module HWProto where

import IO

import Data.List

import Data.Word

import Miscutils

import Maybe (fromMaybe, fromJust)

answerBadCmd = [(clientOnly, ["ERROR", "Bad command, state or incorrect parameter"])]

answerQuit = [(clientOnly, ["off"])]

answerAbandoned = [(sameRoom, ["BYE"])]

answerQuitInform nick = [(othersInRoom, ["LEFT", nick])]

answerNickChosen = [(clientOnly, ["ERROR", "The nick already chosen"])]

answerNickChooseAnother = [(clientOnly, ["WARNING", "Choose another nick"])]

answerNick nick = [(clientOnly, ["NICK", nick])]

answerProtocolKnown = [(clientOnly, ["ERROR", "Protocol number already known"])]

answerBadInput = [(clientOnly, ["ERROR", "Bad input"])]

answerProto protoNum = [(clientOnly, ["PROTO", show protoNum])]

answerRoomsList list = [(clientOnly, ["ROOMS"] ++ list)]

answerRoomExists = [(clientOnly, ["WARNING", "There's already a room with that name"])]

answerJoined nick = [(sameRoom, ["JOINED", nick])]

answerNoRoom = [(clientOnly, ["WARNING", "There's no room with that name"])]

answerWrongPassword = [(clientOnly, ["WARNING", "Wrong password"])]

answerChatString nick msg = [(othersInRoom, ["CHAT_STRING", nick, msg])]

-- Main state-independent cmd handler

handleCmd :: CmdHandler

handleCmd client _ rooms ("QUIT":xs) =

	if null (room client) then

		(noChangeClients, noChangeRooms, answerQuit)

	else if isMaster client then

		(noChangeClients, removeRoom (room client), answerAbandoned) -- core disconnects clients on ROOMABANDONED answer

	else

		(noChangeClients, noChangeRooms, answerQuit ++ (answerQuitInform $ nick client))

-- check state and call state-dependent commmand handlers

handleCmd client clients rooms cmd =

	if null (nick client) || protocol client == 0 then

		handleCmd_noInfo client clients rooms cmd

	else if null (room client) then

		handleCmd_noRoom client clients rooms cmd

	else

		handleCmd_inRoom client clients rooms cmd

-- 'no info' state - need to get protocol number and nickname

handleCmd_noInfo :: CmdHandler

handleCmd_noInfo client clients _ ["NICK", newNick] =

	if not . null $ nick client then

		(noChangeClients, noChangeRooms, answerNickChosen)

	else if haveSameNick then

		(noChangeClients, noChangeRooms, answerNickChooseAnother)

	else

		(modifyClient client{nick = newNick}, noChangeRooms, answerNick newNick)

	where

		haveSameNick = not . null $ filter (\cl -> newNick == nick cl) clients

handleCmd_noInfo client _ _ ["PROTO", protoNum] =

	if protocol client > 0 then

		(noChangeClients, noChangeRooms, answerProtocolKnown)

	else if parsedProto == 0 then

		(noChangeClients, noChangeRooms, answerBadInput)

	else

		(modifyClient client{protocol = parsedProto}, noChangeRooms, answerProto parsedProto)

	where

		parsedProto = fromMaybe 0 (maybeRead protoNum :: Maybe Word16)

handleCmd_noInfo _ _ _ _ = (noChangeClients, noChangeRooms, answerBadCmd)

-- 'noRoom' clients state command handlers

handleCmd_noRoom :: CmdHandler

handleCmd_noRoom client _ rooms ["LIST"] =

		(noChangeClients, noChangeRooms, answerRoomsList $ map name rooms)

handleCmd_noRoom client _ rooms ["CREATE", newRoom, roomPassword] =

	if haveSameRoom then

		(noChangeClients, noChangeRooms, answerRoomExists)

	else

		(modifyClient client{room = newRoom, isMaster = True}, addRoom (RoomInfo newRoom roomPassword []), answerJoined $ nick client)

	where

		haveSameRoom = not . null $ filter (\room -> newRoom == name room) rooms

handleCmd_noRoom client clients rooms ["CREATE", newRoom] =

	handleCmd_noRoom client clients rooms ["CREATE", newRoom, ""]

handleCmd_noRoom client clients rooms ["JOIN", roomName, roomPassword] =

	if noSuchRoom then

		(noChangeClients, noChangeRooms, answerNoRoom)

	else if roomPassword /= password (roomByName roomName rooms) then

		(noChangeClients, noChangeRooms, answerWrongPassword)

	else

		(modifyClient client{room = roomName}, noChangeRooms, (answerJoined $ nick client) ++ answerNicks)

	where

		noSuchRoom = null $ filter (\room -> roomName == name room) rooms

		answerNicks = [(clientOnly, ["JOINED"] ++ (map nick $ filter (\ci -> room ci == roomName) clients))]

handleCmd_noRoom client clients rooms ["JOIN", roomName] =

	handleCmd_noRoom client clients rooms ["JOIN", roomName, ""]

handleCmd_noRoom _ _ _ _ = (noChangeClients, noChangeRooms, answerBadCmd)

-- 'inRoom' clients state command handlers

handleCmd_inRoom :: CmdHandler

handleCmd_inRoom client _ _ ["CHAT_STRING", _, msg] = (noChangeClients, noChangeRooms, answerChatString (nick client) msg)

handleCmd_inRoom _ _ _ _ = (noChangeClients, noChangeRooms, answerBadCmd)