aihunt.c

Go to the documentation of this file.

/***********************************************************************
 Freeciv - Copyright (C) 2003 - The Freeciv Team
   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.
***********************************************************************/
 
#ifdef HAVE_CONFIG_H
#include <fc_config.h>
#endif
 
/* utility */
#include "bitvector.h"
#include "log.h"
 
/* common */
#include "city.h"
#include "combat.h"
#include "game.h"
#include "map.h"
#include "movement.h"
#include "nation.h"
#include "player.h"
#include "unit.h"
#include "unitlist.h"
 
/* aicore */
#include "pf_tools.h"
 
/* server */
#include "citytools.h"
#include "srv_log.h"
#include "unithand.h"
#include "unittools.h"
 
/* server/advisors */
#include "advdata.h"
#include "advgoto.h"
#include "advtools.h"
#include "autosettlers.h"
 
/* ai */
#include "handicaps.h"
 
/* ai/default */
#include "aitools.h"
#include "daicity.h"
#include "daiplayer.h"
 
#include "aihunt.h"
 
 
/**********************************************************************/
static struct unit *dai_hunter_find(struct player *pplayer, 
                                    struct city *pcity)
{
  unit_list_iterate(pcity->units_supported, punit) {
    if (dai_hunter_qualify(pplayer, punit)) {
      return punit;
    }
  } unit_list_iterate_end;
  unit_list_iterate(pcity->tile->units, punit) {
    if (dai_hunter_qualify(pplayer, punit)) {
      return punit;
    }
  } unit_list_iterate_end;
 
  return NULL;
}
 
/**********************************************************************/
static struct unit_type *dai_hunter_guess_best(struct city *pcity,
                                               enum terrain_class tc,
                                               struct ai_type *ait,
                                               bool allow_gold_upkeep)
{
  struct unit_type *bestid = NULL;
  int best = 0;
  struct player *pplayer = city_owner(pcity);
  const struct civ_map *nmap = &(wld.map);
 
  unit_type_iterate(ut) {
    struct unit_type_ai *utai = utype_ai_data(ut, ait);
    int desire;
 
    if (!allow_gold_upkeep && utype_upkeep_cost(ut, pplayer, O_GOLD) > 0) {
      continue;
    }
 
    if (!can_city_build_unit_now(nmap, pcity, ut)
        || ut->attack_strength < ut->transport_capacity
        || (tc == TC_OCEAN && utype_class(ut)->adv.sea_move == MOVE_NONE)
        || (tc == TC_LAND && utype_class(ut)->adv.land_move == MOVE_NONE)) {
      continue;
    }
 
    desire = (ut->hp
              * ut->attack_strength
              * ut->firepower
              * ut->move_rate
              + ut->defense_strength) / MAX(UNITTYPE_COSTS(ut), 1);
 
    if (utai->missile_platform) {
      desire += desire / 6;
    }
 
    if (utype_has_flag(ut, UTYF_IGTER)) {
      desire += desire / 2;
    }
    if (ut->vlayer == V_INVIS) {
      desire += desire / 4;
    }
    if (!can_attack_non_native(ut)) {
      desire -= desire / 4; /* less flexibility */
    }
    /* Causes continual unhappiness */
    if (utype_has_flag(ut, UTYF_FIELDUNIT)) {
      desire /= 2;
    }
 
    desire = amortize(desire,
                      (utype_build_shield_cost(pcity, NULL, ut)
                       / MAX(pcity->surplus[O_SHIELD], 1)));
 
    if (desire > best) {
      best = desire;
      bestid = ut;
    }
  } unit_type_iterate_end;
 
  return bestid;
}
 
/**********************************************************************/
static void dai_hunter_missile_want(struct player *pplayer,
                                    struct city *pcity,
                                    struct adv_choice *choice)
{
  adv_want best = -1;
  struct unit_type *best_unit_type = NULL;
  struct unit *hunter = NULL;
  const struct civ_map *nmap = &(wld.map);
 
