#!/usr/bin/python
# $Id: tsl.py,v 1.5 2006/01/02 11:47:50 ambolt Exp $

# Temperature data logger.
# It is designed to be run by init(8), for instance like this:
# S1:345:respawn:/usr/local/bin/tsl.py /dev/ttyS1 /var/spool

# Copyright (C) 2005 Asgeir S. Nilsen

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.

import serial
import os
import time
import sys

port = sys.argv[1]
dir = sys.argv[2]
if not os.path.isdir(dir):
    raise Exception("Argument is not directory: "+dir)

def COUNT():
    return 5

while True:

    ser = serial.Serial(port,2400,timeout=10)
    ser.readline()

    try:
        list = {}
        sum = {}
        for i in ('1','2','3','4'):
            list[i] = [0.0] * COUNT()
            sum[i] = 0.0
        while True:
            data = ser.readline().split()
            idx = data[0]
            temp = float(data[1])
            old = list[idx].pop(0)
            sum[idx] -= old
            sum[idx] += temp
            list[idx].append(temp)
            f = file(dir+'/tsl.tmp','w')
            f.write(str(sum[idx]/COUNT())+'\n')
            f.close()
            os.rename(dir+'/tsl.tmp', dir+'/tsl.'+idx)

    finally:
        ser.close()
        time.sleep(1)