#!/bin/bash
# update-virtualhosts Virtual hosts updater
# (C) 2019 Nirgal Vourgère <nirgal@debian.org>
# GPL-3

DIRS=()
VERBOSE=1  # 0=only_warnings 1=notice 2=debug
COMMANDLINE="$0 $@"
OUTPUT=""

parsearg() {
	_OPT="${1%=?*}"
	_VAL="${1#?*=}"
}

usage() {
	#echo $'\n' $@ $'\n'
	echo "Usage: $0 [options] basedir..."
	echo "  -h|--help             Display that help"
	echo "  --verbose-lvl=level   Define verbosity level. Defaults to $VERBOSE."
	echo "                        0: Only warnings"
	echo "                        1: Include notices"
	echo "                        2: debug"
	echo "                        Fell free to ignore STDERR"
	echo "  -q|--quiet            Identical to --verbose-lvl=0"
	echo "  -d|--debug            Identical to --verbose-lvl=2"
}

for arg in "$@"; do
	parsearg $arg

	case $_OPT in
	--verbose-lvl)
		VERBOSE=$_VAL
		continue
	;;
	-q|--quiet)
		VERBOSE=0
		continue
	;;
	-d|--debug)
		VERBOSE=2
		continue
	;;
	-h|--help)
		usage 
		exit 0
	;;
	-*)
		echo "Unknown option $_OPT" >&2
		usage >&2
		exit 22
	;;
	*)
		DIRS+=("$_OPT")
		continue
	;;
	esac
done

NORMAL=`tput sgr0 2>/dev/null`
RED=`tput setaf 1 2>/dev/null`
GREEN=`tput setaf 2 2>/dev/null`

log() {
	echo "$@" >&2
}

log_error() {
	log $RED"$@"$NORMAL
}

log_info() {
	if (( $VERBOSE > 0 ))
	then
		log "$@"
	fi
}

log_debug() {
	if (( $VERBOSE > 1 ))
	then
		log "$@"
	fi
}

output() {
	if [[ -n "$OUTPUT" ]]
	then
		echo "$@" >> $OUTPUT
	else
		echo "$@"  # STDOUT
	fi
}

main() {
	basedir="$1"

	# ======================================================================
	# Step 1
	# Parse $INPUT that reads like
	#   www1.lan < example.com www.example.com
	#   192.168.0.11 < example.net www.example.net
	#   fdce:266b:c77a::b < example.net www.example.net
	# and fill these 6 vars:
	redirections4_src=()      # ( "example.com www.example.com" "example.net www.example.net" )
	redirections4_dst=()      # ( "192.168.0.10" "192.168.0.11" )
	redirections4_dstname=()  # ( "www1.lan" "192.168.0.11" )
	redirections6_src=()      # ( "example.com www.example.com" "example.net www.example.net" )
	redirections6_dst=()      # ( "fdce:266b:c77a::a" "fdce:266b:c77a::b" )
	redirections6_dstname=()  # ( "www1.lan" "fdce:266b:c77a::b" )
	redirectionsn_src=()      # ( "example.com www.example.com" )
	redirectionsn_dst=()      # ( "www1.lan" )

