modem repeater

-- local os.pullEvent = os.pullEventRaw

local channel

function drawScreen()
    term.clear()
    term.setCursorPos(1,1)
    term.write("NanoBank Repeater 1.0")
    term.setCursorPos(3,3)
end
drawScreen()

local modem = peripheral.find("modem")
if modem == nil then
    print("Failed to initialise modem.")
else
    print("Initialised modem.")
end

term.setCursorPos(3,4)
if fs.exists("event")==false then shell.run("pastebin get UKPy4iiE event") end
if os.loadAPI("event")==false then error("Failed to load event API") end

if fs.exists("data")==false then shell.run("pastebin get LnvzL7ur data") end
if os.loadAPI("data")==false then error("Failed to load data API") end

if fs.exists("utils")==false then shell.run("pastebin get dyvydHtK utils") end
if os.loadAPI("utils")==false then error("Failed to load utils API") end
term.write("Sucessfully loaded APIs")

if data.get("channel","channel") == nil then
    term.setCursorPos(3,5)
    term.write("Input channel please: ")
    channel = tonumber(read())
    data.set("channel",channel,"channel")
    modem.open(channel)
    term.setCursorPos(3,5)
    term.write("Channel successfully opened ")
else
    channel = tonumber(data.get("channel","channel"))
    modem.open(channel)
    term.setCursorPos(3,5)
    term.write("Channel successfully opened ")
end

function received(side,receiveChannel,replyChannel,message)
    local target = message[1]
    if target == channel - 1 then
        local message = table.remove(message,1)
        modem.transmit(channel-1,replyChannel,message)
    elseif target == channel + 1 then
        local message = table.remove(message,1)
        modem.transmit(channel+1,replyChannel,message)
    elseif target > channel then
        modem.transmit(channel+1,replyChannel,message)
    elseif target < channel then
        modem.transmit(channel-1,replyChannel,message)
    end
end
event.addHandler("modem_message",received)

while true do
    event.handleCCEvents()
end