oChat

local username = "Not set"
local channel = "Not set"
local modem = peripheral.wrap("top")
function topBar()
    term.setCursorPos(1,1)
    term.clearLine()
    print("oChat v 1.0")
    term.clearLine()
    print("User: "..username..", Channel: "..channel)
end
function clearScreen()
    term.clear()
    term.setCursorPos(1,1)
    print("oChat v 1.0")
    print("User: "..username..", Channel: "..channel)
end
function setChannel()
    clearScreen()
    write("Channel number (1-100): ")
    local channelInput = tonumber(read())
    if (channelInput < 1) or (channelInput > 100) then
        print("Invalid channel...")
        sleep(1)
        setChannel()
    else
        channel = channelInput
    end
end
clearScreen()
write("Enter a username: ")
username = read()
setChannel()
modem.open(channel)
function receive()
    local event,modemSide,senderChannel,replyChannel,message,distance = os.pullEvent("modem_message")
    term.clearLine()
    if not (string.match(message, username)) then
        print(message)
        topBar()
    end
end
function send()
    term.setCursorPos(1,19)
    write("> ")
    local message = read()
    modem.transmit(channel,1,"<"..username.."> "..message)
    topBar()
end
clearScreen()
while true do
    parallel.waitForAny(receive, send)
end