Make slave mobs react to master's chase target

This fixes slaves not chasing after master's chase target,
when master was immobilized by an Ankle Snare for example midway.

5 files changed, 58 insertions, 22 deletions

diff --git a/conf/map/battle/monster.conf b/conf/map/battle/monster.conf
index 8f969dc48..389bdc5c7 100644
--- a/conf/map/battle/monster.conf
+++ b/conf/map/battle/monster.conf
@@ -269,3 +269,8 @@ boss_icewall_walk_block: 1
 // only have a range of 9. If you put a number higher than 0, their range will
 // be increased by that number.
 monster_eye_range_bonus: 0
+
+// Should slaves chase after what their master is chasing?
+// false: Don't chase after what master is chasing. (old behavior)
+//  true: Chase after what master is chasing. (official, default)
+slave_chase_masters_chasetarget: true
diff --git a/src/map/battle.c b/src/map/battle.c
index 37fc03bca..606c79357 100644
--- a/src/map/battle.c
+++ b/src/map/battle.c
@@ -4343,7 +4343,7 @@ static struct Damage battle_calc_misc_attack(struct block_list *src, struct bloc
 			}
 		break;
 	}
-	
+
 	battle->reflect_trap(target, src, &md, skill_id);
 
 	return md;
@@ -7321,6 +7321,7 @@ static const struct battle_data {
 	{ "mob_remove_delay",                   &battle_config.mob_remove_delay,                60000,  1000,   INT_MAX,        },
 	{ "mob_active_time",                    &battle_config.mob_active_time,                 0,      0,      INT_MAX,        },
 	{ "boss_active_time",                   &battle_config.boss_active_time,                0,      0,      INT_MAX,        },
+	{ "slave_chase_masters_chasetarget",    &battle_config.slave_chase_masters_chasetarget, 1,      0,      1,              },
 	{ "sg_miracle_skill_duration",          &battle_config.sg_miracle_skill_duration,       3600000, 0,     INT_MAX,        },
 	{ "hvan_explosion_intimate",            &battle_config.hvan_explosion_intimate,         45000,  0,      100000,         },
 	{ "quest_exp_rate",                     &battle_config.quest_exp_rate,                  100,    0,      INT_MAX,        },
diff --git a/src/map/battle.h b/src/map/battle.h
index 4400d37d1..3dee6f239 100644
--- a/src/map/battle.h
+++ b/src/map/battle.h
@@ -405,6 +405,7 @@ struct Battle_Config {
 	int mob_remove_delay; // Dynamic Mobs - delay before removing mobs from a map [Skotlex]
 	int mob_active_time; //Duration through which mobs execute their Hard AI after players leave their area of sight.
 	int boss_active_time;
+	int slave_chase_masters_chasetarget;
 
 	int show_hp_sp_drain, show_hp_sp_gain; //[Skotlex]
 	int show_katar_crit_bonus;
diff --git a/src/map/mob.c b/src/map/mob.c
index e04d6944e..c8226cd57 100644
--- a/src/map/mob.c
+++ b/src/map/mob.c
@@ -1297,6 +1297,27 @@ static int mob_warpchase_sub(struct block_list *bl, va_list ap)
 	}
 	return 0;
 }
+
+/**
+ * Checks if a monster is currently involved in battle,
+ * may it be due to aggression or being attacked.
+ * @param bl: monster's bl
+ * @return true if in battle, false otherwise
+ */
+static bool mob_is_in_battle_state(const struct mob_data *md)
+{
+	nullpo_retr(false, md);
+	switch (md->state.skillstate) {
+	case MSS_BERSERK:
+	case MSS_ANGRY:
+	case MSS_RUSH:
+	case MSS_FOLLOW:
+		return true;
+	default:
+		return false;
+	}
+}
+
 /*==========================================
  * Processing of slave monsters
  *------------------------------------------*/
@@ -1341,8 +1362,11 @@ static int mob_ai_sub_hard_slavemob(struct mob_data *md, int64 tick)
 		) {
 			short x = bl->x, y = bl->y;
 			mob_stop_attack(md);
-			if(map->search_freecell(&md->bl, bl->m, &x, &y, MOB_SLAVEDISTANCE, MOB_SLAVEDISTANCE, 1)
-				&& unit->walktoxy(&md->bl, x, y, 0))
+			const struct mob_data *m_md = BL_CCAST(BL_MOB, bl);
+			nullpo_retr(0, m_md);
+			if (map->search_freecell(&md->bl, bl->m, &x, &y, MOB_SLAVEDISTANCE, MOB_SLAVEDISTANCE, 1)
+			    && (battle_config.slave_chase_masters_chasetarget == 0 || !mob->is_in_battle_state(m_md))
+			    && unit->walktoxy(&md->bl, x, y, 0))
 				return 1;
 		}
 	} else if (bl->m != md->bl.m && map_flag_gvg(md->bl.m)) {
@@ -1353,26 +1377,29 @@ static int mob_ai_sub_hard_slavemob(struct mob_data *md, int64 tick)
 
