diplomats.c

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/***********************************************************************
 Freeciv - Copyright (C) 1996 - 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.
***********************************************************************/
 
#ifdef HAVE_CONFIG_H
#include <fc_config.h>
#endif
 
#include <stdio.h>
 
/* utility */
#include "bitvector.h"
#include "capability.h"
#include "fcintl.h"
#include "log.h"
#include "rand.h"
 
/* common */
#include "base.h"
#include "combat.h"
#include "events.h"
#include "game.h"
#include "government.h"
#include "map.h"
#include "movement.h"
#include "player.h"
#include "research.h"
#include "unitlist.h"
 
/* server */
#include "actiontools.h"
#include "aiiface.h"
#include "citytools.h"
#include "cityturn.h"
#include "diplhand.h"
#include "diplomats.h"
#include "maphand.h"
#include "notify.h"
#include "plrhand.h"
#include "techtools.h"
#include "unithand.h"
#include "unittools.h"
 
/* server/scripting */
#include "script_server.h"
 
/****************************************************************************/
 
static void diplomat_charge_movement (struct unit *pdiplomat,
                                      struct tile *ptile);
static bool diplomat_success_vs_defender(struct unit *patt, struct unit *pdef,
                                         struct tile *pdefender_tile,
                                         int *att_vet, int *def_vet);
static bool diplomat_may_lose_gold(struct player *dec_player,
                                   struct player *inc_player,
                                   int revolt_gold);
static bool diplomat_infiltrate_tile(struct player *pplayer,
                                     struct player *cplayer,
                                     const struct action *paction,
                                     struct unit *pdiplomat,
                                     struct unit *pvictim,
                                     struct tile *ptile,
                                     struct player **defender_owner);
static void diplomat_escape(struct player *pplayer, struct unit *pdiplomat,
                            const struct city *pcity,
                            const struct action *paction);
static void diplomat_escape_full(struct player *pplayer,
                                 struct unit *pdiplomat,
                                 bool city_related,
                                 struct tile *ptile,
                                 const char *vlink,
                                 const struct action *paction);
 
/************************************************************************/
bool spy_poison(struct player *pplayer, struct unit *pdiplomat,
                struct city *pcity, const struct action *paction)
{
  const struct unit_type *act_utype;
  struct player *cplayer;
  struct tile *ctile;
  const char *clink;
 
  /* Fetch target city's player.  Sanity checks. */
  fc_assert_ret_val(pcity, FALSE);
  cplayer = city_owner(pcity);
  fc_assert_ret_val(cplayer, FALSE);
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(pplayer, FALSE);
  fc_assert_ret_val(pdiplomat, FALSE);
 
  act_utype = unit_type_get(pdiplomat);
 
  ctile = city_tile(pcity);
  clink = city_link(pcity);
 
  log_debug("poison: unit: %d", pdiplomat->id);
 
  /* Check if the Diplomat/Spy succeeds against defending Diplomats/Spies. */
  if (!diplomat_infiltrate_tile(pplayer, cplayer, paction,
                                pdiplomat, NULL, ctile, NULL)) {
    return FALSE;
  }
 
  log_debug("poison: infiltrated");
 
  /* The Spy may get caught while trying to poison the city. */
  if (action_failed_dice_roll(pplayer, pdiplomat, pcity, cplayer,
                              paction)) {
    notify_player(pplayer, ctile, E_MY_DIPLOMAT_FAILED, ftc_server,
                  /* TRANS: unit, action */
                  _("Your %s was caught attempting to do %s!"),
                  unit_tile_link(pdiplomat),
                  action_name_translation(paction));
    notify_player(cplayer, ctile, E_ENEMY_DIPLOMAT_FAILED,
                  ftc_server,
                  /* TRANS: nation, unit, action, city */
                  _("You caught %s %s attempting to do %s in %s!"),
                  nation_adjective_for_player(pplayer),
                  unit_tile_link(pdiplomat),
                  action_name_translation(paction),
                  clink);
 
    /* This may cause a diplomatic incident */
    action_consequence_caught(paction, pplayer, act_utype,
                              cplayer, ctile, clink);
 
    /* Execute the caught Spy. */
    wipe_unit(pdiplomat, ULR_CAUGHT, cplayer);
 
    return FALSE;
  }
 
  log_debug("poison: succeeded");
 
  /* Poison people! */
  if (city_reduce_size(pcity, 1, pplayer, "poison")) {
    /* Notify everybody involved. */
    notify_player(pplayer, ctile, E_MY_DIPLOMAT_POISON, ftc_server,
                  _("Your %s poisoned the water supply of %s."),
                  unit_link(pdiplomat), clink);
    notify_player(cplayer, ctile,
                  E_ENEMY_DIPLOMAT_POISON, ftc_server,
                  _("%s is suspected of poisoning the water supply of %s."),
                  player_name(pplayer), clink);
 
    if (game.info.poison_empties_food_stock) {
      /* The food was poisoned too. */
      city_empty_food_stock(pcity);
    }
 
    /* Update clients. */
    city_refresh (pcity);
    send_city_info(NULL, pcity);
  } else {
    /* Notify everybody involved. */
    notify_player(pplayer, ctile, E_MY_DIPLOMAT_POISON, ftc_server,
                  _("Your %s destroyed %s by poisoning its water supply."),
                  unit_link(pdiplomat), clink);
    notify_player(cplayer, ctile,
                  E_ENEMY_DIPLOMAT_POISON, ftc_server,
                  _("%s is suspected of destroying %s by poisoning its"
                    " water supply."),
                  player_name(pplayer), clink);
  }
 
  /* this may cause a diplomatic incident */
  action_consequence_success(paction, pplayer, act_utype,
                             cplayer, ctile, clink);
 
  /* Now lets see if the spy survives. */
  diplomat_escape_full(pplayer, pdiplomat, TRUE, ctile, clink, paction);
 
  return TRUE;
}
 
/************************************************************************/
bool spy_spread_plague(struct player *act_player, struct unit *act_unit,
                       struct city *tgt_city, const struct action *paction)
{
  const struct unit_type *act_utype;
  struct player *tgt_player;
  struct tile *tgt_tile;
 
  const char *tgt_city_link;
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(act_player, FALSE);
  fc_assert_ret_val(act_unit, FALSE);
  act_utype = unit_type_get(act_unit);
 
  /* Sanity check: The target city still exists. */
  fc_assert_ret_val(tgt_city, FALSE);
 
  /* Who to infect. */
  tgt_player = city_owner(tgt_city);
 
  /* Sanity check: The target player still exists. */
  fc_assert_ret_val(tgt_player, FALSE);
 
  tgt_tile = city_tile(tgt_city);
  tgt_city_link = city_link(tgt_city);
 
  log_debug("spread plague: unit: %d", act_unit->id);
 
  /* Battle all units capable of diplomatic defense. */
  if (!diplomat_infiltrate_tile(act_player, tgt_player,
                                paction,
                                act_unit, NULL, tgt_tile, NULL)) {
    return FALSE;
  }
 
  log_debug("spread plague: infiltrated");
 
  /* The infector may get caught while trying to spread a plague in the
   * city. */
  if (action_failed_dice_roll(act_player, act_unit, tgt_city, tgt_player,
                              paction)) {
    notify_player(act_player, tgt_tile, E_MY_DIPLOMAT_FAILED, ftc_server,
                  /* TRANS: unit, action */
                  _("Your %s was caught attempting to do %s!"),
                  unit_tile_link(act_unit),
                  action_name_translation(paction));
    notify_player(tgt_player, tgt_tile, E_ENEMY_DIPLOMAT_FAILED,
                  ftc_server,
                  /* TRANS: nation, unit, action, city */
                  _("You caught %s %s attempting to do %s in %s!"),
                  nation_adjective_for_player(act_player),
                  unit_tile_link(act_unit),
                  action_name_translation(paction),
                  tgt_city_link);
 
    /* This may cause a diplomatic incident */
    action_consequence_caught(paction, act_player, act_utype,
                              tgt_player, tgt_tile, tgt_city_link);
 
    /* Execute the caught infector. */
    wipe_unit(act_unit, ULR_CAUGHT, tgt_player);
 
    return FALSE;
  }
 
  log_debug("spread plague: succeeded");
 
  /* Commit bio-terrorism. */
  if (city_illness_strike(tgt_city)) {
    /* Update the clients. */
    city_refresh(tgt_city);
    send_city_info(NULL, tgt_city);
  }
 
  /* Notify everyone involved. */
  notify_player(act_player, tgt_tile, E_UNIT_ACTION_ACTOR_SUCCESS,
                ftc_server,
                /* TRANS: unit, action, city */
                _("Your %s did %s to %s."),
                unit_link(act_unit), action_name_translation(paction),
                tgt_city_link);
  notify_player(tgt_player, tgt_tile, E_UNIT_ACTION_TARGET_HOSTILE,
                ftc_server,
                /* TRANS: action, city, nation */
                _("%s done to %s, %s suspected."),
                action_name_translation(paction), tgt_city_link,
                nation_plural_for_player(act_player));
 
  /* This may cause a diplomatic incident. */
  action_consequence_success(paction, act_player, act_utype,
                             tgt_player, tgt_tile, tgt_city_link);
 
