--[[

		server.lua by blastbeat of the luadch project

		re-used here under the MIT/X Consortium License

		- this script contains the server loop of the program

		- other scripts can reg a server here

]]--

----------------------------------// DECLARATION //--

--// constants //--

local STAT_UNIT = 1 / ( 1024 * 1024 )    -- mb

--// lua functions //--

local function use( what ) return _G[ what ] end

local type = use "type"

local pairs = use "pairs"

local ipairs = use "ipairs"

local tostring = use "tostring"

local collectgarbage = use "collectgarbage"

--// lua libs //--

local table = use "table"

local coroutine = use "coroutine"

--// lua lib methods //--

local table_concat = table.concat

local table_remove = table.remove

local string_sub = use'string'.sub

local coroutine_wrap = coroutine.wrap

local coroutine_yield = coroutine.yield

local print = print;

local out_put = function () end --print;

local out_error = print;

--// extern libs //--

local luasec = select(2, pcall(require, "ssl"))

local luasocket = require "socket"

--// extern lib methods //--

local ssl_wrap = ( luasec and luasec.wrap )

local socket_bind = luasocket.bind

local socket_select = luasocket.select

local ssl_newcontext = ( luasec and luasec.newcontext )

--// functions //--

local loop

local stats

local addtimer

local closeall

local addserver

local firetimer

local closesocket

local removesocket

local wrapserver

local wraptcpclient

local wrapsslclient

--// tables //--

local listener

local readlist

local writelist

local socketlist

local timelistener

--// simple data types //--

local _

local readlen = 0    -- length of readlist

local writelen = 0    -- lenght of writelist

local sendstat= 0

local receivestat = 0

----------------------------------// DEFINITION //--

listener = { }    -- key = port, value = table

readlist = { }    -- array with sockets to read from

writelist = { }    -- arrary with sockets to write to

socketlist = { }    -- key = socket, value = wrapped socket

timelistener = { }

stats = function( )

	return receivestat, sendstat

end

wrapserver = function( listener, socket, ip, serverport, mode, sslctx )    -- this function wraps a server

	local dispatch, disconnect = listener.listener, listener.disconnect    -- dangerous

	local wrapclient, err

	if sslctx then

		if not ssl_newcontext then

			return nil, "luasec not found"

		end

		if type( sslctx ) ~= "table" then

			out_error "server.lua: wrong server sslctx"

			return nil, "wrong server sslctx"

		end

		sslctx, err = ssl_newcontext( sslctx )

		if not sslctx then

			err = err or "wrong sslctx parameters"

			out_error( "server.lua: ", err )

			return nil, err

		end

		wrapclient = wrapsslclient

		wrapclient = wraptlsclient

	else

		wrapclient = wraptcpclient

	end

	local accept = socket.accept

	local close = socket.close

	--// public methods of the object //--    

	local handler = { }

	handler.shutdown = function( ) end

	--[[handler.listener = function( data, err )

		return ondata( handler, data, err )

	end]]

	handler.ssl = function( )

		return sslctx and true or false

	end

	handler.close = function( closed )

		_ = not closed and close( socket )

		writelen = removesocket( writelist, socket, writelen )

		readlen = removesocket( readlist, socket, readlen )

		socketlist[ socket ] = nil

		handler = nil

	end

	handler.ip = function( )

		return ip

	end

	handler.serverport = function( )

		return serverport

	end

	handler.socket = function( )

		return socket

	end

	handler.receivedata = function( )

		local client, err = accept( socket )    -- try to accept

		if client then

			local ip, clientport = client:getpeername( )

			client:settimeout( 0 )

			local handler, client, err = wrapclient( listener, client, ip, serverport, clientport, mode, sslctx )    -- wrap new client socket

			if err then    -- error while wrapping ssl socket

				return false

			end

			out_put( "server.lua: accepted new client connection from ", ip, ":", clientport )

			return dispatch( handler )

		elseif err then    -- maybe timeout or something else

			out_put( "server.lua: error with new client connection: ", err )

			return false

		end

	end

	return handler

end

wrapsslclient = function( listener, socket, ip, serverport, clientport, mode, sslctx )    -- this function wraps a ssl cleint

	local dispatch, disconnect = listener.listener, listener.disconnect

	--// transform socket to ssl object //--

	local err

	socket, err = ssl_wrap( socket, sslctx )    -- wrap socket

	if err then

		out_put( "server.lua: ssl error: ", err )

		return nil, nil, err    -- fatal error

	end

	socket:settimeout( 0 )

	--// private closures of the object //--

	local writequeue = { }    -- buffer for messages to send

	local eol, fatal_send_error   -- end of buffer

	local sstat, rstat = 0, 0

	--// local import of socket methods //--

	local send = socket.send

	local receive = socket.receive

	local close = socket.close

	--local shutdown = socket.shutdown

	--// public methods of the object //--

	local handler = { }

	handler.getstats = function( )

		return rstat, sstat

	end

	handler.listener = function( data, err )

		return listener( handler, data, err )

	end

	handler.ssl = function( )

		return true

	end

	handler.send = function( _, data, i, j )

			return send( socket, data, i, j )

	end

	handler.receive = function( pattern, prefix )

			return receive( socket, pattern, prefix )

	end

	handler.shutdown = function( pattern )

