Dialogue: full support for flag-based dialogues.

Added support for nested dialogue trees.
Trade: (WIP) Refactor code to support dedicated trading.

trade/trade.lua

@@ -103,9 +103,9 @@ end
 -- items that a NPC has on his/her inventory
 function npc.trade.get_currencies_in_inventory(self)
   local result = {}
-  local tier3 = npc.inventory_contains(self, npc.trade.prices.currency.tier3)
-  local tier2 = npc.inventory_contains(self, npc.trade.prices.currency.tier2)
-  local tier1 = npc.inventory_contains(self, npc.trade.prices.currency.tier1)
+  local tier3 = npc.inventory_contains(self, npc.trade.prices.currency.tier3.string)
+  local tier2 = npc.inventory_contains(self, npc.trade.prices.currency.tier2.string)
+  local tier1 = npc.inventory_contains(self, npc.trade.prices.currency.tier1.string)
   if tier3 ~= nil then
     table.insert(result, {name = npc.get_item_name(tier3.item_string), 
                           count = npc.get_item_count(tier3.item_string)} )
@@ -134,34 +134,20 @@ function npc.trade.get_casual_trade_offer(self, offer_type)
     -- Choose a random currency
     local chosen_tier = currencies[math.random(#currencies)]
     -- Get items for this currency
-    local buyable_items = 
-      npc.trade.prices.get_items_for_currency_count(chosen_tier.name, chosen_tier.count)
+    local buyable_items =
+      npc.trade.prices.get_items_for_currency_count(chosen_tier.name, chosen_tier.count, 0.5)
     -- Select a random item from the buyable items
     local item_set = {}
-    for item,price in pairs(buyable_items) do
+    for item,price_info in pairs(buyable_items) do
       table.insert(item_set, item)
     end
     local item = item_set[math.random(#item_set)]
     -- Choose buying quantity. Since this is a buy offer, NPC will buy items 
     -- at half the price. Therefore, NPC will always ask for even quantities
     -- so that the price count is always an integer number
-    local amount_to_buy = math.random(1,5) * 2
-    local price_item_count = buyable_items[item].count * ((amount_to_buy) / 2)
-    -- Increase the amount to buy if the result of the price is a decimal number
-    while price_item_count % 1 ~= 0 do
-      amount_to_buy = amount_to_buy + 1
-      price_item_count = buyable_items[item].count * ((amount_to_buy) / 2)
-    end
-    -- Create price itemstring
-    local price_string = buyable_items[item].tier.." "
-      ..tostring( buyable_items[item].count * (amount_to_buy / 2) )
-
-    -- Build the return object
-    result = {
-      offer_type = offer_type,
-      item = item.." "..amount_to_buy,
-      price = price_string
-    }
+    local amount_to_buy = math.random(buyable_items[item].min_buyable_item_count, buyable_items[item].max_buyable_item_count)
+    -- Create trade offer
+    result = npc.trade.create_offer(npc.trade.OFFER_BUY, item, price, amount_to_buy)
   else
     -- Make sell offer, NPC will sell items to player at regular price
     -- NPC will also offer items from their inventory
@@ -177,9 +163,61 @@ function npc.trade.get_casual_trade_offer(self, offer_type)
     local item = sellable_items[math.random(#sellable_items)]
     -- Choose how many of this item will be sold to player
     local count = math.random(npc.get_item_count(item))
+    -- Create trade offer
+    result = npc.trade.create_offer(npc.trade.OFFER_SELL, npc.get_item_name(item), nil, count)
+  end
+
+  return result
+end
+
+-- Creates a trade offer based on the offer type, given item and count. If
+-- the offer is a "buy" offer, it is required to provide currency items for
+-- payment. The currencies should come from either the NPC's inventory or a
+-- chest belonging to it.
+function npc.trade.create_offer(offer_type, item, price_item_count, count)
+
+  minetest.log("Item:"..dump(item))
+  local result = {}
+  -- Check offer type
+  if offer_type == npc.trade.OFFER_BUY then
+    -- Get price for the given item
+    local item_price = npc.trade.prices.table[item]
+    minetest.log("Item price: "..dump(item_price))
+    -- Choose buying quantity. Since this is a buy offer, NPC will buy items 
+    -- at half the price. Therefore, NPC will always ask for even quantities
+    -- so that the price count is always an integer number
+    minetest.log("Count: "..dump(count)..", price item count: "..dump(item_price.count))
+    local price_item_count = item_price.count * ((count) / 2)
+    minetest.log("Price item: "..dump(price_item_count))
+    -- Increase the amount to buy if the result of the price is a decimal number
+    while price_item_count % 1 ~= 0 do
+      minetest.log("Count: "..dump(count))
+      count = count + 1
+      price_item_count = item_price.count * ((count) / 2)
+      minetest.log("Price item: "..dump(price_item_count))
+    end
+    -- Check if the currency items can pay for the selected amount to buy
+    for i = 1, #currency_items do
+      minetest.log("Currency item: "..dump(currency_items[i]))
+      minetest.log("Name: "..dump(item_price.tier)..", Count: "..dump(price_item_count))
+      if currency_items[i].name == item_price.tier and currency_items[i].count >= item_price.count then
+        -- Create price itemstring
+        local price_string = item_price.tier.." "
+          ..tostring( item_price.count * (count / 2) )
+
+        -- Build the return object
+        result = {
+          offer_type = offer_type,
+          item = item.." "..count,
+          price = price_string
+        }
+      end
+    end
+  else
+    -- Make sell offer, NPC will sell items to player at regular price
     -- Get and calculate price for this object
     minetest.log("Item: "..dump(item)..", name: "..dump(npc.get_item_name(item)))
-    local price_object = npc.trade.prices.table[npc.get_item_name(item)]
+    local price_object = npc.trade.prices.table[item]
     -- Check price object, if price < 1 then offer to sell for 1
     if price_object.count < 1 then
       price_object.count = 1
@@ -194,8 +232,12 @@ function npc.trade.get_casual_trade_offer(self, offer_type)
   end
 
   return result
+  
 end
 
+
+-- TODO: THis method needs to be refactored to be able to manage
+-- both NPC inventories and chest inventories
 function npc.trade.perform_trade(self, player_name, offer)
 
   local item_stack = ItemStack(offer.item)
@@ -219,7 +261,7 @@ function npc.trade.perform_trade(self, player_name, offer)
         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!")
+          "Looks like you can't get 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...")