modules.lua

-- Advanced NPC System by Jiddo

if Modules == nil then
	-- default words for greeting and ungreeting the npc. Should be a table containing all such words.
	FOCUS_GREETWORDS = {"hi", "hello"}
	FOCUS_FAREWELLWORDS = {"bye", "farewell"}

	-- The words for requesting trade window.
	SHOP_TRADEREQUEST = {"trade"}

	-- The word for accepting/declining an offer. CAN ONLY CONTAIN ONE FIELD! Should be a table with a single string value.
	SHOP_YESWORD = {"yes"}
	SHOP_NOWORD = {"no"}

	-- Pattern used to get the amount of an item a player wants to buy/sell.
	PATTERN_COUNT = "%d+"

	-- Constants used to separate buying from selling.
	SHOPMODULE_SELL_ITEM = 1
	SHOPMODULE_BUY_ITEM = 2
	SHOPMODULE_BUY_ITEM_CONTAINER = 3

	-- Constants used for shop mode. Notice: addBuyableItemContainer is working on all modes
	SHOPMODULE_MODE_TALK = 1 -- Old system used before client version 8.2: sell/buy item name
	SHOPMODULE_MODE_TRADE = 2 -- Trade window system introduced in client version 8.2
	SHOPMODULE_MODE_BOTH = 3 -- Both working at one time

	-- Used shop mode
	SHOPMODULE_MODE = SHOPMODULE_MODE_BOTH

	Modules = {
		parseableModules = {}
	}

	StdModule = {}

	-- These callback function must be called with parameters.npcHandler = npcHandler in the parameters table or they will not work correctly.
	-- Notice: The members of StdModule have not yet been tested. If you find any bugs, please report them to me.
	-- Usage:
		-- keywordHandler:addKeyword({"offer"}, StdModule.say, {npcHandler = npcHandler, text = "I sell many powerful melee weapons."})
	function StdModule.say(cid, message, keywords, parameters, node)
		local npcHandler = parameters.npcHandler
		if npcHandler == nil then
			error("StdModule.say called without any npcHandler instance.")
		end
		local onlyFocus = (parameters.onlyFocus == nil or parameters.onlyFocus == true)
		if not npcHandler:isFocused(cid) and onlyFocus then
			return false
		end

		local parseInfo = {[TAG_PLAYERNAME] = Player(cid):getName()}
		npcHandler:say(npcHandler:parseMessage(parameters.text or parameters.message, parseInfo), cid, parameters.publicize and true)
		if parameters.reset then
			npcHandler:resetNpc(cid)
		elseif parameters.moveup ~= nil then
			npcHandler.keywordHandler:moveUp(cid, parameters.moveup)
		end

		return true
	end

	--Usage:
		-- local node1 = keywordHandler:addKeyword({"promot"}, StdModule.say, {npcHandler = npcHandler, text = "I can promote you for 20000 gold coins. Do you want me to promote you?"})
		-- node1:addChildKeyword({"yes"}, StdModule.promotePlayer, {npcHandler = npcHandler, cost = 20000, level = 20}, text = "Congratulations! You are now promoted.")
		-- node1:addChildKeyword({"no"}, StdModule.say, {npcHandler = npcHandler, text = "Allright then. Come back when you are ready."}, reset = true)
	function StdModule.promotePlayer(cid, message, keywords, parameters, node)
		local npcHandler = parameters.npcHandler
		if npcHandler == nil then
			error("StdModule.promotePlayer called without any npcHandler instance.")
		end

		if not npcHandler:isFocused(cid) then
			return false
		end

		local player = Player(cid)
		if player:isPremium() or not parameters.premium then
			local promotion = player:getVocation():getPromotion()
			if player:getStorageValue(STORAGEVALUE_PROMOTION) == 1 then
				npcHandler:say("You are already promoted!", cid)
			elseif player:getLevel() < parameters.level then
				npcHandler:say("I am sorry, but I can only promote you once you have reached level " .. parameters.level .. ".", cid)
			elseif not player:removeMoney(parameters.cost) then
				npcHandler:say("You do not have enough money!", cid)
			else
				npcHandler:say(parameters.text, cid)
				player:setVocation(promotion)
				player:setStorageValue(STORAGEVALUE_PROMOTION, 1)
			end
		else
			npcHandler:say("You need a premium account in order to get promoted.", cid)
		end
		npcHandler:resetNpc(cid)
		return true
	end

	function StdModule.learnSpell(cid, message, keywords, parameters, node)
		local npcHandler = parameters.npcHandler
		if npcHandler == nil then
			error("StdModule.learnSpell called without any npcHandler instance.")
		end

		if not npcHandler:isFocused(cid) then
			return false
		end

		local player = Player(cid)
		if player:isPremium() or not parameters.premium then
			if player:hasLearnedSpell(parameters.spellName) then
				npcHandler:say("You already know this spell.", cid)
			elseif not player:canLearnSpell(parameters.spellName) then
				npcHandler:say("You cannot learn this spell.", cid)
			elseif not player:removeMoney(parameters.price) then
				npcHandler:say("You do not have enough money, this spell costs " .. parameters.price .. " gold.", cid)
			else
				npcHandler:say("You have learned " .. parameters.spellName .. ".", cid)
				player:learnSpell(parameters.spellName)
			end
		else
			npcHandler:say("You need a premium account in order to buy " .. parameters.spellName .. ".", cid)
		end
		npcHandler:resetNpc(cid)
		return true
	end