  /* Try to escape. */
  diplomat_escape_full(act_player, act_unit, TRUE,
                       tgt_tile, tgt_city_link, paction);
 
  return TRUE;
}
 
/************************************************************************/
bool diplomat_investigate(struct player *pplayer, struct unit *pdiplomat,
                          struct city *pcity,
                          const struct action *paction)
{
  struct player *cplayer;
  struct packet_unit_short_info unit_packet;
  struct packet_city_info city_packet;
  struct packet_city_nationalities nat_packet;
  struct packet_city_rally_point rally_packet;
  struct packet_web_city_info_addition web_packet;
  struct trade_route_packet_list *routes;
  const struct unit_type *act_utype;
 
  /* Fetch target city's player.  Sanity checks. */
  fc_assert_ret_val(pcity, FALSE);
  cplayer = city_owner(pcity);
  fc_assert_ret_val(cplayer, FALSE);
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(pplayer, FALSE);
  fc_assert_ret_val(pdiplomat, FALSE);
 
  act_utype = unit_type_get(pdiplomat);
 
  /* Sanity check: The target is foreign. */
  if (cplayer == pplayer) {
    /* Nothing to do to a domestic target. */
    return FALSE;
  }
 
  log_debug("investigate: unit: %d", pdiplomat->id);
 
  conn_list_iterate(pplayer->connections, pconn) {
    if (has_capability("obsinv", pconn->capability)) {
      dsend_packet_investigate_started(pconn, pdiplomat->id, pdiplomat->id,
                                       pcity->id, pcity->id);
    }
  } conn_list_iterate_end;
 
  /* Do It... */
  update_dumb_city(pplayer, pcity);
  /* Special case for a diplomat/spy investigating a city:
     The investigator needs to know the supported and present
     units of a city, whether or not they are fogged. So, we
     send a list of them all before sending the city info.
     As this is a special case we bypass send_unit_info(). */
  unit_list_iterate(pcity->units_supported, punit) {
    package_short_unit(punit, &unit_packet,
                       UNIT_INFO_CITY_SUPPORTED, pcity->id);
    /* We need to force to send the packet to ensure the client will receive
     * something (e.g. investigating twice). */
    lsend_packet_unit_short_info(pplayer->connections, &unit_packet, TRUE);
  } unit_list_iterate_end;
  unit_list_iterate((pcity->tile)->units, punit) {
    package_short_unit(punit, &unit_packet,
                       UNIT_INFO_CITY_PRESENT, pcity->id);
    /* We need to force to send the packet to ensure the client will receive
     * something (e.g. investigating twice). */
    lsend_packet_unit_short_info(pplayer->connections, &unit_packet, TRUE);
  } unit_list_iterate_end;
  /* Send city info to investigator's player.
     As this is a special case we bypass send_city_info. */
  routes = trade_route_packet_list_new();
  package_city(pcity, &city_packet, &nat_packet, &rally_packet,
               &web_packet, routes, TRUE);
  /* We need to force to send the packet to ensure the client will receive
   * something and popup the city dialog. */
  city_packet.original = city_original_owner(pcity, pplayer);
  lsend_packet_city_info(pplayer->connections, &city_packet, TRUE);
  lsend_packet_city_nationalities(pplayer->connections, &nat_packet, TRUE);
  lsend_packet_city_rally_point(pplayer->connections, &rally_packet, TRUE);
  web_lsend_packet(city_info_addition, pplayer->connections, &web_packet, TRUE);
  trade_route_packet_list_iterate(routes, route_packet) {
    lsend_packet_trade_route_info(pplayer->connections, route_packet);
    FC_FREE(route_packet);
  } trade_route_packet_list_iterate_end;
  trade_route_packet_list_destroy(routes);
 
  /* This may cause a diplomatic incident */
  action_consequence_success(paction, pplayer, act_utype, cplayer,
                             city_tile(pcity), city_link(pcity));
 
  /* The actor unit always survive unless the action it self has determined
   * to always consume it. */
  if (!utype_is_consumed_by_action(paction, unit_type_get(pdiplomat))) {
    /* This unit isn't about to be consumed. Send updated unit information
     * to the clients. */
    send_unit_info(NULL, pdiplomat);
  }
 
  conn_list_iterate(pplayer->connections, pconn) {
    if (has_capability("obsinv", pconn->capability)) {
      dsend_packet_investigate_finished(pconn, pdiplomat->id, pdiplomat->id,
                                        pcity->id, pcity->id);
    }
  } conn_list_iterate_end;
 
  return TRUE;
}
 
/************************************************************************/
void spy_send_sabotage_list(struct connection *pc, struct unit *pdiplomat,
                            struct city *pcity,
                            const struct action *paction,
                            int request_kind)
{
  struct packet_city_sabotage_list packet;
 
  /* Send city improvements info to player. */
  BV_CLR_ALL(packet.improvements);
 
  if (action_has_result(paction, ACTRES_SPY_TARGETED_SABOTAGE_CITY)) {
    /* Can see hidden buildings. */
    improvement_iterate(ptarget) {
      if (city_has_building(pcity, ptarget)) {
        BV_SET(packet.improvements, improvement_index(ptarget));
      }
    } improvement_iterate_end;
  } else {
    /* Can't see hidden buildings. */
    struct vision_site *plrcity;
 
    plrcity = map_get_player_city(city_tile(pcity), unit_owner(pdiplomat));
 
    if (!plrcity) {
      /* Must know city to remember visible buildings. */
      return;
    }
 
    improvement_iterate(ptarget) {
      if (BV_ISSET(plrcity->improvements, improvement_index(ptarget))) {
        BV_SET(packet.improvements, improvement_index(ptarget));
      }
    } improvement_iterate_end;
  }
 
  packet.actor_id32 = pdiplomat->id;
  packet.actor_id16 = packet.actor_id32;
  packet.city_id32 = pcity->id;
  packet.city_id16 = packet.city_id32;
  packet.act_id = paction->id;
  packet.request_kind = request_kind;
  send_packet_city_sabotage_list(pc, &packet);
}
 
/************************************************************************/
bool diplomat_embassy(struct player *pplayer, struct unit *pdiplomat,
                      struct city *pcity, const struct action *paction)
{
  struct player *cplayer;
  const struct unit_type *act_utype;
 
  /* Fetch target city's player.  Sanity checks. */
  fc_assert_ret_val(pcity, FALSE);
  cplayer = city_owner(pcity);
  fc_assert_ret_val(cplayer, FALSE);
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(pplayer, FALSE);
  fc_assert_ret_val(pdiplomat, FALSE);
 
  act_utype = unit_type_get(pdiplomat);
 
  /* Sanity check: The target is foreign. */
  if (cplayer == pplayer) {
    /* Nothing to do to a domestic target. */
    return FALSE;
  }
 
  log_debug("embassy: unit: %d", pdiplomat->id);
 
  log_debug("embassy: succeeded");
 
  establish_embassy(pplayer, cplayer);
 
  /* Notify everybody involved. */
  notify_player(pplayer, city_tile(pcity),
                E_MY_DIPLOMAT_EMBASSY, ftc_server,
                _("You have established an embassy in %s."),
                city_link(pcity));
  notify_player(cplayer, city_tile(pcity),
                E_ENEMY_DIPLOMAT_EMBASSY, ftc_server,
                _("The %s have established an embassy in %s."),
                nation_plural_for_player(pplayer),
                city_link(pcity));
 
  /* this may cause a diplomatic incident */
  action_consequence_success(paction, pplayer, act_utype, cplayer,
                             city_tile(pcity), city_link(pcity));
 
  /* The actor unit always survive unless the action it self has determined
   * to always consume it. */
  if (!utype_is_consumed_by_action(paction, unit_type_get(pdiplomat))) {
    /* This unit isn't about to be consumed. Send updated unit information
     * to the clients. */
    send_unit_info(NULL, pdiplomat);
  }
 
  return TRUE;
}
 
/************************************************************************/
bool spy_sabotage_unit(struct player *pplayer, struct unit *pdiplomat,
                       struct unit *pvictim,
                       const struct action *paction)
{
  char victim_link[MAX_LEN_LINK];
  struct player *uplayer;
  const struct unit_type *act_utype;
 
  /* Fetch target unit's player.  Sanity checks. */
  fc_assert_ret_val(pvictim, FALSE);
  uplayer = unit_owner(pvictim);
  fc_assert_ret_val(uplayer, FALSE);
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(pplayer, FALSE);
  fc_assert_ret_val(pdiplomat, FALSE);
 
  act_utype = unit_type_get(pdiplomat);
 
  log_debug("sabotage-unit: unit: %d", pdiplomat->id);
 
  /* N.B: unit_link() always returns the same pointer. */
  sz_strlcpy(victim_link, unit_link(pvictim));
 
  /* Diplomatic battle against any diplomatic defender except the intended
   * victim of the sabotage. */
  if (!diplomat_infiltrate_tile(pplayer, uplayer,
                                paction,
                                pdiplomat, pvictim,
                                unit_tile(pvictim),
                                NULL)) {
    return FALSE;
  }
 
  log_debug("sabotage-unit: succeeded");
 
  if (pvictim->hp < 2) {
    /* Not possible to halve the hit points. Kill it. */
    wipe_unit(pvictim, ULR_KILLED, pplayer);
 
    /* Notify everybody involved. */
    notify_player(pplayer, unit_tile(pvictim),
                  E_MY_DIPLOMAT_SABOTAGE, ftc_server,
                  _("Your %s's successful sabotage killed the %s %s."),
                  unit_link(pdiplomat),
                  nation_adjective_for_player(uplayer),
                  victim_link);
    notify_player(uplayer, unit_tile(pvictim),
                  E_ENEMY_DIPLOMAT_SABOTAGE, ftc_server,
                  /* TRANS: ... the Poles! */
                  _("Your %s was killed by %s sabotage!"),
                  victim_link,
                  nation_plural_for_player(pplayer));
  } else {
    /* Sabotage the unit by removing half its remaining hit points. */
    pvictim->hp /= 2;
    send_unit_info(NULL, pvictim);
 