  unit_list_iterate(pcity->tile->units, punit) {
    if (dai_hunter_qualify(pplayer, punit)) {
      unit_type_iterate(pcargo) {
        if (can_unit_type_transport(unit_type_get(punit),
                                    utype_class(pcargo))
            && utype_can_do_action(pcargo, ACTION_SUICIDE_ATTACK)) {
          hunter = punit;
          break;
        }
      } unit_type_iterate_end;
      if (hunter) {
        break;
      }
    }
  } unit_list_iterate_end;
 
  if (!hunter) {
    return;
  }
 
  unit_type_iterate(ut) {
    int desire;
 
    if (!utype_can_do_action(ut, ACTION_SUICIDE_ATTACK)
        || !can_city_build_unit_now(nmap, pcity, ut)) {
      continue;
    }
 
    if (!can_unit_type_transport(unit_type_get(hunter), utype_class(ut))) {
      continue;
    }
 
    /* FIXME: We need to store some data that can tell us if
     * enemy transports are protected by anti-missile technology. 
     * In this case, want nuclear much more! */
    desire = (ut->hp
              * MIN(ut->attack_strength, 30) /* nuke fix */
              * ut->firepower
              * ut->move_rate) / UNITTYPE_COSTS(ut) + 1;
 
    /* Causes continual unhappiness */
    if (utype_has_flag(ut, UTYF_FIELDUNIT)) {
      desire /= 2;
    }
 
    desire = amortize(desire,
                      (utype_build_shield_cost(pcity, NULL, ut)
                       / MAX(pcity->surplus[O_SHIELD], 1)));
 
    if (desire > best) {
      best = desire;
      best_unit_type = ut;
    }
  } unit_type_iterate_end;
 
  if (best > choice->want) {
    CITY_LOG(LOGLEVEL_HUNT, pcity,
             "pri missile w/ want " ADV_WANT_PRINTF, best);
    choice->value.utype = best_unit_type;
    choice->want = best;
    choice->type = CT_ATTACKER;
    choice->need_boat = FALSE;
    adv_choice_set_use(choice, "missile");
  } else if (best >= 0) {
    CITY_LOG(LOGLEVEL_HUNT, pcity, "not pri missile w/ want " ADV_WANT_PRINTF
             "(old want " ADV_WANT_PRINTF ")", best, choice->want);
  }
}
 
/**********************************************************************/
static void eval_hunter_want(struct ai_type *ait, struct player *pplayer,
                             struct city *pcity,
                             struct adv_choice *choice,
                             struct unit_type *best_type,
                             int veteran)
{
  struct unit *virtualunit;
  int want = 0;
 
  virtualunit = unit_virtual_create(pplayer, pcity, best_type, veteran);
  want = dai_hunter_manage(ait, pplayer, virtualunit);
  unit_virtual_destroy(virtualunit);
  if (want > choice->want) {
    CITY_LOG(LOGLEVEL_HUNT, pcity, "pri hunter w/ want %d", want);
    choice->value.utype = best_type;
    choice->want = want;
    choice->type = CT_ATTACKER;
    choice->need_boat = FALSE;
    adv_choice_set_use(choice, "hunter");
  }
}
 
/**********************************************************************/
void dai_hunter_choice(struct ai_type *ait, struct player *pplayer,
                       struct city *pcity, struct adv_choice *choice,
                       bool allow_gold_upkeep)
{
  struct unit_type *best_land_hunter
    = dai_hunter_guess_best(pcity, TC_LAND, ait, allow_gold_upkeep);
  struct unit_type *best_sea_hunter
    = dai_hunter_guess_best(pcity, TC_OCEAN, ait, allow_gold_upkeep);
  struct unit *hunter = dai_hunter_find(pplayer, pcity);
 
  if ((!best_land_hunter && !best_sea_hunter)
      || is_barbarian(pplayer) || !pplayer->is_alive
      || has_handicap(pplayer, H_TARGETS)) {
    return; /* None available */
  }
  if (hunter) {
    /* Maybe want missiles to go with a hunter instead? */
    dai_hunter_missile_want(pplayer, pcity, choice);
    return;
  }
 
  if (best_sea_hunter) {
    eval_hunter_want(
      ait, pplayer, pcity, choice, best_sea_hunter,
      city_production_unit_veteran_level(pcity, best_sea_hunter));
  }
  if (best_land_hunter) {
    eval_hunter_want(
      ait, pplayer, pcity, choice, best_land_hunter,
      city_production_unit_veteran_level(pcity, best_land_hunter));
  }
}
 
