#!/bin/bash
#  $HeadURL: https://svn.pasta.freemyip.com/main/miniade/trunk/bin/nop-sh $ $LastChangedRevision: 10133 $

#  Modules
. $(miniade) || { echo "${0##*/}: ERROR: miniade failed (hint: run 'miniade' to see error)" >&2; exit 1; }

#  Configurable stuff
BLACKLIST_URL=https://raw.githubusercontent.com/StevenBlack/hosts/master/alternates/fakenews-gambling/hosts
MIN_LINE_COUNT=90000
MAX_LINE_COUNT=300000
MAX_OLD_BLACKLIST_AGE=1213200   #  14 days 1 hour
DNS_RECORD_FMTSTR="%-40s IN %-5s %s\\n"
RPZ_ZONE_FILE=/etc/bind/db.rpz-remote
NAMESERVER_UNAME=orzo
LOCAL_DOMAIN=pasta.net

#  Other globals
MODROOT=$(cd $(dirname $(realpath $0))/.. && pwd)

main()
{
    local MY_ARGS
    local PROGNAME

    #  Defaults for options
    FORCE_UPDATE_FLAG=false

    #  Process options
    special_opts_handler()
    {
        case $1 in
            -f|--force) FORCE_UPDATE_FLAG=true ;;
            *)          return 1 ;;
        esac
    }
    miniade_process_options --help-handler=help --special-opts-handler=special_opts_handler MY_ARGS "$@" && set -- "${MY_ARGS[@]}"

    #  Process arguments
    [ $# = 0 ] || miniade_bad_usage

    #  Sanity checks and derivations
    miniade_get_progname PROGNAME
    TMP_BLACKLIST_FILE=$MODROOT/var/$PROGNAME/blacklist.tmp
    OLD_BLACKLIST_FILE=$MODROOT/var/$PROGNAME/blacklist.old
    
    #  Guts
    miniade_info "fetching blacklist ..."
    mkdir -p $(dirname $TMP_BLACKLIST_FILE)
    wget -qO - $BLACKLIST_URL > $TMP_BLACKLIST_FILE

    miniade_info "cleaning blacklist ..."
    sed -r -i \
        -e '1,/End of custom host records/d' \
        -e '/^[ \t]*(#|$)/d' \
        -e 's/[ \t]+#.*//' \
        -e 's/^0\.0\.0\.0[ \t]*//' \
        -e '/^[^.]*$/d' \
        $TMP_BLACKLIST_FILE
    sort < $TMP_BLACKLIST_FILE > /tmp/$PROGNAME.$$.sorted
    mv /tmp/$PROGNAME.$$.sorted $TMP_BLACKLIST_FILE

    miniade_info "sanity checking blacklist ..."   
    if [ $(wc -l < $TMP_BLACKLIST_FILE) -lt $MIN_LINE_COUNT ]; then
        miniade_error "new blacklist looks too small (hint: look in $TMP_BLACKLIST_FILE)"
    fi
    if [ $(wc -l < $TMP_BLACKLIST_FILE) -gt $MAX_LINE_COUNT ]; then
        miniade_error "new blacklist looks too big (hint: look in $TMP_BLACKLIST_FILE)"
    fi
    #  Note that 1st char of all-but-last component may be '-' (following kube.-zoonet.net.zooplus.fr).
    if egrep -nv '^([-_a-zA-Z0-9][-_a-zA-Z0-9]*\.){1,}[_a-zA-Z0-9][-_a-zA-Z0-9]*$' $TMP_BLACKLIST_FILE; then
        miniade_error "new blacklist contains badly formatted lines (hint: review above output; list is $TMP_BLACKLIST_FILE)"
    fi

    if $FORCE_UPDATE_FLAG; then
        miniade_warning "forcing update ..."
        CHANGED_FLAG=true
    elif [ ! -f $RPZ_ZONE_FILE ]; then
        miniade_warning "there is no zone file"
        CHANGED_FLAG=true
    elif [ ! -f $OLD_BLACKLIST_FILE ]; then
        miniade_warning "there is no old blacklist to compare the new blacklist with"
        CHANGED_FLAG=true
    elif cmp -s $TMP_BLACKLIST_FILE $OLD_BLACKLIST_FILE; then
        CHANGED_FLAG=false
    else
        miniade_info "new blacklist contains new entries"
        CHANGED_FLAG=true
    fi

    if $CHANGED_FLAG; then
        miniade_info "updating DNS ..."
        {
            echo ";"
            echo ";  This file was generated by $PROGNAME on"
            echo ";  $(date)."
            echo ";"
            echo
            echo "\$TTL 1h"
            echo "rpz-remote. IN SOA ns.$LOCAL_DOMAIN. root.$LOCAL_DOMAIN. ( $(date +%Y%m%d01) 1d 2h 4w 1h )"
            echo "rpz-remote. IN NS $NAMESERVER_UNAME.$LOCAL_DOMAIN."
            echo
            while read FQHN; do
                printf "$DNS_RECORD_FMTSTR" "$FQHN" CNAME .
                printf "$DNS_RECORD_FMTSTR" "*.$FQHN" CNAME .
            done < $TMP_BLACKLIST_FILE
        } > $RPZ_ZONE_FILE
        systemctl reload bind9
    
        miniade_info "archiving new blacklist for future comparisons ..."
        cp $TMP_BLACKLIST_FILE $OLD_BLACKLIST_FILE
    else
        OLD_BLACKLIST_AGE=$(($(date +%s) - $(stat -c %Y $OLD_BLACKLIST_FILE)))
        if [ $OLD_BLACKLIST_AGE -gt $MAX_OLD_BLACKLIST_AGE ]; then
            miniade_warning "blacklist has not changed in ${OLD_BLACKLIST_AGE}s (~$(echo "scale=2;$OLD_BLACKLIST_AGE/3600/24" | bc -q)d!)"
        else
            miniade_info "blacklist has not changed"
        fi
    fi
    rm -f $TMP_BLACKLIST_FILE
}

help()
{
    local PROGNAME

    miniade_get_progname PROGNAME
    echo "Usage: $PROGNAME [ <standard-options> ] [ -f | --force ]"
    exit 0
}

main "$@"