_BARBARIAN_TECH);
 
    /* If unit cannot live on this tile, we just don't create one.
     * Maybe find_a_unit_type() should take tile parameter, so
     * we could get suitable unit if one exist. */
    if (is_native_tile(punittype, ptile)
        && !utype_player_already_has_this_unique(barbarians, punittype)) {
      struct unit *barb_unit;
 
      barb_unit = create_unit(barbarians, ptile, punittype, 0, 0, -1);
      log_debug("Created barbarian unit %s", utype_rule_name(punittype));
      send_unit_info(NULL, barb_unit);
    }
  }
 
  /* Get information about surrounding terrains in terrain class level.
   * Only needed if we consider moving units away to random directions. */
  for (dir = 0; dir < 8; dir++) {
    dir_tiles[dir] = mapstep(nmap, ptile, dir);
    if (dir_tiles[dir] == NULL) {
      terrainc[dir] = terrain_class_invalid();
    } else if (!is_non_allied_unit_tile(dir_tiles[dir], barbarians)) {
      if (is_ocean_tile(dir_tiles[dir])) {
        terrainc[dir] = TC_OCEAN;
        ocean_tiles++;
      } else {
        terrainc[dir] = TC_LAND;
        land_tiles++;
      }
    } else {
      terrainc[dir] = terrain_class_invalid();
    }
  }
 
  if (land_tiles >= 3) {
    /* Enough land, scatter guys around */
    unit_list_iterate_safe((ptile)->units, punit2) {
      if (unit_owner(punit2) == barbarians) {
        bool dest_found = FALSE;
 
        /* Initialize checked status for checking free land tiles */
        init_dir_checked_status(checked, terrainc, TC_LAND);
 
        /* Search tile to move to */
        for (checked_count = 0; !dest_found && checked_count < land_tiles;
             checked_count++) {
          int rdir = random_unchecked_direction(land_tiles - checked_count, checked);
 
          if (unit_can_move_to_tile(nmap, punit2, dir_tiles[rdir],
                                    TRUE, FALSE, FALSE)) {
            /* Move */
            (void) unit_move_pay(punit2, dir_tiles[rdir]);
            log_debug("Moved barbarian unit from (%d, %d) to (%d, %d)", 
                      TILE_XY(ptile), TILE_XY(dir_tiles[rdir]));
            dest_found = TRUE;
          }
 
          checked[rdir] = TRUE;
        }
        if (!dest_found) {
          /* This barbarian failed to move out of hut tile. */
          barbarian_stays = TRUE;
        }
      }
    } unit_list_iterate_safe_end;
 
  } else {
    if (ocean_tiles > 0) {
      /* maybe it's an island, try to get on boats */
      struct unit *boat = NULL; /* Boat */
 
      /* Initialize checked status for checking Ocean tiles */
      init_dir_checked_status(checked, terrainc, TC_OCEAN);
 
      /* Search tile for boat. We always create just one boat. */
      for (checked_count = 0; boat == NULL && checked_count < ocean_tiles;
           checked_count++) {
        struct unit_type *candidate;
        int rdir = random_unchecked_direction(ocean_tiles - checked_count, checked);
 
        candidate = find_a_unit_type(L_BARBARIAN_BOAT, L_BARBARIAN_BOAT_TECH);
        if (is_native_tile(candidate, dir_tiles[rdir])
            && !utype_player_already_has_this_unique(barbarians, candidate)) {
          boat = create_unit(barbarians, dir_tiles[rdir], candidate,
                             0, 0, -1);
        }
 
