goto.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 <string.h>
 
/* utility */
#include "log.h"
#include "mem.h"
 
/* common */
#include "game.h"
#include "map.h"
#include "movement.h"
#include "packets.h"
#include "pf_tools.h"
#include "road.h"
#include "unit.h"
#include "unitlist.h"
 
/* client/include */
#include "client_main.h"
#include "control.h"
#include "mapview_g.h"
 
/* client */
#include "goto.h"
#include "mapctrl_common.h"
 
#define LOG_GOTO_PATH           LOG_DEBUG
#define log_goto_path           log_debug
#define log_goto_packet         log_debug
 
/*
 * The whole path is separated by waypoints into parts. Each part has its
 * own starting position and requires its own map. When the unit is unable
 * to move, end_tile equals start_tile and path is nullptr.
 */
struct part {
  struct tile *start_tile, *end_tile;
  int end_moves_left, end_fuel_left;
  struct pf_path *path;
  struct pf_map *map;
};
 
struct goto_map {
  struct unit *focus;
  struct part *parts;
  int num_parts;
  union {
    struct {
      int initial_turns;
    } connect;
    struct {
      struct pf_path *return_path;
    } patrol;
  };
  struct pf_parameter template;
};
 
/* Get 'struct goto_map_list' and related functions: */
#define SPECLIST_TAG goto_map
#define SPECLIST_TYPE struct goto_map
#include "speclist.h"
#define goto_map_list_iterate(gotolist, pgoto)                          \
  TYPED_LIST_ITERATE(struct goto_map, gotolist, pgoto)
#define goto_map_list_iterate_end                                       \
  LIST_ITERATE_END
 
/* Iterate over goto maps, assumes no dead units. */
#define goto_map_unit_iterate(gotolist, pgoto, punit)                   \
  goto_map_list_iterate(gotolist, pgoto) {                              \
    struct unit *punit = goto_map_unit(pgoto);
 
#define goto_map_unit_iterate_end                                       \
  } goto_map_list_iterate_end;
 
static struct goto_map_list *goto_maps = nullptr;
static bool goto_warned = FALSE;
 
static void reset_last_part(struct goto_map *goto_map);
static void remove_last_part(struct goto_map *goto_map);
static void fill_parameter_part(struct pf_parameter *param,
                                const struct goto_map *goto_map,
                                const struct part *p);
 
/****************************************************************************
  Various stuff for the goto routes
****************************************************************************/
static struct tile *goto_destination = nullptr;
 
/************************************************************************/
static struct goto_map *goto_map_new(struct unit *punit)
{
  struct goto_map *goto_map = fc_malloc(sizeof(*goto_map));
 
  goto_map->focus = punit;
  goto_map->parts = nullptr;
  goto_map->num_parts = 0;
 
  return goto_map;
}
 
/************************************************************************/
static void goto_map_free(struct goto_map *goto_map)
{
  if (goto_map->parts != nullptr) {
    while (goto_map->num_parts > 0) {
      remove_last_part(goto_map);
    }
    free(goto_map->parts);
  }
  if (hover_state == HOVER_PATROL && goto_map->patrol.return_path) {
    pf_path_destroy(goto_map->patrol.return_path);
  }
  free(goto_map);
}
 
/************************************************************************/
static struct unit *goto_map_unit(const struct goto_map *goto_map)
{
  struct unit *punit = goto_map->focus;
 
  fc_assert(punit != nullptr);
  fc_assert(unit_is_in_focus(punit));
  fc_assert(punit == player_unit_by_number(client_player(), punit->id));
 
  return punit;
}
 
/************************************************************************/
void init_client_goto(void)
{
  free_client_goto();
 
  goto_maps = goto_map_list_new();
}
 
/************************************************************************/
void free_client_goto(void)
{
  if (goto_maps != nullptr) {
    goto_map_list_iterate(goto_maps, goto_map) {
      goto_map_free(goto_map);
    } goto_map_list_iterate_end;
    goto_map_list_destroy(goto_maps);
    goto_maps = nullptr;
  }
 
  goto_destination = nullptr;
  goto_warned = FALSE;
}
 
/************************************************************************/
bool is_valid_goto_destination(const struct tile *ptile)
{
  return (goto_destination != nullptr && ptile == goto_destination);
}
 
/************************************************************************/
static void goto_path_redraw(const struct pf_path *new_path,
                             const struct pf_path *old_path)
{
  int start_index = 0;
  int i;
 
  fc_assert_ret(new_path != nullptr);
 
  if (old_path != nullptr) {
    /* We had a path drawn already. Determine how much of it we can reuse
     * in drawing the new path. */
    for (i = 0; i < new_path->length - 1 && i < old_path->length - 1; i++) {
      struct pf_position *old_pos = old_path->positions + i;
      struct pf_position *new_pos = new_path->positions + i;
 
      if (old_pos->dir_to_next_pos != new_pos->dir_to_next_pos
          || old_pos->tile != new_pos->tile) {
        break;
      }
    }
    start_index = i;
 
    /* Erase everything we cannot reuse. */
    for (; i < old_path->length - 1; i++) {
      struct pf_position *pos = old_path->positions + i;
 
      if (is_valid_dir(pos->dir_to_next_pos)) {
        mapdeco_remove_gotoline(pos->tile, pos->dir_to_next_pos);
      } else {
        fc_assert(pos->tile == (pos + 1)->tile);
      }
    }
  }
 
  /* Draw the new path. */
  for (i = start_index; i < new_path->length - 1; i++) {
    struct pf_position *pos = new_path->positions + i;
 
    if (is_valid_dir(pos->dir_to_next_pos)) {
      mapdeco_add_gotoline(pos->tile, pos->dir_to_next_pos);
    } else {
      fc_assert(pos->tile == (pos + 1)->tile);
    }
  }
}
 
/************************************************************************/
static void goto_path_undraw(const struct pf_path *path)
{
  int i;
 
  fc_assert_ret(path != nullptr);
 
  for (i = 0; i < path->length - 1; i++) {
    struct pf_position *pos = path->positions + i;
 
    if (is_valid_dir(pos->dir_to_next_pos)) {
      mapdeco_remove_gotoline(pos->tile, pos->dir_to_next_pos);
    } else {
      fc_assert(pos->tile == (pos + 1)->tile);
    }
  }
}
 
/************************************************************************/
static bool update_last_part(struct goto_map *goto_map,
                             struct tile *ptile)
{
  struct pf_path *old_path, *new_path;
  struct part *p = &goto_map->parts[goto_map->num_parts - 1];
 
  old_path = p->path;
  if (old_path != nullptr && pf_path_last_position(old_path)->tile == ptile) {
    /* Nothing to update. */
    return TRUE;
  }
 
  log_debug("update_last_part(%d,%d) old (%d,%d)-(%d,%d)",
            TILE_XY(ptile), TILE_XY(p->start_tile), TILE_XY(p->end_tile));
  new_path = pf_map_path(p->map, ptile);
 
  if (!new_path) {
    log_goto_path("  no path found");
 
    if (p->start_tile == ptile) {
      /* This mean we cannot reach the start point. It is probably,
       * a path-finding bug, but don't make infinite recursion. */
 
      if (!goto_warned) {
        log_error("No path found to reach the start point.");
        goto_warned = TRUE;
      }
 
