7kaa/OAI_ATTK.cpp

/*
 * Seven Kingdoms: Ancient Adversaries
 *
 * Copyright 1997,1998 Enlight Software Ltd.
 *
 * 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 of the License, 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

//Filename   : OAI_ATTK.CPP
//Description: AI - attacking

#include <stdlib.h>
#include <ALL.h>
#include <OUNIT.h>
#include <OCONFIG.h>
#include <OFIRMALL.h>
#include <OTALKRES.h>
#include <ONATION.h>


//------ Declare static functions --------//

static int get_target_nation_recno(int targetXLoc, int targetYLoc);
static int sort_attack_camp_function( const void *a, const void *b );


//--------- Begin of function Nation::ai_attack_target --------//
//
// Think about attacking a specific target.
//
// <int> targetXLoc, targetYLoc - location of the target
// <int> targetCombatLevel      - the combat level of the target, will
//                                only attack the target if the attacker's
//                                force is larger than it.
// [int] defenseMode            - whether the attack is basically for
//                                defending against an attack
//                                (default: 0)
// [int] justMoveToFlag         - whether just all move there and wait for
//                                the units to attack the enemies automatically
//                                (default: 0)
// [int] attackerMinCombatLevel - the minimum combat level of the attacker,
//											 do not send troops whose combat level
//											 is lower than this.
//                                (default: 0)
// [int] leadAttackCampRecno	  - if this is given, this camp will be
//											 included in the attacker list by passing
//											 checking on it.
//                                (default: 0)
// [int] useAllCamp 				  - use all camps to attack even if defenseMode is 0
//											 (default: defenseMode, which is default to 0)
//
// return: <int> 0  - no attack action
//					  >0 - the total combat level of attacking force.
//
int Nation::ai_attack_target(int targetXLoc, int targetYLoc, int targetCombatLevel, int defenseMode, int justMoveToFlag, int attackerMinCombatLevel, int leadAttackCampRecno, int useAllCamp)
{
/*					// this will be called when the AI tries to capture the town and attack the town's defense.
#ifdef DEBUG	//----- check for attacking own objects error ------//
	{
		int targetNationRecno = get_target_nation_recno(targetXLoc, targetYLoc);

		if( targetNationRecno )
		{
			err_when( get_relation(targetNationRecno)->status >= NATION_FRIENDLY );
		}
	}
#endif
*/
	//--- order nearby mobile units who are on their way to home camps to join this attack mission. ---//

	if( defenseMode )
		useAllCamp = 1;

	if( defenseMode )		// only for defense mode, for attack mission, we should plan and organize it better
	{
		int originalTargetCombatLevel;

		targetCombatLevel = ai_attack_order_nearby_mobile(targetXLoc, targetYLoc, targetCombatLevel);

		if( targetCombatLevel < 0 )		// the mobile force alone can finish all the enemies
			return originalTargetCombatLevel;
	}

	//--- try to send troop with maxTargetCombatLevel, and don't send troop if available combat level < minTargetCombatLevel ---//

	int maxTargetCombatLevel = targetCombatLevel * (150+pref_force_projection/2) / 100;		// 150% to 200%
	int minTargetCombatLevel;

	if( defenseMode )
		minTargetCombatLevel = targetCombatLevel * (100-pref_military_courage/2) / 100;		// 50% to 100%
	else
		minTargetCombatLevel = targetCombatLevel * (125+pref_force_projection/4) / 100;		// 125% to 150%

	//--- if the AI is already on an attack mission ---//

	if( attack_camp_count )
		return 0;

	//---- first locate for camps that do not need to protect any towns ---//

	#define MAX_SUITABLE_TOWN_CAMP      10    // no. of camps in a town

	FirmCamp* firmCamp;
	int   i, j;
	int   targetRegionId = world.get_loc(targetXLoc, targetYLoc)->region_id;

	err_when( targetXLoc < 0 || targetXLoc >= MAX_WORLD_X_LOC );
	err_when( targetYLoc < 0 || targetYLoc >= MAX_WORLD_Y_LOC );

	ai_attack_target_x_loc = targetXLoc;
	ai_attack_target_y_loc = targetYLoc;
	ai_attack_target_nation_recno = get_target_nation_recno(targetXLoc, targetYLoc);

	attack_camp_count=0;