        checked[rdir] = TRUE;
      }
 
      if (boat) {
        /* We do have a boat. Try to get everybody in */
        unit_list_iterate_safe((ptile)->units, punit2) {
          if (unit_owner(punit2) == barbarians) {
            if (is_action_enabled_unit_on_unit(nmap, ACTION_TRANSPORT_EMBARK,
                                               punit2, boat)) {
              /* Load */
              unit_do_action(unit_owner(punit2), punit2->id, boat->id,
                             0, "", ACTION_TRANSPORT_EMBARK);
            } else if (is_action_enabled_unit_on_unit(nmap, ACTION_TRANSPORT_EMBARK2,
                                                      punit2, boat)) {
              /* Load */
              unit_do_action(unit_owner(punit2), punit2->id, boat->id,
                             0, "", ACTION_TRANSPORT_EMBARK2);
            } else if (is_action_enabled_unit_on_unit(nmap, ACTION_TRANSPORT_EMBARK3,
                                                      punit2, boat)) {
              /* Load */
              unit_do_action(unit_owner(punit2), punit2->id, boat->id,
                             0, "", ACTION_TRANSPORT_EMBARK3);
            } else if (is_action_enabled_unit_on_unit(nmap, ACTION_TRANSPORT_EMBARK4,
                                                      punit2, boat)) {
              /* Load */
              unit_do_action(unit_owner(punit2), punit2->id, boat->id,
                             0, "", ACTION_TRANSPORT_EMBARK4);
            }
          }
        } unit_list_iterate_safe_end;
      }
 
      /* Move rest of the barbarians to random land tiles */
      unit_list_iterate_safe((ptile)->units, punit2) {
        if (unit_owner(punit2) == barbarians) {
          bool dest_found = FALSE;
 
          /* Initialize checked status for checking Land tiles */
          init_dir_checked_status(checked, terrainc, TC_LAND);
 
          /* Search tile to move to */
          for (checked_count = 0; !dest_found && checked_count < land_tiles;
               checked_count++) {
            int rdir;
 
            rdir = random_unchecked_direction(land_tiles - checked_count, checked);
 
            if (unit_can_move_to_tile(nmap, punit2, dir_tiles[rdir],
                                      TRUE, FALSE, FALSE)) {
              /* Move */
              (void) unit_move_pay(punit2, dir_tiles[rdir]);
              dest_found = TRUE;
            }
 
            checked[rdir] = TRUE;
          }
          if (!dest_found) {
            /* This barbarian failed to move out of hut tile. */
            barbarian_stays = TRUE;
          }
        }
      } unit_list_iterate_safe_end;
    } else {
      /* The village is surrounded! Barbarians cannot leave. */
      barbarian_stays = TRUE;
    }
  }
 
  if (barbarian_stays) {
    /* There's barbarian in this village! Kill the explorer. */
    unit_list_iterate_safe((ptile)->units, punit2) {
      if (unit_owner(punit2) != barbarians) {
        wipe_unit(punit2, ULR_BARB_UNLEASH, NULL);
        alive = FALSE;
      } else {
        send_unit_info(NULL, punit2);
      }
    } unit_list_iterate_safe_end;
  }
 
  /* FIXME: I don't know if this is needed */
  if (ptile) {
    map_show_circle(barbarians, ptile, BARBARIAN_INITIAL_VISION_RADIUS_SQ);
  }
 
  return alive;
}
 
/**********************************************************************/
static bool is_near_land(struct tile *tile0)
{
  square_iterate(&(wld.map), tile0, 4, ptile) {
    if (!is_ocean_tile(ptile)) {
      return TRUE;
    }
  } square_iterate_end;
 
  return FALSE;
}
 
/**********************************************************************/
static struct tile *find_empty_tile_nearby(struct tile *ptile)
{
  square_iterate(&(wld.map), ptile, 1, tile1) {
    if (unit_list_size(tile1->units) == 0) {
      return tile1;
    }
  } square_iterate_end;
 
  return NULL;
}
 
/**********************************************************************/
static void try_summon_barbarians(void)
{
  struct tile *ptile, *utile;
  int i, dist;
  int uprise;
  struct city *pc;
  struct player *barbarians, *victim;
  struct unit_type *leader_type;
  int barb_count, really_created = 0;
  bool hut_present = FALSE;
  int city_count;
  int city_max;
  const struct civ_map *nmap = &(wld.map);
 
