/********************************************************************** 
 Freeciv - Copyright (C) 2001 - Raimar Falke
   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.
***********************************************************************/
#ifndef FC__CLIENT_AGENTS_GOTO_AGENT_H
#define FC__CLIENT_AGENTS_GOTO_AGENT_H

/*
 * The goto agent computes the optimal path for a goto.
 *
 * TODO:
 *  - air units aren't tested
 *  - units won't attack
 */

/*
 * Maximal number of steps in a path.
 */
#define MAX_PATH_LENGTH	100

struct ga_path {
    /*
     * Is this path a valid. Is set to 0 if there was no path found.
     */
    short int found_a_valid;
    /*
     * Number of positions used in the array "positions".
     */
  short int positions_used;

  struct ga_position {
      /*
       * x, y, turn and remaining_move_points describe a position in
       * place and time.
       */
    short int x, y, turn, remaining_move_points;
    short int direction_for_next_position;
  } positions[MAX_PATH_LENGTH + 1];
};

/*
 * Takes a "struct ga_path *" and returns the last position as a
 * "struct ga_position *".
 */
#define LAST_POSITION(_ppath_) (&((_ppath_)->positions[(_ppath_)->positions_used-1]))

/*
 * Opaque type.
 */
typedef struct ga_map *ga_map_t;

/*
 * Called once per start of the client.
 */
void ga_init(void);

/*
 * Returns a map which can be used to query for paths. The origin is
 * the current position of the unit.
 */
ga_map_t ga_get_map(int unit_id);

/*
 * Tries to find a path in the given map to the given destination
 * position. The path will be written in the given struct ga_path.
 * Caller should test path->found_a_valid. ga_get_path_from_map will
 * not change anything.
 */
void ga_get_path_from_map(ga_map_t map, int dest_x, int dest_y,
			  struct ga_path *path);

/*
 * After usage the map should be destroyed.
 */
void ga_destroy_map(ga_map_t map);

/*
 * ga_get_path is a one shot version. It combines ga_get_map,
 * ga_get_path_from_map and ga_destroy_map.
 */
void ga_get_path(int unit_id, int dest_x,int dest_y,struct ga_path *path);

/*
 * Will move the given unit using the given path.
 */
void ga_apply_path(int unit_id, struct ga_path *path);

/*
 * Revokes ga_apply_path.
 */
void ga_cancel_action(int unit_id);

int ga_is_agent_moving_unit(int unit_id);

void ga_print_path(char *msg, struct ga_path *path);

void ga_show_report(void);
#endif