      if (old_path != nullptr) {
        goto_path_undraw(old_path);
        pf_path_destroy(old_path);
        p->path = nullptr;
      }
      if (hover_state == HOVER_PATROL
          && goto_map->patrol.return_path != nullptr) {
        goto_path_undraw(goto_map->patrol.return_path);
        pf_path_destroy(goto_map->patrol.return_path);
        goto_map->patrol.return_path = nullptr;
      }
      return FALSE;
    }
 
    reset_last_part(goto_map);
    return FALSE;
  }
 
  log_goto_path("  path found:");
  pf_path_print(new_path, LOG_GOTO_PATH);
 
  p->path = new_path;
  p->end_tile = ptile;
  p->end_moves_left = pf_path_last_position(new_path)->moves_left;
  p->end_fuel_left = pf_path_last_position(new_path)->fuel_left;
 
  if (hover_state == HOVER_PATROL) {
    struct pf_parameter parameter;
    struct pf_map *pfm;
    struct pf_path *return_path;
 
    fill_parameter_part(&parameter, goto_map, p);
    pfm = pf_map_new(&parameter);
    return_path = pf_map_path(pfm, goto_map->parts[0].start_tile);
    pf_map_destroy(pfm);
 
    if (return_path == nullptr) {
      log_goto_path("  no return path found");
 
      if (p->start_tile == ptile) {
        /* This mean we cannot reach the start point. It is probably,
         * a path-finding bug, but don't make infinite recursion. */
 
        if (!goto_warned) {
          log_error("No path found to reach the start point.");
          goto_warned = TRUE;
        }
 
        if (old_path != nullptr) {
          goto_path_undraw(old_path);
          pf_path_destroy(old_path);
        }
        pf_path_destroy(new_path);
        p->path = nullptr;
        if (goto_map->patrol.return_path != nullptr) {
          goto_path_undraw(goto_map->patrol.return_path);
          pf_path_destroy(goto_map->patrol.return_path);
          goto_map->patrol.return_path = nullptr;
        }
        return FALSE;
      }
 
      p->path = old_path;
 
      if (p->path != nullptr) {
        const struct pf_position *pos = pf_path_last_position(old_path);
 
        p->end_tile = pos->tile;
        p->end_moves_left = pos->moves_left;
        p->end_fuel_left = pos->fuel_left;
      }
 
      pf_path_destroy(new_path);
      reset_last_part(goto_map);
 
      return FALSE;
    }
 
    log_goto_path("  returned path found:");
    pf_path_print(return_path, LOG_GOTO_PATH);
 
    if (goto_map->patrol.return_path != nullptr) {
      /* We cannot reuse old path because:
       * 1- the start tile isn't the same.
       * 2- the turn number neither (impossible to do in backward mode). */
      goto_path_undraw(goto_map->patrol.return_path);
      pf_path_destroy(goto_map->patrol.return_path);
    }
    goto_path_redraw(return_path, nullptr);
    goto_map->patrol.return_path = return_path;
  }
 
  goto_path_redraw(new_path, old_path);
  pf_path_destroy(old_path);
 
  log_goto_path("To (%d,%d) part %d: total_MC: %d",
                TILE_XY(ptile), goto_map->num_parts,
                pf_path_last_position(hover_state == HOVER_PATROL
                                      ? goto_map->patrol.return_path
                                      : new_path)->total_MC);
 
  return TRUE;
}
 
/************************************************************************/
static void reset_last_part(struct goto_map *goto_map)
{
  struct part *p = &goto_map->parts[goto_map->num_parts - 1];
 
  if (p->path != nullptr) {
    /* Otherwise no need to update */
    update_last_part(goto_map, p->start_tile);
  }
}
 
/************************************************************************/
static void fill_parameter_part(struct pf_parameter *param,
                                const struct goto_map *goto_map,
                                const struct part *p)
{
  *param = goto_map->template;
 
  if (p->start_tile == p->end_tile) {
    /* Copy is enough, we didn't move last part. */
    fc_assert(p->path->length == 1);
    return;
  }
 
  param->start_tile = p->end_tile;
  param->moves_left_initially = p->end_moves_left;
  param->fuel_left_initially = p->end_fuel_left;
  if (can_exist_at_tile(&(wld.map), param->utype, param->start_tile)) {
    param->transported_by_initially = nullptr;
  } else {
    const struct unit *transporter =
        transporter_for_unit_at(goto_map_unit(goto_map), param->start_tile);
 
    param->transported_by_initially = (transporter != nullptr
                                       ? unit_type_get(transporter) : nullptr);
  }
}
 
/************************************************************************/
static void add_part(struct goto_map *goto_map)
{
  struct part *p;
  struct pf_parameter parameter;
  struct unit *punit = goto_map_unit(goto_map);
 
  goto_map->num_parts++;
  goto_map->parts =
      fc_realloc(goto_map->parts,
                 goto_map->num_parts * sizeof(*goto_map->parts));
  p = &goto_map->parts[goto_map->num_parts - 1];
 
  if (goto_map->num_parts == 1) {
    /* First part */
    p->start_tile = unit_tile(punit);
    parameter = goto_map->template;
  } else {
    struct part *prev = &goto_map->parts[goto_map->num_parts - 2];
 
    p->start_tile = prev->end_tile;
    fill_parameter_part(&parameter, goto_map, prev);
  }
 
  p->path = nullptr;
  p->end_tile = p->start_tile;
  parameter.start_tile = p->start_tile;
  p->map = pf_map_new(&parameter);
}
 
/************************************************************************/
static void remove_last_part(struct goto_map *goto_map)
{
  struct part *p = &goto_map->parts[goto_map->num_parts - 1];
 
  fc_assert_ret(goto_map->num_parts >= 1);
 
  reset_last_part(goto_map);
  if (p->path) {
    /* We do not always have a path */
    pf_path_destroy(p->path);
  }
  pf_map_destroy(p->map);
  goto_map->num_parts--;
}
 
/************************************************************************/
bool goto_add_waypoint(void)
{
  bool duplicate_of_last = TRUE;
 
  fc_assert_ret_val(goto_is_active(), FALSE);
 
  if (goto_destination == nullptr) {
    /* Not a valid position. */
    return FALSE;
  }
 
  goto_map_list_iterate(goto_maps, goto_map) {
    const struct part *last_part = &goto_map->parts[goto_map->num_parts - 1];
 
    if (last_part->path == nullptr) {
      /* The current part has zero length. */
      return FALSE;
    }
    if (last_part->start_tile != last_part->end_tile) {
      duplicate_of_last = FALSE;
    }
  } goto_map_list_iterate_end;
  if (duplicate_of_last) {
    return FALSE;
  }
 
  goto_map_list_iterate(goto_maps, goto_map) {
    add_part(goto_map);
  } goto_map_list_iterate_end;
 
  refresh_tile_mapcanvas(goto_destination, FALSE, FALSE);
 
  return TRUE;
}
 
/************************************************************************/
bool goto_pop_waypoint(void)
{
  bool popped = FALSE;
 
  fc_assert_ret_val(goto_is_active(), FALSE);
 
  goto_map_list_iterate(goto_maps, goto_map) {
    struct part *p = &goto_map->parts[goto_map->num_parts - 1];
    struct tile *end_tile = p->end_tile;
 
    if (goto_map->num_parts == 1) {
      /* We don't have any waypoint but the start pos. */
      continue;
    }
    popped = TRUE;
 
    remove_last_part(goto_map);
 
    /*
     * Set the end position of the previous part (now the last) to the
     * end position of the last part (now gone). I.e. redraw a line to
     * the mouse position.
     */
    update_last_part(goto_map, end_tile);
  } goto_map_list_iterate_end;
 
  return popped;
}
 
/************************************************************************/
static unsigned get_EC(const struct tile *ptile, enum known_type known,
                       const struct pf_parameter *param)
{
  return 1;
}
 
