-- Advanced NPC System (Created by Jiddo),
-- Modified by Talaturen.

if(NpcHandler == nil) then
	-- Constant talkdelay behaviors.
	TALKDELAY_NONE = 0 -- No talkdelay. Npc will reply immedeatly.
	TALKDELAY_ONTHINK = 1 -- Talkdelay handled through the onThink callback function. (Default)
	TALKDELAY_EVENT = 2 -- Not yet implemented

	-- Currently applied talkdelay behavior. TALKDELAY_ONTHINK is default.
	NPCHANDLER_TALKDELAY = TALKDELAY_NONE

	-- Constant conversation behaviors.
	CONVERSATION_DEFAULT = 0 -- Conversation through default window, like it was before 8.2 update.
	CONVERSATION_PRIVATE = 1 -- Conversation through NPCs chat window, as of 8.2 update. (Default)
		--Small Note: Private conversations also means the NPC will use multi-focus system.

	-- Currently applied conversation behavior. CONVERSATION_PRIVATE is default.
	NPCHANDLER_CONVBEHAVIOR = CONVERSATION_PRIVATE

	-- Constant indexes for defining default messages.
	MESSAGE_GREET 			= 1 -- When the player greets the npc.
	MESSAGE_FAREWELL 		= 2 -- When the player unGreets the npc.
	MESSAGE_BUY 			= 3 -- When the npc asks the player if he wants to buy something.
	MESSAGE_ONBUY 			= 4 -- When the player successfully buys something via talk.
	MESSAGE_BOUGHT			= 5 -- When the player bought something through the shop window.
	MESSAGE_SELL 			= 6 -- When the npc asks the player if he wants to sell something.
	MESSAGE_ONSELL 			= 7 -- When the player successfully sells something via talk.
	MESSAGE_SOLD			= 8 -- When the player sold something through the shop window.
	MESSAGE_MISSINGMONEY		= 9 -- When the player does not have enough money.
	MESSAGE_NEEDMONEY		= 10 -- Same as above, used for shop window.
	MESSAGE_MISSINGITEM		= 11 -- When the player is trying to sell an item he does not have.
	MESSAGE_NEEDITEM		= 12 -- Same as above, used for shop window.
	MESSAGE_NEEDSPACE 		= 13 -- When the player don't have any space to buy an item
	MESSAGE_NEEDMORESPACE		= 14 -- When the player has some space to buy an item, but not enough space
	MESSAGE_IDLETIMEOUT		= 15 -- When the player has been idle for longer then idleTime allows.
	MESSAGE_WALKAWAY		= 16 -- When the player walks out of the talkRadius of the npc.
	MESSAGE_DECLINE			= 17 -- When the player says no to something.
	MESSAGE_SENDTRADE		= 18 -- When the npc sends the trade window to the player
	MESSAGE_NOSHOP			= 19 -- When the npc's shop is requested but he doesn't have any
	MESSAGE_ONCLOSESHOP		= 20 -- When the player closes the npc's shop window
	MESSAGE_ALREADYFOCUSED		= 21 -- When the player already has the focus of this npc.
	MESSAGE_PLACEDINQUEUE		= 22 -- When the player has been placed in the costumer queue.

	-- Constant indexes for callback functions. These are also used for module callback ids.
	CALLBACK_CREATURE_APPEAR 	= 1
	CALLBACK_CREATURE_DISAPPEAR	= 2
	CALLBACK_CREATURE_SAY 		= 3
	CALLBACK_ONTHINK 		= 4
	CALLBACK_GREET 			= 5
	CALLBACK_FAREWELL 		= 6
	CALLBACK_MESSAGE_DEFAULT 	= 7
	CALLBACK_PLAYER_ENDTRADE 	= 8
	CALLBACK_PLAYER_CLOSECHANNEL	= 9
	CALLBACK_ONBUY			= 10
	CALLBACK_ONSELL			= 11

	-- Addidional module callback ids
	CALLBACK_MODULE_INIT		= 12
	CALLBACK_MODULE_RESET		= 13