	AttackCamp townCampArray[MAX_SUITABLE_TOWN_CAMP];
	short townCampCount;

	//------- if there is a pre-selected camp -------//

	lead_attack_camp_recno = leadAttackCampRecno;

	if( leadAttackCampRecno )
	{
		err_when( firm_array[leadAttackCampRecno]->nation_recno != nation_recno );
		err_when( firm_array[leadAttackCampRecno]->firm_id != FIRM_CAMP );

		attack_camp_array[attack_camp_count].firm_recno   = leadAttackCampRecno;
		attack_camp_array[attack_camp_count].combat_level = ((FirmCamp*)firm_array[leadAttackCampRecno])->total_combat_level();

		err_when( attack_camp_array[attack_camp_count].combat_level < 0 );

		attack_camp_count++;
	}

	//---- if the military courage is low or the king is injured, don't send the king out to battles ---//

	Nation* ownNation = nation_array[nation_recno];
	int	  kingFirmRecno=0;

	if( king_unit_recno )
	{
		Unit* kingUnit = unit_array[king_unit_recno];

		if( kingUnit->unit_mode == UNIT_MODE_OVERSEE )
		{
			Firm* kingFirm = firm_array[kingUnit->unit_mode_para];
			int   rc = 0;

			if( ai_camp_count > 3 + (100-ownNation->pref_military_courage)/20 ) 		// don't use the king if we have other generals, the king won't be used if we have 3 to 8 camps. The higher the military courage is, the smaller will be the number of camps
				rc = 1;

			//--- if the military courage is low or the king is injured ---//

			else if( kingUnit->hit_points < 230-ownNation->pref_military_courage )		// 130 to 230, if over 200, the king will not fight
				rc = 1;

			//--- if the King does have a full troop ----//

			else if( kingFirm->worker_count < MAX_WORKER )
				rc = 1;

			//-------------------------------------------//

			if( rc )
			{
				kingFirmRecno = kingUnit->unit_mode_para;

				//--- if the king is very close to the target, ask him to attack also ---//

				if( kingFirmRecno &&
					 kingUnit->hit_points >= 150-ownNation->pref_military_courage/4 )		// if the king is not heavily injured
				{
					firmCamp = (FirmCamp*) firm_array[kingFirmRecno];

					if( firmCamp->worker_count == MAX_WORKER )		// the king shouldn't go out alone
					{
						if( m.points_distance(firmCamp->center_x, firmCamp->center_y,
							 targetXLoc, targetYLoc) <= EFFECTIVE_FIRM_TOWN_DISTANCE )
						{
							kingFirmRecno = 0;
						}
					}
				}
			}
		}
	}

	//--------- locate for camps that are not linked to towns ---------//

	int rc;

	for( i=0 ; i<ai_camp_count ; i++ )
	{
		firmCamp = (FirmCamp*) firm_array[ ai_camp_array[i] ];

		err_when( firmCamp->firm_id != FIRM_CAMP );

		if( firmCamp->region_id != targetRegionId )
			continue;

		if( !firmCamp->overseer_recno || !firmCamp->worker_count )
			continue;

		if( firmCamp->patrol_unit_count > 0 )     // if there are units patrolling out
			continue;

		if( firmCamp->ai_capture_town_recno )     // the base is trying to capture an independent town
			continue;

		if( firmCamp->is_attack_camp )
			continue;

		if( firmCamp->firm_recno == kingFirmRecno )
			continue;

		//---- don't order this camp if the overseer is injured ----//

		Unit* overseerUnit = unit_array[firmCamp->overseer_recno];

		if( overseerUnit->hit_points < overseerUnit->max_hit_points &&
			 overseerUnit->hit_points < 100-ownNation->pref_military_courage/2 )		// 50 to 100
		{
			continue;
		}

		//----------------------------------------------------------//

		if( attackerMinCombatLevel )
		{
			if( firmCamp->average_combat_level() < attackerMinCombatLevel )
				continue;
		}