 	//Avoid attempting to lock the master's target too often to avoid unnecessary overload. [Skotlex]
 	if (DIFF_TICK(md->last_linktime, tick) < MIN_MOBLINKTIME && !md->target_id) {
-		struct unit_data *ud = unit->bl2ud(bl);
+		struct unit_data  *ud = unit->bl2ud(bl);
+		struct mob_data *m_md = BL_CAST(BL_MOB, bl);
+		nullpo_retr(0, ud);
+		nullpo_retr(0, m_md);
 		md->last_linktime = tick;
-
-		if (ud) {
-			struct block_list *tbl=NULL;
-			if (ud->target && ud->state.attack_continue)
-				tbl=map->id2bl(ud->target);
-			else if (ud->skilltarget) {
-				tbl = map->id2bl(ud->skilltarget);
-				//Required check as skilltarget is not always an enemy. [Skotlex]
-				if (tbl && battle->check_target(&md->bl, tbl, BCT_ENEMY) <= 0)
-					tbl = NULL;
-			}
-			if (tbl && status->check_skilluse(&md->bl, tbl, 0, 0)) {
-				md->target_id=tbl->id;
-				md->min_chase=md->db->range3+distance_bl(&md->bl, tbl);
-				if(md->min_chase>MAX_MINCHASE)
-					md->min_chase=MAX_MINCHASE;
-				return 1;
-			}
+		struct block_list *tbl = NULL;
+
+		if (battle_config.slave_chase_masters_chasetarget == 1 && m_md->target_id != 0) { // possibly chasing something
+			tbl = map->id2bl(m_md->target_id);
+		} else if (ud->target != 0 && ud->state.attack_continue != 0) {
+			tbl = map->id2bl(ud->target);
+		} else if (ud->skilltarget != 0) {
+			tbl = map->id2bl(ud->skilltarget);
+			//Required check as skilltarget is not always an enemy. [Skotlex]
+			if (tbl != NULL && battle->check_target(&md->bl, tbl, BCT_ENEMY) <= 0)
+				tbl = NULL;
+		}
+		if (tbl != NULL && status->check_skilluse(&md->bl, tbl, 0, 0) != 0) {
+			md->target_id = tbl->id;
+			md->min_chase = md->db->range3 + distance_bl(&md->bl, tbl);
+			if (md->min_chase > MAX_MINCHASE)
+				md->min_chase = MAX_MINCHASE;
+			return 1;
 		}
 	}
 	return 0;
@@ -5805,6 +5832,7 @@ void mob_defaults(void)
 	mob->ai_sub_hard_bg_ally = mob_ai_sub_hard_bg_ally;
 	mob->ai_sub_hard_lootsearch = mob_ai_sub_hard_lootsearch;
 	mob->warpchase_sub = mob_warpchase_sub;
+	mob->is_in_battle_state = mob_is_in_battle_state;
 	mob->ai_sub_hard_slavemob = mob_ai_sub_hard_slavemob;
 	mob->unlocktarget = mob_unlocktarget;
 	mob->randomwalk = mob_randomwalk;
diff --git a/src/map/mob.h b/src/map/mob.h
index a48c4cc74..9b0f6ffe0 100644
--- a/src/map/mob.h
+++ b/src/map/mob.h
@@ -529,6 +529,7 @@ struct mob_interface {
 	int (*ai_sub_hard_bg_ally) (struct block_list *bl, va_list ap);
 	int (*ai_sub_hard_lootsearch) (struct block_list *bl, va_list ap);
 	int (*warpchase_sub) (struct block_list *bl, va_list ap);
+	bool (*is_in_battle_state) (const struct mob_data *md);
 	int (*ai_sub_hard_slavemob) (struct mob_data *md, int64 tick);
 	int (*unlocktarget) (struct mob_data *md, int64 tick);
 	int (*randomwalk) (struct mob_data *md, int64 tick);