    /* Notify everybody involved. */
    notify_player(pplayer, unit_tile(pvictim),
                  E_MY_DIPLOMAT_SABOTAGE, ftc_server,
                  _("Your %s succeeded in sabotaging the %s %s."),
                  unit_link(pdiplomat),
                  nation_adjective_for_player(uplayer),
                  victim_link);
    notify_player(uplayer, unit_tile(pvictim),
                  E_ENEMY_DIPLOMAT_SABOTAGE, ftc_server,
                  /* TRANS: ... the Poles! */
                  _("Your %s was sabotaged by the %s!"),
                  victim_link,
                  nation_plural_for_player(pplayer));
  }
 
  /* this may cause a diplomatic incident */
  action_consequence_success(paction, pplayer, act_utype, uplayer,
                             unit_tile(pvictim), victim_link);
 
  /* Now lets see if the spy survives. */
  diplomat_escape(pplayer, pdiplomat, NULL, paction);
 
  return TRUE;
}
 
/************************************************************************/
bool diplomat_bribe(struct player *pplayer, struct unit *pdiplomat,
                    struct unit *pvictim, const struct action *paction)
{
  char victim_link[MAX_LEN_LINK];
  struct player *uplayer;
  struct tile *victim_tile;
  int bribe_cost;
  int diplomat_id;
  const struct unit_type *act_utype, *victim_type;
  struct city *pcity;
  bool bounce;
 
  /* Fetch target unit's player.  Sanity checks. */
  fc_assert_ret_val(pvictim, FALSE);
  uplayer = unit_owner(pvictim);
  victim_type = unit_type_get(pvictim);
  fc_assert_ret_val(uplayer, FALSE);
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(pplayer, FALSE);
  fc_assert_ret_val(pdiplomat, FALSE);
  diplomat_id = pdiplomat->id;
 
  act_utype = unit_type_get(pdiplomat);
 
  /* Sanity check: The target is foreign. */
  if (uplayer == pplayer) {
    /* Nothing to do to a domestic target. */
    return FALSE;
  }
 
  /* Sanity check: The victim isn't a unique unit the actor player already
   * has. */
  fc_assert_ret_val_msg(!utype_player_already_has_this_unique(pplayer,
                             unit_type_get(pvictim)),
                        FALSE,
                        "bribe-unit: already got unique unit");
 
  log_debug("bribe-unit: unit: %d", pdiplomat->id);
 
  /* Get bribe cost, ignoring any previously saved value. */
  bribe_cost = unit_bribe_cost(pvictim, pplayer);
 
  /* If player doesn't have enough gold, can't bribe. */
  if (pplayer->economic.gold < bribe_cost) {
    notify_player(pplayer, unit_tile(pdiplomat),
                  E_MY_DIPLOMAT_FAILED, ftc_server,
                  _("You don't have enough gold to bribe the %s %s."),
                  nation_adjective_for_player(uplayer),
                  unit_link(pvictim));
    log_debug("bribe-unit: not enough gold");
    return FALSE;
  }
 
  log_debug("bribe-unit: enough gold");
 
  /* Diplomatic battle against any diplomatic defender except the one that
   * will get the bribe. */
  if (!diplomat_infiltrate_tile(pplayer, uplayer,
                                paction,
                                pdiplomat, pvictim,
                                pvictim->tile,
                                NULL)) {
    return FALSE;
  }
 
  log_debug("bribe-unit: succeeded");
 
  victim_tile = unit_tile(pvictim);
  pvictim = unit_change_owner(pvictim, pplayer, pdiplomat->homecity,
                              ULR_BRIBED);
 
  if (pvictim) {
    /* N.B.: unit_link always returns the same pointer. As unit_change_owner()
     * currently remove the old unit and replace by a new one (with a new id),
     * we want to make link to the new unit. */
    sz_strlcpy(victim_link, unit_link(pvictim));
  } else {
    sz_strlcpy(victim_link, utype_name_translation(victim_type));
  }
 
  if (!unit_is_alive(diplomat_id)) {
    /* Destroyed by a script */
    pdiplomat = NULL;
  }
 
  /* Notify everybody involved. */
  notify_player(pplayer, victim_tile, E_MY_DIPLOMAT_BRIBE, ftc_server,
                /* TRANS: <diplomat> ... <unit> */
                _("Your %s succeeded in bribing the %s."),
                pdiplomat ? unit_link(pdiplomat)
                : utype_name_translation(act_utype), victim_link);
  if (pdiplomat && maybe_make_veteran(pdiplomat, 100)) {
    notify_unit_experience(pdiplomat);
  }
  notify_player(uplayer, victim_tile, E_ENEMY_DIPLOMAT_BRIBE, ftc_server,
                /* TRANS: <unit> ... <Poles> */
                _("Your %s was bribed by the %s."),
                victim_link, nation_plural_for_player(pplayer));
 
  if (pvictim) {
    /* The unit may have been on a tile shared with a city or a unit
     * it no longer can share a tile with. */
    pcity = tile_city(unit_tile(pvictim));
    bounce = ((NULL != pcity
               && !pplayers_allied(city_owner(pcity), unit_owner(pvictim)))
              /* Keep the old behavior (insto check is_non_allied_unit_tile) */
              || 1 < unit_list_size(unit_tile(pvictim)->units));
    if (bounce) {
      bounce_unit(pvictim, TRUE);
    }
  } else {
    bounce = FALSE;
  }
 
  /* This costs! */
  pplayer->economic.gold -= bribe_cost;
  if (pplayer->economic.gold < 0) {
    /* Scripts have deprived us of too much gold before we paid */
    log_normal("%s has bribed %s but has not %d gold at payment time, "
               "%d is the discount", player_name(pplayer),
               utype_rule_name(victim_type), bribe_cost,
               -pplayer->economic.gold);
    pplayer->economic.gold = 0;
  }
 
  /* This may cause a diplomatic incident */
  action_consequence_success(paction, pplayer, act_utype, uplayer,
                             victim_tile, victim_link);
 
  if (!pdiplomat || !unit_is_alive(diplomat_id)) {
    return TRUE;
  }
 
  /* Try to move the briber onto the victim's square unless the victim has
   * been bounced because it couldn't share tile with a unit or city. */
  if (!bounce
      /* Try to perform post move forced actions. */
      && (NULL == action_auto_perf_unit_do(AAPC_POST_ACTION, pdiplomat,
                                           uplayer, NULL, paction,
                                           victim_tile, tile_city(victim_tile),
                                           pvictim, NULL))
      /* May have died while trying to do forced actions. */
      && unit_is_alive(diplomat_id)) {
    pdiplomat->moves_left = 0;
  }
  if (NULL != player_unit_by_number(pplayer, diplomat_id)) {
    send_unit_info(NULL, pdiplomat);
  }
 
  /* Update clients. */
  send_player_all_c(pplayer, NULL);
 
  return TRUE;
}
 
/************************************************************************/
bool spy_attack(struct player *act_player, struct unit *act_unit,
                struct tile *tgt_tile, const struct action *paction)
{
  int act_unit_id;
  struct player *tgt_player = NULL;
  const struct unit_type *act_utype;
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(act_player, FALSE);
  fc_assert_ret_val(act_unit, FALSE);
 
  act_utype = unit_type_get(act_unit);
  act_unit_id = act_unit->id;
 
  /* Do the diplomatic battle against a diplomatic defender. */
  diplomat_infiltrate_tile(act_player, NULL,
                           paction,
                           act_unit, NULL, tgt_tile,
                           &tgt_player);
 
  /* Sanity check: the defender had an owner. */
  fc_assert_ret_val(tgt_player != NULL, TRUE);
 
  if (!unit_is_alive(act_unit_id)) {
    /* action_consequence_caught() is handled in
     * diplomat_infiltrate_tile() */
 
    /* The action was to start a diplomatic battle. */
    return TRUE;
  }
 
  /* This may cause a diplomatic incident. */
  action_consequence_success(paction, act_player, act_utype,
                             tgt_player, tgt_tile, tile_link(tgt_tile));
 
  /* The action was to start a diplomatic battle. */
  return TRUE;
}
 
/************************************************************************/
int diplomats_unignored_tech_stealings(struct unit *pdiplomat,
                                       struct city *pcity)
{
  int times;
  int bonus = get_unit_bonus(pdiplomat, EFT_STEALINGS_IGNORE);
 
  if (bonus < 0) {
    /* Negative effect value means infinite bonus */
    times = 0;
  } else {
    times = pcity->steal - bonus;
    if (times < 0) {
      times = 0;
    }
  }
 
  return times;
}
 
/************************************************************************/
bool diplomat_get_tech(struct player *pplayer, struct unit *pdiplomat,
                       struct city  *pcity, Tech_type_id technology,
                       const struct action *paction)
{
  struct research *presearch, *cresearch;
  struct player *cplayer;
  const struct unit_type *act_utype;
  int count;
  int times;
  Tech_type_id tech_stolen;
  bool expected_kills;
 
  /* We have to check arguments. They are sent to us by a client,
     so we cannot trust them */
  fc_assert_ret_val(pcity, FALSE);
  cplayer = city_owner(pcity);
  fc_assert_ret_val(cplayer, FALSE);
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(pplayer, FALSE);
  fc_assert_ret_val(pdiplomat, FALSE);
 
  act_utype = unit_type_get(pdiplomat);
 