/************************************************************************/
static enum tile_behavior get_TB_aggr(const struct tile *ptile,
                                      enum known_type known,
                                      const struct pf_parameter *param)
{
  if (known == TILE_UNKNOWN) {
    if (!gui_options.goto_into_unknown) {
      return TB_IGNORE;
    }
  } else if (is_non_allied_unit_tile(ptile, param->owner,
                                     utype_has_flag(param->utype, UTYF_FLAGLESS))
             || is_non_allied_city_tile(ptile, param->owner)) {
    /* Can attack but can't count on going through */
    return TB_DONT_LEAVE;
  }
 
  return TB_NORMAL;
}
 
/************************************************************************/
static enum tile_behavior get_TB_caravan(const struct tile *ptile,
                                         enum known_type known,
                                         const struct pf_parameter *param)
{
  if (known == TILE_UNKNOWN) {
    if (!gui_options.goto_into_unknown) {
      return TB_IGNORE;
    }
  } else if (is_non_allied_city_tile(ptile, param->owner)) {
    /* Units that can establish a trade route, enter a market place or
     * establish an embassy can travel to, but not through, enemy cities.
     * FIXME: ACTION_HELP_WONDER units cannot. */
    return TB_DONT_LEAVE;
  } else if (is_non_allied_unit_tile(ptile, param->owner,
                                     utype_has_flag(param->utype, UTYF_FLAGLESS))) {
    /* Note this must be below the city check. */
    return TB_IGNORE;
  }
 
  /* Includes empty, allied, or allied-city tiles. */
  return TB_NORMAL;
}
 
/************************************************************************/
static int get_activity_time(const struct tile *ptile,
                             const struct player *pplayer)
{
  struct terrain *pterrain = tile_terrain(ptile);
  int activity_mc = 0;
 
  fc_assert_ret_val(hover_state == HOVER_CONNECT, -1);
 
  switch (connect_activity) {
  case ACTIVITY_IRRIGATE:
    if (pterrain->irrigation_time == 0) {
      return -1;
    }
    extra_type_iterate(pextra) {
      if (BV_ISSET(connect_tgt->conflicts, extra_index(pextra))
          && tile_has_extra(ptile, pextra)) {
        /* Don't replace old extras. */
        return -1;
      }
    } extra_type_iterate_end;
 
    if (tile_has_extra(ptile, connect_tgt)) {
      break;
    }
 
    activity_mc = pterrain->irrigation_time;
    break;
  case ACTIVITY_GEN_ROAD:
    fc_assert(is_extra_caused_by(connect_tgt, EC_ROAD));
 
    if (!tile_has_extra(ptile, connect_tgt)) {
      struct tile *vtile;
      int single_mc;
 
      vtile = tile_virtual_new(ptile);
      single_mc = check_recursive_road_connect(vtile, connect_tgt,
                                               nullptr, pplayer, 0);
      tile_virtual_destroy(vtile);
 
      if (single_mc < 0) {
        return -1;
      }
 
      activity_mc += single_mc;
    }
    break;
  default:
    log_error("Invalid connect activity: %d.", connect_activity);
  }
 
  return activity_mc;
}
 
/************************************************************************/
static bool is_non_allied_city_adjacent(const struct player *pplayer,
                                        const struct tile *ptile)
{
  adjc_iterate(&(wld.map), ptile, tile1) {
    if (is_non_allied_city_tile(tile1, pplayer)) {
      return TRUE;
    }
  } adjc_iterate_end;
 
  return FALSE;
}
 
/************************************************************************/
static int get_connect_road(const struct tile *src_tile, enum direction8 dir,
                            const struct tile *dest_tile,
                            int src_cost, int src_extra,
                            unsigned *dest_cost, unsigned *dest_extra,
                            const struct pf_parameter *param)
{
  int activity_time, move_cost, moves_left;
  int total_cost, total_extra;
  struct road_type *proad;
 
  if (tile_get_known(dest_tile, param->owner) == TILE_UNKNOWN) {
    return -1;
  }
 
  activity_time = get_activity_time(dest_tile, param->owner);
  if (activity_time < 0) {
    return -1;
  }
 
  move_cost = param->get_MC(src_tile, PF_MS_NATIVE, dest_tile, PF_MS_NATIVE,
                            param);
  if (move_cost == PF_IMPOSSIBLE_MC) {
    return -1;
  }
 
  if (is_non_allied_city_adjacent(param->owner, dest_tile)) {
    /* We don't want to build roads to enemies plus get ZoC problems */
    return -1;
  }
 
  fc_assert(connect_activity == ACTIVITY_GEN_ROAD);
 
  proad = extra_road_get(connect_tgt);
 
  if (proad == nullptr) {
    /* No suitable road type available */
    return -1;
  }
 
  /* Ok, the move is possible. What are the costs? */
 
  /* Extra cost here is the final length of the road */
  total_extra = src_extra + 1;
 
  /* Special cases: get_MC function doesn't know that we would have built
   * a road (railroad) on src tile by that time.
   * We assume that settler building the road can also travel it. */
  if (tile_has_road(dest_tile, proad)) {
    move_cost = proad->move_cost;
  }
 
  move_cost = MIN(move_cost, param->move_rate);
  total_cost = src_cost;
  moves_left = param->move_rate - (src_cost % param->move_rate);
  if (moves_left < move_cost) {
    total_cost += moves_left;
  } else {
    total_cost += move_cost;
  }
 
  /* Now need to include the activity cost. If we have moves left, they
   * will count as a full turn towards the activity time */
  moves_left = param->move_rate - (total_cost % param->move_rate);
  if (activity_time > 0) {
    int speed = FC_PTR_TO_INT(param->data);
 
    activity_time = ((activity_time * ACTIVITY_FACTOR)
                     + (speed - 1)) / speed;
    activity_time--;
    total_cost += moves_left;
  }
  total_cost += activity_time * param->move_rate;
 
  /* Now we determine if we have found a better path. When building
   * road type with positive move_cost, we care most about the length
   * of the result. When building road type with move_cost 0, we
   * care most about construction time. */
 
  /* *dest_cost == -1 means we haven't reached dest until now */
 
  if (*dest_cost != -1) {
    if (proad->move_cost > 0) {
      if (total_extra > *dest_extra
          || (total_extra == *dest_extra && total_cost >= *dest_cost)) {
        /* No, this path is worse than what we already have */
        return -1;
      }
    } else {
      if (total_cost > *dest_cost
          || (total_cost == *dest_cost && total_extra >= *dest_extra)) {
        return -1;
      }
    }
  }
 
  /* Ok, we found a better path! */
  *dest_cost = total_cost;
  *dest_extra = total_extra;
 
  return (proad->move_cost > 0 ?
          total_extra * PF_TURN_FACTOR + total_cost :
          total_cost * PF_TURN_FACTOR + total_extra);
}
 
