-- Function to handle redstone control
local function controlRedstone(side, action, duration)
    if side == "back" or side == "left" then
        if action == "on" then
            redstone.setOutput(side, true)
        elseif action == "off" then
            redstone.setOutput(side, false)
            if duration then
                sleep(duration) -- Wait for the specified duration
                redstone.setOutput(side, true) -- Turn it back on after the duration
            end
        end
    end
end

-- Attach the modem
local modem = peripheral.find("modem")

if not modem then
    print("No modem found. Please attach a modem.")
    return
end

modem.open(1) -- Open channel 1 for communication

-- Initialize redstone to "on" on boot for both sides
local sides = {"back", "left"}
for _, side in ipairs(sides) do
    redstone.setOutput(side, true)
end

-- Main loop to listen for messages
while true do
    local event, side, senderChannel, receiverChannel, message, distance = os.pullEvent("modem_message")

    -- Check if the message has the expected format
    if type(message) == "table" and message.action and message.side then
        controlRedstone(message.side, message.action, message.duration)
    end
end