/**********************************************************************/
bool dai_hunter_qualify(struct player *pplayer, struct unit *punit)
{
  if (is_barbarian(pplayer) || unit_owner(punit) != pplayer) {
    return FALSE;
  }
  if (unit_has_type_role(punit, L_HUNTER)) {
    return TRUE;
  }
  return FALSE;
}
 
/**********************************************************************/
static void dai_hunter_try_launch(struct ai_type *ait,
                                  struct player *pplayer,
                                  struct unit *punit,
                                  struct unit *target)
{
  int target_sanity = target->id;
  struct pf_parameter parameter;
  struct pf_map *pfm;
  const struct civ_map *nmap = &(wld.map);
 
  /* Only directly transported units. Not launching cargo of cargo */
  unit_list_iterate_safe(punit->transporting, missile) {
    struct unit *sucker = NULL;
 
    if (unit_owner(missile) == pplayer
        && utype_can_do_action(unit_type_get(missile),
                               ACTION_SUICIDE_ATTACK)) {
      UNIT_LOG(LOGLEVEL_HUNT, missile, "checking for hunt targets");
      pft_fill_unit_parameter(&parameter, nmap, punit);
      parameter.omniscience = !has_handicap(pplayer, H_MAP);
      pfm = pf_map_new(&parameter);
 
      pf_map_move_costs_iterate(pfm, ptile, move_cost, FALSE) {
        if (move_cost > missile->moves_left / SINGLE_MOVE) {
          break;
        }
        if (tile_city(ptile)
            || !can_unit_attack_tile(punit, NULL, ptile)) {
          continue;
        }
        unit_list_iterate(ptile->units, victim) {
          enum diplstate_type ds =
            player_diplstate_get(pplayer, unit_owner(victim))->type;
          const struct unit_type *ptype;
          const struct unit_type *victim_type;
 
          if (ds != DS_WAR) {
            continue;
          }
          if (victim == target) {
            sucker = victim;
            UNIT_LOG(LOGLEVEL_HUNT, missile, "found primary target %d(%d, %d)"
                     " dist %d", victim->id, TILE_XY(unit_tile(victim)),
                     move_cost);
            break; /* Our target! Get it!!! */
          }
 
          victim_type = unit_type_get(victim);
          ptype = unit_type_get(punit);
 
          if (ATTACK_POWER(victim_type) > DEFENSE_POWER(ptype)
              && dai_unit_can_strike_my_unit(victim, punit)) {
            sucker = victim;
            UNIT_LOG(LOGLEVEL_HUNT, missile, "found aux target %d(%d, %d)",
                     victim->id, TILE_XY(unit_tile(victim)));
            break;
          }
        } unit_list_iterate_end;
        if (sucker) {
          break; /* Found something - kill it! */
        }
      } pf_map_move_costs_iterate_end;
      pf_map_destroy(pfm);
 
      if (sucker) {
        if (unit_transported(missile)) {
          struct unit *ptrans = unit_transport_get(missile);
 
          if (is_action_enabled_unit_on_unit(nmap, ACTION_TRANSPORT_DEBOARD,
                                             missile, ptrans)) {
            unit_do_action(unit_owner(punit), punit->id, ptrans->id,
                           0, "", ACTION_TRANSPORT_DEBOARD);
          }
        }
 
        missile->goto_tile = unit_tile(sucker);
        if (dai_unit_goto(ait, missile, unit_tile(sucker))) {
          /* We survived; did they? */
          sucker = game_unit_by_number(target_sanity); /* Sanity */
          if (sucker && is_tiles_adjacent(unit_tile(sucker),
                                          unit_tile(missile))) {
            dai_unit_attack(ait, missile, unit_tile(sucker));
          }
        }
        if (game_unit_by_number(target_sanity) == NULL) {
          return; /* Target killed */
        }
      }
    } /* if */
  } unit_list_iterate_safe_end;
}
 
/**********************************************************************/
static void dai_hunter_juiciness(struct player *pplayer, struct unit *punit,
                                 struct unit *target, unsigned *stackthreat,
                                 unsigned *stackcost)
{
  *stackthreat = 0;
  *stackcost = 0;
 
  unit_list_iterate(unit_tile(target)->units, sucker) {
    const struct unit_type *suck_type = unit_type_get(sucker);
 