  /* Sanity check: The target is foreign. */
  if (cplayer == pplayer) {
    /* Nothing to do to a domestic target. */
    return FALSE;
  }
 
  /* Currently based on if unit is consumed or not. */
  expected_kills = utype_is_consumed_by_action(paction,
                                               unit_type_get(pdiplomat));
 
  if (action_has_result(paction, ACTRES_SPY_STEAL_TECH)) {
    /* Can't choose target. Will steal a random tech. */
    technology = A_UNSET;
  }
 
  /* Targeted technology should be a ruleset defined tech,
   * "At Spy's Discretion" (A_UNSET) or a future tech (A_FUTURE). */
  if (technology == A_NONE
      || (technology != A_FUTURE
          && !(technology == A_UNSET
               && action_has_result(paction, ACTRES_SPY_STEAL_TECH))
          && !valid_advance_by_number(technology))) {
    return FALSE;
  }
 
  presearch = research_get(pplayer);
  cresearch = research_get(cplayer);
 
  if (technology == A_FUTURE) {
    if (presearch->future_tech >= cresearch->future_tech) {
      return FALSE;
    }
  } else if (technology != A_UNSET) {
    if (research_invention_state(presearch, technology) == TECH_KNOWN) {
      return FALSE;
    }
    if (research_invention_state(cresearch, technology) != TECH_KNOWN) {
      return FALSE;
    }
    if (!research_invention_gettable(presearch, technology,
                                     game.info.tech_steal_allow_holes)) {
      return FALSE;
    }
  }
 
  log_debug("steal-tech: unit: %d", pdiplomat->id);
 
  /* Check if the Diplomat/Spy succeeds against defending Diplomats/Spies. */
  if (!diplomat_infiltrate_tile(pplayer, cplayer,
                                paction,
                                pdiplomat, NULL,
                                pcity->tile,
                                NULL)) {
    return FALSE;
  }
 
  log_debug("steal-tech: infiltrated");
 
  times = diplomats_unignored_tech_stealings(pdiplomat, pcity);
 
  /* Check if the Diplomat/Spy succeeds with their task. */
  /* (Twice as difficult if target is specified.) */
  /* (If already stolen from, impossible for Diplomats and harder for Spies.) */
  if (times > 0 && expected_kills) {
    /* Already stolen from: Diplomat always fails! */
    count = 1;
    log_debug("steal-tech: difficulty: impossible");
  } else {
    /* Determine difficulty. */
    count = 1;
    if (action_has_result(paction, ACTRES_SPY_TARGETED_STEAL_TECH)) {
      /* Targeted steal tech is more difficult. */
      count++;
    }
    count += times;
    log_debug("steal-tech: difficulty: %d", count);
    /* Determine success or failure. */
    while (count > 0) {
      if (action_failed_dice_roll(pplayer, pdiplomat, pcity, cplayer,
                                  paction)) {
        break;
      }
      count--;
    }
  }
 
  if (count > 0) {
    /* Failed to steal a tech. */
    if (times > 0 && expected_kills) {
      notify_player(pplayer, city_tile(pcity),
                    E_MY_DIPLOMAT_FAILED, ftc_server,
                    /* TRANS: Paris was expecting ... Your Spy was caught */
                    _("%s was expecting your attempt to steal technology "
                      "again. Your %s was caught and executed."),
                    city_link(pcity),
                    unit_tile_link(pdiplomat));
      notify_player(cplayer, city_tile(pcity),
                    E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                    /* TRANS: The Belgian Spy ... from Paris */
                    _("The %s %s failed to steal technology again from %s. "
                      "We were prepared for the attempt."),
                    nation_adjective_for_player(pplayer),
                    unit_tile_link(pdiplomat),
                    city_link(pcity));
    } else {
      notify_player(pplayer, city_tile(pcity),
                    E_MY_DIPLOMAT_FAILED, ftc_server,
                    /* TRANS: Your Spy was caught ... from %s. */
                    _("Your %s was caught in the attempt of"
                      " stealing technology from %s."),
                    unit_tile_link(pdiplomat),
                    city_link(pcity));
      notify_player(cplayer, city_tile(pcity),
                    E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                    /* TRANS: The Belgian Spy ... from Paris */
                    _("The %s %s failed to steal technology from %s."),
                    nation_adjective_for_player(pplayer),
                    unit_tile_link(pdiplomat),
                    city_link(pcity));
    }
 
    /* This may cause a diplomatic incident */
    action_consequence_caught(paction, pplayer, act_utype, cplayer,
                              city_tile(pcity), city_link(pcity));
    wipe_unit(pdiplomat, ULR_CAUGHT, cplayer);
    return FALSE;
  }
 
  tech_stolen = steal_a_tech(pplayer, cplayer, technology);
 
  if (tech_stolen == A_NONE) {
    notify_player(pplayer, city_tile(pcity),
                  E_MY_DIPLOMAT_FAILED, ftc_server,
                  _("No new technology found in %s."),
                  city_link(pcity));
    diplomat_charge_movement (pdiplomat, pcity->tile);
    send_unit_info(NULL, pdiplomat);
    return FALSE;
  }
 
  /* Update stealing player's science progress and research fields */
  send_player_all_c(pplayer, NULL);
 
  /* Record the theft. */
  (pcity->steal)++;
 
  /* this may cause a diplomatic incident */
  action_consequence_success(paction, pplayer, act_utype, cplayer,
                             city_tile(pcity), city_link(pcity));
 
  /* Check if a spy survives her mission. */
  diplomat_escape(pplayer, pdiplomat, pcity, paction);
 
  return TRUE;
}
 
/************************************************************************/
bool diplomat_may_lose_gold(struct player *dec_player, struct player *inc_player,
                            int revolt_gold)
{
  if (game.server.incite_gold_loss_chance <= 0) {
    return FALSE;
  }
 
  /* Roll the dice. */
  if (fc_rand(100) < game.server.incite_gold_loss_chance) {
    notify_player(dec_player, NULL, E_MY_DIPLOMAT_FAILED, ftc_server,
                  PL_("Your %d gold prepared to incite the revolt was lost!",
                      "Your %d gold prepared to incite the revolt was lost!",
                      revolt_gold), revolt_gold);
    dec_player->economic.gold -= revolt_gold;
    /* Lost money was pocketed by fraudulent executioners?
     * Or returned to local authority?
     * Roll the dice twice. */
    if (fc_rand(100) < game.server.incite_gold_capt_chance) {
      inc_player->economic.gold += revolt_gold;
      notify_player(inc_player, NULL, E_ENEMY_DIPLOMAT_FAILED,
                    ftc_server,
                    PL_("Your security service captured %d gold prepared "
                        "to incite your town!",
                        "Your security service captured %d gold prepared "
                        "to incite your town!", revolt_gold), revolt_gold);
    }
    /* Update clients. */
    send_player_all_c(dec_player, NULL);
    send_player_all_c(inc_player, NULL);
 
    return TRUE;
  } else {
    return FALSE;
  }
}
 
/************************************************************************/
bool diplomat_incite(struct player *pplayer, struct unit *pdiplomat,
                     struct city *pcity, const struct action *paction)
{
  struct player *cplayer;
  struct tile *ctile;
  const char *clink;
  int revolt_cost;
  const struct unit_type *act_utype;
 
  /* Fetch target civilization's player.  Sanity checks. */
  fc_assert_ret_val(pcity, FALSE);
  cplayer = city_owner(pcity);
  fc_assert_ret_val(cplayer, FALSE);
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(pplayer, FALSE);
  fc_assert_ret_val(pdiplomat, FALSE);
 
  /* Sanity check: The target is foreign. */
  if (cplayer == pplayer) {
    /* Nothing to do to a domestic target. */
    return FALSE;
  }
 
  act_utype = unit_type_get(pdiplomat);
 
  ctile = city_tile(pcity);
  clink = city_link(pcity);
 
  log_debug("incite: unit: %d", pdiplomat->id);
 
  /* Get incite cost, ignoring any previously saved value. */
  revolt_cost = city_incite_cost(pplayer, pcity);
 
  /* If player doesn't have enough gold, can't incite a revolt. */
  if (pplayer->economic.gold < revolt_cost) {
    notify_player(pplayer, ctile, E_MY_DIPLOMAT_FAILED, ftc_server,
                  _("You don't have enough gold to subvert %s."),
                  clink);
    log_debug("incite: not enough gold");
    return FALSE;
  }
 
  /* Check if the Diplomat/Spy succeeds against defending Diplomats/Spies. */
  if (!diplomat_infiltrate_tile(pplayer, cplayer,
                                paction,
                                pdiplomat, NULL,
                                pcity->tile,
                                NULL)) {
    diplomat_may_lose_gold(pplayer, cplayer, revolt_cost / 2 );
    return FALSE;
  }
 
  log_debug("incite: infiltrated");
 
  /* Check if the Diplomat/Spy succeeds with their task. */
  if (action_failed_dice_roll(pplayer, pdiplomat, pcity, cplayer,
                              paction)) {
    notify_player(pplayer, ctile, E_MY_DIPLOMAT_FAILED, ftc_server,
                  _("Your %s was caught in the attempt"
                    " of inciting a revolt!"),
                  unit_tile_link(pdiplomat));
    notify_player(cplayer, ctile, E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                  _("You caught %s %s attempting"
                    " to incite a revolt in %s!"),
                  nation_adjective_for_player(pplayer),
                  unit_tile_link(pdiplomat),
                  clink);
 
    diplomat_may_lose_gold(pplayer, cplayer, revolt_cost / 4);
 