/************************************************************************/
static int get_connect_irrig(const struct tile *src_tile,
                             enum direction8 dir,
                             const struct tile *dest_tile,
                             int src_cost, int src_extra,
                             unsigned *dest_cost, unsigned *dest_extra,
                             const struct pf_parameter *param)
{
  int activity_time, move_cost, moves_left, total_cost;
 
  if (tile_get_known(dest_tile, param->owner) == TILE_UNKNOWN) {
    return -1;
  }
 
  activity_time = get_activity_time(dest_tile, param->owner);
  if (activity_time < 0) {
    return -1;
  }
 
  if (!is_cardinal_dir(dir)) {
    return -1;
  }
 
  move_cost = param->get_MC(src_tile, PF_MS_NATIVE, dest_tile, PF_MS_NATIVE,
                            param);
  if (move_cost == PF_IMPOSSIBLE_MC) {
    return -1;
  }
 
  if (is_non_allied_city_adjacent(param->owner, dest_tile)) {
    /* We don't want to build irrigation for enemies plus get ZoC problems */
    return -1;
  }
 
  /* Ok, the move is possible. What are the costs? */
 
  move_cost = MIN(move_cost, param->move_rate);
  total_cost = src_cost;
  moves_left = param->move_rate - (src_cost % param->move_rate);
  if (moves_left < move_cost) {
    total_cost += moves_left;
  } else {
    total_cost += move_cost;
  }
 
  /* Now need to include the activity cost. If we have moves left, they
   * will count as a full turn towards the activity time */
  moves_left = param->move_rate - (total_cost % param->move_rate);
  if (activity_time > 0) {
    int speed = FC_PTR_TO_INT(param->data);
 
    activity_time = ((activity_time * ACTIVITY_FACTOR)
                     + (speed - 1)) / speed;
    activity_time--;
    total_cost += moves_left;
  }
  total_cost += activity_time * param->move_rate;
 
  /* *dest_cost == -1 means we haven't reached dest until now */
  if (*dest_cost != -1 && total_cost > *dest_cost) {
    return -1;
  }
 
  /* Ok, we found a better path! */
  *dest_cost = total_cost;
  *dest_extra = 0;
 
  return total_cost;
}
 
/************************************************************************/
static enum tile_behavior
no_fights_or_unknown_goto(const struct tile *ptile,
                          enum known_type known,
                          const struct pf_parameter *p)
{
  if (known == TILE_UNKNOWN && gui_options.goto_into_unknown) {
    /* Special case allowing goto into the unknown. */
    return TB_NORMAL;
  }
 
  return no_fights_or_unknown(ptile, known, p);
}
 
/************************************************************************/
static void goto_fill_parameter_base(struct pf_parameter *parameter,
                                     const struct unit *punit)
{
  pft_fill_unit_parameter(parameter, &(wld.map), punit);
 
  fc_assert(parameter->get_EC == nullptr);
  fc_assert(parameter->get_TB == nullptr);
  fc_assert(parameter->get_MC != nullptr);
  fc_assert(parameter->start_tile == unit_tile(punit));
  fc_assert(!parameter->omniscience);
 
  parameter->get_EC = get_EC;
  if (utype_acts_hostile(unit_type_get(punit))) {
    parameter->get_TB = get_TB_aggr;
  } else if (utype_may_act_at_all(unit_type_get(punit))
             && !utype_acts_hostile(unit_type_get(punit))) {
    parameter->get_TB = get_TB_caravan;
  } else {
    parameter->get_TB = no_fights_or_unknown_goto;
  }
}
 
/************************************************************************/
static void goto_fill_parameter_full(struct goto_map *goto_map,
                                     const struct unit *punit)
{
  struct pf_parameter *parameter = &goto_map->template;
 
  goto_fill_parameter_base(parameter, punit);
 
  fc_assert_ret(goto_is_active());
 
  switch (hover_state) {
  case HOVER_CONNECT:
    {
      int activity_initial;
      int speed;
 
      if (connect_activity == ACTIVITY_IRRIGATE) {
        parameter->get_costs = get_connect_irrig;
      } else {
        parameter->get_costs = get_connect_road;
      }
      parameter->get_moves_left_req = nullptr;
 
      speed = get_activity_rate(punit);
      parameter->data = FC_INT_TO_PTR(speed);
 
      /* Take into account the activity time at the origin */
      activity_initial = get_activity_time(unit_tile(punit),
                                           unit_owner(punit));
 
      if (activity_initial > 0) {
        /* First action is activity */
        parameter->moves_left_initially = parameter->move_rate;
        /* Number of turns, rounding up */
        goto_map->connect.initial_turns
          = ((activity_initial * ACTIVITY_FACTOR + (speed - 1)) / speed);
        if (punit->moves_left == 0) {
          goto_map->connect.initial_turns++;
        }
      } else {
        goto_map->connect.initial_turns = 0;
      }
    }
    break;
  case HOVER_GOTO:
  case HOVER_PATROL:
    if (action_id_has_result_safe(goto_last_action, ACTRES_NUKE_UNITS)
        || action_id_has_result_safe(goto_last_action, ACTRES_NUKE)) {
      /* TODO: consider doing the same for other actor consuming actions. */
      /* We only want targets reachable immediately... */
      parameter->move_rate = 0;
      /* ...then we don't need to deal with dangers or refuel points. */
      parameter->is_pos_dangerous = nullptr;
      parameter->get_moves_left_req = nullptr;
    } else {
      goto_map->patrol.return_path = nullptr;
    }
    break;
  case HOVER_GOTO_SEL_TGT:
    fc_assert_msg(hover_state != HOVER_GOTO_SEL_TGT,
                  "Path finding during target selection");
    break;
  case HOVER_TELEPORT:
    fc_assert_msg(hover_state != HOVER_TELEPORT, "Goto with HOVER_TELEPORT?");
    break;
  case HOVER_NONE:
  case HOVER_PARADROP:
  case HOVER_ACT_SEL_TGT:
    fc_assert_msg(hover_state != HOVER_NONE, "Goto with HOVER_NONE?");
    fc_assert_msg(hover_state != HOVER_PARADROP,
                  "Goto with HOVER_PARADROP?");
    fc_assert_msg(hover_state != HOVER_ACT_SEL_TGT,
                  "Goto with HOVER_ACT_SEL_TGT?");
    break;
  };
}
 
/************************************************************************/
void enter_goto_state(struct unit_list *punits)
{
  fc_assert_ret(!goto_is_active());
 
  /* Can't have selection rectangle and goto going on at the same time. */
  cancel_selection_rectangle();
 
  unit_list_iterate(punits, punit) {
    struct goto_map *goto_map = goto_map_new(punit);
 
    goto_map_list_append(goto_maps, goto_map);
 
    goto_fill_parameter_full(goto_map, punit);
    add_part(goto_map);
  } unit_list_iterate_end;
 
  goto_warned = FALSE;
}
 
/************************************************************************/
void exit_goto_state(void)
{
  if (!goto_is_active()) {
    return;
  }
 
  goto_map_list_iterate(goto_maps, goto_map) {
    goto_map_free(goto_map);
  } goto_map_list_iterate_end;
  goto_map_list_clear(goto_maps);
 
  goto_destination = nullptr;
  goto_warned = FALSE;
}
 
/************************************************************************/
void goto_unit_killed(struct unit *punit)
{
  if (!goto_is_active()) {
    return;
  }
 
  goto_map_unit_iterate(goto_maps, goto_map, ptest) {
    if (ptest == punit) {
      goto_map_list_remove(goto_maps, goto_map);
      goto_map_free(goto_map);
      /* Stop now, links are gone! */
      break;
    }
  } goto_map_unit_iterate_end;
}
 
/************************************************************************/
bool goto_is_active(void)
{
  return (goto_maps != nullptr && 0 != goto_map_list_size(goto_maps));
}
 