	-- Constant strings defining the keywords to replace in the default messages.
	TAG_PLAYERNAME = '|PLAYERNAME|'
	TAG_ITEMCOUNT = '|ITEMCOUNT|'
	TAG_TOTALCOST = '|TOTALCOST|'
	TAG_ITEMNAME = '|ITEMNAME|'
	TAG_QUEUESIZE = '|QUEUESIZE|'

	NpcHandler = {
		keywordHandler = nil,
		focuses = nil,
		talkRadius = 3,
		--talkDelayTime = 0, -- Seconds to delay outgoing messages.
		--queue = nil,
		talkDelay = nil,
		callbackFunctions = nil,
		modules = nil,
		shopItems = nil, -- They must be here since ShopModule uses "static" functions
		messages = {
			-- These are the default replies of all npcs. They can/should be changed individually for each npc.
			[MESSAGE_GREET] 	= 'Hello, |PLAYERNAME|!',
			[MESSAGE_FAREWELL] 	= 'Good bye, |PLAYERNAME|!',
			[MESSAGE_BOUGHT] 	= 'Bought |ITEMCOUNT|x |ITEMNAME| for |TOTALCOST| gold.',
			[MESSAGE_SOLD]	 	= 'Sold |ITEMCOUNT|x |ITEMNAME| for |TOTALCOST| gold.',
			[MESSAGE_NEEDMONEY] 	= 'You do not have enough money.',
			[MESSAGE_NEEDITEM]	= 'You do not have this object.',
			[MESSAGE_NEEDSPACE]	= 'You do not have enough capacity.',
			[MESSAGE_NEEDMORESPACE]	= 'You do not have enough capacity for all items.',
			[MESSAGE_WALKAWAY] 	= 'Good bye.',
			[MESSAGE_SENDTRADE]	= 'Of course, just browse through my wares.',
			[MESSAGE_ONCLOSESHOP]	= 'Thank you, come back when you want something more.',
		}
	}

	-- Creates a new NpcHandler with an empty callbackFunction stack.
	function NpcHandler:new(keywordHandler)
		local obj = {}
		obj.callbackFunctions = {}
		obj.modules = {}
		obj.focuses = {}
		obj.talkDelay = {}
		obj.keywordHandler = keywordHandler
		obj.messages = {}
		obj.shopItems = {}

		setmetatable(obj.messages, self.messages)
		self.messages.__index = self.messages

		setmetatable(obj, self)
		self.__index = self
		return obj
	end

	-- Attackes a new keyword handler to this npchandler
	function NpcHandler:setKeywordHandler(newHandler)
		self.keywordHandler = newHandler
	end

	-- Function used to change the focus of this npc.
	function NpcHandler:addFocus(newFocus)
		if(self:isFocused(newFocus)) then
			return
		end

		table.insert(self.focuses, newFocus)

		self:updateFocus()
	end

	-- Function used to verify if npc is focused to certain player
	function NpcHandler:isFocused(focus)
		for k,v in pairs(self.focuses) do
			if v == focus then
				return true
			end
		end

		return false

	end

	-- This function should be called on each onThink and makes sure the npc faces the player it is talking to.
	--	Should also be called whenever a new player is focused.
	function NpcHandler:updateFocus()
		for pos, focus in pairs(self.focuses) do
			if(focus ~= nil) then
				doNpcSetCreatureFocus(focus)
				return
			end
		end

		doNpcSetCreatureFocus(0)
	end

	-- Used when the npc should un-focus the player.
	function NpcHandler:releaseFocus(focus)
		if(not self:isFocused(focus)) then
			return
		end

		local pos = nil
		for k,v in pairs(self.focuses) do
			if v == focus then
				pos = k
			end
		end
		table.remove(self.focuses, pos)
		closeShopWindow(focus) --Even if it can not exist, we need to prevent it.
		self:updateFocus()
	end

	-- Returns the callback function with the specified id or nil if no such callback function exists.
	function NpcHandler:getCallback(id)
		local ret = nil
		if(self.callbackFunctions ~= nil) then
			ret = self.callbackFunctions[id]
		end

		return ret
	end

	-- Changes the callback function for the given id to callback.
	function NpcHandler:setCallback(id, callback)
		if(self.callbackFunctions ~= nil) then
			self.callbackFunctions[id] = callback
		end
	end