    /* This may cause a diplomatic incident */
    action_consequence_caught(paction, pplayer, act_utype,
                              cplayer, ctile, clink);
 
    wipe_unit(pdiplomat, ULR_CAUGHT, cplayer);
    return FALSE;
  }
 
  log_debug("incite: succeeded");
 
  /* Subvert the city to your cause... */
 
  /* City loses some population. */
  if (city_size_get(pcity) > 1) {
    city_reduce_size(pcity, 1, pplayer, "incited");
  }
 
  /* This costs! */
  pplayer->economic.gold -= revolt_cost;
 
  /* Notify everybody involved. */
  notify_player(pplayer, ctile, E_MY_DIPLOMAT_INCITE, ftc_server,
                _("Revolt incited in %s, you now rule the city!"),
                clink);
  notify_player(cplayer, ctile, E_ENEMY_DIPLOMAT_INCITE, ftc_server,
                _("%s has revolted, %s influence suspected."),
                clink,
                nation_adjective_for_player(pplayer));
 
  pcity->shield_stock = 0;
  nullify_prechange_production(pcity);
 
  /* You get a technology advance, too! */
  steal_a_tech(pplayer, cplayer, A_UNSET);
 
  /* this may cause a diplomatic incident */
  action_consequence_success(paction, pplayer, act_utype,
                             cplayer, ctile, clink);
 
  /* Transfer city and units supported by this city (that
     are within one square of the city) to the new owner. */
  if (transfer_city(pplayer, pcity, 1, TRUE, TRUE, FALSE,
                    !is_barbarian(pplayer))) {
    script_server_signal_emit("city_transferred", pcity, cplayer, pplayer,
                              "incited");
  }
 
  /* Check if a spy survives her mission.
   * _After_ transferring the city, or the city area is first fogged
   * when the diplomat is removed, and then unfogged when the city
   * is transferred. */
  diplomat_escape_full(pplayer, pdiplomat, TRUE, ctile, clink, paction);
 
  /* Update the players gold in the client */
  send_player_info_c(pplayer, pplayer->connections);
 
  return TRUE;
}
 
/************************************************************************/
bool diplomat_sabotage(struct player *pplayer, struct unit *pdiplomat,
                       struct city *pcity, Impr_type_id improvement,
                       const struct action *paction)
{
  struct player *cplayer;
  struct impr_type *ptarget;
  int count, which;
  const struct unit_type *act_utype;
 
  /* Fetch target city's player.  Sanity checks. */
  fc_assert_ret_val(pcity, FALSE);
  cplayer = city_owner(pcity);
  fc_assert_ret_val(cplayer, FALSE);
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(pplayer, FALSE);
  fc_assert_ret_val(pdiplomat, FALSE);
 
  act_utype = unit_type_get(pdiplomat);
 
  log_debug("sabotage: unit: %d", pdiplomat->id);
 
  /* Check if the Diplomat/Spy succeeds against defending Diplomats/Spies. */
  if (!diplomat_infiltrate_tile(pplayer, cplayer,
                                paction,
                                pdiplomat, NULL,
                                pcity->tile,
                                NULL)) {
    return FALSE;
  }
 
  log_debug("sabotage: infiltrated");
 
  /* Check if the Diplomat/Spy succeeds with their task. */
  if (action_failed_dice_roll(pplayer, pdiplomat, pcity, cplayer,
                              paction)) {
    notify_player(pplayer, city_tile(pcity),
                  E_MY_DIPLOMAT_FAILED, ftc_server,
                  _("Your %s was caught in the attempt"
                    " of industrial sabotage!"),
                  unit_tile_link(pdiplomat));
    notify_player(cplayer, city_tile(pcity),
                  E_ENEMY_DIPLOMAT_SABOTAGE, ftc_server,
                  _("You caught %s %s attempting sabotage in %s!"),
                  nation_adjective_for_player(pplayer),
                  unit_tile_link(pdiplomat),
                  city_link(pcity));
 
    /* This may cause a diplomatic incident */
    action_consequence_caught(paction, pplayer, act_utype, cplayer,
                              city_tile(pcity), city_link(pcity));
 
    wipe_unit(pdiplomat, ULR_CAUGHT, cplayer);
    return FALSE;
  }
 
  log_debug("sabotage: succeeded");
 
  /* Examine the city for improvements to sabotage. */
  count = 0;
  city_built_iterate(pcity, pimprove) {
    if (pimprove->sabotage > 0) {
      count++;
    }
  } city_built_iterate_end;
 
  log_debug("sabotage: count of improvements: %d", count);
 
  /* Determine the target (-1 is production). */
  if (action_has_result(paction, ACTRES_SPY_SABOTAGE_CITY)) {
    /*
     * Pick random:
     * 50/50 chance to pick production or some improvement.
     * Won't pick something that doesn't exit.
     * If nothing to do, say so, deduct movement cost and return.
     */
    if (count == 0 && pcity->shield_stock == 0) {
      notify_player(pplayer, city_tile(pcity),
                    E_MY_DIPLOMAT_FAILED, ftc_server,
                    _("Your %s could not find anything to sabotage in %s."),
                    unit_link(pdiplomat),
                    city_link(pcity));
      diplomat_charge_movement(pdiplomat, pcity->tile);
      send_unit_info(NULL, pdiplomat);
      log_debug("sabotage: random: nothing to do");
      return FALSE;
    }
    if (count == 0 || fc_rand (2) == 1) {
      ptarget = NULL;
      log_debug("sabotage: random: targeted production");
    } else {
      ptarget = NULL;
      which = fc_rand (count);
 
      city_built_iterate(pcity, pimprove) {
        if (pimprove->sabotage > 0) {
          if (which > 0) {
            which--;
          } else {
            ptarget = pimprove;
            break;
          }
        }
      } city_built_iterate_end;
 
      if (NULL != ptarget) {
        log_debug("sabotage: random: targeted improvement: %d (%s)",
                  improvement_number(ptarget),
                  improvement_rule_name(ptarget));
      } else {
        log_error("sabotage: random: targeted improvement error!");
      }
    }
  } else if (improvement < 0) {
    /* If told to sabotage production, do so. */
    ptarget = NULL;
    log_debug("sabotage: specified target production");
  } else {
    struct impr_type *pimprove = improvement_by_number(improvement);
    if (pimprove == NULL) {
      log_error("sabotage: requested for invalid improvement %d", improvement);
      return FALSE;
    }
    /*
     * Told which improvement to pick:
     * If try for wonder or palace, complain, deduct movement cost and return.
     * If not available, say so, deduct movement cost and return.
     */
    if (city_has_building(pcity, pimprove)) {
      if (pimprove->sabotage > 0) {
        ptarget = pimprove;
        log_debug("sabotage: specified target improvement: %d (%s)",
                  improvement, improvement_rule_name(pimprove));
      } else {
        notify_player(pplayer, city_tile(pcity),
                      E_MY_DIPLOMAT_FAILED, ftc_server,
                      _("You cannot sabotage a %s!"),
                      improvement_name_translation(pimprove));
        diplomat_charge_movement(pdiplomat, pcity->tile);
        send_unit_info(NULL, pdiplomat);
        log_debug("sabotage: disallowed target improvement: %d (%s)",
                  improvement, improvement_rule_name(pimprove));
        return FALSE;
      }
    } else {
      notify_player(pplayer, city_tile(pcity),
                    E_MY_DIPLOMAT_FAILED, ftc_server,
                    _("Your %s could not find the %s to sabotage in %s."),
                    unit_name_translation(pdiplomat),
                    improvement_name_translation(pimprove),
                    city_link(pcity));
      diplomat_charge_movement(pdiplomat, pcity->tile);
      send_unit_info(NULL, pdiplomat);
      log_debug("sabotage: target improvement not found: %d (%s)",
                improvement, improvement_rule_name(pimprove));
      return FALSE;
    }
  }
 
  /* Now, the fun stuff!  Do the sabotage! */
  if (NULL == ptarget) {
     char prod[256];
 
    /* Do it. */
    pcity->shield_stock = 0;
    nullify_prechange_production(pcity); /* Make it impossible to recover */
 
    /* Report it. */
    universal_name_translation(&pcity->production, prod, sizeof(prod));
 
    notify_player(pplayer, city_tile(pcity),
                  E_MY_DIPLOMAT_SABOTAGE, ftc_server,
                  _("Your %s succeeded in destroying"
                    " the production of %s in %s."),
                  unit_link(pdiplomat),
                  prod,
                  city_name_get(pcity));
    notify_player(cplayer, city_tile(pcity),
                  E_ENEMY_DIPLOMAT_SABOTAGE, ftc_server,
                  _("The production of %s was destroyed in %s,"
                    " %s are suspected."),
                  prod,
                  city_link(pcity),
                  nation_plural_for_player(pplayer));
    log_debug("sabotage: sabotaged production");
  } else {
    int vulnerability = ptarget->sabotage;
 
    /* Sabotage a city improvement. */
 
    /*
     * One last chance to get caught:
     * If target was specified, and it is in the capital or are
     * City Walls, then there is a 50% chance of getting caught.
     */
    vulnerability -= (vulnerability
                      * get_city_bonus(pcity, EFT_SABOTEUR_RESISTANT)
                      / 100);
 
    if (fc_rand(100) >= vulnerability) {
      /* Caught! */
      notify_player(pplayer, city_tile(pcity),
                    E_MY_DIPLOMAT_FAILED, ftc_server,
                    _("Your %s was caught in the attempt of sabotage!"),
                    unit_tile_link(pdiplomat));
      notify_player(cplayer, city_tile(pcity),
                    E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                    _("You caught %s %s attempting"
                      " to sabotage the %s in %s!"),
                    nation_adjective_for_player(pplayer),
                    unit_tile_link(pdiplomat),
                    improvement_name_translation(ptarget),
                    city_link(pcity));
 