	function StdModule.bless(cid, message, keywords, parameters, node)
		local npcHandler = parameters.npcHandler
		if npcHandler == nil then
			error("StdModule.bless called without any npcHandler instance.")
		end

		if not npcHandler:isFocused(cid) or getWorldType() == WORLD_TYPE_PVP_ENFORCED then
			return false
		end

		local player = Player(cid)
		if player:isPremium() or not parameters.premium then
			if player:hasBlessing(parameters.bless) then
				npcHandler:say("Gods have already blessed you with this blessing!", cid)
			elseif not player:removeMoney(parameters.cost) then
				npcHandler:say("You don't have enough money for blessing.", cid)
			else
				player:addBlessing(parameters.bless)
				npcHandler:say("You have been blessed by one of the five gods!", cid)
			end
		else
			npcHandler:say("You need a premium account in order to be blessed.", cid)
		end
		npcHandler:resetNpc(cid)
		return true
	end

	function StdModule.travel(cid, message, keywords, parameters, node)
		local npcHandler = parameters.npcHandler
		if npcHandler == nil then
			error("StdModule.travel called without any npcHandler instance.")
		end

		if not npcHandler:isFocused(cid) then
			return false
		end

		local player = Player(cid)
		if player:isPremium() or not parameters.premium then
			if player:isPzLocked() then
				npcHandler:say("First get rid of those blood stains! You are not going to ruin my vehicle!", cid)
			elseif parameters.level and player:getLevel() < parameters.level then
				npcHandler:say("You must reach level " .. parameters.level .. " before I can let you go there.", cid)
			elseif not player:removeMoney(parameters.cost) then
				npcHandler:say("You don't have enough money.", cid)
			else
				npcHandler:say(parameters.msg or "Set the sails!", cid)
				npcHandler:releaseFocus(cid)

				local destination = Position(parameters.destination)
				local position = player:getPosition()
				player:teleportTo(destination)

				position:sendMagicEffect(CONST_ME_TELEPORT)
				destination:sendMagicEffect(CONST_ME_TELEPORT)
			end
		else
			npcHandler:say("I'm sorry, but you need a premium account in order to travel onboard our ships.", cid)
		end
		npcHandler:resetNpc(cid)
		return true
	end

	FocusModule = {
		npcHandler = nil
	}

	-- Creates a new instance of FocusModule without an associated NpcHandler.
	function FocusModule:new()
		local obj = {}
		setmetatable(obj, self)
		self.__index = self
		return obj
	end

	-- Inits the module and associates handler to it.
	function FocusModule:init(handler)
		self.npcHandler = handler
		for i, word in pairs(FOCUS_GREETWORDS) do
			local obj = {}
			obj[#obj + 1] = word
			obj.callback = FOCUS_GREETWORDS.callback or FocusModule.messageMatcher
			handler.keywordHandler:addKeyword(obj, FocusModule.onGreet, {module = self})
		end

		for i, word in pairs(FOCUS_FAREWELLWORDS) do
			local obj = {}
			obj[#obj + 1] = word
			obj.callback = FOCUS_FAREWELLWORDS.callback or FocusModule.messageMatcher
			handler.keywordHandler:addKeyword(obj, FocusModule.onFarewell, {module = self})
		end

		return true
	end

	-- Greeting callback function.
	function FocusModule.onGreet(cid, message, keywords, parameters)
		parameters.module.npcHandler:onGreet(cid)
		return true
	end

	-- UnGreeting callback function.
	function FocusModule.onFarewell(cid, message, keywords, parameters)
		if parameters.module.npcHandler:isFocused(cid) then
			parameters.module.npcHandler:onFarewell(cid)
			return true
		else
			return false
		end
	end

	-- Custom message matching callback function for greeting messages.
	function FocusModule.messageMatcher(keywords, message)
		for i, word in pairs(keywords) do
			if type(word) == "string" then
				if string.find(message, word) and not string.find(message, "[%w+]" .. word) and not string.find(message, word .. "[%w+]") then
					return true
				end
			end
		end
		return false
	end

	KeywordModule = {
		npcHandler = nil
	}
	-- Add it to the parseable module list.
	Modules.parseableModules["module_keywords"] = KeywordModule

	function KeywordModule:new()
		local obj = {}
		setmetatable(obj, self)
		self.__index = self
		return obj
	end

	function KeywordModule:init(handler)
		self.npcHandler = handler
		return true
	end

	-- Parses all known parameters.
	function KeywordModule:parseParameters()
		local ret = NpcSystem.getParameter("keywords")
		if ret ~= nil then
			self:parseKeywords(ret)
		end
	end

	function KeywordModule:parseKeywords(data)
		local n = 1
		for keys in string.gmatch(data, "[^;]+") do
			local i = 1

			local keywords = {}
			for temp in string.gmatch(keys, "[^,]+") do
				keywords[#keywords + 1] = temp
				i = i + 1
			end

			if i ~= 1 then
				local reply = NpcSystem.getParameter("keyword_reply" .. n)
				if reply ~= nil then
					self:addKeyword(keywords, reply)
				else
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Parameter '" .. "keyword_reply" .. n .. "' missing. Skipping...")
				end
			else
				print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "No keywords found for keyword set #" .. n .. ". Skipping...")
			end

			n = n + 1
		end
	end

	function KeywordModule:addKeyword(keywords, reply)
		self.npcHandler.keywordHandler:addKeyword(keywords, StdModule.say, {npcHandler = self.npcHandler, onlyFocus = true, text = reply, reset = true})
	end