    *stackthreat += ATTACK_POWER(suck_type);
    if (unit_has_type_flag(sucker, UTYF_GAMELOSS)) {
      *stackcost += 1000;
      *stackthreat += 5000;
    }
    if (utype_acts_hostile(unit_type_get(sucker))) {
      *stackthreat += 500; /* Extra threatening */
    }
    *stackcost += unit_build_shield_cost_base(sucker);
  } unit_list_iterate_end;
 
  *stackthreat *= 9; /* WAG - reduced by distance later */
  *stackthreat += *stackcost;
}
 
/**********************************************************************/
int dai_hunter_manage(struct ai_type *ait, struct player *pplayer,
                      struct unit *punit)
{
  bool is_virtual = (punit->id == 0);
  struct pf_parameter parameter;
  struct pf_map *pfm;
  int limit = unit_move_rate(punit) * 6;
  struct unit_ai *unit_data = def_ai_unit_data(punit, ait);
  struct unit *original_target = game_unit_by_number(unit_data->target);
  unsigned original_threat = 0, original_cost = 0;
  struct civ_map *nmap = &(wld.map);
 
  fc_assert_ret_val(!is_barbarian(pplayer), 0);
  fc_assert_ret_val(pplayer->is_alive, 0);
 
  pft_fill_unit_parameter(&parameter, nmap, punit);
  parameter.omniscience = !has_handicap(pplayer, H_MAP);
  pfm = pf_map_new(&parameter);
 
  if (original_target) {
    dai_hunter_juiciness(pplayer, punit, original_target,
                         &original_threat, &original_cost);
  }
 
  pf_map_move_costs_iterate(pfm, ptile, move_cost, FALSE) {
    /* End faster if we have a target */
    if (move_cost > limit) {
      UNIT_LOG(LOGLEVEL_HUNT, punit, "gave up finding hunt target");
      pf_map_destroy(pfm);
      return 0;
    }
 
    if (tile_city(ptile)
        || !can_unit_attack_tile(punit, NULL, ptile)) {
      continue;
    }
 
    unit_list_iterate_safe(ptile->units, target) {
      struct player *aplayer = unit_owner(target);
      int dist1, dist2;
      unsigned stackthreat = 0, stackcost = 0;
      int sanity_target = target->id;
      struct pf_path *path;
      struct unit_ai *target_data;
      struct tile *target_tile;
      struct unit *defender;
 
      /* Note that we need not (yet) be at war with aplayer */
      if (!adv_is_player_dangerous(pplayer, aplayer)) {
        continue;
      }
 
      target_data = def_ai_unit_data(target, ait);
      if (BV_ISSET(target_data->hunted, player_index(pplayer))) {
        /* Can't hunt this one. The bit is cleared in the beginning
         * of each turn. */
        continue;
      }
      if (!utype_acts_hostile(unit_type_get(target))
          && get_transporter_capacity(target) == 0
          && !unit_has_type_flag(target, UTYF_GAMELOSS)) {
        /* Won't hunt this one. */
        continue;
      }
 
      target_tile = unit_tile(target);
      if (!unit_attack_unit_at_tile_result(punit, NULL, target, target_tile)) {
        /* We can't attack the target */
        continue;
      }
 
      /* Figure out whether unit is coming closer */
      if (target_data->cur_pos && target_data->prev_pos) {
        dist1 = real_map_distance(unit_tile(punit), *target_data->cur_pos);
        dist2 = real_map_distance(unit_tile(punit), *target_data->prev_pos);
      } else {
        dist1 = dist2 = 0;
      }
      UNIT_LOG(LOGLEVEL_HUNT, punit, "considering chasing %s[%d](%d, %d) "
                                     "dist1 %d dist2 %d",
               unit_rule_name(target), target->id, TILE_XY(target_tile),
               dist1, dist2);
 
