From ef602d98cb1e0cfdf654cfe2fb135ffc5d1fb109 Mon Sep 17 00:00:00 2001
From: Atemo <Atemo@users.noreply.github.com>
Date: Fri, 16 Dec 2022 21:22:31 +0100
Subject: [PATCH] Multiple dynamic npc (#7486)

* Vectorize npc_id_dynamic to support multiple dynamic npc with different ids

Co-authored-by: Lemongrass3110 <lemongrass@kstp.at>

Thanks to @dimasshotta and @eppc0330 !
---
 src/map/npc.cpp  | 20 ++++++++++++++------
 src/map/pc.hpp   |  2 +-
 src/map/unit.cpp | 21 +++++++++++++--------
 3 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/src/map/npc.cpp b/src/map/npc.cpp
index d2bfcfe816..4bc1bded2a 100644
--- a/src/map/npc.cpp
+++ b/src/map/npc.cpp
@@ -3528,7 +3528,7 @@ int npc_unload(struct npc_data* nd, bool single) {
 		map_session_data* owner = map_charid2sd( nd->dynamicnpc.owner_char_id );
 
 		if( owner != nullptr ){
-			owner->npc_id_dynamic = 0;
+			util::vector_erase_if_exists(owner->npc_id_dynamic, nd->bl.id);
 		}
 	}
 
@@ -4515,7 +4515,7 @@ const char* npc_parse_duplicate( char* w1, char* w2, char* w3, char* w4, const c
 
 	if( owner != nullptr ){
 		nd->dynamicnpc.owner_char_id = owner->status.char_id;
-		owner->npc_id_dynamic = nd->bl.id;
+		owner->npc_id_dynamic.push_back(nd->bl.id);
 	}
 
 	switch( type ) {
@@ -5796,7 +5796,7 @@ TIMER_FUNC(npc_dynamicnpc_removal_timer){
 			return 0;
 		}
 
-		sd->npc_id_dynamic = 0;
+		// npc id from sd->npc_id_dynamic is removed in npc_unload
 	}
 
 	// Delete the NPC
@@ -5808,9 +5808,17 @@ TIMER_FUNC(npc_dynamicnpc_removal_timer){
 }
 
 struct npc_data* npc_duplicate_npc_for_player( struct npc_data& nd, map_session_data& sd ){
-	if( sd.npc_id_dynamic != 0 ){
-		clif_msg_color( &sd, C_DYNAMICNPC_TWICE, color_table[COLOR_LIGHT_YELLOW] );
-		return nullptr;
+	// A duplicate of a duplicate is still a duplicate of the same NPC
+	int src_id = nd.src_id > 0 ? nd.src_id : nd.bl.id;
+
+	for (const auto &it : sd.npc_id_dynamic) {
+		struct npc_data* src_nd = map_id2nd( it );
+
+		// Check if the source NPC id of currently active duplicates already exists.
+		if( src_nd != nullptr && src_nd->src_id == src_id ){
+			clif_msg_color( &sd, C_DYNAMICNPC_TWICE, color_table[COLOR_LIGHT_YELLOW] );
+			return nullptr;
+		}
 	}
 
 	if( map_getmapflag( sd.bl.m, MF_NODYNAMICNPC ) ){
diff --git a/src/map/pc.hpp b/src/map/pc.hpp
index 801105c087..c62b5dc0ad 100644
--- a/src/map/pc.hpp
+++ b/src/map/pc.hpp
@@ -492,7 +492,7 @@ public:
 	unsigned char head_dir; //0: Look forward. 1: Look right, 2: Look left.
 	t_tick client_tick;
 	int npc_id,npc_shopid; //for script follow scriptoid;   ,npcid
-	int npc_id_dynamic;
+	std::vector<int> npc_id_dynamic;
 	std::vector<int> areanpc, npc_ontouch_;	///< Array of OnTouch and OnTouch_ NPC ID
 	int npc_item_flag; //Marks the npc_id with which you can use items during interactions with said npc (see script command enable_itemuse)
 	int npc_menu; // internal variable, used in npc menu handling
diff --git a/src/map/unit.cpp b/src/map/unit.cpp
index 873f55e196..cd7e57a8ab 100644
--- a/src/map/unit.cpp
+++ b/src/map/unit.cpp
@@ -3423,17 +3423,22 @@ int unit_free(struct block_list *bl, clr_type clrtype)
 				sd->npc_id = 0;
 			}
 
-			if( sd->npc_id_dynamic != 0 ){
-				struct npc_data* nd = map_id2nd( sd->npc_id_dynamic );
+			if( !sd->npc_id_dynamic.empty() ){
+				for (const auto &it : sd->npc_id_dynamic) {
+					struct npc_data* nd = map_id2nd( it );
 
-				if( nd != nullptr ){
-					// Delete the NPC
-					npc_unload( nd, true );
-					// Update NPC event database
-					npc_read_event_script();
+					if( nd != nullptr ){
+						// Erase the owner first to prevent loops from npc_unload
+						nd->dynamicnpc.owner_char_id = 0;
+
+						// Delete the NPC
+						npc_unload( nd, true );
+					}
 				}
+				// Update NPC event database
+				npc_read_event_script();
 
-				sd->npc_id_dynamic = 0;
+				sd->npc_id_dynamic.clear();
 			}
 
 			sd->combos.clear();