	-- Adds a module to this npchandler and inits it.
	function NpcHandler:addModule(module)
		if(self.modules == nil or module == nil) then
			return false
		end

		module:init(self)
		if(module.parseParameters ~= nil) then
			module:parseParameters()
		end

		table.insert(self.modules, module)
		return true
	end

	-- Calls the callback function represented by id for all modules added to this npchandler with the given arguments.
	function NpcHandler:processModuleCallback(id, ...)
		local ret = true
		for i, module in pairs(self.modules) do
			local tmpRet = true
			if(id == CALLBACK_CREATURE_APPEAR and module.callbackOnCreatureAppear ~= nil) then
				tmpRet = module:callbackOnCreatureAppear(unpack(arg))
			elseif(id == CALLBACK_CREATURE_DISAPPEAR and module.callbackOnCreatureDisappear ~= nil) then
				tmpRet = module:callbackOnCreatureDisappear(unpack(arg))
			elseif(id == CALLBACK_CREATURE_SAY and module.callbackOnCreatureSay ~= nil) then
				tmpRet = module:callbackOnCreatureSay(unpack(arg))
			elseif(id == CALLBACK_PLAYER_ENDTRADE and module.callbackOnPlayerEndTrade ~= nil) then
				tmpRet = module:callbackOnPlayerEndTrade(unpack(arg))
			elseif(id == CALLBACK_PLAYER_CLOSECHANNEL and module.callbackOnPlayerCloseChannel ~= nil) then
				tmpRet = module:callbackOnPlayerCloseChannel(unpack(arg))
			elseif(id == CALLBACK_ONBUY and module.callbackOnBuy ~= nil) then
				tmpRet = module:callbackOnBuy(unpack(arg))
			elseif(id == CALLBACK_ONSELL and module.callbackOnSell ~= nil) then
				tmpRet = module:callbackOnSell(unpack(arg))
			elseif(id == CALLBACK_ONTHINK and module.callbackOnThink ~= nil) then
				tmpRet = module:callbackOnThink(unpack(arg))
			elseif(id == CALLBACK_GREET and module.callbackOnGreet ~= nil) then
				tmpRet = module:callbackOnGreet(unpack(arg))
			elseif(id == CALLBACK_FAREWELL and module.callbackOnFarewell ~= nil) then
				tmpRet = module:callbackOnFarewell(unpack(arg))
			elseif(id == CALLBACK_MESSAGE_DEFAULT and module.callbackOnMessageDefault ~= nil) then
				tmpRet = module:callbackOnMessageDefault(unpack(arg))
			elseif(id == CALLBACK_MODULE_RESET and module.callbackOnModuleReset ~= nil) then
				tmpRet = module:callbackOnModuleReset(unpack(arg))
			end

			if(not tmpRet) then
				ret = false
				break
			end
		end

		return ret
	end

	-- Returns the message represented by id.
	function NpcHandler:getMessage(id)
		local ret = nil
		if(self.messages ~= nil) then
			ret = self.messages[id]
		end

		return ret
	end

	-- Changes the default response message with the specified id to newMessage.
	function NpcHandler:setMessage(id, newMessage)
		if(self.messages ~= nil) then
			self.messages[id] = newMessage
		end
	end

	-- Translates all message tags found in msg using parseInfo
	function NpcHandler:parseMessage(msg, parseInfo)
		local ret = msg
		--[[if getNpcName() == 'Varkhal' or getNpcName() == 'Promotion Guy' then
			doPlayerSendTextMessage(getPlayerByName('Cykotitan'), 25, '------')
			for k, v in pairs(parseInfo) do
			doPlayerSendTextMessage(getPlayerByName('Cykotitan'), 25, k .. '='..v)
			end
		end]]
		for search, replace in pairs(parseInfo) do
			if search and replace then
				ret = string.gsub(ret, search, replace)
			end
		end

		return ret
	end

	-- Makes sure the npc un-focuses the currently focused player
	function NpcHandler:unGreet(cid)
		if(not self:isFocused(cid)) then
			return
		end

		local callback = self:getCallback(CALLBACK_FAREWELL)
		if(callback == nil or callback(cid)) then
			if(self:processModuleCallback(CALLBACK_FAREWELL)) then
				if(self.queue == nil or not self.queue:greetNext()) then
					local msg = self:getMessage(MESSAGE_FAREWELL)
					local parseInfo = { [TAG_PLAYERNAME] = getPlayerName(cid) }
					msg = self:parseMessage(msg, parseInfo)

					self:say(msg, cid)
					self:releaseFocus(cid)
					--self:say(msg)
				end
			end
		end
	end

