#!/bin/sh

FILE_TO_WATCH="/tmp/ndnproxymain.conf"
PREVIOUS_HASH=""

# Commands to execute when the file changes
COMMANDS_ON_CHANGE="
    ipset flush bypass
    /opt/etc/init.d/S52ipset-dns restart
"

# Function to calculate MD5 hash of the file
calculate_md5() {
    md5sum "$FILE_TO_WATCH" | awk '{ print $1 }'
}

# Function to execute commands when the file changes
on_file_change() {
    eval "$COMMANDS_ON_CHANGE"
}

# Function to start the script
start() {
    echo "Starting ipset watcher..."
    PREVIOUS_HASH=$(calculate_md5)
    inotifywait -q -m -e close_write "$FILE_TO_WATCH" | while read _; do
        CURRENT_HASH=$(calculate_md5)
        if [ "$CURRENT_HASH" != "$PREVIOUS_HASH" ]; then
            PREVIOUS_HASH="$CURRENT_HASH"
            on_file_change
        fi
    done &
    echo $! > /var/run/ipset_watcher.pid
}

# Function to stop the script
stop() {
    echo "Stopping ipset watcher..."
    kill $(cat /var/run/ipset_watcher.pid)
    rm /var/run/ipset_watcher.pid
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    restart)
        stop
        start
        ;;
    *)
        echo "Usage: $0 {start|stop|restart}"
        exit 1
        ;;
esac

exit 0