	TravelModule = {
		npcHandler = nil,
		destinations = nil,
		yesNode = nil,
		noNode = nil,
	}

	-- Add it to the parseable module list.
	Modules.parseableModules["module_travel"] = TravelModule

	function TravelModule:new()
		local obj = {}
		setmetatable(obj, self)
		self.__index = self
		return obj
	end

	function TravelModule:init(handler)
		self.npcHandler = handler
		self.yesNode = KeywordNode:new(SHOP_YESWORD, TravelModule.onConfirm, {module = self})
		self.noNode = KeywordNode:new(SHOP_NOWORD, TravelModule.onDecline, {module = self})
		self.destinations = {}
		return true
	end

	-- Parses all known parameters.
	function TravelModule:parseParameters()
		local ret = NpcSystem.getParameter("travel_destinations")
		if ret ~= nil then
			self:parseDestinations(ret)

			self.npcHandler.keywordHandler:addKeyword({"destination"}, TravelModule.listDestinations, {module = self})
			self.npcHandler.keywordHandler:addKeyword({"where"}, TravelModule.listDestinations, {module = self})
			self.npcHandler.keywordHandler:addKeyword({"travel"}, TravelModule.listDestinations, {module = self})

		end
	end

	function TravelModule:parseDestinations(data)
		for destination in string.gmatch(data, "[^;]+") do
			local i = 1

			local name = nil
			local x = nil
			local y = nil
			local z = nil
			local cost = nil
			local premium = false

			for temp in string.gmatch(destination, "[^,]+") do
				if i == 1 then
					name = temp
				elseif i == 2 then
					x = tonumber(temp)
				elseif i == 3 then
					y = tonumber(temp)
				elseif i == 4 then
					z = tonumber(temp)
				elseif i == 5 then
					cost = tonumber(temp)
				elseif i == 6 then
					premium = temp == "true"
				else
					print("[Warning : " .. getCreatureName(getNpcCid()) .. "] NpcSystem:", "Unknown parameter found in travel destination parameter.", temp, destination)
				end
				i = i + 1
			end

			if name ~= nil and x ~= nil and y ~= nil and z ~= nil and cost ~= nil then
				self:addDestination(name, {x=x, y=y, z=z}, cost, premium)
			else
				print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Parameter(s) missing for travel destination:", name, x, y, z, cost, premium)
			end
		end
	end

	function TravelModule:addDestination(name, position, price, premium)
		self.destinations[#self.destinations + 1] = name

		local parameters = {
			cost = price,
			destination = position,
			premium = premium,
			module = self
		}
		local keywords = {}
		keywords[#keywords + 1] = name

		local keywords2 = {}
		keywords2[#keywords2 + 1] = "bring me to " .. name
		local node = self.npcHandler.keywordHandler:addKeyword(keywords, TravelModule.travel, parameters)
		self.npcHandler.keywordHandler:addKeyword(keywords2, TravelModule.bringMeTo, parameters)
		node:addChildKeywordNode(self.yesNode)
		node:addChildKeywordNode(self.noNode)

		if npcs_loaded_travel[getNpcCid()] == nil then
			npcs_loaded_travel[getNpcCid()] = getNpcCid()
			self.npcHandler.keywordHandler:addKeyword({'yes'}, TravelModule.onConfirm, {module = self})
			self.npcHandler.keywordHandler:addKeyword({'no'}, TravelModule.onDecline, {module = self})
		end
	end

	function TravelModule.travel(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) then
			return false
		end

		local npcHandler = module.npcHandler

		shop_destination[cid] = parameters.destination
		shop_cost[cid] = parameters.cost
		shop_premium[cid] = parameters.premium
		shop_npcuid[cid] = getNpcCid()

		local cost = parameters.cost
		local destination = parameters.destination
		local premium = parameters.premium

		module.npcHandler:say("Do you want to travel to " .. keywords[1] .. " for " .. cost .. " gold coins?", cid)
		return true
	end

	function TravelModule.onConfirm(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) then
			return false
		end

		if shop_npcuid[cid] ~= Npc().uid then
			return false
		end

		local npcHandler = module.npcHandler

		local cost = shop_cost[cid]
		local destination = Position(shop_destination[cid])

		local player = Player(cid)
		if player:isPremium() or not shop_premium[cid] then
			if not player:removeMoney(cost) then
				npcHandler:say("You do not have enough money!", cid)
			elseif player:isPzLocked(cid) then
				npcHandler:say("Get out of there with this blood.", cid)
			else
				npcHandler:say("It was a pleasure doing business with you.", cid)
				npcHandler:releaseFocus(cid)

				local position = player:getPosition()
				player:teleportTo(destination)

