implemented trading via buy button in yl_speak_up.do_trade_direct (plus showing how many times traded)

trade_simple.lua

@@ -42,6 +42,16 @@ yl_speak_up.input_do_trade_simple = function(player, formname, fields)
 	end
 
 	if(fields.buy_directly) then
+		local error_msg = yl_speak_up.do_trade_direct(player)
+
+		if(error_msg ~= "") then
+			yl_speak_up.show_fs(player, "msg", {
+				input_to = "yl_speak_up:do_trade_simple",
+				formspec = "size[6,2]"..
+					"label[0.2,-0.2;"..error_msg.."]"..
+					"button[2,1.5;1,0.9;back_from_error_msg;Back]"})
+			return
+		end
 		yl_speak_up.show_fs(player, "trade_simple", yl_speak_up.speak_to[pname].trade_id)
 		return
 	end
@@ -516,6 +526,65 @@ yl_speak_up.do_trade_simple = function(player, count)
 end
 
 
+-- try to do the trade directly - without moving items in the buy/sell inventory slot
+-- returns error_msg or "" when successful
+yl_speak_up.do_trade_direct = function(player)
+	if(not(player)) then
+		return "Player, where are you?"
+	end
+	local pname = player:get_player_name()
+	-- which trade are we talking about?
+	local trade = yl_speak_up.trade[pname]
+	-- do we have all the necessary data?
+	if(not(trade) or trade.trade_type ~= "trade_simple") then
+		return "No trade found!"
+	end
+	-- the players' inventory
+	local player_inv = player:get_inventory()
+	-- the NPCs' inventory
+	local npc_inv = minetest.get_inventory({type="detached", name="yl_speak_up_npc_"..tostring(trade.n_id)})
+	-- has the NPC the item he wants to sell?
+	if(    not(npc_inv:contains_item("npc_main", trade.npc_gives))) then
+		return "Sorry. This item is sold out!"
+	-- has the NPC room for the payment?
+	elseif(not(npc_inv:room_for_item("npc_main", trade.player_gives))) then
+		return "Sorry. No room to store your payment!\n"..
+			"Please try again later."
+	-- can the player pay the price?
+	elseif(not(player_inv:contains_item("main", trade.player_gives))) then
+		return "You can't pay the price!"
+	-- has the player room for the sold item?
+	elseif(not(player_inv:room_for_item("main", trade.npc_gives))) then
+		return "You don't have enough free inventory space.\n"..
+			"Trade aborted."
+	end
+	local payment = player_inv:remove_item("main", trade.player_gives)
+	local sold    = npc_inv:remove_item("npc_main", trade.npc_gives)
+	-- used items cannot be sold as there is no fair way to indicate how
+	-- much they are used
+	if(payment:get_wear() > 0 or sold:get_wear() > 0) then
+		-- revert the trade
+		player_inv:add_item("main", payment)
+		npc_inv:add_item("npc_main", sold)
+		return "At least one of the items that shall be traded\n"..
+			"is dammaged. Trade aborted."
+	end
+	player_inv:add_item("main", sold)
+	npc_inv:add_item("npc_main", payment)
+	-- save the inventory of the npc so that the payment does not get lost
+	yl_speak_up.save_npc_inventory( trade.n_id )
+	-- store for statistics how many times the player has executed this trade
+	-- (this is also necessary to switch to the right target dialog when
+	--  dealing with dialog options trades)
+	yl_speak_up.trade[pname].trade_done = yl_speak_up.trade[pname].trade_done + 1
+	-- log the trade
+	yl_speak_up.log_change(pname, trade.n_id,
+		"bought "..tostring(trade.npc_gives)..
+		" for "..tostring(trade.player_gives))
+	return ""
+end
+
+
 -- simple trade: one item(stack) for another
 -- handles configuration of new trades and showing the formspec for trades;
 -- checks if payment and buying is possible
@@ -688,6 +757,11 @@ yl_speak_up.get_fs_trade_simple = function(player, trade_id)
 				"free inventory space to store your purchase."
 	end
 
+	local trades_done = "Not yet traded."
+	if(yl_speak_up.trade[pname].trade_done > 0) then
+		trades_done = "Traded: "..tostring(yl_speak_up.trade[pname].trade_done).." time(s)"
+	end
+
 	return formspec..
 		"label[2.5,0.0;Trading with "..minetest.formspec_escape(trade.npc_name).."]"..
 		"label[1.5,0.7;You pay:]"..
@@ -701,7 +775,8 @@ yl_speak_up.get_fs_trade_simple = function(player, trade_id)
 		"list[detached:yl_speak_up_player_"..pname..";pay;2,2.0;1,1;]" ..
 		-- show the buy slot from the same inventory
 		"list[detached:yl_speak_up_player_"..pname..";buy;5,2.0;1,1;]" ..
-		"label[1.5,3.0;"..trade_possible_msg.."]"
+		"label[1.5,3.0;"..trade_possible_msg.."]"..
+		"label[6.0,1.5;"..trades_done.."]"
 end