      /* We can't chase if we aren't faster or on intercept vector */
      if (unit_type_get(punit)->move_rate < unit_type_get(target)->move_rate
          && dist1 >= dist2) {
        UNIT_LOG(LOGLEVEL_HUNT, punit,
                 "giving up racing %s (%d, %d)->(%d, %d)",
                 unit_rule_name(target),
                 target_data->prev_pos
                   ? index_to_map_pos_x(tile_index(*target_data->prev_pos))
                   : -1,
                 target_data->prev_pos
                   ? index_to_map_pos_y(tile_index(*target_data->prev_pos))
                   : -1,
                 TILE_XY(target_tile));
        continue;
      }
 
      /* Calculate juiciness of target, compare with existing target,
       * if any. */
      dai_hunter_juiciness(pplayer, punit, target, &stackthreat, &stackcost);
      defender = get_defender(nmap, punit, target_tile, NULL);
      if (defender != NULL) {
        stackcost *= unit_win_chance(nmap, punit, defender, NULL);
      }
      if (stackcost < unit_build_shield_cost_base(punit)) {
        UNIT_LOG(LOGLEVEL_HUNT, punit, "%d is too expensive (it %d vs us %d)",
                 target->id, stackcost,
                 unit_build_shield_cost_base(punit));
        continue; /* Too expensive */
      }
      stackthreat /= move_cost + 1;
      if (!is_virtual
          && original_target != target
          && original_threat > stackthreat) {
        UNIT_LOG(LOGLEVEL_HUNT, punit, "Unit %d is not worse than %d",
                 target->id, original_target->id);
        continue; /* The threat we found originally was worse than this! */
      }
      if (stackthreat < unit_build_shield_cost_base(punit)) {
        UNIT_LOG(LOGLEVEL_HUNT, punit, "%d is not worth it", target->id);
        continue; /* Not worth it */
      }
 
      UNIT_LOG(LOGLEVEL_HUNT, punit, "hunting %s %s[%d](%d,%d) "
               "with want %d, dist1 %d, dist2 %d", 
               nation_rule_name(nation_of_unit(target)),
               unit_rule_name(target), 
               target->id,
               TILE_XY(target_tile),
               stackthreat,
               dist1,
               dist2);
      /* Ok, now we FINALLY have a target worth destroying! */
      unit_data->target = target->id;
      if (is_virtual) {
        pf_map_destroy(pfm);
        return stackthreat;
      }
 
      /* This assigns missiles to us */
      dai_unit_new_task(ait, punit, AIUNIT_HUNTER, target_tile);
 
      /* Check if we can nuke it */
      dai_hunter_try_launch(ait, pplayer, punit, target);
 
      /* Check if we have nuked it */
      if (target != game_unit_by_number(sanity_target)) {
        UNIT_LOG(LOGLEVEL_HUNT, punit, "mission accomplished by cargo (pre)");
        dai_unit_new_task(ait, punit, AIUNIT_NONE, NULL);
        pf_map_destroy(pfm);
        return -1; /* try again */
      }
 
      /* Go towards it. */
      path = pf_map_path(pfm, target_tile);
      if (!adv_unit_execute_path(punit, path)) {
        pf_path_destroy(path);
        pf_map_destroy(pfm);
        return 0;
      }
      pf_path_destroy(path);
 
      if (target != game_unit_by_number(sanity_target)) {
        UNIT_LOG(LOGLEVEL_HUNT, punit, "mission accomplished");
        dai_unit_new_task(ait, punit, AIUNIT_NONE, NULL);
        pf_map_destroy(pfm);
        return -1; /* try again */
      }
 
      /* Check if we can nuke it now */
      dai_hunter_try_launch(ait, pplayer, punit, target);
      if (target != game_unit_by_number(sanity_target)) {
        UNIT_LOG(LOGLEVEL_HUNT, punit, "mission accomplished by cargo (post)");
        dai_unit_new_task(ait, punit, AIUNIT_NONE, NULL);
        pf_map_destroy(pfm);
        return -1; /* try again */
      }
 
      pf_map_destroy(pfm);
      unit_data->done = TRUE;
      return stackthreat; /* still have work to do */
    } unit_list_iterate_safe_end;
  } pf_map_move_costs_iterate_end;
 
  UNIT_LOG(LOGLEVEL_HUNT, punit, "ran out of map finding hunt target");
  pf_map_destroy(pfm);
  return 0; /* found nothing */
}