				position:sendMagicEffect(CONST_ME_TELEPORT)
				destination:sendMagicEffect(CONST_ME_TELEPORT)
			end
		else
			npcHandler:say("I can only allow premium players to travel there.", cid)
		end

		npcHandler:resetNpc(cid)
		return true
	end

	-- onDecline keyword callback function. Generally called when the player sais "no" after wanting to buy an item.
	function TravelModule.onDecline(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) or shop_npcuid[cid] ~= getNpcCid() then
			return false
		end
		local parentParameters = node:getParent():getParameters()
		local parseInfo = { [TAG_PLAYERNAME] = Player(cid):getName() }
		local msg = module.npcHandler:parseMessage(module.npcHandler:getMessage(MESSAGE_DECLINE), parseInfo)
		module.npcHandler:say(msg, cid)
		module.npcHandler:resetNpc(cid)
		return true
	end

	function TravelModule.bringMeTo(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) then
			return false
		end

		local cost = parameters.cost
		local destination = Position(parameters.destination)

		local player = Player(cid)
		if player:isPremium() or not parameters.premium then
			if player:removeMoney(cost) then
				local position = player:getPosition()
				player:teleportTo(destination)

				position:sendMagicEffect(CONST_ME_TELEPORT)
				destination:sendMagicEffect(CONST_ME_TELEPORT)
			end
		end
		return true
	end

	function TravelModule.listDestinations(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) then
			return false
		end

		local msg = "I can bring you to "
		--local i = 1
		local maxn = #module.destinations
		for i, destination in pairs(module.destinations) do
			msg = msg .. destination
			if i == maxn - 1 then
				msg = msg .. " and "
			elseif i == maxn then
				msg = msg .. "."
			else
				msg = msg .. ", "
			end
			i = i + 1
		end

		module.npcHandler:say(msg, cid)
		module.npcHandler:resetNpc(cid)
		return true
	end

	ShopModule = {
		npcHandler = nil,
		yesNode = nil,
		noNode = nil,
		noText = "",
		maxCount = 100,
		amount = 0
	}

	-- Add it to the parseable module list.
	Modules.parseableModules["module_shop"] = ShopModule

	-- Creates a new instance of ShopModule
	function ShopModule:new()
		local obj = {}
		setmetatable(obj, self)
		self.__index = self
		return obj
	end

	-- Parses all known parameters.
	function ShopModule:parseParameters()
		local ret = NpcSystem.getParameter("shop_buyable")
		if ret ~= nil then
			self:parseBuyable(ret)
		end

		local ret = NpcSystem.getParameter("shop_sellable")
		if ret ~= nil then
			self:parseSellable(ret)
		end

		local ret = NpcSystem.getParameter("shop_buyable_containers")
		if ret ~= nil then
			self:parseBuyableContainers(ret)
		end
	end

	-- Parse a string contaning a set of buyable items.
	function ShopModule:parseBuyable(data)
		for item in string.gmatch(data, "[^;]+") do
			local i = 1

			local name = nil
			local itemid = nil
			local cost = nil
			local subType = nil
			local realName = nil

			for temp in string.gmatch(item, "[^,]+") do
				if i == 1 then
					name = temp
				elseif i == 2 then
					itemid = tonumber(temp)
				elseif i == 3 then
					cost = tonumber(temp)
				elseif i == 4 then
					subType = tonumber(temp)
				elseif i == 5 then
					realName = temp
				else
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Unknown parameter found in buyable items parameter.", temp, item)
				end
				i = i + 1
			end

			local it = ItemType(itemid)
			if subType == nil and it:getCharges() ~= 0 then
				subType = it:getCharges()
			end

			if SHOPMODULE_MODE == SHOPMODULE_MODE_TRADE then
				if itemid ~= nil and cost ~= nil then
					if subType == nil and it:isFluidContainer() then
						print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "SubType missing for parameter item:", item)
					else
						self:addBuyableItem(nil, itemid, cost, subType, realName)
					end
				else
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Parameter(s) missing for item:", itemid, cost)
				end
			else
				if name ~= nil and itemid ~= nil and cost ~= nil then
					if subType == nil and it:isFluidContainer() then
						print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "SubType missing for parameter item:", item)
					else
						local names = {}
						names[#names + 1] = name
						self:addBuyableItem(names, itemid, cost, subType, realName)
					end
				else
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Parameter(s) missing for item:", name, itemid, cost)
				end
			end
		end
	end

	-- Parse a string contaning a set of sellable items.
	function ShopModule:parseSellable(data)
		for item in string.gmatch(data, "[^;]+") do
			local i = 1

			local name = nil
			local itemid = nil
			local cost = nil
			local realName = nil
			local subType = nil

			for temp in string.gmatch(item, "[^,]+") do
				if i == 1 then
					name = temp
				elseif i == 2 then
					itemid = tonumber(temp)
				elseif i == 3 then
					cost = tonumber(temp)
				elseif i == 4 then
					realName = temp
				elseif i == 5 then
					subType = tonumber(temp)
				else
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Unknown parameter found in sellable items parameter.", temp, item)
				end
				i = i + 1
			end

			if SHOPMODULE_MODE == SHOPMODULE_MODE_TRADE then
				if itemid ~= nil and cost ~= nil then
					self:addSellableItem(nil, itemid, cost, realName, subType)
				else
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Parameter(s) missing for item:", itemid, cost)
				end
			else
				if name ~= nil and itemid ~= nil and cost ~= nil then
					local names = {}
					names[#names + 1] = name
					self:addSellableItem(names, itemid, cost, realName, subType)
				else
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Parameter(s) missing for item:", name, itemid, cost)
				end
			end
		end
	end