	-- Greets a new player.
	function NpcHandler:greet(cid)
		if(cid ~= 0) then
			local callback = self:getCallback(CALLBACK_GREET)
			if(callback == nil or callback(cid)) then
				if(self:processModuleCallback(CALLBACK_GREET, cid)) then
					local msg = self:getMessage(MESSAGE_GREET)
					local parseInfo = { [TAG_PLAYERNAME] = getCreatureName(cid) }
					msg = self:parseMessage(msg, parseInfo)

					--self:say(msg)
					self:addFocus(cid)
					self:say(msg, cid)
				end
			end
		end
	end

	-- Handles onCreatureAppear events. If you with to handle this yourself, please use the CALLBACK_CREATURE_APPEAR callback.
	function NpcHandler:onCreatureAppear(cid)
		local callback = self:getCallback(CALLBACK_CREATURE_APPEAR)
		if(callback == nil or callback(cid)) then
			if(self:processModuleCallback(CALLBACK_CREATURE_APPEAR, cid)) then
				--
			end
		end
	end

	-- Handles onCreatureDisappear events. If you with to handle this yourself, please use the CALLBACK_CREATURE_DISAPPEAR callback.
	function NpcHandler:onCreatureDisappear(cid)
		local callback = self:getCallback(CALLBACK_CREATURE_DISAPPEAR)
		if(callback == nil or callback(cid)) then
			if(self:processModuleCallback(CALLBACK_CREATURE_DISAPPEAR, cid)) then
				if(self:isFocused(cid)) then
					self:unGreet(cid)
				end
			end
		end
	end

	-- Handles onCreatureSay events. If you with to handle this yourself, please use the CALLBACK_CREATURE_SAY callback.
	function NpcHandler:onCreatureSay(cid, class, msg)
		local callback = self:getCallback(CALLBACK_CREATURE_SAY)
		if(callback == nil or callback(cid, class, msg)) then
			if(self:processModuleCallback(CALLBACK_CREATURE_SAY, cid, class, msg)) then
				if(not self:isInRange(cid)) then
					return
				elseif(self.keywordHandler ~= nil) and ((self:isFocused(cid) and class == TALKTYPE_PRIVATE_PN) or not self:isFocused(cid)) then
					local ret = self.keywordHandler:processMessage(cid, msg)
					if(not ret) then
						local callback = self:getCallback(CALLBACK_MESSAGE_DEFAULT)
						if(callback) then
							callback(cid, class, msg)
						end
					end
				end
			end
		end
	end

	-- Handles onPlayerEndTrade events. If you wish to handle this yourself, use the CALLBACK_PLAYER_ENDTRADE callback.
	function NpcHandler:onPlayerEndTrade(cid)
		local callback = self:getCallback(CALLBACK_PLAYER_ENDTRADE)
		if(callback == nil or callback(cid)) then
			if(self:processModuleCallback(CALLBACK_PLAYER_ENDTRADE, cid, class, msg)) then
				if(self:isFocused(cid)) then
					local parseInfo = { [TAG_PLAYERNAME] = getPlayerName(cid) }
					local msg = self:parseMessage(self:getMessage(MESSAGE_ONCLOSESHOP), parseInfo)
					self:say(msg, cid)
				end
			end
		end
	end

