local modem = peripheral.wrap("right")
modem.open(999)
modem.open(997)
modem.open(995)
while true do
    local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
    print("I just received a message on channel: "..senderChannel.."Respond on:"..replyChannel)
    print(message)
    if(senderChannel==999) then
		local file = fs.open("Locked.lua","r")
		local check = file.readLine()
		local isLocked =false;
		for line in file.readLine do

			if(line==message.."") then
				isLocked=true;
			end

		end

		if(isLocked) then
			modem.transmit(998,997,"Locked")
		else
			modem.transmit(998,997,"Go")
		end
		file.close()
     elseif (senderChannel==997) then
         file = fs.open(message..".lua","r")
         modem.transmit(996,995,file.readAll())
		 local lFile = fs.open("Locked.lua","a")
		 lFile.write(message.."\n")
		 lFile.close()
     elseif(senderChannel==995) then
         local fname = string.sub(message,1,1)
         local fcontents= string.sub(message,2,-1)
         file = fs.open(fname..".lua","w")
         file.write(fcontents)
         file.close()

		 local lFile = fs.open("Locked.lua","r")
		 local temp = ""
		 for line in lFile.readLine do

			if(line==fname.."") then
				print("removed file lock:"..line)
			else
				temp=temp.."\n"+line
			end

		end

		lFile.close()
		lFile = fs.open("Locked.lua","w")
		lFile.write(temp)
		lFile.close()

         modem.transmit(994,995,"Success")
       end
end