      /* This may cause a diplomatic incident */
      action_consequence_caught(paction, pplayer, act_utype, cplayer,
                                city_tile(pcity), city_link(pcity));
 
      wipe_unit(pdiplomat, ULR_CAUGHT, cplayer);
      log_debug("sabotage: caught in capital or on city walls");
      return FALSE;
    }
 
    /* Report it. */
    notify_player(pplayer, city_tile(pcity),
                  E_MY_DIPLOMAT_SABOTAGE, ftc_server,
                  _("Your %s destroyed the %s in %s."),
                  unit_link(pdiplomat),
                  improvement_name_translation(ptarget),
                  city_link(pcity));
    notify_player(cplayer, city_tile(pcity),
                  E_ENEMY_DIPLOMAT_SABOTAGE, ftc_server,
                  _("The %s destroyed the %s in %s."),
                  nation_plural_for_player(pplayer),
                  improvement_name_translation(ptarget),
                  city_link(pcity));
    log_debug("sabotage: sabotaged improvement: %d (%s)",
              improvement_number(ptarget),
              improvement_rule_name(ptarget));
 
    /* Do it. */
    building_lost(pcity, ptarget, "sabotaged", pdiplomat);
 
    /* FIXME: Lua script might have destroyed the diplomat, the city, or even the player.
     *        Avoid dangling pointers below in that case. */
  }
 
  /* Update clients. */
  send_city_info(NULL, pcity);
 
  /* this may cause a diplomatic incident */
  action_consequence_success(paction, pplayer, act_utype, cplayer,
                             city_tile(pcity), city_link(pcity));
 
  /* Check if a spy survives her mission. */
  diplomat_escape(pplayer, pdiplomat, pcity, paction);
 
  return TRUE;
}
 
/************************************************************************/
bool spy_steal_gold(struct player *act_player, struct unit *act_unit,
                    struct city *tgt_city, const struct action *paction)
{
  struct player *tgt_player;
  struct tile *tgt_tile;
 
  const char *tgt_city_link;
 
  int gold_take;
  int gold_give;
  const struct unit_type *act_utype;
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(act_player, FALSE);
  fc_assert_ret_val(act_unit, FALSE);
 
  act_utype = unit_type_get(act_unit);
 
  /* Sanity check: The target city still exists. */
  fc_assert_ret_val(tgt_city, FALSE);
 
  /* Who to steal from. */
  tgt_player = city_owner(tgt_city);
 
  /* Sanity check: The target player still exists. */
  fc_assert_ret_val(tgt_player, FALSE);
 
  /* Sanity check: The target is foreign. */
  if (tgt_player == act_player) {
    /* Nothing to do to a domestic target. */
    return FALSE;
  }
 
  /* Sanity check: There is something to steal. */
  if (tgt_player->economic.gold <= 0) {
    return FALSE;
  }
 
  tgt_tile = city_tile(tgt_city);
  tgt_city_link = city_link(tgt_city);
 
  log_debug("steal gold: unit: %d", act_unit->id);
 
  /* Battle all units capable of diplomatic defense. */
  if (!diplomat_infiltrate_tile(act_player, tgt_player,
                                paction,
                                act_unit, NULL, tgt_tile,
                                NULL)) {
    return FALSE;
  }
 
  log_debug("steal gold: infiltrated");
 
  /* The thief may get caught while trying to steal the gold. */
  if (action_failed_dice_roll(act_player, act_unit, tgt_city, tgt_player,
                              paction)) {
    notify_player(act_player, tgt_tile, E_MY_DIPLOMAT_FAILED, ftc_server,
                  _("Your %s was caught attempting to steal gold!"),
                  unit_tile_link(act_unit));
    notify_player(tgt_player, tgt_tile, E_ENEMY_DIPLOMAT_FAILED,
                  ftc_server,
                  /* TRANS: nation, unit, city */
                  _("You caught %s %s attempting"
                    " to steal your gold in %s!"),
                  nation_adjective_for_player(act_player),
                  unit_tile_link(act_unit),
                  tgt_city_link);
 
    /* This may cause a diplomatic incident */
    action_consequence_caught(paction, act_player, act_utype,
                              tgt_player, tgt_tile, tgt_city_link);
 
    /* Execute the caught thief. */
    wipe_unit(act_unit, ULR_CAUGHT, tgt_player);
 
    return FALSE;
  }
 
  log_debug("steal gold: succeeded");
 
  /* The upper limit on how much gold the thief can steal. */
  gold_take = (tgt_player->economic.gold
               * get_city_bonus(tgt_city, EFT_MAX_STOLEN_GOLD_PM))
              / 1000;
 
  /* How much to actually take. 1 gold is the smallest amount that can be
   * stolen. The victim player has at least 1 gold. If they didn't, the
   * something to steal sanity check would have aborted the theft. */
  gold_take = fc_rand(gold_take) + 1;
 
  log_debug("steal gold: will take %d gold", gold_take);
 
  /* Steal the gold. */
  tgt_player->economic.gold -= gold_take;
 
  /* Some gold may be lost during transfer. */
  gold_give = gold_take
            - (gold_take * get_unit_bonus(act_unit, EFT_THIEFS_SHARE_PM))
              / 1000;
 
  log_debug("steal gold: will give %d gold", gold_give);
 
  /* Pocket the stolen money. */
  act_player->economic.gold += gold_give;
 
  /* Notify everyone involved. */
  notify_player(act_player, tgt_tile, E_MY_SPY_STEAL_GOLD, ftc_server,
                /* TRANS: unit, gold, city */
                PL_("Your %s stole %d gold from %s.",
                    "Your %s stole %d gold from %s.", gold_give),
                unit_link(act_unit), gold_give, tgt_city_link);
  notify_player(tgt_player, tgt_tile, E_ENEMY_SPY_STEAL_GOLD, ftc_server,
                /* TRANS: gold, city, nation */
                PL_("%d gold stolen from %s, %s suspected.",
                    "%d gold stolen from %s, %s suspected.", gold_take),
                gold_take, tgt_city_link,
                nation_plural_for_player(act_player));
 
  /* This may cause a diplomatic incident. */
  action_consequence_success(paction, act_player, act_utype,
                             tgt_player, tgt_tile, tgt_city_link);
 
  /* Try to escape. */
  diplomat_escape_full(act_player, act_unit, TRUE,
                       tgt_tile, tgt_city_link, paction);
 
  /* Update the players' gold in the client */
  send_player_info_c(act_player, act_player->connections);
  send_player_info_c(tgt_player, tgt_player->connections);
 
  return TRUE;
}
 
/************************************************************************/
bool spy_steal_some_maps(struct player *act_player, struct unit *act_unit,
                         struct city *tgt_city,
                         const struct action *paction)
{
  struct player *tgt_player;
  struct tile *tgt_tile;
  const struct unit_type *act_utype;
 
  int normal_tile_prob;
 
  const char *tgt_city_link;
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(act_player, FALSE);
  fc_assert_ret_val(act_unit, FALSE);
 
  act_utype = unit_type_get(act_unit);
 
  /* Sanity check: The target city still exists. */
  fc_assert_ret_val(tgt_city, FALSE);
 
  /* Who to steal from. */
  tgt_player = city_owner(tgt_city);
 
  /* Sanity check: The target player still exists. */
  fc_assert_ret_val(tgt_player, FALSE);
 
  /* Sanity check: The target is foreign. */
  if (tgt_player == act_player) {
    /* Nothing to do to a domestic target. */
    return FALSE;
  }
 
  tgt_tile = city_tile(tgt_city);
  tgt_city_link = city_link(tgt_city);
 
  log_debug("steal some maps: unit: %d", act_unit->id);
 
  /* Battle all units capable of diplomatic defense. */
  if (!diplomat_infiltrate_tile(act_player, tgt_player,
                                paction,
                                act_unit, NULL, tgt_tile,
                                NULL)) {
    return FALSE;
  }
 
  log_debug("steal some maps: infiltrated");
 
  /* Try to steal the map. */
  if (action_failed_dice_roll(act_player, act_unit, tgt_city, tgt_player,
                              paction)) {
    notify_player(act_player, tgt_tile, E_MY_DIPLOMAT_FAILED, ftc_server,
                  _("Your %s was caught in an attempt of"
                    " stealing parts of the %s world map!"),
                  unit_tile_link(act_unit),
                  nation_adjective_for_player(tgt_player));
    notify_player(tgt_player, tgt_tile, E_ENEMY_DIPLOMAT_FAILED,
                  ftc_server,
                  _("You caught %s %s attempting to steal"
                    " parts of your world map in %s!"),
                  nation_adjective_for_player(act_player),
                  unit_tile_link(act_unit),
                  tgt_city_link);
 
    /* This may cause a diplomatic incident. */
    action_consequence_caught(paction, act_player, act_utype,
                              tgt_player, tgt_tile, tgt_city_link);
 
    /* Execute the caught thief. */
    wipe_unit(act_unit, ULR_CAUGHT, tgt_player);
 
    return FALSE;
  }
 
  log_debug("steal some maps: succeeded");
 