  /* We attempt the summons on a particular, random position.  If this is
   * an invalid position then the summons simply fails this time.  This means
   * that a particular tile's chance of being summoned on is independent of
   * all the other tiles on the map - which is essential for balanced
   * gameplay. */
  ptile = rand_map_pos(nmap);
 
  if (terrain_has_flag(tile_terrain(ptile), TER_NO_BARBS)) {
    return;
  }
 
  if (!(pc = find_closest_city(ptile, NULL, NULL, FALSE, FALSE, FALSE, FALSE,
                               FALSE, NULL))) {
    /* any city */
    return;
  }
 
  victim = city_owner(pc);
 
  dist = real_map_distance(ptile, pc->tile);
  log_debug("Closest city (to %d,%d) is %s (at %d,%d) distance %d.",
            TILE_XY(ptile), city_name_get(pc), TILE_XY(pc->tile), dist);
  if (dist > MAX_UNREST_DIST || dist < MIN_UNREST_DIST) {
    return;
  }
 
  /* I think Sea Raiders can come out of unknown sea territory */
  if (!(utile = find_empty_tile_nearby(ptile))
      || (!map_is_known(utile, victim)
          && !is_ocean_tile(utile))
      || !is_near_land(utile)) {
    return;
  }
 
  fc_assert(1 < game.server.barbarianrate);
 
  /* do not harass small civs - in practice: do not uprise at the beginning */
  if ((int)fc_rand(30) + 1 >
      (int)city_list_size(victim->cities) * (game.server.barbarianrate - 1)
      || fc_rand(100) > get_player_bonus(victim, EFT_CIVIL_WAR_CHANCE)) {
    return;
  }
  log_debug("Barbarians are willing to fight");
 
  /* Remove huts in place of uprising */
  /* FIXME: Should we really always do it? */
  extra_type_by_rmcause_iterate(ERM_ENTER, pextra) {
    if (tile_has_extra(utile, pextra)) {
      tile_extra_rm_apply(utile, pextra);
      hut_present = TRUE;
    }
  } extra_type_by_rmcause_iterate_end;
 
  if (hut_present) {
    update_tile_knowledge(utile);
  }
 
  city_count = city_list_size(victim->cities);
  city_max = UPRISE_CIV_SIZE;
  uprise = 1;
 
  while (city_max <= city_count) {
    uprise++;
    city_max += (city_max * 1.2) + UPRISE_CIV_SIZE;
  }
 
  barb_count = fc_rand(3) + uprise * game.server.barbarianrate;
  leader_type = get_role_unit(L_BARBARIAN_LEADER, 0);
 
  if (!is_ocean_tile(utile)) {
    /* land (disembark) barbarians */
    barbarians = create_barbarian_player(LAND_BARBARIAN);
    if (!barbarians) {
      return;
    }
    for (i = 0; i < barb_count; i++) {
      struct unit_type *punittype
        = find_a_unit_type(L_BARBARIAN, L_BARBARIAN_TECH);
 
      /* If unit cannot live on this tile, we just don't create one.
       * Maybe find_a_unit_type() should take tile parameter, so
       * we could get suitable unit if one exist. */
      if (is_native_tile(punittype, utile)
          && !utype_player_already_has_this_unique(barbarians, punittype)) {
        (void) create_unit(barbarians, utile, punittype, 0, 0, -1);
        really_created++;
        log_debug("Created barbarian unit %s", utype_rule_name(punittype));
      }
    }
 
    if (is_native_tile(leader_type, utile)
        && !utype_player_already_has_this_unique(barbarians, leader_type)) {
      (void) create_unit(barbarians, utile,
                         leader_type, 0, 0, -1);
      really_created++;
    }
  } else {                   /* Sea raiders - their units will be veteran */
    struct unit *ptrans;
    struct unit_type *boat;
    bool miniphase;
 
    barbarians = create_barbarian_player(SEA_BARBARIAN);
    if (!barbarians) {
      return;
    }
    /* Setup data phase if it's not already set up. Created ferries may
       need that data.
       We don't know if create_barbarian_player() above created completely
       new player or did it just return existing one. If it was existing
       one, phase has already been set up at turn begin and will be closed
       at turn end. If this is completely new player, we have to take care
       of both opening and closing the data phase. Return value of
       adv_data_phase_init() tells us if data phase was already initialized
       at turn beginning. */
    miniphase = adv_data_phase_init(barbarians, TRUE);
    if (miniphase) {
      CALL_PLR_AI_FUNC(phase_begin, barbarians, barbarians, TRUE);
    }
 
    boat = find_a_unit_type(L_BARBARIAN_BOAT, L_BARBARIAN_BOAT_TECH);
 
    if (is_native_tile(boat, utile)
        && !utype_player_already_has_this_unique(barbarians, boat)
        && (is_safe_ocean(nmap, utile)
            || (!utype_has_flag(boat, UTYF_COAST_STRICT)
                && !utype_has_flag(boat, UTYF_COAST)))) {
      int cap;
 
      ptrans = create_unit(barbarians, utile, boat, 0, 0, -1);
      really_created++;
      cap = get_transporter_capacity(ptrans);
 
