modem = peripheral.find("modem")
rednet.open("top")

local channelID
local currentLine = 2
local privateOrPublic
local inChat = false
local computerID

function publicOrPrivate()
    while true do
    term.clear()
    term.setCursorPos(1,1)
    term.write("Please Type 1 For Private and 2 For Public")
    term.setCursorPos(1,2)
    privateOrPublic = tonumber(read())
    if privateOrPublic then
        break
    else
    term.clear()
    term.setCursorPos(1,1)
    term.write("INVALID SELECTION PRESS ANY KEY TO CONTINUE")
    local event, key = os.pullEvent("key")
    end
    end
end

function privateMessage()
    while true do
    term.clear()
    term.setCursorPos(1,1)
    term.write("Please Input The ID of The Computer")
    term.setCursorPos(1,2)
    term.write("ID: ")
    computerID = tonumber(read())
    if computerID then
        term.clear()
        term.setCursorPos(1,1)
        inChat = true
        term.write("Press F4 to Exit at Anytime")
        term.setCursorPos(1,2)
        rednet.send(computerID, "User Has Joined The Chat")

    while inChat do
        parallel.waitForAny(listenForMessages, sendMessageToID, endMessaging)
    end
    break

    else
        term.clear()
        term.setCursorPos(1,1)
        term.write("INVALID COMPUTER ID PRESS ANY KEY TO TRY AGAIN")
        local event, key = os.pullEvent("key")
    end
    end


end

function listenForMessages()
    while inChat do
        local senderID, message = rednet.receive()
        term.write("ID " .. senderID .. ": " .. message)
        currentLine = currentLine + 1
        term.setCursorPos(1, currentLine)
    end
end

function sendMessageToID()
    while inChat do
        local message = read()
        rednet.send(computerID, message)
        currentLine = currentLine + 1
        term.setCursorPos(1, currentLine)
    end
end

function endMessaging()
    while inChat do
        local event, key = os.pullEvent("key")
        if key == keys.f4 then
            rednet.send(computerID, "User Has Exited The Chat")
            inChat = false
        end
    end

end




function publicMessage()

    while true do
        term.clear()
        term.setCursorPos(1,1)
        term.write("Please Input The ID of The Channel")
        term.setCursorPos(1,2)
        term.write("ID: ")
        channelID = tonumber(read())
        modem.open(channelID)
        if channelID then
            term.clear()
            term.setCursorPos(1,1)
            inChat = true
            term.write("Press F4 to Exit at Anytime")
            term.setCursorPos(1,2)
            modem.transmit(channelID, channelID, "ID ".. os.computerID() .. ":" .. "Has Joined The Chat")

        while inChat do
            parallel.waitForAny(listenForMessagesPublic, sendMessageToChannel, endMessagingPublic)
        end
        break

        else
            term.clear()
            term.setCursorPos(1,1)
            term.write("INVALID COMPUTER ID PRESS ANY KEY TO TRY AGAIN")
            local event, key = os.pullEvent("key")
        end
    end
end

function listenForMessages()
    while inChat do
        local event, side, channel, replyChannel, message, distance = os.pullEvent("modem_message")
        term.write(message)
        currentLine = currentLine + 1
        term.setCursorPos(1, currentLine)
    end
end

function sendMessageToID()
    while inChat do
        local message = read()
        modem.transmit(channelID, channelID, "ID ".. os.computerID() .. ":" .. message)
        currentLine = currentLine + 1
        term.setCursorPos(1, currentLine)
    end
end

function endMessaging()
    while inChat do
        local event, key = os.pullEvent("key")
        if key == keys.f4 then
            modem.transmit(channelID, channelID, "ID ".. os.computerID() .. ":" .. "Has Left The Chat")
            inChat = false
        end
    end

end










while true do
    publicOrPrivate()
    if privateOrPublic == 1 then
        privateMessage()
    else
        publicMessage()
    end
end