#!/usr/bin/lua

function file_exists(name)
    local f=io.open(name,"r")
    if f~=nil then io.close(f) return true else return false end
end

function watch_mac(mac)
    command = "batctl n | grep -i " .. mac .. " | tr -s ' ' | cut -d' ' -f4"
    local handle = io.popen(command)
    local result = handle:read("*a")
    handle:close()
    return result:match("(.-)%s*$")
end

counterfile = "/var/run/alarmcounter"
lastseen = watch_mac("a2:1b:3a:0b:3e:72")
age_seconds = tonumber(lastseen:sub(1, -2)) or 1000
if age_seconds > 30 then
    if not file_exists(counterfile) then
        file = io.open(counterfile, "w")
        file:write("1")
        file:close()
        command = "ssh alarmuser@srv01.ffpi ./alarmmail.sh"
        local handle = io.popen(command)
        local result = handle:read("*a")
        handle:close()
    end
else
    if file_exists(counterfile) then
        os.remove(counterfile)
    end
end