      /* Fill boat with barb_count barbarians at max, leave space for leader */
      for (i = 0; i < cap - 1 && i < barb_count; i++) {
        struct unit_type *barb
          = find_a_unit_type(L_BARBARIAN_SEA, L_BARBARIAN_SEA_TECH);
 
        if (can_unit_type_transport(boat, utype_class(barb))
            && !utype_player_already_has_this_unique(barbarians, barb)) {
          (void) create_unit_full(barbarians, utile, barb, 0, 0, -1, -1,
                                  ptrans);
          really_created++;
          log_debug("Created barbarian unit %s", utype_rule_name(barb));
        }
      }
 
      if (can_unit_type_transport(boat, utype_class(leader_type))
          && !utype_player_already_has_this_unique(barbarians, leader_type)) {
        (void) create_unit_full(barbarians, utile, leader_type, 0, 0,
                                -1, -1, ptrans);
        really_created++;
      }
    }
 
    if (miniphase) {
      CALL_PLR_AI_FUNC(phase_finished, barbarians, barbarians);
      adv_data_phase_done(barbarians);
    }
  }
 
  if (really_created == 0) {
    /* No barbarians found suitable spot */
    return;
  }
 
  /* Is this necessary?  create_unit_full() already sends unit info. */
  unit_list_iterate(utile->units, punit2) {
    send_unit_info(NULL, punit2);
  } unit_list_iterate_end;
 
  /* to let them know where to get you */
  map_show_circle(barbarians, utile, BARBARIAN_INITIAL_VISION_RADIUS_SQ);
  map_show_circle(barbarians, pc->tile, BARBARIAN_INITIAL_VISION_RADIUS_SQ);
 
  /* There should probably be a different message about Sea Raiders */
  if (is_land_barbarian(barbarians)) {
    notify_player(victim, utile, E_UPRISING, ftc_server,
                  _("Native unrest near %s led by %s."),
                  city_link(pc),
                  player_name(barbarians));
  } else if (map_is_known_and_seen(utile, victim, V_MAIN)) {
    notify_player(victim, utile, E_UPRISING, ftc_server,
                  _("Sea raiders seen near %s!"),
                  city_link(pc));
  }
}
 
/**********************************************************************/
void summon_barbarians(void)
{
  int i, n;
 
  if (BARBS_DISABLED == game.server.barbarianrate
      || BARBS_HUTS_ONLY == game.server.barbarianrate) {
    return;
  }
 
  if (game.info.turn < game.server.onsetbarbarian) {
    return;
  }
 
  n = map_num_tiles() / MAP_FACTOR;
  if (n == 0) {
    /* Allow barbarians on maps smaller than MAP_FACTOR */
    n = 1;
  }
 
  for (i = 0; i < n * (game.server.barbarianrate - 1); i++) {
    try_summon_barbarians();
  }
}
 
/**********************************************************************/
void barbarian_initial_wars(struct player *barbarians)
{
  /* It would be nice to get rid of this special case,
   * and make barbarians to switch from "No Contact" to "War"
   * upon first contact like everyone else. Then other parts
   * of the code would not need to be prepared to the possibility
   * of a war between no-contact nations.
   * The problem is that if barbarians were not in War, they would
   * likely not to head to attack towards yet-unknown players
   * as aggressively */
 
  players_iterate(pplayer) {
    if (pplayer != barbarians) {
      set_diplstate_type(player_diplstate_get(pplayer, barbarians),
                         player_diplstate_get(barbarians, pplayer),
                         DS_WAR);
    }
  } players_iterate_end;
}