/************************************************************************/
bool goto_get_turns(int *min, int *max)
{
  fc_assert_ret_val(min != nullptr, FALSE);
  fc_assert_ret_val(max != nullptr, FALSE);
 
  *min = FC_INFINITY;
  *max = -1;
 
  if (!goto_is_active()) {
    return FALSE;
  }
 
  if (goto_destination == nullptr) {
    /* Not a valid position. */
    return FALSE;
  }
 
  if (hover_state == HOVER_CONNECT) {
    /* In connect mode, we want to know the turn number the activity will
     * be finished. */
    int activity_time = get_activity_time(goto_destination, client_player());
 
    goto_map_list_iterate(goto_maps, goto_map) {
      bool moved = FALSE;
      int turns = goto_map->connect.initial_turns;
      int i;
 
      for (i = 0; i < goto_map->num_parts; i++) {
        const struct pf_path *path = goto_map->parts[i].path;
 
        turns += pf_path_last_position(goto_map->parts[i].path)->turn;
        if (!moved && path->length > 1) {
          moved = TRUE;
        }
      }
 
      if (moved && activity_time > 0) {
        turns++;
      }
 
      if (turns < *min) {
        *min = turns;
      }
      if (turns > *max) {
        *max = turns;
      }
    } goto_map_list_iterate_end;
  } else {
    /* In other modes, we want to know the turn number to reach the tile. */
    goto_map_list_iterate(goto_maps, goto_map) {
      int turns = 0;
      int i;
 
      for (i = 0; i < goto_map->num_parts; i++) {
        turns += pf_path_last_position(goto_map->parts[i].path)->turn;
      }
      if (hover_state == HOVER_PATROL
          && goto_map->patrol.return_path != nullptr) {
        turns += pf_path_last_position(goto_map->patrol.return_path)->turn;
      }
 
      if (turns < *min) {
        *min = turns;
      }
      if (turns > *max) {
        *max = turns;
      }
    } goto_map_list_iterate_end;
  }
 
  return TRUE;
}
 
/************************************************************************/
bool goto_tile_state(const struct tile *ptile, enum goto_tile_state *state,
                     int *turns, bool *waypoint)
{
  fc_assert_ret_val(ptile != nullptr, FALSE);
  fc_assert_ret_val(turns != nullptr, FALSE);
  fc_assert_ret_val(waypoint != nullptr, FALSE);
 
  if (!goto_is_active()) {
    return FALSE;
  }
 
  *state = -1;
  *turns = -1;
  *waypoint = FALSE;
 
  if (hover_state == HOVER_CONNECT) {
    /* In connect mode, we want to know the turn number the activity will
     * be finished. */
    int activity_time;
 
    if (tile_get_known(ptile, client_player()) == TILE_UNKNOWN) {
      return FALSE; /* We never connect on unknown tiles. */
    }
 
    activity_time = get_activity_time(ptile, client_player());
 
    goto_map_list_iterate(goto_maps, goto_map) {
      const struct pf_path *path;
      const struct pf_position *pos = nullptr; /* Keep compiler happy! */
      int map_turns = goto_map->connect.initial_turns;
      int turns_for_map = -2;
      bool moved = FALSE;
      int i, j;
 
      for (i = 0; i < goto_map->num_parts; i++) {
        if (i > 0 && goto_map->parts[i].start_tile == ptile) {
          *waypoint = TRUE;
        }
 
        path = goto_map->parts[i].path;
        if (path == nullptr || path->length == 0) {
          continue;
        }
 
        for (j = 0; j < path->length; j++) {
          pos = path->positions + j;
          if (!moved && j > 0) {
            moved = TRUE;
          }
          if (pos->tile != ptile) {
            continue;
          }
          if (activity_time > 0) {
            if (map_turns + pos->turn + moved > turns_for_map) {
              turns_for_map = map_turns + pos->turn + moved;
            }
          } else if (pos->moves_left == 0) {
            if (map_turns + pos->turn > turns_for_map) {
              turns_for_map = map_turns + pos->turn + moved;
            }
          }
        }
        map_turns += pos->turn;
      }
 
      if (ptile == goto_destination) {
        int ml = (pos != nullptr ? pos->moves_left : 0);
 
        if (moved && activity_time > 0) {
          map_turns++;
        }
        if (map_turns > *turns) {
          *state = (activity_time > 0 || ml == 0
                    ? GTS_EXHAUSTED_MP : GTS_MP_LEFT);
          *turns = map_turns;
        } else if (map_turns == *turns
                   && *state == GTS_MP_LEFT
                   && (activity_time > 0 || ml == 0)) {
          *state = GTS_EXHAUSTED_MP;
        }
      } else {
        if (activity_time > 0) {
          if (turns_for_map > *turns) {
            *state = GTS_TURN_STEP;
            *turns = turns_for_map;
          }
        } else {
          if (turns_for_map + 1 > *turns) {
            *state = GTS_TURN_STEP;
            *turns = turns_for_map + 1;
          }
        }
      }
    } goto_map_list_iterate_end;
  } else {
    bool mark_on_map = FALSE;
 
    /* In other modes, we want to know the turn number to reach the tile. */
    goto_map_list_iterate(goto_maps, goto_map) {
      const struct tile *destination;
      const struct pf_path *path;
      const struct pf_position *pos = nullptr; /* Keep compiler happy! */
      const struct pf_position *last_pos = nullptr;
      int map_turns = 0;
      int turns_for_map = -2;
      int i, j;
 
      for (i = 0; i < goto_map->num_parts; i++) {
        if (i > 0 && goto_map->parts[i].start_tile == ptile) {
          mark_on_map = *waypoint = TRUE;
        }
 
        path = goto_map->parts[i].path;
        if (path == nullptr || path->length == 0) {
          continue;
        }
        last_pos = path->positions;
        for (j = 0; j < path->length; j++) {
          pos = path->positions + j;
          /* turn to reach was increased in that step */
          if (pos->turn != last_pos->turn
              && pos->tile == ptile) {
            mark_on_map = TRUE;
          }
          if (pos->moves_left == 0 && last_pos->moves_left != 0
              && pos->tile == ptile) {
            mark_on_map = TRUE;
          }
          if (pos->tile == ptile
              /* End turn case. */
              && (pos->moves_left == 0
                  /* Waiting case. */
                  || (j < path->length - 1 && (pos + 1)->tile == ptile))
              && map_turns + pos->turn > turns_for_map) {
            turns_for_map = map_turns + pos->turn;
          }
          last_pos = pos;
        }
        map_turns += pos->turn;
      }
 
      if (hover_state == HOVER_PATROL
          && goto_map->patrol.return_path != nullptr
          && goto_map->patrol.return_path->length > 0) {
        path = goto_map->patrol.return_path;
 
        for (j = 0; j < path->length; j++) {
          pos = path->positions + j;
          if (pos->tile == ptile
              /* End turn case. */
              && (pos->moves_left == 0
                  /* Waiting case. */
                  || (j < path->length - 1 && (pos + 1)->tile == ptile))
              && map_turns + pos->turn > turns_for_map) {
            turns_for_map = map_turns + pos->turn;
          }
        }
        map_turns += pos->turn;
        destination = pos->tile;
      } else {
        destination = goto_destination;
      }
 
      if (ptile == destination) {
        int ml = (pos != nullptr ? pos->moves_left : 0);
 
        if (map_turns > *turns) {
          mark_on_map = TRUE;
          *state = (ml == 0 ? GTS_EXHAUSTED_MP : GTS_MP_LEFT);
          *turns = map_turns;
        } else if (map_turns == *turns
                   && *state == GTS_MP_LEFT
                   && ml == 0) {
          *state = GTS_EXHAUSTED_MP;
        }
      } else {
        if (turns_for_map > *turns) {
          *state = GTS_TURN_STEP;
          *turns = turns_for_map;
        }
      }
    } goto_map_list_iterate_end;
 
    return mark_on_map;
  }
 
  return (*turns != -1 || *waypoint);
}
 
/************************************************************************/
bool is_valid_goto_draw_line(struct tile *dest_tile)
{
  fc_assert_ret_val(goto_is_active(), FALSE);
 
  if (dest_tile == nullptr) {
    return FALSE;
  }
 
  /* Assume valid destination */
  goto_destination = dest_tile;
 
  goto_map_list_iterate(goto_maps, goto_map) {
    if (!update_last_part(goto_map, dest_tile)) {
      goto_destination = nullptr;
    }
  } goto_map_list_iterate_end;
 
