-- client.lua

-- Function to find and open the modem
local function openModem()
    local sides = {"left", "right", "top", "bottom", "front", "back"}
    for _, side in ipairs(sides) do
        if peripheral.isPresent(side) and peripheral.getType(side) == "modem" then
            rednet.open(side)
            return true
        end
    end
    return false
end

-- Open the modem
if not openModem() then
    print("No modem found!")
    return
end

local paired = false

-- Function to pair with the host
local function pairWithHost(pairingKey)
    rednet.broadcast(pairingKey, "pairing")
    local senderId, response, protocol = rednet.receive("pairing_response", 30)
    if protocol == "pairing_response" and response == "success" then
        paired = true
        print("Paired with host.")
    else
        print("Pairing failed or timed out.")
    end
end

-- Main loop
while true do
    if not paired then
        print("Enter pairing key (4-digit hex): ")
        local pairingKey = read()
        pairWithHost(pairingKey)
    else
        local senderId, command, protocol = rednet.receive("command")
        if protocol == "command" then
            local handle = io.popen(command)
            local result = handle:read("*a")
            handle:close()
            rednet.send(senderId, result, "response")
        end
    end
end