added inventory to npc which is stored to disk

config.lua

@@ -6,6 +6,9 @@ yl_speak_up.talk_after_spawn = true
 
 yl_speak_up.path = "yl_speak_up_dialogs"
 
+-- What shall we call the folder all the inventories of the NPC will reside in?
+yl_speak_up.inventory_path = "yl_speak_up_inventories"
+
 -- Texts
 
 yl_speak_up.message_button_option_exit = "Farewell!"

functions.lua

@@ -1457,6 +1457,14 @@ local function get_fs_talkdialog(player, n_id, d_id)
 			"a conversation is started.]")
             end
 
+	    -- access the inventory of the NPC
+	    h = h + 1
+            table.insert(formspec, "button[0.5," .. h .. ";53.8,0.9;show_inventory;]")
+            table.insert(formspec, "tooltip[show_inventory;Access and manage the inventory of the NPC. "..
+			"This is used for adding trade items, getting collected payments and managing "..
+			"quest items.]")
+            table.insert(formspec, "label[0.7,"..(h+0.45)..";I am your owner. Show me your inventory!]")
+
 	    -- chat option: Mute/Unmute NPC
             h = h + 1
             local obj = yl_speak_up.speak_to[pname].obj
@@ -1717,10 +1725,26 @@ minetest.register_on_player_receive_fields( function(player, formname, fields)
 	elseif formname == "yl_speak_up:fashion" then
 		yl_speak_up.input_fashion(player, formname, fields)
 		return true
+	elseif formname == "yl_speak_up:inventory" then
+		yl_speak_up.input_inventory(player, formname, fields)
+		return true
 	end
 end)
 
 
+-- the player has closed the inventory formspec of the NPC - save it
+yl_speak_up.input_inventory = function(player, formname, fields)
+        local pname = player:get_player_name()
+	local d_id = yl_speak_up.speak_to[pname].d_id
+	local n_id = yl_speak_up.speak_to[pname].n_id
+	-- after closing the inventory formspec:
+	-- ..save the (very probably) modified inventory
+	yl_speak_up.save_npc_inventory(n_id)
+	-- ..and go back to the normal talk formspec
+	minetest.show_formspec(pname, "yl_speak_up:talk", get_fs_talkdialog(player, n_id, d_id))
+end
+
+
 yl_speak_up.input_optiondialog = function(player, formname, fields)
         if formname ~= "yl_speak_up:optiondialog" then
             return
@@ -2742,6 +2766,14 @@ yl_speak_up.input_talk = function(player, formname, fields)
 		return
 	end
 
+	-- the player wants to access the inventory of the NPC
+	if(edit_mode and fields.show_inventory) then
+		local dialog = yl_speak_up.speak_to[pname].dialog
+		-- the inventory is just an inventory with a back button; come back to this dialog here
+		minetest.show_formspec(pname, "yl_speak_up:inventory", yl_speak_up.get_fs_inventory(player, n_id, dialog.n_npc))
+		return
+	end
+
 	-- change skin, cape and wielded items
 	if(edit_mode and fields.edit_skin) then
 		local dialog = yl_speak_up.speak_to[pname].dialog
@@ -3147,6 +3179,9 @@ function yl_speak_up.after_activate(self, staticdata, def, dtime)
     end
 
     yl_speak_up.update_nametag(self)
+
+    -- create a detached inventory for the npc and load its inventory
+    yl_speak_up.load_npc_inventory("n_"..tostring(self.yl_speak_up.id))
 end
 
 function yl_speak_up.talk(self, clicker)

init.lua

@@ -17,12 +17,16 @@ yl_speak_up.speak_to = {}
 
 dofile(modpath .. "config.lua")
 dofile(modpath .. "privs.lua")
+-- inventory management, trading and handling of quest items:
+dofile(modpath .. "inventory.lua")
 dofile(modpath .. "functions.lua")
 dofile(modpath .. "tools.lua")
 dofile(modpath .. "mobs.lua")
 --dofile(modpath .. "debug.lua")
 
 minetest.mkdir(yl_speak_up.worldpath..yl_speak_up.path)
+minetest.mkdir(yl_speak_up.worldpath..yl_speak_up.inventory_path)
+
 yl_speak_up.mob_table = yl_speak_up.init_mob_table() or {}
 