  /* Update goto data in info label. */
  update_unit_info_label(get_units_in_focus());
 
  return (goto_destination != nullptr);
}
 
/************************************************************************/
void request_orders_cleared(struct unit *punit)
{
  struct packet_unit_orders p;
 
  if (!can_client_issue_orders()) {
    return;
  }
 
  /* Clear the orders by sending an empty orders path. */
  log_goto_packet("Clearing orders for unit %d.", punit->id);
  p.unit_id = punit->id;
  p.src_tile = tile_index(unit_tile(punit));
  p.repeat = p.vigilant = FALSE;
  p.length = 0;
  p.dest_tile = tile_index(unit_tile(punit));
  request_unit_ssa_set(punit, SSA_NONE);
  send_packet_unit_orders(&client.conn, &p);
}
 
/************************************************************************/
static void make_path_orders(struct unit *punit, struct pf_path *path,
                             enum unit_orders orders,
                             struct unit_order *final_order,
                             struct unit_order *order_list,
                             int *length, int *dest_tile)
{
  int i;
  struct tile *old_tile;
 
  fc_assert_ret(path != nullptr);
  fc_assert_ret_msg(unit_tile(punit) == path->positions[0].tile,
                    "Unit %d has moved without goto cancellation.",
                    punit->id);
  fc_assert_ret(length != nullptr);
 
  /* We skip the start position. */
  *length = path->length - 1;
  fc_assert(*length < MAX_LEN_ROUTE);
  old_tile = path->positions[0].tile;
 
  /* If the path has n positions it takes n-1 steps. */
  for (i = 0; i < path->length - 1; i++) {
    struct tile *new_tile = path->positions[i + 1].tile;
 
    if (same_pos(new_tile, old_tile)) {
      order_list[i].order = ORDER_FULL_MP;
      order_list[i].dir = DIR8_ORIGIN;
      order_list[i].activity = ACTIVITY_LAST;
      order_list[i].target = NO_TARGET;
      order_list[i].sub_target = NO_TARGET;
      order_list[i].action = ACTION_NONE;
      log_goto_packet("  packet[%d] = wait: %d,%d", i, TILE_XY(old_tile));
    } else {
      order_list[i].order = orders;
      order_list[i].dir = get_direction_for_step(&(wld.map), old_tile, new_tile);
      order_list[i].activity = ACTIVITY_LAST;
      order_list[i].target = NO_TARGET;
      order_list[i].sub_target = NO_TARGET;
      order_list[i].action = ACTION_NONE;
      log_goto_packet("  packet[%d] = move %s: %d,%d => %d,%d",
                      i, dir_get_name(order_list[i].dir),
                      TILE_XY(old_tile), TILE_XY(new_tile));
    }
    old_tile = new_tile;
  }
 
  if (i > 0
      && order_list[i - 1].order == ORDER_MOVE) {
    struct player *cplayer = client_player();
 
    if (is_non_allied_city_tile(old_tile, cplayer)
        || is_non_allied_unit_tile(old_tile, cplayer,
                                   unit_has_type_flag(punit, UTYF_FLAGLESS))) {
      /* Won't be able to perform a regular move to the target tile... */
      if (!final_order) {
        /* ...and no final order exists. Choose what to do when the unit gets
         * there. */
        order_list[i - 1].order = ORDER_ACTION_MOVE;
      } else {
        /* ...and a final order exist. Can't assume an action move. Did the
         * caller hope that the situation would change before the unit got
         * there? */
 
        /* It's currently illegal to walk into tiles with non-allied units or
         * cities. Some actions causes the actor to enter the target tile but
         * that is a part of the action it self, not a regular pre action
         * move. */
        log_verbose("unit or city blocks the path of your %s",
                    unit_rule_name(punit));
      }
    }
  }
 
  if (final_order) {
    /* Append the final order after moving to the target tile. */
    order_list[i].order = final_order->order;
    order_list[i].dir = final_order->dir;
    order_list[i].activity = (final_order->order == ORDER_ACTIVITY)
      ? final_order->activity : ACTIVITY_LAST;
    order_list[i].target = final_order->target;
    order_list[i].sub_target = final_order->sub_target;
    order_list[i].action = final_order->action;
    (*length)++;
  }
 
  if (dest_tile) {
    *dest_tile = tile_index(old_tile);
  }
}
 
/************************************************************************/
static void send_path_orders(struct unit *punit, struct pf_path *path,
                             bool repeat, bool vigilant,
                             enum unit_orders orders,
                             struct unit_order *final_order)
{
  struct packet_unit_orders p;
 
  if (path->length == 1 && final_order == nullptr) {
    return; /* No path at all, no need to spam the server. */
  }
 
  memset(&p, 0, sizeof(p));
  p.unit_id = punit->id;
  p.src_tile = tile_index(unit_tile(punit));
  p.repeat = repeat;
  p.vigilant = vigilant;
 
  log_goto_packet("Orders for unit %d:", punit->id);
  log_goto_packet("  Repeat: %d. Vigilant: %d.",
                  p.repeat, p.vigilant);
 
  make_path_orders(punit, path, orders, final_order,
                   p.orders, &p.length, &p.dest_tile);
 
  request_unit_ssa_set(punit, SSA_NONE);
  send_packet_unit_orders(&client.conn, &p);
}
 
/************************************************************************/
static void send_rally_path_orders(struct city *pcity, struct unit *punit,
                                   struct pf_path *path, bool vigilant,
                                   bool persistent,
                                   enum unit_orders orders,
                                   struct unit_order *final_order)
{
  struct packet_city_rally_point p;
 
  memset(&p, 0, sizeof(p));
  p.id = pcity->id;
  p.vigilant = vigilant;
  p.persistent = persistent;
 
  log_goto_packet("Rally orders for city %d:", pcity->id);
  log_goto_packet("  Vigilant: %d.", p.vigilant);
 
  make_path_orders(punit, path, orders, final_order,
                   p.orders, &p.length, nullptr);
 
  send_packet_city_rally_point(&client.conn, &p, FALSE);
}
 
/************************************************************************/
void send_goto_path(struct unit *punit, struct pf_path *path,
                    struct unit_order *final_order)
{
  send_path_orders(punit, path, FALSE, FALSE, ORDER_MOVE, final_order);
}
 
/************************************************************************/
static void send_rally_path(struct city *pcity, struct unit *punit,
                            bool persistent, struct pf_path *path,
                            struct unit_order *final_order)
{
  send_rally_path_orders(pcity, punit, path, FALSE, persistent,
                         ORDER_MOVE, final_order);
}
 