	-- Parse a string contaning a set of buyable items.
	function ShopModule:parseBuyableContainers(data)
		for item in string.gmatch(data, "[^;]+") do
			local i = 1

			local name = nil
			local container = nil
			local itemid = nil
			local cost = nil
			local subType = nil
			local realName = nil

			for temp in string.gmatch(item, "[^,]+") do
				if i == 1 then
					name = temp
				elseif i == 2 then
					itemid = tonumber(temp)
				elseif i == 3 then
					itemid = tonumber(temp)
				elseif i == 4 then
					cost = tonumber(temp)
				elseif i == 5 then
					subType = tonumber(temp)
				elseif i == 6 then
					realName = temp
				else
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Unknown parameter found in buyable items parameter.", temp, item)
				end
				i = i + 1
			end

			if name ~= nil and container ~= nil and itemid ~= nil and cost ~= nil then
				if subType == nil and ItemType(itemid):isFluidContainer() then
					print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "SubType missing for parameter item:", item)
				else
					local names = {}
					names[#names + 1] = name
					self:addBuyableItemContainer(names, container, itemid, cost, subType, realName)
				end
			else
				print("[Warning : " .. Npc():getName() .. "] NpcSystem:", "Parameter(s) missing for item:", name, container, itemid, cost)
			end
		end
	end

	-- Initializes the module and associates handler to it.
	function ShopModule:init(handler)
		self.npcHandler = handler
		self.yesNode = KeywordNode:new(SHOP_YESWORD, ShopModule.onConfirm, {module = self})
		self.noNode = KeywordNode:new(SHOP_NOWORD, ShopModule.onDecline, {module = self})
		self.noText = handler:getMessage(MESSAGE_DECLINE)

		if SHOPMODULE_MODE ~= SHOPMODULE_MODE_TALK then
			for i, word in pairs(SHOP_TRADEREQUEST) do
				local obj = {}
				obj[#obj + 1] = word
				obj.callback = SHOP_TRADEREQUEST.callback or ShopModule.messageMatcher
				handler.keywordHandler:addKeyword(obj, ShopModule.requestTrade, {module = self})
			end
		end

		return true
	end

	-- Custom message matching callback function for requesting trade messages.
	function ShopModule.messageMatcher(keywords, message)
		for i, word in pairs(keywords) do
			if type(word) == "string" then
				if string.find(message, word) and not string.find(message, "[%w+]" .. word) and not string.find(message, word .. "[%w+]") then
					return true
				end
			end
		end

		return false
	end

	-- Resets the module-specific variables.
	function ShopModule:reset()
		self.amount = 0
	end

	-- Function used to match a number value from a string.
	function ShopModule:getCount(message)
		local ret = 1
		local b, e = string.find(message, PATTERN_COUNT)
		if b ~= nil and e ~= nil then
			ret = tonumber(string.sub(message, b, e))
		end

		if ret <= 0 then
			ret = 1
		elseif ret > self.maxCount then
			ret = self.maxCount
		end

		return ret
	end

	-- Adds a new buyable item.
	--	names = A table containing one or more strings of alternative names to this item. Used only for old buy/sell system.
	--	itemid = The itemid of the buyable item
	--	cost = The price of one single item
	--	subType - The subType of each rune or fluidcontainer item. Can be left out if it is not a rune/fluidcontainer. Default value is 1.
	--	realName - The real, full name for the item. Will be used as ITEMNAME in MESSAGE_ONBUY and MESSAGE_ONSELL if defined. Default value is nil (getItemName will be used)
	function ShopModule:addBuyableItem(names, itemid, cost, itemSubType, realName)
		if SHOPMODULE_MODE ~= SHOPMODULE_MODE_TALK then
			if itemSubType == nil then
				itemSubType = 1
			end

			local shopItem = self:getShopItem(itemid, itemSubType)
			if shopItem == nil then
				self.npcHandler.shopItems[#self.npcHandler.shopItems + 1] = {id = itemid, buy = cost, sell = -1, subType = itemSubType, name = realName or ItemType(itemid):getName()}
			else
				shopItem.buy = cost
			end
		end

		if names ~= nil and SHOPMODULE_MODE ~= SHOPMODULE_MODE_TRADE then
			for i, name in pairs(names) do
				local parameters = {
						itemid = itemid,
						cost = cost,
						eventType = SHOPMODULE_BUY_ITEM,
						module = self,
						realName = realName or ItemType(itemid):getName(),
						subType = itemSubType or 1
					}

				keywords = {}
				keywords[#keywords + 1] = "buy"
				keywords[#keywords + 1] = name
				local node = self.npcHandler.keywordHandler:addKeyword(keywords, ShopModule.tradeItem, parameters)
				node:addChildKeywordNode(self.yesNode)
				node:addChildKeywordNode(self.noNode)
			end
		end