  /* Steal it. */
  normal_tile_prob = 100
      + get_target_bonus_effects(NULL,
                                 &(const struct req_context) {
                                   .player = act_player,
                                 /* City: Decide once requests from ruleset
                                  * authors arrive. Could be target city or
                                  * - with a refactoring - the city at the
                                  * tile that may be transferred. */
                                 /* Tile: Decide once requests from ruleset
                                  * authors arrive. Could be actor unit
                                  * tile, target city tile or even - with a
                                  * refactoring - the tile that may be
                                  * transferred. */
                                   .unit = act_unit,
                                   .unittype = unit_type_get(act_unit),
                                   .action = paction,
                                 },
                                 tgt_player,
                                 EFT_MAPS_STOLEN_PCT);
  give_distorted_map(tgt_player, act_player,
                     normal_tile_prob,
                     /* Could - with a refactoring where EFT_MAPS_STOLEN_PCT
                      * is evaulated for each tile and the city sent to it
                      * is the tile to transfer's city - be moved into
                      * EFT_MAPS_STOLEN_PCT. */
                     game.info.steal_maps_reveals_all_cities);
 
  /* Notify everyone involved. */
  notify_player(act_player, tgt_tile, E_MY_SPY_STEAL_MAP, ftc_server,
                _("Your %s stole parts of the %s world map in %s."),
                unit_link(act_unit),
                nation_adjective_for_player(tgt_player),
                tgt_city_link);
  notify_player(tgt_player, tgt_tile, E_ENEMY_SPY_STEAL_MAP, ftc_server,
                _("The %s are suspected of stealing"
                  " parts of your world map in %s."),
                nation_plural_for_player(act_player),
                tgt_city_link);
 
  /* This may cause a diplomatic incident. */
  action_consequence_success(paction, act_player, act_utype,
                             tgt_player, tgt_tile, tgt_city_link);
 
  /* Try to escape. */
  diplomat_escape_full(act_player, act_unit, TRUE,
                       tgt_tile, tgt_city_link, paction);
 
  return TRUE;
}
 
/************************************************************************/
bool spy_nuke_city(struct player *act_player, struct unit *act_unit,
                   struct city *tgt_city, const struct action *paction)
{
  struct player *tgt_player;
  struct tile *tgt_tile;
 
  const char *tgt_city_link;
  const struct unit_type *act_utype;
 
  /* Sanity check: The actor still exists. */
  fc_assert_ret_val(act_player, FALSE);
  fc_assert_ret_val(act_unit, FALSE);
 
  act_utype = unit_type_get(act_unit);
 
  /* Sanity check: The target city still exists. */
  fc_assert_ret_val(tgt_city, FALSE);
 
  /* The victim. */
  tgt_player = city_owner(tgt_city);
 
  /* Sanity check: The target player still exists. */
  fc_assert_ret_val(tgt_player, FALSE);
 
  tgt_tile = city_tile(tgt_city);
  tgt_city_link = city_link(tgt_city);
 
  log_debug("suitcase nuke: unit: %d", act_unit->id);
 
  /* Battle all units capable of diplomatic defense. */
  if (!diplomat_infiltrate_tile(act_player, tgt_player,
                                paction,
                                act_unit, NULL, tgt_tile,
                                NULL)) {
    return FALSE;
  }
 
  log_debug("suitcase nuke: infiltrated");
 
  /* Try to hide the nuke. */
  if (action_failed_dice_roll(act_player, act_unit, tgt_city, tgt_player,
                              paction)) {
    notify_player(act_player, tgt_tile, E_MY_DIPLOMAT_FAILED, ftc_server,
                  _("Your %s was caught in an attempt of"
                    " hiding a nuke in %s!"),
                  unit_tile_link(act_unit),
                  tgt_city_link);
    notify_player(tgt_player, tgt_tile, E_ENEMY_DIPLOMAT_FAILED,
                  ftc_server,
                  _("You caught %s %s attempting to hide a nuke in %s!"),
                  nation_adjective_for_player(act_player),
                  unit_tile_link(act_unit),
                  tgt_city_link);
 
    /* This may cause a diplomatic incident. */
    action_consequence_caught(paction, act_player, act_utype,
                              tgt_player, tgt_tile, tgt_city_link);
 
    /* Execute the caught terrorist. */
    wipe_unit(act_unit, ULR_CAUGHT, tgt_player);
 
    return FALSE;
  }
 
  log_debug("suitcase nuke: succeeded");
 
  /* Notify everyone involved. */
  notify_player(act_player, tgt_tile, E_MY_SPY_NUKE, ftc_server,
                _("Your %s hid a nuke in %s."),
                unit_link(act_unit),
                tgt_city_link);
  notify_player(tgt_player, tgt_tile, E_ENEMY_SPY_NUKE, ftc_server,
                _("The %s are suspected of hiding a nuke in %s."),
                nation_plural_for_player(act_player),
                tgt_city_link);
 
  /* Try to escape before the blast. */
  diplomat_escape_full(act_player, act_unit, TRUE,
                       tgt_tile, tgt_city_link, paction);
 
  if (utype_is_consumed_by_action(paction, unit_type_get(act_unit))) {
    /* The unit must be wiped here so it won't be seen as a victim of the
     * detonation of its own nuke. */
    wipe_unit(act_unit, ULR_USED, NULL);
  }
 
  /* TODO: In real life a suitcase nuke is way less powerful than an ICBM.
   * Maybe the size of the suitcase nuke explosion should be ruleset
   * configurable? */
 
  /* Detonate the nuke. */
  dlsend_packet_nuke_tile_info(game.est_connections, tile_index(tgt_tile));
  do_nuclear_explosion(act_player, tgt_tile);
 
  /* This may cause a diplomatic incident. */
  action_consequence_success(paction, act_player, act_utype,
                             tgt_player, tgt_tile, tgt_city_link);
 
  return TRUE;
}
 
/************************************************************************/
static void diplomat_charge_movement(struct unit *pdiplomat, struct tile *ptile)
{
  pdiplomat->moves_left -=
    map_move_cost_unit(&(wld.map), pdiplomat, ptile);
  if (pdiplomat->moves_left < 0) {
    pdiplomat->moves_left = 0;
  }
}
 
/************************************************************************/
static bool diplomat_success_vs_defender(struct unit *pattacker,
                                         struct unit *pdefender,
                                         struct tile *pdefender_tile,
                                         int *att_vet, int *def_vet)
{
  int chance = 50; /* Base 50% chance */
 
  /* There's no challenge for the SuperSpy to gain veterancy from,
   * i.e. no veterancy if we exit early in next couple of checks. */
  *att_vet = 0;
  *def_vet = 0;
 
  if (unit_has_type_flag(pdefender, UTYF_SUPERSPY)) {
    /* A defending UTYF_SUPERSPY will defeat every possible attacker. */
    return FALSE;
  }
  if (unit_has_type_flag(pattacker, UTYF_SUPERSPY)) {
    /* An attacking UTYF_SUPERSPY will defeat every possible defender
     * except another UTYF_SUPERSPY. */
    return TRUE;
  }
 
  /* Add or remove 25% if spy flag. */
  if (unit_has_type_flag(pattacker, UTYF_SPY)) {
    chance += 25;
  }
  if (unit_has_type_flag(pdefender, UTYF_SPY)) {
    chance -= 25;
  }
 
  /* Use power_fact from veteran level to modify chance in a linear way.
   * Equal veteran levels cancel out.
   * It's probably not good for rulesets to allow this to have more than
   * 20% effect. */
  {
    const struct veteran_level
      *vatt = utype_veteran_level(unit_type_get(pattacker), pattacker->veteran);
    const struct veteran_level
      *vdef = utype_veteran_level(unit_type_get(pdefender), pdefender->veteran);
 
    fc_assert_ret_val(vatt != NULL && vdef != NULL, FALSE);
 
    chance += vatt->power_fact - vdef->power_fact;
  }
 
  /* Reduce the chance of an attack by EFT_SPY_RESISTANT percent. */
  chance -= chance * get_target_bonus_effects(
                         NULL,
                         &(const struct req_context) {
                           .player = tile_owner(pdefender_tile),
                           .city = tile_city(pdefender_tile),
                           .tile = pdefender_tile,
                         },
                         NULL,
                         EFT_SPY_RESISTANT
                     ) / 100;
 
  chance = CLIP(0, chance, 100);
 
  /* In a combat between equal strength units the values are 50% / 50%.
   * -> scaling that to 100% by doubling, to match scale of chances
   *    in existing rulesets, and in !combat_odds_scaled_veterancy case. */
  *att_vet = (100 - chance) * 2;
  *def_vet = chance * 2;
 
  return (int)fc_rand(100) < chance;
}
 
/************************************************************************/
static bool diplomat_infiltrate_tile(struct player *pplayer,
                                     struct player *cplayer,
                                     const struct action *paction,
                                     struct unit *pdiplomat,
                                     struct unit *pvictim,
                                     struct tile *ptile,
                                     struct player **defender_owner)
{
  struct unit *punit;
  char link_city[MAX_LEN_LINK] = "";
  char link_diplomat[MAX_LEN_LINK];
  char link_unit[MAX_LEN_LINK];
  struct city *pcity = tile_city(ptile);
  const struct unit_type *act_utype = unit_type_get(pdiplomat);
  int att_vet;
  int def_vet;
 
  if (pcity) {
    /* N.B.: *_link() always returns the same pointer. */
    sz_strlcpy(link_city, city_link(pcity));
  }
 
  if ((punit = get_diplomatic_defender(pdiplomat, pvictim, ptile))) {
    struct player *uplayer = unit_owner(punit);
 
    if (defender_owner != NULL) {
      /* Some action performers may want to know defender player. */
      *defender_owner = uplayer;
    }
 
    if (diplomat_success_vs_defender(pdiplomat, punit, ptile,
                                     &att_vet, &def_vet)) {
      /* Defending Spy/Diplomat dies. */
 
