ComputerCraft EnderChat

-- Chat Client with MiniChat support
local args = { ... }
if #args < 1 then
    print("Usage: chat_client <username>")
    return
end

local username = args[1]
local modem = peripheral.find("modem")
if not modem then
    print("Ender Modem not found!")
    return
end

local defaultChannel = 1
modem.open(defaultChannel)

-- Message history
local messages = {}
local maxMessages = 18

-- Current channel
local currentChannel = "global"

-- Function to display chat history
function displayMessages()
    term.clear()
    term.setCursorPos(1, 1)
    for _, msg in ipairs(messages) do
        print(msg)
    end
end

-- Function to send a chat message
function sendMessage(message)
    modem.transmit(defaultChannel, defaultChannel, {type="message", username=username, channel=currentChannel, message=message})
end

-- Function to join a MiniChat channel
function joinChannel(channel)
    currentChannel = channel
    modem.transmit(defaultChannel, defaultChannel, {type="join", username=username, channel=channel})
end

-- Function to receive incoming messages
function handleIncomingMessage(event, side, freq, replyFreq, message, dist)
    if freq == defaultChannel and type(message) == "table" then
        if message.type == "message" then
            table.insert(messages, message.data)
            if #messages > maxMessages then
                table.remove(messages, 1)
            end
            displayMessages()
        elseif message.type == "status" then
            print(message.data)
        end
    end
end

-- Main function for sending and receiving messages
function chatLoop()
    parallel.waitForAny(
        function()
            while true do
                local input = read()

                if input:sub(1, 8) == "/minichat" then
                    local channel = input:sub(10)
                    joinChannel(channel)
                else
                    sendMessage(input)
                end
            end
        end,
        function()
            while true do
                local event, side, freq, replyFreq, message, dist = os.pullEvent("modem_message")
                handleIncomingMessage(event, side, freq, replyFreq, message, dist)
            end
        end
    )
end

-- Start the chat loop
chatLoop()

modem.close(defaultChannel)