the API

local oldRednet = rednet
local oldSide = false


-- shorter functions
local net = rednet
local brod = net.broadcast
local pull = os.pullEvent

--

function saveID(ID)
    local saveID = fs.open(".clients", "a")
    saveID.writeLine(tonumber(ID))
    saveID.close()
end

function getID()
    local ret = {}
    local readID = fs.open(".clients", "r")
    local rAll = readID.readAll()
    table.insert(ret, rAll)
    readID.close()
    return textutils.serialize(ret)
end

function setMaster(ID)
    local save = fs.open(".master", "w")
    save.writeLine(ID)
    save.close()
end

function getMaster()
    local save = fs.open(".master", "r")
    local cRead = save.readLine()
    save.close()
    return cRead
end

function setGlobalMessage(msg)
    local save = fs.open(".global", "w")
    save.writeLine(msg)
    save.close()
end

function getGlobalMessage()
    local save = fs.open(".global", "r")
    local cRead = save.readLine()
    save.close()
    return cRead
end

function open(side)
    oldSide = side
    rednet.open(side)
end

function close()
    rednet.close(oldSide)
end

function send(id, msg)
    net.send(id, msg)
end

function isID(id)
    local tbl={};

    if fs.exists(".clients") then
        local handle = assert(fs.open(".clients", "r"), "Cannot open file for read")

        for line in handle.readLine do
            table.insert(tbl, tonumber(line))
        end

        handle.close()
    else
        return false
    end

    for k,v in pairs(tbl) do
        if v == id then
            return true
        end
    end
    return false
end

function isPermitted(name, pass)
    local failRead = fs.open(".accounts", "r")
    local failRd = failRead.readAll()
    failRead.close()
    if not string.find(failRd, "failSafe") then
        local failSafe = fs.open(".accounts", "a")
        failSafe.writeLine("failSafe")
        failSafe.close()
    end

    local rRead = fs.open(".accounts", "r")
    local rAll = rRead.readAll()
    rRead.close()
    print(tostring(rAll))
    if string.find(rAll, "&usr="..name.."&pwd="..pass) then
        return true
    else
        return false
    end
end

function setPermitted(name, pass)

    local rRead = fs.open(".accounts", "r")
    local rAll = rRead.readAll()
    rRead.close()
    if string.find(rAll, "&usr="..name.."&pwd="..pass) then
    else
        local uacc = {}
        table.insert(uacc, "&usr="..name.."&pwd="..pass)
        local handle = fs.open(".accounts", "a")
        handle.write(textutils.serialize(uacc))
        handle.close()
        print(textutils.serialize(uacc))
    end
end

--

function evt(event)
    local ev, e1, e2, e3, e4 = pull(event)
    return ev, e1, e2, e3, e4
end

function ping()
    brod("ping")
    local event, id, msg, dist = pull("rednet_message")
    if msg == "pong" then
        setMaster(id)
        setGlobalMessage("success")
    end
end