		//-------------------------------------//
		//
		// Add this camp if:
		// 1. we are in defense mode, and have to get all the forces available to defend against the attack.
		// 2. this camp isn't linked to any of our towns.
		//
		//-------------------------------------//

		if( useAllCamp )
			rc = 1;
		else
		{
			rc = firmCamp->linked_town_count==0;		// don't use this camp as it may be in the process of capturing an indepdendent town or an enemy town
/*
			for( int j=firmCamp->linked_town_count-1 ; j>=0 ; j-- )
			{
				if( town_array[firmCamp->linked_town_array[j]]->nation_recno == nation_recno )
					break;
			}

			rc = j<0;		// j<0 means not linked to any of our towns.
*/
		}

		if( rc )
		{
			//--- if this camp into the list of suitable attacker firm ---//

			if( attack_camp_count < MAX_SUITABLE_ATTACK_CAMP )
			{
				err_when( firmCamp->nation_recno != nation_recno );

				attack_camp_array[attack_camp_count].firm_recno   = firmCamp->firm_recno;
				attack_camp_array[attack_camp_count].combat_level = firmCamp->total_combat_level();

				err_when( attack_camp_array[attack_camp_count].combat_level < 0 );

				attack_camp_count++;
			}
		}
	}

	//---- locate for camps that are extra for protecting towns (there are basic ones doing the protection job only) ----//

	int   totalCombatLevel, protectionNeeded;
	Town* townPtr;
	Firm* firmPtr;

	if( !useAllCamp )         // in defense mode, every camp has been already counted
	{
		for( i=0 ; i<ai_town_count ; i++ )
		{
			townPtr = town_array[ ai_town_array[i] ];

			if( townPtr->region_id != targetRegionId )
				continue;

			err_when( townPtr->nation_recno != nation_recno );

			//----- calculate the protection needed for this town ----//

			protectionNeeded = townPtr->protection_needed();

			townCampCount =0;
			totalCombatLevel=0;

			for( j=townPtr->linked_firm_count-1 ; j>=0 ; j-- )
			{
				firmPtr = firm_array[ townPtr->linked_firm_array[j] ];

				if( firmPtr->nation_recno != nation_recno )
					continue;

				if( firmPtr->firm_recno == kingFirmRecno )
					continue;

				//----- if this is a camp, add combat level points -----//

				if( firmPtr->firm_id == FIRM_CAMP )
				{
					if( !firmPtr->overseer_recno && !firmPtr->worker_count )
						continue;

					firmCamp = (FirmCamp*) firmPtr;

					if( firmCamp->patrol_unit_count > 0 )     // if there are units patrolling out
						continue;

					if( firmCamp->ai_capture_town_recno )     // the base is trying to capture an independent town
						continue;

					if( firmCamp->is_attack_camp )
						continue;

					totalCombatLevel += firmCamp->total_combat_level();

					if( townCampCount < MAX_SUITABLE_TOWN_CAMP )
					{
						err_when( firmCamp->nation_recno != nation_recno );

						townCampArray[townCampCount].firm_recno   = firmCamp->firm_recno;
						townCampArray[townCampCount].combat_level = firmCamp->total_combat_level();

						err_when( townCampArray[townCampCount].combat_level < 0 );

						townCampCount++;
					}
				}

				//--- if this is a civilian firm, add needed protection points ---//

				else
				{
					if( firmPtr->firm_id == FIRM_MARKET )
						protectionNeeded += ((FirmMarket*)firmPtr)->stock_value_index();
					else
						protectionNeeded += (int) firmPtr->productivity;
				}
			}

			//--- see if the current combat level is larger than the protection needed ---//

			if( totalCombatLevel > protectionNeeded )
			{
				//--- see if the protection is still enough if we put one of the camps into the upcoming battle ---//

				for( int j=0 ; j<townCampCount ; j++ )
				{
					if( totalCombatLevel - townCampArray[j].combat_level > protectionNeeded )
					{
						//--- if so, add this camp to the suitable camp list ---//

						if( attack_camp_count < MAX_SUITABLE_ATTACK_CAMP )
						{
							//--- this camp can be linked to a town previously processed already (in this case, two towns linked to the same camp) ---//

							int k;
							for( k=0 ; k<attack_camp_count ; k++ )
							{
								if( attack_camp_array[k].firm_recno == townCampArray[j].firm_recno )
									break;
							}

