#!/usr/bin/lua

local socket = require("socket")

local devicepath = "/sys/class/ddbridge/ddbridge0"
local interval = 30
local nValues = 2880
local LogFile = "/tmp/Temperatur.log"
local HighTemp = 50
local LowTemp = 45

function ReadAttribute(attribute)
  local value = 0
  local ddbridge = io.open(devicepath.."/"..attribute,"r");
  if ddbridge then
    value = ddbridge:read("*l")
    ddbridge:close()
  end
  return value
end

function ReadTemp(sensor)
   local temp = 0
   local file;

   if sensor > 3 then
      sensor = sensor - 4
      if sensor == 0 then
         file = io.open(devicepath.."/temp")
      else
         file = io.open(devicepath.."/templ"..sensor)
      end
   else
      file = io.open(devicepath.."/temp"..sensor)
   end

   if file then
      temp = file:read()
      if temp == "no sensor" then
         temp = 0
      else
         temp = math.floor(tonumber(temp)/1000)
      end
      file:close()
   end
   return temp
end

function sleep(sec)
   socket.select(nil,nil,sec)
end

function SetFan(value)
   local gpio = io.open("/sys/class/gpio/gpio106/value","w");
   if gpio then
     gpio:write(value)
     gpio:close()
   end
end

local gpio = io.open("/sys/class/gpio/export","w");
if gpio then
  gpio:write("106")
  gpio:close()
end

local NumSensors = 0
local i
local temps
local temp
local Sensor = {}

local TempList = {}
local StartIndex = 1
local count = interval
local fanstate = -1

sleep(30)

local devid = ReadAttribute("devid0")
if devid == "0307dd01" then 
  fanstate = 1
  local devid1 = ReadAttribute("devid1")
  if devid1 == "0009dd01" or devid1 == "000add01" then
     fanstate = -2
  else
    local fs = tonumber(ReadAttribute("fanspeed1"))
    if fs > 0 and fs < 17000 then 
       fanstate = -2
    end
  end
end 

for i = 0,8,1 do
   temp = ReadTemp(i)
   if temp > 0 then
      Sensor[NumSensors] = i
      NumSensors = NumSensors + 1
   end
end

local fh = io.open(LogFile,"w")
if fh then
   fh:write(NumSensors..","..interval..","..fanstate.."\n")
   fh:close()
end

if NumSensors == 0 then
   return
end

while true do
   sleep(1)
   temps = ""
   for i = 0, NumSensors - 1, 1 do
      temp  = ReadTemp(Sensor[i])

      if temp == 0 then
         print(" fanControl Error ")
         return
      end

      if i == 0 then
         temps = temp
      else
         temps = temps .. "," .. temp
      end

      if fanstate == 0 and temp >= HighTemp then
        SetFan(1)
        fanstate = 1
      elseif fanstate == 1 and temp < LowTemp then
        SetFan(0)
        fanstate = 0
      end

   end

   count = count - 1
   if count == 0 then
      count = interval

      if #TempList < nValues then
         TempList[#TempList+1] = temps
      else
         TempList[StartIndex] = temps
         StartIndex = StartIndex + 1
         if StartIndex > nValues then StartIndex = 1 end
      end

      TmpLogFile = os.tmpname()

      fh = io.open(TmpLogFile,"w")
      if fh then
         fh:write(NumSensors..","..interval..","..fanstate.."\n")

         for i = StartIndex-1, 1, -1 do
            fh:write(TempList[i].."\n")
         end

         for i = #TempList, StartIndex, -1 do
            fh:write(TempList[i].."\n")
         end

         fh:close()
         os.remove(LogFile)
         os.rename(TmpLogFile,LogFile)
      end
   end
   collectgarbage()
end