Rednet Communication Test

-- Rednet Communication Test Program for Computer A and B
-- This program runs in two modes based on the configuration in an INI file.

-- Save INI Configuration File
local function saveConfig(config)
    local file = fs.open("config.ini", "w")
    for key, value in pairs(config) do
        file.writeLine(key .. "=" .. value)
    end
    file.close()
end

-- Load INI Configuration File
local function loadConfig()
    if not fs.exists("config.ini") then
        -- Create a default config.ini file with mode A
        local defaultConfig = { mode = "A" }
        saveConfig(defaultConfig)
    end

    local file = fs.open("config.ini", "r")
    local config = {}
    for line in file.readLine do
        local key, value = string.match(line, "(%w+)%s*=%s*(%w+)")
        if key and value then
            config[key] = value
        end
    end
    file.close()
    return config
end

-- Message Queue to hold incoming messages
local messageQueue = {}

-- Function to receive messages and append them to the queue
local function messageListener()
    while true do
        local senderId, message = rednet.receive()
        table.insert(messageQueue, {senderId = senderId, message = message})
    end
end

-- Function to control the lamp based on received messages
local function lampController()
    while true do
        if #messageQueue > 0 then
            local receivedMessage = table.remove(messageQueue, 1)
            local message = receivedMessage.message
            if message == "on" then
                redstone.setOutput("right", true)
                print("Lamp turned ON")
            elseif message == "off" then
                redstone.setOutput("right", false)
                print("Lamp turned OFF")
            end
        end
        sleep(0.1)  -- Small delay to avoid busy waiting
    end
end

-- Main Program
local config = loadConfig()

if config["mode"] == "A" then
    -- Computer A: Operating the Switch
    rednet.open("back")
    print("Running as Computer A - Switch Controller")
    local previousState = nil
    while true do
        local switchState = redstone.getInput("left")
        if switchState ~= previousState then
            local message = switchState and "on" or "off"
            rednet.broadcast(message)
            print("Broadcasting switch state: " .. message)
            previousState = switchState
        end
        sleep(0.1)  -- Small delay to reduce CPU usage
    end

elseif config["mode"] == "B" then
    -- Computer B: Operating the Lamp
    rednet.open("back")
    print("Running as Computer B - Lamp Controller")
    -- Run both the message listener and the lamp controller in parallel
    parallel.waitForAll(messageListener, lampController)

else
    error("Invalid mode in configuration file! Must be 'A' or 'B'")
end