							//---- if this camp hasn't been added yet ----//

							if( k==attack_camp_count )
							{
								err_when( firm_array[townCampArray[j].firm_recno]->nation_recno != nation_recno );

								attack_camp_array[attack_camp_count] = townCampArray[j];
								attack_camp_count++;

								totalCombatLevel -= townCampArray[j].combat_level;    // reduce it from the total combat level as its combat level has just been used, and is no longer available
							}
						}
					}
				}
			}
		}
	}

	//---- now we get all suitable camps in the list, it's time to attack ---//

	//----- think about which ones in the list should be used -----//

	//--- first calculate the total combat level of these camps ---//

	totalCombatLevel = 0;

	for( i=0 ; i<attack_camp_count ; i++ )
		totalCombatLevel += attack_camp_array[i].combat_level;

	//--- see if we are not strong enough to attack yet -----//

	if( totalCombatLevel < minTargetCombatLevel )		// if we are not strong enough to attack yet
	{
		attack_camp_count=0;
		return 0;
	}

	//----- build an array of the distance data first -----//

	for( i=0 ; i<attack_camp_count ; i++ )
	{
		firmPtr = firm_array[ attack_camp_array[i].firm_recno ];

		err_when( firmPtr->nation_recno != nation_recno );

		attack_camp_array[i].distance = m.points_distance( firmPtr->center_x, firmPtr->center_y,
												targetXLoc, targetYLoc );

		err_when( attack_camp_array[i].distance < 0 );
	}

	//---- now sort the camps based on their distances & combat levels ----//

	qsort( &attack_camp_array, attack_camp_count, sizeof(attack_camp_array[0]), sort_attack_camp_function );

	//----- now take out the lowest rating ones -----//

	for( i=attack_camp_count-1 ; i>=0 ; i-- )
	{
		if( totalCombatLevel - attack_camp_array[i].combat_level > maxTargetCombatLevel )
		{
			totalCombatLevel -= attack_camp_array[i].combat_level;
			attack_camp_count--;
		}
	}

	err_when( attack_camp_count < 0 );

	//------- synchronize the attack date for different camps ----//

	ai_attack_target_sync();

	ai_attack_target_execute(!justMoveToFlag);

	return totalCombatLevel;
}
//---------- End of function Nation::ai_attack_target --------//


//--------- Begin of function Nation::ai_attack_order_nearby_mobile --------//
//
// Order nearby mobile units who are on their way to home camps to
// join this attack mission.
//
// <int> targetXLoc, targetYLoc - location of the target
// <int> targetCombatLevel      - the combat level of the target, will
//                                only attack the target if the attacker's
//                                force is larger than it.
//
// return: <int> the remaining target combat level of the target
//					  after ordering the mobile units to deal with some of them.
//
int Nation::ai_attack_order_nearby_mobile(int targetXLoc, int targetYLoc, int targetCombatLevel)
{
	int		 scanRange = 15+pref_military_development/20;		// 15 to 20
	int		 xOffset, yOffset;
	int		 xLoc, yLoc;
	int		 targetRegionId = world.get_region_id(targetXLoc, targetYLoc);
	Location* locPtr;

	for( int i=2 ; i<scanRange*scanRange ; i++ )
	{
		m.cal_move_around_a_point(i, scanRange, scanRange, xOffset, yOffset);

		xLoc = targetXLoc + xOffset;
		yLoc = targetYLoc + yOffset;

		xLoc = max(0, xLoc);
		xLoc = min(MAX_WORLD_X_LOC-1, xLoc);

		yLoc = max(0, yLoc);
		yLoc = min(MAX_WORLD_Y_LOC-1, yLoc);

		locPtr = world.get_loc(xLoc, yLoc);

		if( locPtr->region_id != targetRegionId )
			continue;

		if( !locPtr->has_unit(UNIT_LAND) )
			continue;