		if npcs_loaded_shop[getNpcCid()] == nil then
			npcs_loaded_shop[getNpcCid()] = getNpcCid()
			self.npcHandler.keywordHandler:addKeyword({'yes'}, ShopModule.onConfirm, {module = self})
			self.npcHandler.keywordHandler:addKeyword({'no'}, ShopModule.onDecline, {module = self})
		end
	end

	function ShopModule:getShopItem(itemId, itemSubType)
		if ItemType(itemId):isFluidContainer() then
			for i = 1, #self.npcHandler.shopItems do
				local shopItem = self.npcHandler.shopItems[i]
				if shopItem.id == itemId and shopItem.subType == itemSubType then
					return shopItem
				end
			end
		else
			for i = 1, #self.npcHandler.shopItems do
				local shopItem = self.npcHandler.shopItems[i]
				if shopItem.id == itemId then
					return shopItem
				end
			end
		end
		return nil
	end

	-- Adds a new buyable container of items.
	--	names = A table containing one or more strings of alternative names to this item.
	--	container = Backpack, bag or any other itemid of container where bought items will be stored
	--	itemid = The itemid of the buyable item
	--	cost = The price of one single item
	--	subType - The subType of each rune or fluidcontainer item. Can be left out if it is not a rune/fluidcontainer. Default value is 1.
	--	realName - The real, full name for the item. Will be used as ITEMNAME in MESSAGE_ONBUY and MESSAGE_ONSELL if defined. Default value is nil (getItemName will be used)
	function ShopModule:addBuyableItemContainer(names, container, itemid, cost, subType, realName)
		if names ~= nil then
			for i, name in pairs(names) do
				local parameters = {
						container = container,
						itemid = itemid,
						cost = cost,
						eventType = SHOPMODULE_BUY_ITEM_CONTAINER,
						module = self,
						realName = realName or ItemType(itemid):getName(),
						subType = subType or 1
					}

				keywords = {}
				keywords[#keywords + 1] = "buy"
				keywords[#keywords + 1] = name
				local node = self.npcHandler.keywordHandler:addKeyword(keywords, ShopModule.tradeItem, parameters)
				node:addChildKeywordNode(self.yesNode)
				node:addChildKeywordNode(self.noNode)
			end
		end
	end

	-- Adds a new sellable item.
	--	names = A table containing one or more strings of alternative names to this item. Used only by old buy/sell system.
	--	itemid = The itemid of the sellable item
	--	cost = The price of one single item
	--	realName - The real, full name for the item. Will be used as ITEMNAME in MESSAGE_ONBUY and MESSAGE_ONSELL if defined. Default value is nil (getItemName will be used)
	function ShopModule:addSellableItem(names, itemid, cost, realName, itemSubType)
		if SHOPMODULE_MODE ~= SHOPMODULE_MODE_TALK then
			if itemSubType == nil then
				itemSubType = 0
			end

			local shopItem = self:getShopItem(itemid, itemSubType)
			if shopItem == nil then
				self.npcHandler.shopItems[#self.npcHandler.shopItems + 1] = {id = itemid, buy = -1, sell = cost, subType = itemSubType, name = realName or getItemName(itemid)}
			else
				shopItem.sell = cost
			end
		end

		if names ~= nil and SHOPMODULE_MODE ~= SHOPMODULE_MODE_TRADE then
			for i, name in pairs(names) do
				local parameters = {
					itemid = itemid,
					cost = cost,
					eventType = SHOPMODULE_SELL_ITEM,
					module = self,
					realName = realName or getItemName(itemid)
				}

				keywords = {}
				keywords[#keywords + 1] = "sell"
				keywords[#keywords + 1] = name

				local node = self.npcHandler.keywordHandler:addKeyword(keywords, ShopModule.tradeItem, parameters)
				node:addChildKeywordNode(self.yesNode)
				node:addChildKeywordNode(self.noNode)
			end
		end
	end

	-- onModuleReset callback function. Calls ShopModule:reset()
	function ShopModule:callbackOnModuleReset()
		self:reset()
		return true
	end

	-- Callback onBuy() function. If you wish, you can change certain Npc to use your onBuy().
	function ShopModule:callbackOnBuy(cid, itemid, subType, amount, ignoreCap, inBackpacks)
		local shopItem = self:getShopItem(itemid, subType)
		if shopItem == nil then
			error("[ShopModule.onBuy] shopItem == nil")
			return false
		end

		if shopItem.buy == -1 then
			error("[ShopModule.onSell] attempt to buy a non-buyable item")
			return false
		end

		local backpack = 1988
		local totalCost = amount * shopItem.buy
		if inBackpacks then
			totalCost = isItemStackable(itemid) == TRUE and totalCost + 20 or totalCost + (math.max(1, math.floor(amount / getContainerCapById(backpack))) * 20)
		end

		local parseInfo = {
			[TAG_PLAYERNAME] = getPlayerName(cid),
			[TAG_ITEMCOUNT] = amount,
			[TAG_TOTALCOST] = totalCost,
			[TAG_ITEMNAME] = shopItem.name
		}

