###
### Configuration settings
###

# maps entries to IPv4 0.0.0.0 (default)
# ENDPOINT_IP4="0.0.0.0"
ENDPOINT_IP4=$(uci get network.lan.ipaddr)
# can be used if you want to use a local web server to suppress connection error requests

# directory where the compressed host files are being stored persistently
PERSISTENTDIR="/usr/share/inithost/hostfiles"

# directory where dnsmasq expects the active uncompressed host files
ACTIVEHOSTDIR="/tmp/hosts"
# if you change this default you will need to add a 'addnhost' config entry in /etc/dnsmasq.conf

# Use rule files in this directory to rewrite /etc/dnsmasq.conf to apply certain DNS rules
# for hosts which satisfy wildcard expressions
RULESDIR="/usr/share/inithost/dnsmasq_rules"

# Define whitelists
HOSTWHITELIST="$PERSISTENTDIR/whitelist"
RULEWHITELIST="$RULESDIR/whitelist"


###
### Functions -- if other host files are used from the web these need to get extended
###

# for a better understanding read also /etc/init.d/inithost

### filter_whitelist
# remove white listed items from the contents of a host file and prepends the routed IP
# no params
filter_whitelist() {
        awk '
          BEGIN{ while (getline<"'$HOSTWHITELIST'"){wl[$1]=1} }                                                       
          { if (!($1 in wl)) print "'$ENDPOINT_IP4'",$0; }
        '
}

### update_active_hostfile
# updates an active host file from the web and prepares it for use with dnsmasq
# $1 -- name of the active host file
# $2 -- URL from where to fetch the updated host file

update_active_hostfile() {

        # declare the URL where to fetch the host file
        hname="$1"
        url="$2"
        hf="$PERSISTENTDIR/$hname"
        hfl=$(readlink $hf)

        # by default we'd avoid frequent updates
        local needs_updating="0"

        # does an compressed persistent host file exist?
        if [ -f ${hf}.gz ]; then
                # Yes! then compare time stamps of persistent host file and web host file
                logger "check ${hf}.gz for update..."
                remote_mtime=$(last_mtime $url)
                local_mtime=$(date +%s -r ${hf}.gz)

                # if not disabled and host file is newer than local copy perform an update
                if [ "$hfl" == "/dev/null" ]; then
                        logger "disabled by configuration"
                elif [ "$remote_mtime" -gt "$local_mtime" ]; then
                        needs_updating="1"
                else
                        logger "already up-to-date"
                fi
        else
	        # Does an uncompressed persistent host file exist?
	        if [ -f $hf ]; then
		        logger "check $hf for update..."
			remote_mtime=$(last_mtime $url)
			local_mtime=$(date +%s -r $hf)

			# if host file is newer perform an update
			if [ "$remote_mtime" -gt "$local_mtime" ]; then
			        needs_updating="1"
			else
			        logger "already up-to-date"
			fi
		else
                        # No! We probably retrieve it from the web for the first time!
                        needs_updating="1"
		fi
        fi

        if [[ "$needs_updating" -eq "1" ]]; then
                logger "updating $hf ..."
                curl -m 20 -s $url | hostfilter "$hname" |\
                sed 's/^0.0.0.0[[:space:]]*//' | sort -u |\
                awk 'NF==1{print}' | filter_whitelist > $hf && touch $hf.gz
        fi
}

hostfilter() {
        case $1 in
        "mvps")    grep 0.0.0.0 | sed 's/[[:space:]]*#.*$//g' | grep -v localhost | tr -d '\r' | tr -s '\t' | tr -d '\015' ;;
        "adaway")  grep -v "#" | grep -v "::1" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $2}' | grep -v '^\\' | grep -v '\\$' ;;
        "hfnet")   grep -v "#" | grep -v "::1" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $2}' | grep -v '^\\' | grep -v '\\$' ;;
        "mwd")     grep -v "#" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $3}' | grep -v '^\\' | grep -v '\\$' ;;
        "sowc")    grep -v "#" | sed '/^$/d' | sed 's/\ /\\ /g' | grep -v '^\\' | grep -v '\\$' | awk '{print $2}' | grep -v '^\\' | grep -v '\\$' ;;
        "gjtech")  grep -v "#" | sed '/^$/d' | sed 's/\ /\\ /g' | awk '{print $2}' | grep -v '^\\' | grep -v '\\$' ;;
        "yoyo")    grep -v "#" | grep -v '^<' | grep -v '^ ' | grep -v '^$(printf '\t')' ;;
        "quidsup") grep -v "#" ;;
        *)         awk '{print "filter undefined"; exit(1)}' ;;
        esac
}

### MAIN FUNCTION

# for any new host file add a new entry here!
update_hostfiles_from_web() {
        update_active_hostfile "mvps"    "http://winhelp2002.mvps.org/hosts.txt" 
        update_active_hostfile "adaway"  "http://adaway.org/hosts.txt"         
        update_active_hostfile "hfnet"   "http://hosts-file.net/.%5Cad_servers.txt"
        update_active_hostfile "mwd"     "http://www.malwaredomainlist.com/hostslist/hosts.txt"
        update_active_hostfile "sowc"    "http://someonewhocares.org/hosts/hosts"
	update_active_hostfile "gjtech"  "http://adblock.gjtech.net/?format=unix-hosts"
        update_active_hostfile "yoyo"    "http://pgl.yoyo.org/adservers/serverlist.php?hostformat=;showintro=0"
        update_active_hostfile "quidsup" "https://raw.githubusercontent.com/quidsup/notrack/master/trackers.txt"

        # static host files (no web updates available):
        # $PERSISTENTDIR/custom
        # $PERSISTENTDIR/porn
}