		//----- if there is a unit on the location ------//

		int unitRecno = locPtr->unit_recno(UNIT_LAND);

		if( unit_array.is_deleted(unitRecno) )		// the unit is dying
			continue;

		Unit* unitPtr = unit_array[unitRecno];

		//--- if if this is our own military unit ----//

		if( unitPtr->nation_recno != nation_recno ||
			 unitPtr->skill.skill_id != SKILL_LEADING )
		{
			continue;
		}

		//--------- if this unit is injured ----------//

		if( unitPtr->hit_points <
			 unitPtr->max_hit_points * (150-pref_military_courage/2) / 200 )
		{
			continue;
		}

		//---- only if this is not assigned to an action ---//

		if( unitPtr->ai_action_id )
			continue;

		//---- if this unit is stop or assigning to a firm ----//

		if( unitPtr->action_mode2 == ACTION_STOP ||
			 unitPtr->action_mode2 == ACTION_ASSIGN_TO_FIRM )
		{
			//-------- set should_attack on the target to 1 --------//

			enable_should_attack_on_target(targetXLoc, targetYLoc);

			//---------- attack now -----------//

			unitPtr->attack_unit(targetXLoc, targetYLoc);

			targetCombatLevel -= (int) unitPtr->hit_points;		// reduce the target combat level

			if( targetCombatLevel <= 0 )
				break;
		}
	}

	return targetCombatLevel;
}
//--------- End of function Nation::ai_attack_order_nearby_mobile --------//
//

//--------- Begin of function Nation::ai_attack_target_sync --------//
//
// Synchronize the timing of attacking a target. Camps that are further
// away from the target will move first while camps that are closer
// to the target will move later.
//
void Nation::ai_attack_target_sync()
{
	//---- find the distance of the camp that is farest to the target ----//

	int maxDistance=0;

	int i;
	for( i=0 ; i<attack_camp_count ; i++ )
	{
		err_when( attack_camp_array[i].distance < 0 );

		if( attack_camp_array[i].distance > maxDistance )
			maxDistance = attack_camp_array[i].distance;
	}

	int maxTravelDays = sprite_res[ unit_res[UNIT_NORMAN]->sprite_id ]->travel_days(maxDistance);

	//------ set the date which the troop should start moving -----//

	int travelDays;

	for( i=0 ; i<attack_camp_count ; i++ )
	{
		travelDays = maxTravelDays * attack_camp_array[i].distance / maxDistance;

		attack_camp_array[i].patrol_date = info.game_date + (maxTravelDays-travelDays);
	}

	//----- set the is_attack_camp flag of the camps ------//

	for( i=0 ; i<attack_camp_count ; i++ )
	{
		Firm* firmPtr = firm_array[ attack_camp_array[i].firm_recno ];

		err_when( firmPtr->firm_id != FIRM_CAMP );
		err_when( firmPtr->nation_recno != nation_recno );

		((FirmCamp*)firmPtr)->is_attack_camp = 1;
	}
}
//---------- End of function Nation::ai_attack_target_sync --------//


//--------- Begin of function Nation::ai_attack_target_execute --------//
//
// Synchronize the timing of attacking a target. Camps that are further
// away from the target will move first while camps that are closer
// to the target will move later.
//
// <int> directAttack - whether directly attack the target or
//								just move close to the target.
//
void Nation::ai_attack_target_execute(int directAttack)
{
	FirmCamp* firmCamp;
	int		 firmRecno;

	err_when( ai_attack_target_x_loc < 0 || ai_attack_target_x_loc >= MAX_WORLD_X_LOC );
	err_when( ai_attack_target_y_loc < 0 || ai_attack_target_y_loc >= MAX_WORLD_Y_LOC );

	//---- if the target no longer exist -----//

	if( ai_attack_target_nation_recno != get_target_nation_recno(ai_attack_target_x_loc, ai_attack_target_y_loc) )
	{
		reset_ai_attack_target();
	}

	//----------------------------------------//

	for( int i=attack_camp_count-1 ; i>=0 ; i-- )
	{
		//----- if it's still not the date to move to attack ----//

		if( info.game_date < attack_camp_array[i].patrol_date )
			continue;