	-- Handles onPlayerCloseChannel events. If you wish to handle this yourself, use the CALLBACK_PLAYER_CLOSECHANNEL callback.
	function NpcHandler:onPlayerCloseChannel(cid)
		local callback = self:getCallback(CALLBACK_PLAYER_CLOSECHANNEL)
		if(callback == nil or callback(cid)) then
			if(self:processModuleCallback(CALLBACK_PLAYER_CLOSECHANNEL, cid, class, msg)) then
				if(self:isFocused(cid)) then
					self:unGreet(cid)
				end
			end
		end
	end

	-- Handles onBuy events. If you wish to handle this yourself, use the CALLBACK_ONBUY callback.
	function NpcHandler:onBuy(cid, itemid, subType, amount, ignoreCap, inBackpacks)
		local callback = self:getCallback(CALLBACK_ONBUY)
		if(callback == nil or callback(cid, itemid, subType, amount, ignoreCap, inBackpacks)) then
			if(self:processModuleCallback(CALLBACK_ONBUY, cid, itemid, subType, amount, ignoreCap, inBackpacks)) then
				--
			end
		end
	end

	-- Handles onSell events. If you wish to handle this yourself, use the CALLBACK_ONSELL callback.
	function NpcHandler:onSell(cid, itemid, subType, amount, ignoreCap, inBackpacks)
		local callback = self:getCallback(CALLBACK_ONSELL)
		if(callback == nil or callback(cid, itemid, subType, amount, ignoreCap, inBackpacks)) then
			if(self:processModuleCallback(CALLBACK_ONSELL, cid, itemid, subType, amount, ignoreCap, inBackpacks)) then
				--
			end
		end
	end

	-- Handles onThink events. If you wish to handle this yourself, please use the CALLBACK_ONTHINK callback.
	function NpcHandler:onThink()
		local callback = self:getCallback(CALLBACK_ONTHINK)
		if(callback == nil or callback()) and self:processModuleCallback(CALLBACK_ONTHINK) then
			for pos, focus in pairs(self.focuses) do
				if(focus) then
					if(not self:isInRange(focus)) then
						self:onWalkAway(focus)
					else
						self:updateFocus()
					end
				end
			end
		end
	end

	-- Tries to greet the player with the given cid.
	function NpcHandler:onGreet(cid)
		if self:isInRange(cid) and not self:isFocused(cid) then
			self:greet(cid)
		end
	end

	-- Simply calls the underlying unGreet function.
	function NpcHandler:onFarewell(cid)
		self:unGreet(cid)
	end

	-- Should be called on this npc's focus if the distance to focus is greater then talkRadius.
	function NpcHandler:onWalkAway(cid)
		if(self:isFocused(cid)) then
			local callback = self:getCallback(CALLBACK_CREATURE_DISAPPEAR)
			if(callback == nil or callback(cid)) then
				if(self:processModuleCallback(CALLBACK_CREATURE_DISAPPEAR, cid)) then
					if(self.queue == nil or not self.queue:greetNext()) then
						if isPlayer(cid) then
							local msg = self:getMessage(MESSAGE_WALKAWAY)
							local parseInfo = { [TAG_PLAYERNAME] = getPlayerName(cid) }
							msg = self:parseMessage(msg, parseInfo)
							self:say(msg)
						end

						--self:say(msg, cid)
						self:releaseFocus(cid)
						
					end
				end
			end
		end
	end

	-- Returns true if cid is within the talkRadius of this npc.
	function NpcHandler:isInRange(cid)
		local distance = (isPlayer(cid) and getDistanceTo(cid)) or -1
		if(distance == -1) then
			return false
		end

		return (distance <= self.talkRadius)
	end

	-- Resets the npc into it's initial state (in regard of the keyrodhandler).
	--	All modules are also receiving a reset call through their callbackOnModuleReset function.
	function NpcHandler:resetNpc()
		if(self:processModuleCallback(CALLBACK_MODULE_RESET)) then
			self.keywordHandler:reset()
		end
	end

	-- Makes the npc represented by this instance of NpcHandler say something.
	--	This implements the currently set type of talkdelay.
	--	shallDelay is a boolean value. If it is false, the message is not delayed. Default value is false.
	function NpcHandler:say(message, focus, shallDelay)
		if focus and isPlayer(focus) then
			selfSay(message, focus)
		else
			selfSay(message)
		end
	end
end