	if test -r "$basedir/config"
	then
		log_info "Reading $basedir/config"
		source "$basedir/config"
	else
		log_error "Cannot read $basedir/config. Skiping."
		return
	fi
	if [[ -z "$INPUT" ]]
	then
		log_error "Variable INPUT is empty. Skiping $basedir."
		return
	fi
	while read line
	do
		if [[ "$line" =~ ^([^\>]*)[[:space:]]*\>[[:space:]]*(.*)$ ]]
		then
			sources="${BASH_REMATCH[1]}"
			destination=${BASH_REMATCH[2]}
			if [[ "$destination" =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]
			then
				log_info "Virtual host(s) $sources redirect(s) to ipv4 $destination, no ipv6."
				redirections4_src+=("$sources")
				redirections4_dst+=($destination)
				redirections4_dstname+=($destination)
			elif [[ "$destination" =~ ^[0-9a-f:]*:[0-9a-f:]* ]]
			then
				log_info "Virtual host(s) $sources redirect(s) to ipv6 $destination, no ipv4."
				redirections6_src+=("$sources")
				redirections6_dst+=("$destination")
				redirections6_dstname+=("$destination")
			else
				msg="Virtual host(s) $sources redirect(s) to host $destination: "
				redirectionsn_src+=("$sources")
				redirectionsn_dst+=("$destination")
				ipv4=$(getent ahostsv4 "$destination" | cut -d ' ' -f 1 | sort -u)
				ipv6=$(getent ahostsv6 "$destination" | cut -d ' ' -f 1 | sort -u)
				if (( $(echo "$ipv4" | wc -l) > 1 ))
				then
					log_error "ERROR: $destination has several ipv4 addresses. This is not supported. ipv4 disabled for this domain."
					ipv4=""
				fi
				if (( $(echo "$ipv6" | wc -l) > 1 ))
				then
					log_error "ERROR: $destination has several ipv6 addresses. This is not supported. ipv6 disabled for this domain."
					ipv6=""
				fi
				if [[ -n "$ipv4" ]]
				then
					msg+="ipv4=$ipv4, "
					redirections4_src+=("$sources")
					redirections4_dst+=($ipv4)
					redirections4_dstname+=($destination)
				else
					msg+="no ipv4,"
				fi
				if [[ -n "$ipv6" ]]
				then
					msg+="ipv6=$ipv6."
					redirections6_src+=("$sources")
					redirections6_dst+=($ipv6)
					redirections6_dstname+=($destination)
				else
					msg+="no ipv6."
				fi
				log_info "$msg"
				if [[ -z "$ipv4" && -z "$ipv6" && ! -d "$basedir/hostname" ]]
				then
					log_error "ERROR: $destination has no ipv4 nor ipv6."
				fi
			fi
		else
			log_error "ERROR: syntax error while parsing $line"
		fi
	done < "$INPUT"

	#log_debug "============================================================="
	#
	#for (( i=0; i<${#redirections4_dst[@]}; i++ ))
	#do
	#	log_debug "${redirections4_dst[$i]}"
	#	sources=${redirections4_src[$i]}
	#	for s in ${sources[*]}
	#	do
	#		log_debug "  if $s"
	#	done
	#done

	# ======================================================================
	# Step 2: write the file
	if [[ -n "$OUTPUT" ]]
	then
		log_debug "Backup'ing $OUTPUT"
		mv "$OUTPUT" "$OUTPUT.bak"
		log_info "Writing to $OUTPUT."
		echo -n > "$OUTPUT"
	fi

	log_debug "============================================================="

	output "############################################################################"
	output "# DO NOT EDIT THAT FILE"
	output "# Notice: That file was generated using:"
	output "#    $COMMANDLINE"
	output "# See $basedir/config"
	output "############################################################################"

	if [[ -f "$basedir/prolog" ]]
	then
		fragment=$(cat "$basedir/prolog")
		output "${fragment}"
	fi

	if [[ -d "$basedir/ipv4" ]]
	then
		for fragmentdir in $( find "$basedir/ipv4" -mindepth 1 -maxdepth 1 -type d | sort )
		do
			log_debug "Processing $fragmentdir"
			if test -f "$fragmentdir/prolog"
			then
				fragment=$(cat "$fragmentdir/prolog")
				output "${fragment}"
			fi
			for (( i=0; i<${#redirections4_dst[@]}; i++ ))
			do
				destination="${redirections4_dst[$i]}"
				dstname="${redirections4_dstname[$i]}"
				log_debug "Processing $fragmentdir for destination $destination"
				if test -f "$fragmentdir/destination"
				then
					fragment=$(cat "$fragmentdir/destination")
					fragment="${fragment//[$]destination/$destination}"
					fragment="${fragment//[$]dstname/$dstname}"
					output "${fragment}"
				fi
				sources=${redirections4_src[$i]}
				for source in ${sources[*]}
				do
					if test -f "$fragmentdir/line_$source"
					then
						fragment=$(cat "$fragmentdir/line_$source")
						fragment="${fragment//[$]destination/$destination}"
						fragment="${fragment//[$]dstname/$dstname}"
						fragment="${fragment//[$]source/$source}"
						output "${fragment}"
					elif test -f "$fragmentdir/line"
					then
						fragment=$(cat "$fragmentdir/line")
						fragment="${fragment//[$]destination/$destination}"
						fragment="${fragment//[$]dstname/$dstname}"
						fragment="${fragment//[$]source/$source}"
						output "${fragment}"
					fi
				done
			done
		done
	fi