		//-------------------------------------------------------//

		firmRecno = attack_camp_array[i].firm_recno;

		firmCamp = (FirmCamp*) firm_array[firmRecno];

		if( firmCamp->overseer_recno || firmCamp->worker_count )
		{
			//--- if this is the lead attack camp, don't mobilize the overseer ---//

			if( lead_attack_camp_recno == firmRecno )
				firmCamp->patrol_all_soldier(); 	// don't mobilize the overseer
			else
				firmCamp->patrol();    // mobilize the overseer and the soldiers

			//----------------------------------------//

			if( firmCamp->patrol_unit_count > 0 )     // there could be chances that there are no some for mobilizing the units
			{
				//------- declare war with the target nation -------//

				if( ai_attack_target_nation_recno )
					talk_res.ai_send_talk_msg(ai_attack_target_nation_recno, nation_recno, TALK_DECLARE_WAR);

				//--- in defense mode, just move close to the target, the unit will start attacking themselves as their relationship is hostile already ---//

				if( !directAttack )
				{
					unit_array.move_to(ai_attack_target_x_loc, ai_attack_target_y_loc, 0, firmCamp->patrol_unit_array,
											 firmCamp->patrol_unit_count, COMMAND_AI);
				}
				else
				{
					//-------- set should_attack on the target to 1 --------//

					enable_should_attack_on_target(ai_attack_target_x_loc, ai_attack_target_y_loc);

					//---------- attack now -----------//

					// ##### patch begin Gilbert 5/8 ######//
					unit_array.attack(ai_attack_target_x_loc, ai_attack_target_y_loc, 0, firmCamp->patrol_unit_array,
											firmCamp->patrol_unit_count, COMMAND_AI, 0);
					// ##### patch end Gilbert 5/8 ######//
				}
			}
		}

		//--------- reset FirmCamp::is_attack_camp ---------//

		firmCamp->is_attack_camp = 0;

		//------- remove this from attack_camp_array -------//

		m.del_array_rec(attack_camp_array, attack_camp_count, sizeof(AttackCamp), i+1 );
		attack_camp_count--;
	}
}
//---------- End of function Nation::ai_attack_target_execute --------//


//--------- Begin of function Nation::reset_ai_attack_target --------//
//
void Nation::reset_ai_attack_target()
{
	//------ reset all is_attack_camp -------//

	for( int i=0 ; i<attack_camp_count ; i++ )
	{
		Firm* firmPtr = firm_array[ attack_camp_array[i].firm_recno ];

		err_when( firmPtr->firm_id != FIRM_CAMP ||
					 firmPtr->nation_recno != nation_recno );

		((FirmCamp*)firmPtr)->is_attack_camp = 0;
	}

	//--------------------------------------//

	attack_camp_count = 0;
}
//---------- End of function Nation::reset_ai_attack_target --------//


//--------- Begin of function Nation::enable_should_attack_on_target --------//
//
void Nation::enable_should_attack_on_target(int targetXLoc, int targetYLoc)
{
	//------ set should attack to 1 --------//

	int targetNationRecno = 0;

	Location* locPtr = world.get_loc(targetXLoc, targetYLoc);

	if( locPtr->has_unit(UNIT_LAND) )
		targetNationRecno = unit_array[ locPtr->unit_recno(UNIT_LAND) ]->nation_recno;

	else if( locPtr->is_firm() )
		targetNationRecno = firm_array[locPtr->firm_recno()]->nation_recno;

	else if( locPtr->is_town() )
		targetNationRecno = town_array[locPtr->town_recno()]->nation_recno;

	if( targetNationRecno )
	{
		set_relation_should_attack(targetNationRecno, 1, COMMAND_AI);
	}
}
//--------- End of function Nation::enable_should_attack_on_target --------//


