added yl_speak_up.get_npc_users_of_variable and modified saving of npc data so that the necessary data is stored

functions.lua

@@ -152,6 +152,8 @@ yl_speak_up.save_dialog = function(n_id, dialog)
         return false
     end
     local p = save_path(n_id)
+    -- save some data (in particular usage of quest variables)
+    yl_speak_up.update_stored_npc_data(n_id, dialog)
     local content = minetest.write_json(dialog)
     return minetest.safe_file_write(p, content)
 end

quest_api.lua

@@ -49,6 +49,9 @@ yl_speak_up.load_quest_variables = function()
 		end
 	end
 	yl_speak_up.player_vars = data
+	if(not(yl_speak_up.player_vars.meta)) then
+		yl_speak_up.player_vars["meta"] = {}
+	end
 end
 -- do so when this file is parsed
 yl_speak_up.load_quest_variables()
@@ -237,3 +240,138 @@ yl_speak_up.strip_pname_from_varlist = function(var_list, pname)
 	end
 	return var_list_text
 end
+
+
+-- helper function for saving NPC data;
+-- this only works if *someone* is currently talking to that NPC
+yl_speak_up.get_pname_for_n_id = function(n_id)
+	for k, v in pairs(yl_speak_up.speak_to) do
+		if(v and v.n_id and v.n_id == n_id) then
+			return k
+		end
+	end
+end
+
+
+-- the dialog data of an NPC is saved - use this to save some statistical data
+-- plus store which variables are used by this NPC
+yl_speak_up.update_stored_npc_data = function(n_id, dialog)
+	-- in order to determine the position of the NPC, we need its object
+	local pname = yl_speak_up.get_pname_for_n_id(n_id)
+	local npc_pos = ""
+	if(pname) then
+		local obj = yl_speak_up.speak_to[pname].obj
+		if(obj and obj:get_pos()) then
+			npc_pos = minetest.pos_to_string(obj:get_pos())
+		end
+	end
+	-- gather statistical data about the NPC and find out which variables it uses
+	local anz_dialogs = 0
+	local anz_options = 0
+	local anz_preconditions = 0
+	local anz_actions = 0
+	local anz_effects = 0
+	local anz_trades  = 0
+	local variables_p = {}
+	local variables_e = {}
+	if(dialog and dialog.n_dialogs) then
+		for d_id, d in pairs(dialog.n_dialogs) do
+			anz_dialogs = anz_dialogs + 1
+			if(d and d.d_options) then
+				for o_id, o in pairs(d.d_options) do
+					anz_options = anz_options + 1
+					if(o and o.o_prerequisites) then
+						for p_id, p in pairs(o.o_prerequisites) do
+							anz_preconditions = anz_preconditions + 1
+							if(p and p.p_type and p.p_type == "state"
+							  and p.p_variable and p.p_variable ~= "") then
+								variables_p[ p.p_variable ] = true
+							end
+						end
+					end
+					if(o and o.actions) then
+						for a_id, a_data in pairs(o.actions) do
+							anz_actions = anz_actions + 1
+						end
+					end
+					if(o and o.o_results) then
+						for r_id, r in pairs(o.o_results) do
+							anz_effects = anz_effects + 1
+							if(r and r.r_type and r.r_type == "state"
+							  and r.r_variable and r.r_variable ~= "") then
+								variables_e[ r.r_variable ] = true
+							end
+						end
+					end
+				end
+			end
+		end
+	end
+	if(dialog and dialog.trades) then
+		for trade_id, t_data in pairs(dialog.trades) do
+			-- not a trade that is the action of a dialog option; only trade list trades count
+			if(not(t_data.d_id)) then
+				anz_trades = anz_trades + 1
+			end
+		end
+	end
+	-- add a special variable (if needed) for saving the NPC meta data
+	if(not(yl_speak_up.player_vars[ "$NPC_META_DATA$" ])) then
+		yl_speak_up.player_vars[ "$NPC_META_DATA$" ] = {}
+	end
+	yl_speak_up.player_vars[ "$NPC_META_DATA$" ][ n_id ] = {
+		n_id = n_id,
+		name = tostring(dialog.n_npc),
+		owner = tostring(yl_speak_up.npc_owner[ n_id ]),
+		pos = tostring(npc_pos),
+		anz_dialogs = anz_dialogs,
+		anz_options = anz_options,
+		anz_preconditions = anz_preconditions,
+		anz_actions = anz_actions,
+		anz_effects = anz_effects,
+		anz_trades = anz_trades,
+		last_modified = os.date(),
+	}
+
+	-- save in the variables' metadata which NPC uses it
+	-- (this is what we're mostly after - know which variable is used in which NPC)
+	for k, v in pairs(variables_p) do
+		-- if the variable does not exist: create it
+		if(not(yl_speak_up.player_vars[ k ])) then
+			yl_speak_up.player_vars[ k ] = {}
+		end
+		if(not(yl_speak_up.player_vars[ k ][ "$META$" ])) then
+			yl_speak_up.player_vars[ k ][ "$META$"] = { used_by_npc = {} }
+		end
+		yl_speak_up.player_vars[ k ][ "$META$"][ "used_by_npc" ][ n_id ] = true
+	end
+	for k, v in pairs(variables_e) do
+		-- if the variable does not exist: create it
+		if(not(yl_speak_up.player_vars[ k ])) then
+			yl_speak_up.player_vars[ k ] = {}
+		end
+		if(not(yl_speak_up.player_vars[ k ][ "$META$" ])) then
+			yl_speak_up.player_vars[ k ][ "$META$"] = { used_by_npc = {} }
+		end
+		yl_speak_up.player_vars[ k ][ "$META$"][ "used_by_npc" ][ n_id ] = true
+	end
+	-- force writing the data
+	yl_speak_up.save_quest_variables(true)
+end
+
+
+yl_speak_up.get_npc_users_of_variable = function(var_name)
+	-- no variable, or nothing stored? then it's not used by any NPC either
+	if(not(var_name)
+	  or not(yl_speak_up.player_vars[ var_name ])
+	  or not(yl_speak_up.player_vars[ var_name ][ "$META$"])
+	  or not(yl_speak_up.player_vars[ var_name ][ "$META$"][ "used_by_npc" ])) then
+		return {}
+	end
+	local npc_list = {}
+	for n_id, v in pairs(yl_speak_up.player_vars[ var_name ][ "$META$"][ "used_by_npc" ]) do
+		table.insert(npc_list, n_id)
+	end
+	table.sort(npc_list)
+	return npc_list
+end