	if [[ -d "$basedir/ipv6" ]]
	then
		for fragmentdir in $( find "$basedir/ipv6" -mindepth 1 -maxdepth 1 -type d | sort )
		do
			log_debug "processing $fragmentdir"
			if test -f "$fragmentdir/prolog"
			then
				fragment=$(cat "$fragmentdir/prolog")
				output "${fragment}"
			fi
			for (( i=0; i<${#redirections6_dst[@]}; i++ ))
			do
				destination="${redirections6_dst[$i]}"
				dstname="${redirections6_dstname[$i]}"
				log_debug "processing $fragmentdir for destination $destination"
				if test -f "$fragmentdir/destination"
				then
					fragment=$(cat "$fragmentdir/destination")
					fragment="${fragment//[$]destination/$destination}"
					fragment="${fragment//[$]dstname/$dstname}"
					output "${fragment}"
				fi
				sources=${redirections6_src[$i]}
				for source in ${sources[*]}
				do
					if test -f "$fragmentdir/line_$source"
					then
						fragment=$(cat "$fragmentdir/line_$source")
						fragment="${fragment//[$]destination/$destination}"
						fragment="${fragment//[$]dstname/$dstname}"
						fragment="${fragment//[$]source/$source}"
						output "${fragment}"
					elif test -f "$fragmentdir/line"
					then
						fragment=$(cat "$fragmentdir/line")
						fragment="${fragment//[$]destination/$destination}"
						fragment="${fragment//[$]dstname/$dstname}"
						fragment="${fragment//[$]source/$source}"
						output "${fragment}"
					fi
				done
			done
		done
	fi

	if [[ -d "$basedir/hostname" ]]
	then
		for fragmentdir in $( find "$basedir/hostname" -mindepth 1 -maxdepth 1 -type d | sort )
		do
			log_debug "processing $fragmentdir"
			if test -f "$fragmentdir/prolog"
			then
				fragment=$(cat "$fragmentdir/prolog")
				output "${fragment}"
			fi
			for (( i=0; i<${#redirectionsn_dst[@]}; i++ ))
			do
				destination="${redirectionsn_dst[$i]}"
				log_debug "processing $fragmentdir for destination $destination"
				if test -f "$fragmentdir/destination"
				then
					fragment=$(cat "$fragmentdir/destination")
					fragment="${fragment//[$]destination/$destination}"
					output "${fragment}"
				fi
				sources=${redirectionsn_src[$i]}
				for source in ${sources[*]}
				do
					if test -f "$fragmentdir/line_$source"
					then
						fragment=$(cat "$fragmentdir/line_$source")
						fragment="${fragment//[$]destination/$destination}"
						fragment="${fragment//[$]source/$source}"
						output "${fragment}"
					elif test -f "$fragmentdir/line"
					then
						fragment=$(cat "$fragmentdir/line")
						fragment="${fragment//[$]destination/$destination}"
						fragment="${fragment//[$]source/$source}"
						output "${fragment}"
					fi
				done
			done
		done
	fi

	# ======================================================================
	# Step 3: run the hook
	if [[ -n "$HOOK" ]]
	then
		read -p "$HOOK ? (y/n): " -n 1 confirm
		echo >&2
		if [[ "$confirm" = "y" ]]
		then
			log_info "Running hook: $HOOK"
			$HOOK
		else
			log_debug "Skipping hook: $HOOK"
		fi
	fi
}

for dir in "${DIRS[@]}"
do
	# Reset some vars that are supposed to be in $dir/condig
	# We don't want to keep the value from previous dir
	INPUT=""
	OUTPUT=""
	HOOK=""
	main "$dir"
done

# vim: set ts=4 noet: