Trade: Working buy/sell trade mechanism.

Various cleanups and modularizations for supporting dedicated traders.
Data: Added more favorite items for phase 1.

dialogue.lua

@@ -34,7 +34,7 @@ function npc.dialogue.show_options_dialogue(self,
 	for i = 1, #responses do
 		local y = 0.8;
 		if i > 1 then
-			y = (0.7 * i)
+			y = (0.75 * i)
 		end
 		formspec = formspec.."button_exit[0.5,"
 			..(y - 0.5)..";6,0.5;opt"..tostring(i)..";"..responses[i].text.."]"

npc.lua

@@ -39,12 +39,14 @@ end
 
 -- Utility function to get item name from a string
 local function get_item_name(item_string)
-  return item_string.sub(item_string, 1, string.find(item_string, " "))
+  local i,j = string.find(item_string, " ")
+  return item_string.sub(item_string, 1, i-1)
 end
 
 -- Utility function to get item count from a string
 local function get_item_count(item_string)
-  return tonumber(item_string.sub(item_string, string.find(item_string, " ")))
+  local i,j = string.find(item_string, " ")
+  return tonumber(item_string.sub(item_string, i+1))
 end
 
 local function initialize_inventory()
@@ -98,6 +100,13 @@ function npc.add_item_to_inventory(self, item_name, count)
   end
 end
 
+-- Same add method but with itemstring for convenience
+function npc.add_item_to_inventory_itemstring(self, item_string)
+  local item_name = get_item_name(item_string)
+  local item_count = get_item_count(item_string)
+  npc.add_item_to_inventory(self, item_name, item_count)
+end
+
 -- Checks if an item is contained in the inventory. Returns
 -- the item string or nil if not found
 function npc.inventory_contains(self, item_name)

random_data.lua

@@ -276,7 +276,31 @@ npc.FAVORITE_ITEMS.female["phase1"] = {
    hint = "I could really do with an apple..."},
   {item = "farming:bread",
    response = "Thanks, you didn't have to, but thanks...",
-   hint = "Some fresh bread would be good!"}
+   hint = "Some fresh bread would be good!"},
+  {item = "farming:seed_cotton",        
+   response = "Thank you, I will plant this really soon",
+   hint = "I would like to have some cotton plants around"},
+  {item = "farming:seed_wheat",
+   response = "Thank you! These seeds will make a good wheat plant!",
+   hint = "I've been thinking I should get wheat seeds"},
+  {item = "flowers:rose",        
+   response = "Thanks...",
+   hint = "Red roses make a nice gift!"},
+  {item = "flowers:geranium",
+   response = "Oh, for me? Thank you!",
+   hint = "Blue geraniums are so beautiful"},
+  {item = "default:clay_lump",        
+   response = "Thanks! Now, what can I do with this...",
+   hint = "If I had some clay lump, I may do some pottery"},
+  {item = "mobs:meat_raw",
+   response = "This will be great for tonight! Thanks",
+   hint = "A good dinner always have meat"},
+  {item = "mobs:leather",        
+   response = "Thank you! I needed this leather!",
+   hint = "If only I could get some leather"},
+  {item = "default:sapling",
+   response = "Now I can plant that tree...",
+   hint = "I really would like an apple tree close by."}
 }
 npc.FAVORITE_ITEMS.female["phase2"] = {
   {item = "farming:cotton",        
@@ -320,12 +344,36 @@ npc.FAVORITE_ITEMS.female["phase6"] = {
 }
 -- Male
 npc.FAVORITE_ITEMS.male["phase1"] = {
-  {item = "default:apple",        
+   {item = "default:apple",        
    response = "Hey, I really wanted an apple, thank you!",
    hint = "I could really do with an apple..."},
   {item = "farming:bread",
    response = "Thanks, you didn't have to, but thanks...",
-   hint = "Some fresh bread would be good!"}
+   hint = "Some fresh bread would be good!"},
+  {item = "farming:seed_cotton",        
+   response = "Thank you, I will plant this really soon",
+   hint = "I would like to have some cotton plants around"},
+  {item = "farming:seed_wheat",
+   response = "Thank you! These seeds will make a good wheat plant!",
+   hint = "I've been thinking I should get wheat seeds"},
+  {item = "default:wood",        
+   response = "Thanks, I needed this.",
+   hint = "Some wood without having to cut a tree would be good."},
+  {item = "default:tree",
+   response = "Excellent to get that furnace going!",
+   hint = "I need logs, do you have some?"},
+  {item = "default:clay_lump",        
+   response = "Thanks! Now, what can I do with this...",
+   hint = "I wish I had some clay"},
+  {item = "mobs:meat_raw",
+   response = "This makes a great meal. Thank you",
+   hint = "Meat is always great"},
+  {item = "mobs:leather",        
+   response = "Time to tan some leathers!",
+   hint = "I have been needing leather these days"},
+  {item = "default:sapling",
+   response = "Thanks, I will plant this right now",
+   hint = "I really would like an apple tree close by."}
 }
 npc.FAVORITE_ITEMS.male["phase2"] = {
   {item = "farming:cotton",        

trade/trade.lua

@@ -11,8 +11,8 @@ npc.trade.OFFER_SELL = "sell"
 
 -- This table holds all responses for trades  
 npc.trade.results = {
-  casual = {},
+  single_trade_offer = {},
-  formal = {}
+  trade_offers = {}
 }
 
