#!/bin/bash

#
# Copyright (c) 2018 leopold@shdx.org
# Author: Der_Leopold
#
# This script simply parses the text file created by readSensor and
# prints the requested value. It is supposed to be called by the Zabbix
# agent.
# To prevent processing of stale data, it compares the timestamp from
# the file to the current one and returns an error if the difference is
# too big.
#

# Maximum data age in seconds. If the data is older, print an error and exit.
MAXAGE=300

# File to read the sensor data from
DATAFILE=/opt/Zabbix-1wire/output

function print_usage () {
    echo ""
    echo "Usage:"
    echo ""
    echo "  parseOutput <LuftTemp|WasserTemp|BodenTemp>"
    echo ""
}

function parse_datafile () {
#    REGEX="^(\w+)=(\d+\.*\d*)$"  # should work but does not?
    REGEX="^(\w+)=(.*)$"
    while read -r LINE; do
        if [[ $LINE =~ $REGEX ]]; then
	    KEY=${BASH_REMATCH[1]}
	    VALUE=${BASH_REMATCH[2]}
            case $KEY in
                "Timestamp")
		    THRESHOLD=$(( $VALUE + $MAXAGE ))
		    TS=$(date +"%s")
		    if (( $TS <= $THRESHOLD )); then
		        TSVALID=1
		    fi
                    ;;
                "LuftTemp")
                    if [ $PARAM == "LuftTemp" ]; then
		        RESULT=$VALUE
		    fi
		    ;;
                "WasserTemp")
		    if [ $PARAM == "WasserTemp" ]; then
                        RESULT=$VALUE
                    fi
		    ;;
                "BodenTemp")
                    if [ $PARAM == "BodenTemp" ]; then
                        RESULT=$VALUE
                    fi
                    ;;
            esac
        fi
    done < "$DATAFILE"
}

PARAM="$1"

if [[ ( ! $# -eq 1 ) || ( $PARAM != "LuftTemp" && $PARAM != "WasserTemp" && $PARAM != "BodenTemp" ) ]]; then
    print_usage
    exit 1
fi

if [ ! -r $DATAFILE ]; then
    echo "Error: cannot read data file"
    exit 1
else
    TSVALID=0
    parse_datafile
fi

if [ $TSVALID -eq 0 ]; then
    echo "Error: Data file contains old or invalid data"
    exit 1
else
    echo "$RESULT"
    exit 0
fi