delchat v1.1.0

local functionStack = {}
local chat = {}
local users = {}

-- config
chat[0] = "Welcome To DelChat"
local bar = "-" --character the header/footer of input section
-- end

local hScreen, vScreen = term.getSize()
local update = true
local loc = vScreen - 1
local cache = 1
local devider = bar
local localuser

function menu()
    term.clear()
    term.setCursorPos(1, 1)
    print("Enter Your Username:")
    localuser = read()
end

function clear()
    for i=2, hScreen do
        devider = devider .. bar
    end
    header = vScreen - 2
    term.clear()
    term.setCursorPos(1, header)
    term.write(devider)
    term.setCursorPos(1, vScreen)
    term.write(devider)
    term.setCursorPos(1, loc)
end

function openModem()
    sides = rs.getSides()
    for index, side in pairs(sides) do

        if peripheral.isPresent(sides[index]) and peripheral.getType(sides[index]) == "modem" then
            rednet.open(sides[index])
            return
        end
    end
    error("No modem found to perform rednet reception.")
end

function getUser(i)
    if users[i] == nil then
        rednet.send(i, "/userRequest")
        id, msg = rednet.receive(10)

        if id == nil then
            error("No response from client")
        else
            users[i] = msg
        end
    end
    return users[i]
end

function receiveChat()
    while true do
        id, message = rednet.receive()

        if message == "/userRequest" then
            rednet.send(id, tostring(localuser))
        else
            uName = getUser(id)
            if uName == nil then
                chat[cache] = "From " .. id .. ": " .. message
            else
                chat[cache] = uName .. ": " .. message
            end
            cache = cache + 1
            update = true
        end
    end
end

function sendChat()
    while true do
        term.setCursorPos(1, loc)
        term.clearLine()
        send = read()
        rednet.broadcast(send)
        chat[cache] = localuser .. ": " .. send
        cache = cache + 1
        update = true
    end
end

function display()
    while true do
        if update == true then
            term.setCursorPos(1, 1)
            screen = vScreen - 4
            line = cache - screen

            if line < 0 then
                line = 0
            end

            for i=0, screen do
                term.clearLine()
                print(chat[line + i])
            end

            term.setCursorPos(1, loc)
            update = false
        else
            sleep(0.25)
        end
    end
end

table.insert(functionStack, receiveChat)
table.insert(functionStack, sendChat)
table.insert(functionStack, display)

menu()
openModem()
clear()

while true do
        parallel.waitForAny(unpack(functionStack))
end