-minetest.log("action","[MOD] yl_speak_up loaded")
+minetest.log("action","[MOD] yl_speak_up loaded")

inventory.lua

@@ -0,0 +1,126 @@
+-- inventory management, trading and handling of quest items for talking to NPCs
+
+-- cache the inventory of NPCs for easier access
+yl_speak_up.npc_inventory = {}
+
+-- where are they stored on the disk?
+yl_speak_up.get_inventory_save_path = function(n_id)
+    return yl_speak_up.worldpath .. yl_speak_up.inventory_path .. DIR_DELIM .. "inv_" .. n_id .. ".json"
+end
+
+
+-- access the inventory of the NPC (only possible for players with the right priv)
+yl_speak_up.get_fs_inventory = function(player, n_id, npc_name)
+	return "size[12,11]" ..
+		"label[2,-0.2;Inventory of "..minetest.formspec_escape(npc_name)..
+			" (ID: "..tostring(n_id).."):]"..
+		"list[detached:yl_npc_"..tostring(n_id)..";npc_main;0,0.3;12,6;]" ..
+		"list[current_player;main;2,6.85;8,1;]" ..
+		"list[current_player;main;2,8.08;8,3;8]" ..
+		"listring[detached:yl_npc_"..tostring(n_id)..";npc_main]" ..
+		"listring[current_player;main]" ..
+		"button[10.0,10.2;2,0.9;back_from_inventory;Back]"
+end
+
+
+-- save the inventory of the NPC with the id n_id
+yl_speak_up.save_npc_inventory = function( n_id )
+	-- only save something if we actually can
+	if(not(n_id) or not(yl_speak_up.npc_inventory[ n_id ])) then
+		return
+	end
+	-- convert the inventory data to something we can actually store
+	local inv = yl_speak_up.npc_inventory[ n_id ]
+	local inv_as_table = {}
+	for i=1, inv:get_size("npc_main") do
+		local stack = inv:get_stack("npc_main", i)
+		-- only save those slots that are not empty
+		if(not(stack:is_empty())) then
+			inv_as_table[ i ] = stack:to_table()
+		end
+	end
+	-- convert the table into json
+	local json = minetest.write_json( inv_as_table )
+	-- get a file name for storing the data
+	local file_name = yl_speak_up.get_inventory_save_path(n_id)
+	-- actually store it on disk
+	minetest.safe_file_write(file_name, json)
+end
+
+
+-- create and load the detached inventory in yl_speak_up.after_activate;
+-- direct access to this inventory is only possible for players with the right privs
+yl_speak_up.load_npc_inventory = function(n_id)
+	if(not(n_id)) then
+		return
+	end
+	-- the inventory is already loaded
+	if( yl_speak_up.npc_inventory[ n_id ]) then
+		return
+	end
+	-- create the detached inventory (it is empty for now)
+	local npc_inv = minetest.create_detached_inventory("yl_npc_"..tostring(n_id), {
+		allow_move = function(inv, from_list, from_index, to_list, to_index, count, player)
+			if(not(yl_speak_up.may_edit_npc(player, n_id))) then
+				return 0
+			end
+			return count
+		end,
+	        -- Called when a player wants to move items inside the inventory.
+	        -- Return value: number of items allowed to move.
+
+	        allow_put = function(inv, listname, index, stack, player)
+			if(not(yl_speak_up.may_edit_npc(player, n_id))) then
+				return 0
+			end
+			return stack:get_count()
+		end,
+	        -- Called when a player wants to put something into the inventory.
+	        -- Return value: number of items allowed to put.
+	        -- Return value -1: Allow and don't modify item count in inventory.
+
+	        allow_take = function(inv, listname, index, stack, player)
+			if(not(yl_speak_up.may_edit_npc(player, n_id))) then
+				return 0
+			end
+			return stack:get_count()
+		end
+	        -- Called when a player wants to take something out of the inventory.
+	        -- Return value: number of items allowed to take.
+	        -- Return value -1: Allow and don't modify item count in inventory.
+
+--	        on_move = function(inv, from_list, from_index, to_list, to_index, count, player) end,
+--	        on_put = function(inv, listname, index, stack, player) end,
+--	        on_take = function(inv, listname, index, stack, player) end,
+	        -- Called after the actual action has happened, according to what was
+	        -- allowed.
+	        -- No return value.
+	})
+	-- the NPC needs enough room for trade items, payment and questitems
+	npc_inv:set_size("npc_main", 6*12)
+
+	-- cache a pointer to this inventory for easier access
+	yl_speak_up.npc_inventory[ n_id ] = npc_inv
+
+	-- find out where the inventory of the NPC is stored
+	local file_name = yl_speak_up.get_inventory_save_path(n_id)
+
+	-- load the data from the file
+	local file, err = io.open(file_name, "r")
+	if err then
+		return
+	end
+	io.input(file)
+	local text = io.read()
+	local inv_as_table = minetest.parse_json(text)
+	io.close(file)
+
+	if(type(inv_as_table) ~= "table") then
+		return
+	end
+
+	-- restore the inventory
+	for i=1, npc_inv:get_size("npc_main") do
+		npc_inv:set_stack("npc_main", i, ItemStack( inv_as_table[ i ]))
+	end
+end