ROBCO Network

--========================================================--
--   ROBCO INDUSTRIES (TM) UNIFIED OPERATING SYSTEM
--   NETWORK MODULE — ENCRYPTED REDNET COMMUNICATION
--========================================================--

local network = {}

local ui = require("robco/ui")

------------------------------------------------------------
-- ENCRYPTION KEY
------------------------------------------------------------
local ENCRYPTION_KEY = "ROBCO-SECURE-KEY"

------------------------------------------------------------
-- XOR BYTE (Minecraft‑compatible)
------------------------------------------------------------
local function xorByte(a, b)
    local r = 0
    for i = 0, 7 do
        local x = a % 2
        local y = b % 2
        if x ~= y then r = r + 2^i end
        a = math.floor(a / 2)
        b = math.floor(b / 2)
    end
    return r
end

------------------------------------------------------------
-- ENCRYPT / DECRYPT
------------------------------------------------------------
local function encrypt(text, key)
    if not key or key == "" then return text end
    local out = {}
    for i = 1, #text do
        local c = text:byte(i)
        local k = key:byte(((i-1) % #key) + 1)
        table.insert(out, string.char(xorByte(c, k)))
    end
    return table.concat(out)
end

local function decrypt(text, key)
    return encrypt(text, key)
end

------------------------------------------------------------
-- MODEM DETECTION
------------------------------------------------------------
local modem = peripheral.find("modem")

function network.hasModem()
    return modem ~= nil
end

if modem then
    rednet.open(peripheral.getName(modem))
end

------------------------------------------------------------
-- CONNECT TO ANOTHER TERMINAL
------------------------------------------------------------
function network.connect(id)
    if not modem then
        ui.statusLine("NO MODEM DETECTED")
        return
    end

    if not id then
        ui.statusLine("USAGE: connect <id>")
        return
    end

    ui.statusLine("PINGING " .. id .. "...")

    rednet.send(id, encrypt("ROBCO_CONNECT", ENCRYPTION_KEY), "robco")

    local sender, msg = rednet.receive("robco", 2)
    if sender == id and decrypt(msg, ENCRYPTION_KEY) == "ROBCO_ACK" then
        ui.statusLine("CONNECTION ESTABLISHED")
    else
        ui.statusLine("NO RESPONSE")
    end
end

------------------------------------------------------------
-- SEND ENCRYPTED MESSAGE
------------------------------------------------------------
function network.sendMsg(id, msg)
    if not modem then
        ui.statusLine("NO MODEM DETECTED")
        return
    end

    if not id or msg == "" then
        ui.statusLine("USAGE: send <id> <msg>")
        return
    end

    rednet.send(id, encrypt(msg, ENCRYPTION_KEY), "robco")
    ui.statusLine("ENCRYPTED MESSAGE SENT")
end

------------------------------------------------------------
-- LISTEN FOR ENCRYPTED MESSAGE
------------------------------------------------------------
function network.listen()
    if not modem then
        ui.statusLine("NO MODEM DETECTED")
        return
    end

    ui.statusLine("LISTENING...")

    local sender, msg = rednet.receive("robco")
    local dec = decrypt(msg, ENCRYPTION_KEY)

    term.setCursorPos(3, 9)
    print("MESSAGE FROM " .. sender .. ":")
    term.setCursorPos(3, 10)
    print(dec)

    ui.statusLine("MESSAGE RECEIVED")
end

------------------------------------------------------------
-- BACKGROUND LISTENER (AUTO‑ACK)
------------------------------------------------------------
function network.backgroundListener()
    if not modem then return end

    while true do
        local sender, msg = rednet.receive("robco")
        if decrypt(msg, ENCRYPTION_KEY) == "ROBCO_CONNECT" then
            rednet.send(sender, encrypt("ROBCO_ACK", ENCRYPTION_KEY), "robco")
        end
    end
end

return network