 -- Casual trader NPC dialogues definition
@@ -26,7 +26,7 @@ npc.trade.CASUAL_TRADE_BUY_DIALOGUE = {
       action_type = "function",
       response_id = 1,
       action = function(self, player)
-        npc.trade.show_casual_trade_formspec(self, player, npc.trade.OFFER_BUY)
+        npc.trade.show_trade_offer_formspec(self, player, npc.trade.OFFER_BUY)
       end
     }
   }
@@ -42,13 +42,13 @@ npc.trade.CASUAL_TRADE_SELL_DIALOGUE = {
       action_type = "function",
       response_id = 1,
       action = function(self, player)
-        npc.trade.show_casual_trade_formspec(self, player, npc.trade.OFFER_SELL)
+        npc.trade.show_trade_offer_formspec(self, player, npc.trade.OFFER_SELL)
       end
     }
   }
 }
 
-function npc.trade.show_casual_trade_formspec(self, player, offer_type)
+function npc.trade.show_trade_offer_formspec(self, player, offer_type)
   
   -- Strings for formspec, to include international support later
   local prompt_string = " offers to buy from you"
@@ -76,11 +76,12 @@ function npc.trade.show_casual_trade_formspec(self, player, offer_type)
                 "button_exit[4.1,3.3;2.9,0.5;no_option;"..npc.dialogue.NEGATIVE_ANSWER_LABEL.."]" 
 
   -- Create entry into results table
-  npc.trade.results.casual[player:get_player_name()] = {
+  npc.trade.results.single_trade_offer[player:get_player_name()] = {
-    trade_offer = trade_offer
+    trade_offer = trade_offer,
+    npc = self
   }
   -- Show formspec to player
-  minetest.show_formspec(player:get_player_name(), "advanced_npc:casual_trade", formspec)
+  minetest.show_formspec(player:get_player_name(), "advanced_npc:trade_offer", formspec)
 end
 
 function npc.trade.get_random_trade_status()
@@ -114,32 +115,70 @@ function npc.trade.get_casual_trade_offer(self, offer_type)
          }
 end
 
+function npc.trade.perform_trade(self, player_name, offer)
+
+  local item_stack = ItemStack(offer.item)
+  local price_stack = ItemStack(offer.price)
+  local inv = minetest.get_inventory({type = "player", name = player_name})
+
+  -- Check if offer is a buy or sell
+  if offer.offer_type == npc.trade.OFFER_BUY then
+    -- If NPC is buying from player, then player loses item, gets price
+    -- Check player has the item being buyed
+    if inv:contains_item("main", item_stack) then
+      -- Check if there is enough room to add the price item to player
+      if inv:room_for_item("main", price_stack) then
+      -- Remove item from player
+        inv:remove_item("main", item_stack)
+        -- Add item to NPC's inventory
+        npc.add_item_to_inventory_itemstring(self, offer.item)
+        -- Add price items to player
+        inv:add_item("main", price_stack)
+        -- Send message to player
+        minetest.chat_send_player(player_name, "Thank you!")
+      else
+        minetest.chat_send_player(player_name, 
+          "Looks like you can't what I'm giving you for payment!")
+      end
+    else
+      minetest.chat_send_player(player_name, "Looks like you don't have what I want to buy...")
+    end
+  else
+    -- If NPC is selling to the player, then player gives price and gets
+    -- item, NPC loses item and gets price
+    -- Check NPC has the required item to pay
+    if inv:contains_item("main", price_stack) then
+      -- Check if there is enough room to add the item to player
+      if inv:room_for_item("main", item_stack) then
+      -- Remove item from player
+        inv:remove_item("main", price_stack)
+        -- Add item to NPC's inventory
+        npc.add_item_to_inventory_itemstring(self, offer.price)
+        -- Add price items to player
+        inv:add_item("main", item_stack)
+        -- Send message to player
+        minetest.chat_send_player(player_name, "Thank you!")
+      else
+        minetest.chat_send_player(player_name, "Looks like you can't carry anything else...")
+      end
+    else
+      minetest.chat_send_player(player_name, "Looks like you don't have what I'm asking for!")
+    end
+  end
+end
+
 
 -- Handler for chat formspec
 minetest.register_on_player_receive_fields(function (player, formname, fields)
   -- Additional checks for other forms should be handled here
   -- Handle yes/no dialogue
-  if formname == "advanced_npc:casual_trade" then
+  if formname == "advanced_npc:trade_offer" then
     local player_name = player:get_player_name()
 
     if fields then
-      local player_response = npc.trade.results.casual[player_name]
+      local player_response = npc.trade.results.single_trade_offer[player_name]
       if fields.yes_option then
-        -- Check if offer is a buy or sell
+        npc.trade.perform_trade(player_response.npc, player_name, player_response.trade_offer)
-        if player_response.trade_offer.offer_type == npc.trade.OFFER_BUY then
-          -- If NPC is buying from player, then player loses item, gets price
-          local inv = minetest.get_inventory({type = "player", name = player_name})
-          -- Check NPC has the item being buyed
-          if inv:contains_item("main", ItemStack(player_response.trade_offer.item)) then
-            -- Remove item from player
-            inv:remove_item("main", ItemStack(player_response.trade_offer.item))
-            -- TODO: Add to NPC
-            -- Add price items to player
-            inv:add_item("main", ItemStack(player_response.trade_offer.price))
-          end
-        else
-
-        end
       elseif fields.no_option then
         minetest.chat_send_player(player_name, "Talk to me if you change your mind!")
       end