//--------- Begin of static function get_target_nation_recno --------//
//
// Return the nation recno of the target.
//
static int get_target_nation_recno(int targetXLoc, int targetYLoc)
{
   Location* locPtr = world.get_loc(targetXLoc, targetYLoc);

   if( locPtr->is_firm() )
   {
		return firm_array[locPtr->firm_recno()]->nation_recno;
   }
   else if( locPtr->is_town() )
   {
		return town_array[locPtr->town_recno()]->nation_recno;
	}
   else if( locPtr->has_unit(UNIT_LAND) )
   {
      return unit_array[locPtr->unit_recno(UNIT_LAND)]->nation_recno;
   }

   return 0;
}
//---------- End of static function get_target_nation_recno --------//


//------ Begin of function sort_attack_camp_function ------//
//
static int sort_attack_camp_function( const void *a, const void *b )
{
	int ratingA = ((AttackCamp*)a)->combat_level - ((AttackCamp*)a)->distance;
	int ratingB = ((AttackCamp*)b)->combat_level - ((AttackCamp*)b)->distance;

	return ratingB - ratingA;
}
//------- End of function sort_attack_camp_function ------//


//--------- Begin of function Nation::think_secret_attack --------//
//
// Think about secret assault plans.
//
int Nation::think_secret_attack()
{
	//--- never secret attack if its peacefulness >= 80 ---//

	if( pref_peacefulness >= 80 )
		return 0;

	//--- don't try to get new enemies if we already have many ---//

	int totalEnemyMilitary = total_enemy_military();

	if( totalEnemyMilitary > 20+pref_military_courage-pref_peacefulness )
		return 0;

	//---------------------------------------------//

	int     curRating=0, bestRating=0, bestNationRecno=0;
	int     ourMilitary = military_rank_rating();
	int     relationStatus, tradeRating;
	Nation* nationPtr;
	NationRelation* nationRelation;

	for( int i=1 ; i<=nation_array.size() ; i++ )
	{
		if( nation_array.is_deleted(i) || nation_recno == i )
			continue;

		nationPtr = nation_array[i];

		nationRelation = get_relation(i);
		relationStatus = nationRelation->status;

		//---- if the secret attack flag is not enabled yet ----//

		if( !nationRelation->ai_secret_attack )
		{
			//---- if we have a friendly treaty with this nation ----//

			if( relationStatus == NATION_FRIENDLY )
			{
				if( totalEnemyMilitary > 0 )     // do not attack if we still have enemies
					continue;
			}

			//-------- never attacks an ally ---------//

			else if( relationStatus == NATION_ALLIANCE )
			{
				continue;
			}

			//---- don't attack if we have a big trade volume with the nation ---//

			tradeRating = trade_rating(i)/2 +      		// existing trade
							  ai_trade_with_rating(i)/2;		// possible trade

			if( tradeRating > (50-pref_trading_tendency/2) )	// 0 to 50, 0 if trade tendency is 100, it is 0
			{
				continue;
			}
		}

		//--------- calculate the rating ----------//

		curRating = (ourMilitary - nationPtr->military_rank_rating()) * 2
						 + (overall_rank_rating() - 50) 		// if <50 negative, if >50 positive
						 - tradeRating*2
						 - get_relation(i)->ai_relation_level/2
						 - pref_peacefulness/2;

		//------- if aggressiveness config is medium or high ----// 

		if( !nationPtr->is_ai() )		// more aggressive towards human players
		{
			switch( config.ai_aggressiveness )
			{
				case OPTION_MODERATE:
					curRating += 100;
					break;

				case OPTION_HIGH:
					curRating += 300;
					break;

				case OPTION_VERY_HIGH:
					curRating += 500;
					break;
			}
		}

		//----- if the secret attack is already on -----//

		if( nationRelation->ai_secret_attack )
		{
			//--- cancel secret attack if the situation has changed ---//

			if( curRating < 0 )
			{
				nationRelation->ai_secret_attack = 0;
				continue;
			}
		}

		//--------- compare ratings -----------//

		if( curRating > bestRating )
      {
         bestRating = curRating;
         bestNationRecno = i;
      }
   }

   //-------------------------------//

   if( bestNationRecno )
   {
		get_relation(bestNationRecno)->ai_secret_attack = 1;
		return 1;
   }

   return 0;
}
//---------- End of function Nation::think_secret_attack --------//