      /* N.B.: *_link() always returns the same pointer. */
      sz_strlcpy(link_unit, unit_tile_link(punit));
      sz_strlcpy(link_diplomat, unit_link(pdiplomat));
 
      notify_player(pplayer, ptile, E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                    /* TRANS: <unit> ... <diplomat> */
                    _("An enemy %s has been eliminated by your %s."),
                    link_unit, link_diplomat);
 
      if (pcity) {
        if (uplayer == cplayer || cplayer == NULL) {
          notify_player(uplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                        /* TRANS: <unit> ... <city> ... <diplomat> */
                        _("Your %s has been eliminated defending %s"
                          " against a %s."), link_unit, link_city,
                        link_diplomat);
        } else {
          notify_player(cplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                        /* TRANS: <nation adj> <unit> ... <city>
                                         * TRANS: ... <diplomat> */
                        _("A %s %s has been eliminated defending %s "
                          "against a %s."),
                        nation_adjective_for_player(uplayer),
                        link_unit, link_city, link_diplomat);
          notify_player(uplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                        /* TRANS: ... <unit> ... <nation adj> <city>
                                         * TRANS: ... <diplomat> */
                        _("Your %s has been eliminated defending %s %s "
                          "against a %s."), link_unit,
                        nation_adjective_for_player(cplayer),
                        link_city, link_diplomat);
        }
      } else {
        if (uplayer == cplayer || cplayer == NULL) {
          notify_player(uplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                        /* TRANS: <unit> ... <diplomat> */
                        _("Your %s has been eliminated defending "
                          "against a %s."), link_unit, link_diplomat);
        } else {
          notify_player(cplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                        /* TRANS: <nation adj> <unit> ... <diplomat> */
                        _("A %s %s has been eliminated defending "
                          "against a %s."),
                        nation_adjective_for_player(uplayer),
                        link_unit, link_diplomat);
          notify_player(uplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                        /* TRANS: ... <unit> ... <diplomat> */
                        _("Your %s has been eliminated defending "
                          "against a %s."), link_unit, link_diplomat);
        }
      }
 
      pdiplomat->moves_left = MAX(0, pdiplomat->moves_left - SINGLE_MOVE);
 
      /* Attacking unit became more experienced? */
      if (maybe_make_veteran(pdiplomat,
                             game.info.combat_odds_scaled_veterancy ? att_vet : 100)) {
        notify_unit_experience(pdiplomat);
      }
      send_unit_info(NULL, pdiplomat);
      wipe_unit(punit, ULR_ELIMINATED, pplayer);
      return FALSE;
    } else {
      /* Attacking Spy/Diplomat dies. */
 
      const char *victim_link;
 
      /* N.B.: *_link() always returns the same pointer. */
      sz_strlcpy(link_unit, unit_link(punit));
      sz_strlcpy(link_diplomat, unit_tile_link(pdiplomat));
 
      notify_player(pplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                    _("Your %s was eliminated by a defending %s."),
                    link_diplomat, link_unit);
 
      if (pcity) {
        if (uplayer == cplayer || cplayer == NULL) {
          notify_player(uplayer, ptile, E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                        _("Eliminated a %s %s while infiltrating %s."),
                        nation_adjective_for_player(pplayer),
                        link_diplomat, link_city);
        } else {
          notify_player(cplayer, ptile, E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                        _("A %s %s eliminated a %s %s while infiltrating "
                          "%s."), nation_adjective_for_player(uplayer),
                        link_unit, nation_adjective_for_player(pplayer),
                        link_diplomat, link_city);
          notify_player(uplayer, ptile, E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                        _("Your %s eliminated a %s %s while infiltrating "
                          "%s."), link_unit,
                        nation_adjective_for_player(pplayer),
                        link_diplomat, link_city);
        }
      } else {
        if (uplayer == cplayer || cplayer == NULL) {
          notify_player(uplayer, ptile, E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                        _("Eliminated a %s %s while infiltrating our troops."),
                        nation_adjective_for_player(pplayer),
                        link_diplomat);
        } else {
          notify_player(cplayer, ptile, E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                        _("A %s %s eliminated a %s %s while infiltrating our "
                          "troops."), nation_adjective_for_player(uplayer),
                        link_unit, nation_adjective_for_player(pplayer),
                        link_diplomat);
          notify_player(uplayer, ptile, E_ENEMY_DIPLOMAT_FAILED, ftc_server,
                        /* TRANS: ... <unit> ... <diplomat> */
                        _("Your %s eliminated a %s %s while infiltrating our "
                          "troops."), link_unit,
                        nation_adjective_for_player(pplayer),
                        link_diplomat);
        }
      }
 
      /* Defending unit became more experienced? */
      if (maybe_make_veteran(punit,
                             game.info.combat_odds_scaled_veterancy ? def_vet : 100)) {
        notify_unit_experience(punit);
      }
 
      victim_link = NULL;
 
      switch (action_get_target_kind(paction)) {
      case ATK_CITY:
        victim_link = city_link(pcity);
        break;
      case ATK_UNIT:
      case ATK_UNITS:
        victim_link = pvictim ? unit_tile_link(pvictim)
                              : tile_link(ptile);
        break;
      case ATK_TILE:
      case ATK_EXTRAS:
        victim_link = tile_link(ptile);
        break;
      case ATK_SELF:
        /* How did a self targeted action end up here? */
        fc_assert(action_get_target_kind(paction) != ATK_SELF);
        break;
      case ATK_COUNT:
        break;
      }
 
      fc_assert(victim_link != NULL);
 
      action_consequence_caught(paction, pplayer, act_utype, uplayer,
                                ptile, victim_link);
 
      wipe_unit(pdiplomat, ULR_ELIMINATED, uplayer);
      return FALSE;
    }
  }
 
  return TRUE;
}
 
/************************************************************************/
static void diplomat_escape(struct player *pplayer, struct unit *pdiplomat,
                            const struct city *pcity,
                            const struct action *paction)
{
  struct tile *ptile;
  const char *vlink;
 
  if (pcity) {
    ptile = city_tile(pcity);
    vlink = city_link(pcity);
  } else {
    ptile = unit_tile(pdiplomat);
    vlink = NULL;
  }
 
  return diplomat_escape_full(pplayer, pdiplomat, pcity != NULL,
                              ptile, vlink, paction);
}
 
/************************************************************************/
static void diplomat_escape_full(struct player *pplayer,
                                 struct unit *pdiplomat,
                                 bool city_related,
                                 struct tile *ptile,
                                 const char *vlink,
                                 const struct action *paction)
{
  int escapechance;
  struct city *spyhome;
  const struct unit_type *dipltype = unit_type_get(pdiplomat);
 
  fc_assert(paction->actor.is_unit.moves_actor == MAK_ESCAPE);
 
  /* Veteran level's power factor's effect on escape chance is relative to
   * unpromoted unit's power factor */
  {
    const struct veteran_level
      *vunit = utype_veteran_level(dipltype, pdiplomat->veteran);
    const struct veteran_level
      *vbase = utype_veteran_level(dipltype, 0);
 
    escapechance = game.server.diplchance
      + (vunit->power_fact - vbase->power_fact);
  }
 
  /* find closest city for escape target */
  spyhome = find_closest_city(ptile, NULL, unit_owner(pdiplomat), FALSE,
                              FALSE, FALSE, TRUE, FALSE, NULL);
 
  if (spyhome
      && !utype_is_consumed_by_action(paction, dipltype)
      && (unit_has_type_flag(pdiplomat, UTYF_SUPERSPY)
          || fc_rand (100) < escapechance)) {
    /* Attacking Spy/Diplomat survives. */
    notify_player(pplayer, ptile, E_MY_DIPLOMAT_ESCAPE, ftc_server,
                  _("Your %s has successfully completed"
                    " the mission and returned unharmed to %s."),
                  unit_link(pdiplomat),
                  city_link(spyhome));
    if (maybe_make_veteran(pdiplomat, 100)) {
      notify_unit_experience(pdiplomat);
    }
 
    if (!teleport_unit_to_city (pdiplomat, spyhome,
                                /* Handled by the ruleset. */
                                0,
                                FALSE)) {
      send_unit_info(NULL, pdiplomat);
      log_error("Bug in diplomat_escape: Spy can't teleport.");
      return;
    }
 
    return;
  } else {
    if (city_related) {
      notify_player(pplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                    _("Your %s was captured after completing"
                      " the mission in %s."),
                    unit_tile_link(pdiplomat),
                    vlink);
    } else {
      notify_player(pplayer, ptile, E_MY_DIPLOMAT_FAILED, ftc_server,
                    _("Your %s was captured after completing"
                      " the mission."),
                    unit_tile_link(pdiplomat));
    }
  }
 
  if (!utype_is_consumed_by_action(paction, dipltype)) {
    /* The unit was caught, not spent. It must therefore be deleted by
     * hand. */
    wipe_unit(pdiplomat, ULR_CAUGHT, NULL);
  }
}
 
/************************************************************************/
int count_diplomats_on_tile(struct tile *ptile)
{
  int count = 0;
 
  unit_list_iterate((ptile)->units, punit) {
    if (unit_has_type_flag(punit, UTYF_DIPLOMAT)) {
      count++;
    }
  } unit_list_iterate_end;
 
  return count;
}