		--return shutdown( socket, pattern )

	end

	handler.close = function( closed )

		if eol and not fatal_send_error then handler._dispatchdata(); end

		close( socket )

		writelen = ( eol and removesocket( writelist, socket, writelen ) ) or writelen

		readlen = removesocket( readlist, socket, readlen )

		socketlist[ socket ] = nil

		out_put "server.lua: closed handler and removed socket from list"

	end

	handler.ip = function( )

		return ip

	end

	handler.serverport = function( )

		return serverport

	end

	handler.clientport = function( ) 

		return clientport

	end

	handler.write = function( data )

		if not eol then

			writelen = writelen + 1

			writelist[ writelen ] = socket

			eol = 0

		end

		eol = eol + 1

		writequeue[ eol ] = data

	end

	handler.writequeue = function( )

		return writequeue

	end

	handler.socket = function( )

		return socket

	end

	handler.mode = function( )

		return mode

	end

	handler._receivedata = function( )

		local data, err, part = receive( socket, mode )    -- receive data in "mode"

		if not err or ( err == "timeout" or err == "wantread" ) then    -- received something

			local data = data or part or ""

			local count = #data * STAT_UNIT

			rstat = rstat + count

			receivestat = receivestat + count

			out_put( "server.lua: read data '", data, "', error: ", err )

			return dispatch( handler, data, err )

		else    -- connections was closed or fatal error

			out_put( "server.lua: client ", ip, ":", clientport, " error: ", err )

			handler.close( )

			disconnect( handler, err )

			writequeue = nil

			handler = nil

			return false

		end

	end

	handler._dispatchdata = function( )    -- this function writes data to handlers

		local buffer = table_concat( writequeue, "", 1, eol )

		local succ, err, byte = send( socket, buffer )

		local count = ( succ or 0 ) * STAT_UNIT

		sstat = sstat + count

		sendstat = sendstat + count

		out_put( "server.lua: sended '", buffer, "', bytes: ", succ, ", error: ", err, ", part: ", byte, ", to: ", ip, ":", clientport )

		if succ then    -- sending succesful

			--writequeue = { }

			eol = nil

			writelen = removesocket( writelist, socket, writelen )    -- delete socket from writelist

			return true

		elseif byte and ( err == "timeout" or err == "wantwrite" ) then    -- want write

			buffer = string_sub( buffer, byte + 1, -1 )    -- new buffer

			writequeue[ 1 ] = buffer    -- insert new buffer in queue

			eol = 1

			return true

		else    -- connection was closed during sending or fatal error

			fatal_send_error = true;

			out_put( "server.lua: client ", ip, ":", clientport, " error: ", err )

			handler.close( )

			disconnect( handler, err )

			writequeue = nil

			handler = nil

			return false

		end

	end

	-- // COMPAT // --

	handler.getIp = handler.ip

	handler.getPort = handler.clientport

	--// handshake //--

	local wrote

	handler.handshake = coroutine_wrap( function( client )

			local err

			for i = 1, 10 do    -- 10 handshake attemps

				_, err = client:dohandshake( )

				if not err then

					out_put( "server.lua: ssl handshake done" )

					writelen = ( wrote and removesocket( writelist, socket, writelen ) ) or writelen

					handler.receivedata = handler._receivedata    -- when handshake is done, replace the handshake function with regular functions

					handler.dispatchdata = handler._dispatchdata

					return dispatch( handler )

				else

					out_put( "server.lua: error during ssl handshake: ", err )

					if err == "wantwrite" then

						if wrote == nil then

							writelen = writelen + 1

							writelist[ writelen ] = client

							wrote = true

						end

					end

					coroutine_yield( handler, nil, err )    -- handshake not finished

				end

			end

			_ = err ~= "closed" and close( socket )

			handler.close( )

			disconnect( handler, err )

			writequeue = nil

			handler = nil

			return false    -- handshake failed

		end

	)

	handler.receivedata = handler.handshake

	handler.dispatchdata = handler.handshake

	handler.handshake( socket )    -- do handshake

	socketlist[ socket ] = handler

	readlen = readlen + 1

	readlist[ readlen ] = socket

	return handler, socket

end

wraptlsclient = function( listener, socket, ip, serverport, clientport, mode, sslctx )    -- this function wraps a tls cleint

	local dispatch, disconnect = listener.listener, listener.disconnect

	--// transform socket to ssl object //--

	local err

	socket:settimeout( 0 )

	out_put("setting linger on "..tostring(socket))

	socket:setoption("linger", { on = true, timeout = 10 });

	--// private closures of the object //--

	local writequeue = { }    -- buffer for messages to send

	local eol, fatal_send_error   -- end of buffer

	local sstat, rstat = 0, 0

	--// local import of socket methods //--

	local send = socket.send