/************************************************************************/
bool send_goto_tile(struct unit *punit, struct tile *ptile)
{
  struct pf_parameter parameter;
  struct pf_map *pfm;
  struct pf_path *path;
 
  goto_fill_parameter_base(&parameter, punit);
  pfm = pf_map_new(&parameter);
  path = pf_map_path(pfm, ptile);
  pf_map_destroy(pfm);
 
  if (path != nullptr) {
    send_goto_path(punit, path, nullptr);
    pf_path_destroy(path);
    return TRUE;
  } else {
    return FALSE;
  }
}
 
/************************************************************************/
bool send_rally_tile(struct city *pcity, struct tile *ptile, bool persistent)
{
  const struct unit_type *putype;
  struct unit *punit;
  struct pf_parameter parameter;
  struct pf_map *pfm;
  struct pf_path *path;
 
  fc_assert_ret_val(pcity != nullptr, FALSE);
  fc_assert_ret_val(ptile != nullptr, FALSE);
 
  /* Create a virtual unit of the type being produced by the city. */
  if (pcity->production.kind != VUT_UTYPE) {
    /* Can only give orders to units. */
    return FALSE;
  }
 
  putype = pcity->production.value.utype;
  punit = unit_virtual_create(client_player(), pcity, putype,
                              city_production_unit_veteran_level(pcity,
                                                                 putype));
 
  /* Use the unit to find a path to the destination tile. */
  goto_fill_parameter_base(&parameter, punit);
  pfm = pf_map_new(&parameter);
  path = pf_map_path(pfm, ptile);
  pf_map_destroy(pfm);
 
  if (path != nullptr) {
    /* Send orders to server. */
    send_rally_path(pcity, punit, persistent, path, nullptr);
    unit_virtual_destroy(punit);
    pf_path_destroy(path);
 
    return TRUE;
  } else {
    unit_virtual_destroy(punit);
 
    return FALSE;
  }
}
 
/************************************************************************/
bool send_attack_tile(struct unit *punit, struct tile *ptile)
{
  struct pf_parameter parameter;
  struct pf_map *pfm;
  struct pf_path *path;
 
  goto_fill_parameter_base(&parameter, punit);
  parameter.move_rate = 0;
  parameter.is_pos_dangerous = nullptr;
  parameter.get_moves_left_req = nullptr;
  pfm = pf_map_new(&parameter);
  path = pf_map_path(pfm, ptile);
  pf_map_destroy(pfm);
 
  if (path != nullptr) {
   send_path_orders(punit, path, FALSE, FALSE, ORDER_ACTION_MOVE, nullptr);
   pf_path_destroy(path);
   return TRUE;
  }
 
  return FALSE;
}
 
/************************************************************************/
void send_patrol_route(void)
{
  fc_assert_ret(goto_is_active());
 
  goto_map_unit_iterate(goto_maps, goto_map, punit) {
    int i;
    struct pf_path *path = nullptr;
    struct part *last_part = &goto_map->parts[goto_map->num_parts - 1];
 
    if (last_part->path == nullptr) {
      /* Cannot move there */
      continue;
    }
 
    for (i = 0; i < goto_map->num_parts; i++) {
      path = pf_path_concat(path, goto_map->parts[i].path);
    }
    path = pf_path_concat(path, goto_map->patrol.return_path);
 
    send_path_orders(punit, path, TRUE, TRUE, ORDER_MOVE, nullptr);
 
    pf_path_destroy(path);
  } goto_map_unit_iterate_end;
}
 
/************************************************************************/
static bool order_recursive_roads(struct tile *ptile, struct extra_type *pextra,
                                 struct packet_unit_orders *p, int rec)
{
  if (rec > MAX_EXTRA_TYPES) {
    return FALSE;
  }
 
  if (!is_extra_caused_by(pextra, EC_ROAD)) {
    return FALSE;
  }
 
  if (tile_has_extra(ptile, pextra)) {
    /* No need to build what is already there. */
    return TRUE;
  }
 
  extra_deps_iterate(&(pextra->reqs), pdep) {
    if (!tile_has_extra(ptile, pdep)) {
      if (!order_recursive_roads(ptile, pdep, p, rec + 1)) {
        return FALSE;
      }
    }
  } extra_deps_iterate_end;
 
  p->orders[p->length].order = ORDER_PERFORM_ACTION;
  p->orders[p->length].dir = DIR8_ORIGIN;
  p->orders[p->length].activity = ACTIVITY_LAST;
  p->orders[p->length].target = ptile->index;
  p->orders[p->length].sub_target = extra_index(pextra);
  p->orders[p->length].action = ACTION_ROAD;
  p->length++;
 
  return TRUE;
}
 
/************************************************************************/
void send_connect_route(enum unit_activity activity,
                        struct extra_type *tgt)
{
  fc_assert_ret(goto_is_active());
 
  goto_map_unit_iterate(goto_maps, goto_map, punit) {
    int i;
    struct packet_unit_orders p;
    struct tile *old_tile;
    struct pf_path *path = nullptr;
    struct part *last_part = &goto_map->parts[goto_map->num_parts - 1];
 
    if (last_part->path == nullptr) {
      /* Cannot move there */
      continue;
    }
 
    memset(&p, 0, sizeof(p));
 
    i = 0;
    do {
      path = pf_path_concat(path, goto_map->parts[i].path);
      i++;
    } while (i < goto_map->num_parts);
 
    p.unit_id = punit->id;
    p.src_tile = tile_index(unit_tile(punit));
    p.repeat = FALSE;
    p.vigilant = FALSE; /* Should be TRUE? */
 
    p.length = 0;
    old_tile = path->positions[0].tile;
 
    for (i = 0; i < path->length; i++) {
      switch (activity) {
      case ACTIVITY_IRRIGATE:
        if (!tile_has_extra(old_tile, tgt)) {
          /* Assume the unit can irrigate or we wouldn't be here. */
          p.orders[p.length].order = ORDER_PERFORM_ACTION;
          p.orders[p.length].dir = DIR8_ORIGIN;
          p.orders[p.length].activity = ACTIVITY_LAST;
          p.orders[p.length].target = old_tile->index;
          p.orders[p.length].sub_target = extra_index(tgt);
          p.orders[p.length].action = ACTION_IRRIGATE;
          p.length++;
        }
        break;
      case ACTIVITY_GEN_ROAD:
        order_recursive_roads(old_tile, tgt, &p, 0);
        break;
      default:
        log_error("Invalid connect activity: %d.", activity);
        break;
      }
 
      if (i != path->length - 1) {
        struct tile *new_tile = path->positions[i + 1].tile;
 
        fc_assert(!same_pos(new_tile, old_tile));
 
        p.orders[p.length].order = ORDER_MOVE;
        p.orders[p.length].dir = get_direction_for_step(&(wld.map),
                                                        old_tile, new_tile);
        p.orders[p.length].activity = ACTIVITY_LAST;
        p.orders[p.length].target = NO_TARGET;
        p.orders[p.length].sub_target = NO_TARGET;
        p.orders[p.length].action = ACTION_NONE;
        p.length++;
 
        old_tile = new_tile;
      }
    }
 
    p.dest_tile = tile_index(old_tile);
 
    request_unit_ssa_set(punit, SSA_NONE);
    send_packet_unit_orders(&client.conn, &p);
  } goto_map_unit_iterate_end;
}
 
