BitNet Rednet Repeater (MoarPeripherals)

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--        BitNet Rednet Repeater       --
-----------------------------------------

-- By Jeffrey Alexander, aka Bomb Bloke.

-- Acts as repeater software for BitNet transmitters:
-- https://github.com/theoriginalbit/MoarPeripherals/wiki/BitNet-Mini-Antenna
-- https://github.com/theoriginalbit/MoarPeripherals/wiki/BitNet-Communication-Tower

-- Pretty much the same thing as the default "repeat" script:
-- http://www.computercraft.info/wiki/Repeat
-- ... though it supports BitNet devices as well. Can work with any combination
-- of modems/towers or alongside the vanilla repeat script itself.

---------------------------------------------

local modem = {peripheral.find("modem")}
for i = 1, #modem do modem[i].open(rednet.CHANNEL_REPEAT) end

local antenna = {peripheral.find("bitnet_antenna")}
local tower = {peripheral.find("bitnet_tower", function(name, object) return object.isTowerComplete() end)}

if #modem == 0 then error("No modems found - can't send / receive rednet messages without one!") end

local repeated, msgID, timerID, myEvent = 0, {}, {}

print(#modem.." modem"..(#modem==1 and "" or "s").." found.")
print(#antenna.." antenna"..(#antenna==1 and "" or "s").." found.")
print(#tower.." tower"..(#tower==1 and "" or "s").." found.")
print("0 messages repeated.")

-- Repeat a message:
local function resend(message)
    -- Determine if the message has already been repeated by this system:
    if msgID[tostring(message.nMessageID)] then return end

    -- Flag the message as having passed through this system:
    msgID[tostring(message.nMessageID)] = true
    timerID[tostring(os.startTimer(30))] = tostring(message.nMessageID)

    -- Update the onscreen repeat counter:
    local curX, curY = term.getCursorPos()
    term.setCursorPos(1,curY-1)
    repeated = repeated + 1
    print(repeated.." messages repeated.")

    -- Send a copy via all attached BitNet devices:
    for i = 1, #antenna do antenna[i].transmit(message) end
    for i = 1, #tower do tower[i].transmit(message) end

    -- Send a copy via all attached modems:
    for i = 1, #modem do
        modem[i].transmit(message.nRecipient,    message.nSender, message)
        modem[i].transmit(rednet.CHANNEL_REPEAT, message.nSender, message)
    end
end

-- Main loop:
while true do
    myEvent = {os.pullEvent()}

    -- Message arriving via tower:
    if myEvent[1] == "bitnet_message" and type(myEvent[3]) == "table" and myEvent[3].nMessageID then
        resend(myEvent[3])

    -- Message arriving via a modem:
    elseif myEvent[1] == "modem_message" then
        if not myEvent[5].nSender then myEvent[5].nSender = myEvent[4] end
        resend(myEvent[5])

    -- Unmark a given message previously logged as repeated:
    elseif myEvent[1] == "timer" and timerID[tostring(myEvent[2])] then
        msgID[timerID[tostring(myEvent[2])]] = nil
        timerID[tostring(myEvent[2])] = nil

    -- Quit:
    elseif myEvent[1] == "key" and (myEvent[2] == keys.q or myEvent[2] == keys.x) then
        os.pullEvent("char")
        error()

    end
end