#!/bin/bash
#
#stream-monitor.sh
#Developed on Debian
#Requires mpd
#
#Its an extension of http://mpd.wikia.com/wiki/Hack:stream-monitor?oldid=3932
# You can use the same Init-Script
#
#To Install:
# cp stream-monitor.sh /usr/bin/stream-monitor.sh
# chmod 755 /usr/bin/stream-monitor.sh
#
#This script monitors mpd while it is playing an internet stream. It checks every $INTERVAL_CHECK seconds
# to see if the status time variable has changed. (The stream is not playing when the time
# is not changing.) Then it restart playing.
#It also checks the current state of MPD and only take care of state 'play'. This provides you the comfort
# to use MPD like before without have to care about the watchdog when you want to pause or stop the stream.
#If the mpd daemon is not running for some reason, it starts it. i.e. if mpd were to crash.
#
#This is great for a robust stream player that keeps on playing, even after a network
# outage or stream server outage. Useful in situations where the networking is less than perfect.
#
#Check with your streaming server provider before running this. It's not nice to connect to
# a stream 24/7 if you don't need it or own it.
#
#Also does logging trough syslog.
#

INTERVAL_CHECK=5  # Seconds between checks
INTERVAL_WAIT=10  # Seconds to wait after mpd (re)start (buffering)

LOG_TAG="mpd-watchdog"

LOGGER="logger -st \"$LOG_TAG\" -- "


$LOGGER Startup with interval of $INTERVAL_CHECK Seconds


OLD_TIME=
OLD_STATE="UNKNOWN"

while sleep $INTERVAL_CHECK;
do
    STATUS=`ps -A | grep -c mpd`
        if [ $STATUS -eq 0 ]; then
                $LOGGER "no mpd processes, starting mpd"
                /etc/init.d/mpd start
                $LOGGER waiting $INTERVAL_WAIT Seconds...
                sleep $INTERVAL_WAIT
                continue
        fi


    TIME="0"
    STATE="UNKNOWN"

    RESP=`echo -e "status\\nclose" | nc localhost 6600 `

    IFS=": "
    while read KEY VALUE; do
        case "$KEY" in
            state) STATE="$VALUE";;
            time)  TIME="$VALUE";;
        esac
    done <<<"$RESP"
    unset IFS

    if   [ "$OLD_STATE" != "$STATE" ]; then
        $LOGGER "MPD changed state from '$OLD_STATE' to '$STATE' "
    fi

    if   [ "$STATE" == "play" ]; then

                if [ "$TIME" = "$OLD_TIME" ]; then
                        $LOGGER "mpd hanging, restarting"
                        mpc stop
                        mpc play
                        $LOGGER waiting $INTERVAL_WAIT Seconds...
            sleep $INTERVAL_WAIT
                fi
        fi

        OLD_STATE=$STATE
    OLD_TIME=$TIME
done