/************************************************************************/
static bool order_wants_direction(enum unit_orders order, action_id act_id,
                                  struct tile *tgt_tile, struct unit *punit)
{
  struct player *cplayer;
 
  switch (order) {
  case ORDER_MOVE:
  case ORDER_ACTION_MOVE:
    /* Not only is it legal. It is mandatory. A move is always done in a
     * direction. */
    return TRUE;
  case ORDER_PERFORM_ACTION:
    if (!action_id_distance_accepted(act_id, 0)) {
      /* Always illegal to do to a target on the actor's own tile. */
      return TRUE;
    }
 
    if (!action_id_distance_accepted(act_id, 1)) {
      /* Always illegal to perform to a target on a neighbor tile. */
      return FALSE;
    }
 
    cplayer = client_player();
    if (is_non_allied_city_tile(tgt_tile, cplayer)
        || is_non_allied_unit_tile(tgt_tile, cplayer,
                                   unit_has_type_flag(punit, UTYF_FLAGLESS))) {
      /* Won't be able to move to the target tile to perform the action on
       * top of it. */
      /* TODO: Detect situations where it also would be illegal to perform
       * the action from the neighbor tile. */
      return TRUE;
    }
 
    if (gui_options.popup_last_move_to_allied) {
      /* Prefer efficiency over safety among allies. */
      fc_assert_ret_val(action_id_distance_accepted(act_id, 1), FALSE);
      return TRUE;
    }
 
    return FALSE;
  default:
    return FALSE;
  }
}
 
/************************************************************************/
static bool order_demands_direction(enum unit_orders order, action_id act_id)
{
  switch (order) {
  case ORDER_MOVE:
  case ORDER_ACTION_MOVE:
    /* A move is always done in a direction. */
    return TRUE;
  case ORDER_PERFORM_ACTION:
    if (!action_id_distance_accepted(act_id, 0)) {
      /* Always illegal to do to a target on the actor's own tile. */
      return TRUE;
    }
 
    return FALSE;
  default:
    return FALSE;
  }
}
 
/************************************************************************/
void send_goto_route(void)
{
  fc_assert_ret(goto_is_active());
  goto_map_unit_iterate(goto_maps, goto_map, punit) {
    int i;
    struct tile *tgt_tile;
    struct pf_path *path = nullptr;
    struct part *last_part = &goto_map->parts[goto_map->num_parts - 1];
 
    if (last_part->path == nullptr) {
      /* Cannot move there */
      continue;
    }
 
    i = 0;
    do {
      path = pf_path_concat(path, goto_map->parts[i].path);
      i++;
    } while (i < goto_map->num_parts);
 
    clear_unit_orders(punit);
 
    tgt_tile = pf_path_last_position(path)->tile;
 
    /* Make the last move in a plain goto try to pop up the action
     * selection dialog rather than moving to the last tile if it contains
     * a domestic, allied or team mate city, unit or unit stack. This can,
     * in cases where the action requires movement left, save a turn. */
    if (gui_options.popup_last_move_to_allied
        && goto_last_order == ORDER_LAST
        && ((is_allied_city_tile(tgt_tile, client_player())
             || is_allied_unit_tile(tgt_tile, client_player()))
            && (can_utype_do_act_if_tgt_diplrel(unit_type_get(punit),
                                                ACTION_ANY,
                                                DRO_FOREIGN,
                                                FALSE)
                || can_utype_do_act_if_tgt_diplrel(unit_type_get(punit),
                                                   ACTION_ANY,
                                                   DS_ALLIANCE,
                                                   TRUE)
                || can_utype_do_act_if_tgt_diplrel(unit_type_get(punit),
                                                   ACTION_ANY,
                                                   DS_TEAM,
                                                   TRUE)))) {
      /* Try to pop up the action selection dialog before moving to the
       * target tile. */
      goto_last_order = ORDER_ACTION_MOVE;
    }
 
    /* Handle single-step goto like single-step move. */
    if (goto_last_order == ORDER_LAST && path->length == 2
        && gui_options.popup_last_move_to_allied) {
      goto_last_order = ORDER_ACTION_MOVE;
    }
 
    if (goto_last_order == ORDER_LAST) {
      send_goto_path(punit, path, nullptr);
    } else if (path->length > 1
               || !order_demands_direction(goto_last_order,
                                           goto_last_action)) {
      struct unit_order order;
      int last_order_dir;
      struct tile *on_tile;
      int last_order_target = NO_TARGET;
 
      if (path->length > 1 && goto_last_tgt == NO_TARGET
          && ((on_tile = path->positions[path->length - 2].tile))
          && order_wants_direction(goto_last_order, goto_last_action,
                                   tgt_tile, punit)
          && !same_pos(on_tile, tgt_tile)) {
        /* The last order prefers to handle the last direction it self.
         * There exists a tile before the target tile to do it from. */
 
        /* Give the last path direction to the final order. */
        last_order_dir = get_direction_for_step(&(wld.map), on_tile, tgt_tile);
 
        /* The last path direction is now spent. */
        pf_path_backtrack(path, on_tile);
      } else {
        fc_assert(goto_last_tgt != NO_TARGET
                  || !order_demands_direction(goto_last_order,
                                              goto_last_action));
 
        /* Target the tile the actor is standing on or goto_last_tgt. */
        last_order_dir = DIR8_ORIGIN;
      }
 
      if (action_id_exists(goto_last_action)) {
        last_order_target = (goto_last_tgt == NO_TARGET
                             ? tgt_tile->index : goto_last_tgt);
        last_order_dir = DIR8_ORIGIN;
      }
 
      order.order = goto_last_order;
      order.dir = last_order_dir;
      order.activity = ACTIVITY_LAST;
      order.target = last_order_target;
      order.sub_target = goto_last_sub_tgt;
      order.action = goto_last_action;
 
      /* ORDER_ACTIVITY would require real activity */
      fc_assert(goto_last_order != ORDER_ACTIVITY);
 
      send_goto_path(punit, path, &order);
    }
    pf_path_destroy(path);
  } goto_map_unit_iterate_end;
}
 
/************************************************************************/
struct pf_path *path_to_nearest_allied_city(struct unit *punit)
{
  struct pf_parameter parameter;
  struct pf_map *pfm;
  struct pf_path *path = nullptr;
 
  if (is_allied_city_tile(unit_tile(punit), unit_owner(punit))) {
    /* We're already on a city - don't go anywhere. */
    return nullptr;
  }
 
  goto_fill_parameter_base(&parameter, punit);
  pfm = pf_map_new(&parameter);
 
  pf_map_tiles_iterate(pfm, ptile, FALSE) {
    if (is_allied_city_tile(ptile, unit_owner(punit))) {
      path = pf_map_path(pfm, ptile);
      break;
    }
  } pf_map_tiles_iterate_end;
 
  pf_map_destroy(pfm);
 
  return path;
}
 
/************************************************************************/
struct tile *tile_before_end_path(struct unit *punit, struct tile *ptile)
{
  struct pf_parameter parameter;
  struct pf_map *pfm;
  struct tile *dtile;
  struct pf_path *path;
 
  goto_fill_parameter_base(&parameter, punit);
  parameter.move_rate = 0;
  parameter.is_pos_dangerous = nullptr;
  parameter.get_moves_left_req = nullptr;
  pfm = pf_map_new(&parameter);
  path = pf_map_path(pfm, ptile);
 
  if (path == nullptr) {
    return nullptr;
  }
 
  if (path->length < 2) {
    dtile = nullptr;
  } else {
    dtile = path->positions[path->length - 2].tile;
  }
  pf_map_destroy(pfm);
 
  return dtile;
}