		if getPlayerMoney(cid) < totalCost then
			local msg = self.npcHandler:getMessage(MESSAGE_NEEDMONEY)
			msg = self.npcHandler:parseMessage(msg, parseInfo)
			doPlayerSendCancel(cid, msg)
			return false
		end

		local subType = shopItem.subType or 1
		local a, b = doNpcSellItem(cid, itemid, amount, subType, ignoreCap, inBackpacks, backpack)
		if a < amount then
			local msgId = MESSAGE_NEEDMORESPACE
			if a == 0 then
				msgId = MESSAGE_NEEDSPACE
			end

			local msg = self.npcHandler:getMessage(msgId)
			parseInfo[TAG_ITEMCOUNT] = a
			msg = self.npcHandler:parseMessage(msg, parseInfo)
			doPlayerSendCancel(cid, msg)
			self.npcHandler.talkStart[cid] = os.time()

			if a > 0 then
				doPlayerRemoveMoney(cid, ((a * shopItem.buy) + (b * 20)))
				return true
			end

			return false
		else
			local msg = self.npcHandler:getMessage(MESSAGE_BOUGHT)
			msg = self.npcHandler:parseMessage(msg, parseInfo)
			doPlayerSendTextMessage(cid, MESSAGE_INFO_DESCR, msg)
			doPlayerRemoveMoney(cid, totalCost)
			self.npcHandler.talkStart[cid] = os.time()
			return true
		end
	end

	-- Callback onSell() function. If you wish, you can change certain Npc to use your onSell().
	function ShopModule:callbackOnSell(cid, itemid, subType, amount, ignoreEquipped, _)
		local shopItem = self:getShopItem(itemid, subType)
		if shopItem == nil then
			error("[ShopModule.onSell] items[itemid] == nil")
			return false
		end

		if shopItem.sell == -1 then
			error("[ShopModule.onSell] attempt to sell a non-sellable item")
			return false
		end

		local parseInfo = {
			[TAG_PLAYERNAME] = getPlayerName(cid),
			[TAG_ITEMCOUNT] = amount,
			[TAG_TOTALCOST] = amount * shopItem.sell,
			[TAG_ITEMNAME] = shopItem.name
		}

		if not isItemFluidContainer(itemid) then
			subType = -1
		end

		if doPlayerRemoveItem(cid, itemid, amount, subType, ignoreEquipped) then
			local msg = self.npcHandler:getMessage(MESSAGE_SOLD)
			msg = self.npcHandler:parseMessage(msg, parseInfo)
			doPlayerSendTextMessage(cid, MESSAGE_INFO_DESCR, msg)
			doPlayerAddMoney(cid, amount * shopItem.sell)
			self.npcHandler.talkStart[cid] = os.time()
			return true
		else
			local msg = self.npcHandler:getMessage(MESSAGE_NEEDITEM)
			msg = self.npcHandler:parseMessage(msg, parseInfo)
			doPlayerSendCancel(cid, msg)
			self.npcHandler.talkStart[cid] = os.time()
			return false
		end
	end

	-- Callback for requesting a trade window with the NPC.
	function ShopModule.requestTrade(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) then
			return false
		end

		if not module.npcHandler:onTradeRequest(cid) then
			return false
		end

		local itemWindow = {}
		for i = 1, #module.npcHandler.shopItems do
			itemWindow[#itemWindow + 1] = module.npcHandler.shopItems[i]
		end

		if itemWindow[1] == nil then
			local parseInfo = { [TAG_PLAYERNAME] = getPlayerName(cid) }
			local msg = module.npcHandler:parseMessage(module.npcHandler:getMessage(MESSAGE_NOSHOP), parseInfo)
			module.npcHandler:say(msg, cid)
			return true
		end

		local parseInfo = { [TAG_PLAYERNAME] = getPlayerName(cid) }
		local msg = module.npcHandler:parseMessage(module.npcHandler:getMessage(MESSAGE_SENDTRADE), parseInfo)
		module.npcHandler:say(msg, cid)
		return true
	end

	-- onConfirm keyword callback function. Sells/buys the actual item.
	function ShopModule.onConfirm(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) or shop_npcuid[cid] ~= getNpcCid() then
			return false
		end
		shop_npcuid[cid] = 0

		local parentParameters = node:getParent():getParameters()
		local parseInfo = {
			[TAG_PLAYERNAME] = getPlayerName(cid),
			[TAG_ITEMCOUNT] = shop_amount[cid],
			[TAG_TOTALCOST] = shop_cost[cid] * shop_amount[cid],
			[TAG_ITEMNAME] = shop_rlname[cid]
		}

		if shop_eventtype[cid] == SHOPMODULE_SELL_ITEM then
			local ret = doPlayerSellItem(cid, shop_itemid[cid], shop_amount[cid], shop_cost[cid] * shop_amount[cid])
			if ret == true then
				local msg = module.npcHandler:getMessage(MESSAGE_ONSELL)
				msg = module.npcHandler:parseMessage(msg, parseInfo)
				module.npcHandler:say(msg, cid)
			else
				local msg = module.npcHandler:getMessage(MESSAGE_MISSINGITEM)
				msg = module.npcHandler:parseMessage(msg, parseInfo)
				module.npcHandler:say(msg, cid)
			end
		elseif shop_eventtype[cid] == SHOPMODULE_BUY_ITEM then
			local cost = shop_cost[cid] * shop_amount[cid]
			if getPlayerMoney(cid) < cost then
				local msg = module.npcHandler:getMessage(MESSAGE_MISSINGMONEY)
				msg = module.npcHandler:parseMessage(msg, parseInfo)
				module.npcHandler:say(msg, cid)
				return false
			end

