Train route counter

local periList = peripheral.getNames()
modem = false
for i = 1, #periList do
  if peripheral.getType(periList[i])=="modem" then
    modem = peripheral.wrap(periList[i])
    rednet.open(periList[i])
  end
end

if not(modem) then
  error("No modem found")
end

function SaveToFile(filename, value)
  fs.delete(filename)
  local file = fs.open(filename, "w")
  file.writeLine(value .. "")
  file.close()
  return 0
end

function LoadFromFile(filename)
  local file = fs.open(filename, "r")
  local data = file.readLine()
  file.close()
  return data
end

function get_realtime()
  s, d, p = rednet.receive()
  return d
end

function math_round(num, idp)
  return tonumber(string.format("%." .. (idp or 0) .. "f", num))
end

if fs.exists("counter.dat") then
  temp = LoadFromFile("counter.dat")
  counter = tonumber(temp)
else
  counter = 0
  SaveToFile("counter.dat", counter)
end

if fs.exists("last.dat") then
  temp = LoadFromFile("last.dat")
  last_passage = tonumber(temp)
else
  last_passage = -1
  SaveToFile("last.dat", last_passage)
end

if fs.exists("name.dat") then
  name = LoadFromFile("name.dat")
else
  print("Enter route name:")
  name = read()
  SaveToFile("name.dat", name)
end

pulse_counted = false
if fs.exists("timings.dat") then
  timings = textutils.unserialize(LoadFromFile("timings.dat"))
else
  timings = {}
  SaveToFile("timings.dat", textutils.serialize(timings))
end


function checktrain()
  while true do
    os.pullEvent("redstone")
    if rs.getInput("bottom") and not(pulse_counted) then
      pulse_counted = true
      counter = counter + 1;
      passage = get_realtime()
      if last_passage and last_passage>1 then
        diff = passage - last_passage
        average = get_average()
        if average and average * 2 > diff then
          table.insert(timings, diff)
        end
        SaveToFile("timings.dat", textutils.serialize(timings))
      end
      last_passage = passage
      SaveToFile("last.dat", last_passage)
      SaveToFile("counter.dat", counter)
    end
    if not(rs.getInput("bottom")) and pulse_counted then
      pulse_counted = false
    end
  end
end

function get_average ()
    average = false
    if #timings > 0 then
      sum = 0
      for i=1,#timings do
        sum = sum + timings[i]
      end
      average = math_round(sum/#timings,0)
    end
    return average
end

function showStat()
  while true do
    term.clear()
    term.setCursorPos(1,1)
    print("Current route: "..name)
    print("Current counter:"..counter)
    if last_passage then
      if last_passage and last_passage > 1 then
        rtime = get_realtime()
        from_last_passage = (rtime - last_passage) .. " seconds from last train"
      else
        from_last_passage = "No trains passed"
      end
      print(from_last_passage)
    end
    if #timings > 0 then
      sum = 0
      for i=1,#timings do
        sum = sum + timings[i]
      end
      average = math_round(sum/#timings,0)
      print("Average route time:"..average)
    end

    os.sleep(1)
  end
end

parallel.waitForAny(showStat,checktrain)