Refactor the Bard/Dancer Soul Link temporary skill granting code

The code no longer relies on invalid assumptions about the mapping between skill IDs and indices

Fixes #2670

Signed-off-by: Haru <haru@dotalux.com>

3 files changed, 58 insertions, 24 deletions

diff --git a/src/map/pc.c b/src/map/pc.c
index a8ed4430e..599317dee 100644
--- a/src/map/pc.c
+++ b/src/map/pc.c
@@ -1627,31 +1627,32 @@ static int pc_calc_skilltree(struct map_session_data *sd)
 			sd->status.skill[i].flag = SKILL_FLAG_PERMANENT;
 		}
 
-		if( sd->sc.count && sd->sc.data[SC_SOULLINK] && sd->sc.data[SC_SOULLINK]->val2 == SL_BARDDANCER && skill->dbs->db[i].nameid >= DC_HUMMING && skill->dbs->db[i].nameid <= DC_SERVICEFORYOU )
-		{ //Enable Bard/Dancer spirit linked skills.
-			if (sd->status.sex) {
-				// Link dancer skills to bard.
-				if (i < 8) {
-					Assert_report(i >= 8);
-					continue;
-				}
-				if (sd->status.skill[i-8].lv < 10)
-					continue;
-				sd->status.skill[i].id = skill->dbs->db[i].nameid;
-				sd->status.skill[i].lv = sd->status.skill[i-8].lv; // Set the level to the same as the linking skill
-				sd->status.skill[i].flag = SKILL_FLAG_TEMPORARY; // Tag it as a non-savable, non-uppable, bonus skill
-			} else {
-				// Link bard skills to dancer.
-				if (i < 8) {
-					Assert_report(i >= 8);
-					continue;
-				}
-				if (sd->status.skill[i].lv < 10)
-					continue;
-				sd->status.skill[i-8].id = skill->dbs->db[i-8].nameid;
-				sd->status.skill[i-8].lv = sd->status.skill[i].lv; // Set the level to the same as the linking skill
-				sd->status.skill[i-8].flag = SKILL_FLAG_TEMPORARY; // Tag it as a non-savable, non-uppable, bonus skill
+		if (sd->sc.count && sd->sc.data[SC_SOULLINK] && sd->sc.data[SC_SOULLINK]->val2 == SL_BARDDANCER
+		 && ((skill->dbs->db[i].nameid >= BA_WHISTLE && skill->dbs->db[i].nameid <= BA_APPLEIDUN)
+		  || (skill->dbs->db[i].nameid >= DC_HUMMING && skill->dbs->db[i].nameid <= DC_SERVICEFORYOU))
+		) {
+			//Enable Bard/Dancer spirit linked skills.
+			int linked_nameid = skill->get_linked_song_dance_id(skill->dbs->db[i].nameid);
+			if (linked_nameid == 0) {
+				Assert_report("Linked bard/dance skill not found");
+				continue;
 			}
+			int copy_from_index;
+			int copy_to_index;
+			if (sd->status.sex == SEX_MALE && skill->dbs->db[i].nameid >= BA_WHISTLE && skill->dbs->db[i].nameid <= BA_APPLEIDUN) {
+				copy_from_index = i;
+				copy_to_index = skill->get_index(linked_nameid);
+			} else {
+				copy_from_index = skill->get_index(linked_nameid);
+				copy_to_index = i;
+			}
+			if (copy_from_index < copy_to_index)
+				continue; // Copy only after the source skill has been filled into the tree
+			if (sd->status.skill[copy_from_index].lv < 10)
+				continue; // Copy only if the linked skill has been mastered
+			sd->status.skill[copy_to_index].id = skill->dbs->db[copy_to_index].nameid;
+			sd->status.skill[copy_to_index].lv = sd->status.skill[copy_from_index].lv; // Set the level to the same as the linking skill
+			sd->status.skill[copy_to_index].flag = SKILL_FLAG_TEMPORARY; // Tag it as a non-savable, non-uppable, bonus skill
 		}
 	}
 
diff --git a/src/map/skill.c b/src/map/skill.c
index 0fcd5fd0c..2fae7e7f9 100644
--- a/src/map/skill.c
+++ b/src/map/skill.c
@@ -10938,6 +10938,37 @@ static int skill_count_wos(struct block_list *bl, va_list ap)
 	return 0;
 }
 
+/**
+ * Returns the linked song/dance skill ID, if any (for the Bard/Dancer Soul Link).
+ *
+ * @param skill_id The skill ID to look up
+ *
+ * @return The linked song or dance's skill ID if any
+ * @retval 0 if the given skill_id doesn't have a linked skill ID
+ */
+static int skill_get_linked_song_dance_id(int skill_id)
+{
+	switch (skill_id) {
+		case BA_WHISTLE:
+			return DC_HUMMING;
+		case BA_ASSASSINCROSS:
+			return DC_DONTFORGETME;
+		case BA_POEMBRAGI:
+			return DC_FORTUNEKISS;
+		case BA_APPLEIDUN:
+			return DC_SERVICEFORYOU;
+		case DC_HUMMING:
+			return BA_WHISTLE;
+		case DC_DONTFORGETME:
+			return BA_ASSASSINCROSS;
+		case DC_FORTUNEKISS:
+			return BA_POEMBRAGI;
+		case DC_SERVICEFORYOU:
+			return BA_APPLEIDUN;
+	}
+	return 0;
+}
+
 /*==========================================
  *
  *------------------------------------------*/
@@ -21812,4 +21843,5 @@ void skill_defaults(void)
 	skill->splash_target = skill_splash_target;
 	skill->check_npc_chaospanic = skill_check_npc_chaospanic;
 	skill->count_wos = skill_count_wos;
+	skill->get_linked_song_dance_id = skill_get_linked_song_dance_id;
 }
diff --git a/src/map/skill.h b/src/map/skill.h
index 65195dc75..4dbbaf147 100644
--- a/src/map/skill.h
+++ b/src/map/skill.h
@@ -2200,6 +2200,7 @@ struct skill_interface {
 	int (*splash_target) (struct block_list* bl);
 	int (*check_npc_chaospanic) (struct block_list *bl, va_list args);
 	int (*count_wos) (struct block_list *bl, va_list ap);
+	int (*get_linked_song_dance_id) (int skill_id);
 };
 
 #ifdef HERCULES_CORE