			local a, b = doNpcSellItem(cid, shop_itemid[cid], shop_amount[cid], shop_subtype[cid], false, false, 1988)
			if a < shop_amount[cid] then
				local msgId = MESSAGE_NEEDMORESPACE
				if a == 0 then
					msgId = MESSAGE_NEEDSPACE
				end

				local msg = module.npcHandler:getMessage(msgId)
				msg = module.npcHandler:parseMessage(msg, parseInfo)
				module.npcHandler:say(msg, cid)
				if a > 0 then
					doPlayerRemoveMoney(cid, a * shop_cost[cid])
					if shop_itemid[cid] == ITEM_PARCEL then
						doNpcSellItem(cid, ITEM_LABEL, shop_amount[cid], shop_subtype[cid], true, false, 1988)
					end
					return true
				end
				return false
			else
				local msg = module.npcHandler:getMessage(MESSAGE_ONBUY)
				msg = module.npcHandler:parseMessage(msg, parseInfo)
				module.npcHandler:say(msg, cid)
				doPlayerRemoveMoney(cid, cost)
				if shop_itemid[cid] == ITEM_PARCEL then
					doNpcSellItem(cid, ITEM_LABEL, shop_amount[cid], shop_subtype[cid], true, false, 1988)
				end
				return true
			end
		elseif shop_eventtype[cid] == SHOPMODULE_BUY_ITEM_CONTAINER then
			local ret = doPlayerBuyItemContainer(cid, shop_container[cid], shop_itemid[cid], shop_amount[cid], shop_cost[cid] * shop_amount[cid], shop_subtype[cid])
			if ret == true then
				local msg = module.npcHandler:getMessage(MESSAGE_ONBUY)
				msg = module.npcHandler:parseMessage(msg, parseInfo)
				module.npcHandler:say(msg, cid)
			else
				local msg = module.npcHandler:getMessage(MESSAGE_MISSINGMONEY)
				msg = module.npcHandler:parseMessage(msg, parseInfo)
				module.npcHandler:say(msg, cid)
			end
		end

		module.npcHandler:resetNpc(cid)
		return true
	end

	-- onDecline keyword callback function. Generally called when the player sais "no" after wanting to buy an item.
	function ShopModule.onDecline(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) or shop_npcuid[cid] ~= getNpcCid() then
			return false
		end
		shop_npcuid[cid] = 0

		local parentParameters = node:getParent():getParameters()
		local parseInfo = {
			[TAG_PLAYERNAME] = getPlayerName(cid),
			[TAG_ITEMCOUNT] = shop_amount[cid],
			[TAG_TOTALCOST] = shop_cost[cid] * shop_amount[cid],
			[TAG_ITEMNAME] = shop_rlname[cid]
		}

		local msg = module.npcHandler:parseMessage(module.noText, parseInfo)
		module.npcHandler:say(msg, cid)
		module.npcHandler:resetNpc(cid)
		return true
	end

	-- tradeItem callback function. Makes the npc say the message defined by MESSAGE_BUY or MESSAGE_SELL
	function ShopModule.tradeItem(cid, message, keywords, parameters, node)
		local module = parameters.module
		if not module.npcHandler:isFocused(cid) then
			return false
		end

		if not module.npcHandler:onTradeRequest(cid) then
			return true
		end

		local count = module:getCount(message)
		module.amount = count

		shop_amount[cid] = module.amount
		shop_cost[cid] = parameters.cost
		shop_rlname[cid] = parameters.realName
		shop_itemid[cid] = parameters.itemid
		shop_container[cid] = parameters.container
		shop_npcuid[cid] = getNpcCid()
		shop_eventtype[cid] = parameters.eventType
		shop_subtype[cid] = parameters.subType

		local parseInfo = {
			[TAG_PLAYERNAME] = getPlayerName(cid),
			[TAG_ITEMCOUNT] = shop_amount[cid],
			[TAG_TOTALCOST] = shop_cost[cid] * shop_amount[cid],
			[TAG_ITEMNAME] = shop_rlname[cid]
		}

		if shop_eventtype[cid] == SHOPMODULE_SELL_ITEM then
			local msg = module.npcHandler:getMessage(MESSAGE_SELL)
			msg = module.npcHandler:parseMessage(msg, parseInfo)
			module.npcHandler:say(msg, cid)
		elseif shop_eventtype[cid] == SHOPMODULE_BUY_ITEM then
			local msg = module.npcHandler:getMessage(MESSAGE_BUY)
			msg = module.npcHandler:parseMessage(msg, parseInfo)
			module.npcHandler:say(msg, cid)
		elseif shop_eventtype[cid] == SHOPMODULE_BUY_ITEM_CONTAINER then
			local msg = module.npcHandler:getMessage(MESSAGE_BUY)
			msg = module.npcHandler:parseMessage(msg, parseInfo)
			module.npcHandler:say(msg, cid)
		end
		return true
	end
end