#!/bin/bash
#                                                                             #
# --------------------------------------------------------------------------- #
# Local Sync (for Gentoo) -- lclsync                                          #
# --------------------------------------------------------------------------- #
#                                                                             #
# A script to update your local Gentoo portage tree with computers on the LAN #
# and make maintenance easier.                                                #
#                                                                             #
# Checks a list of local IPs for a more recent Gentoo portage tree and then   #
# syncs with it, performs an update world, depclean & revdep-rebuild and      #
# eclean.                                                                     #
#                                                                             #
# Author: Graham Russell                                                      #
#                                                                             #
# For the latest version please visit: http://ham1.co.uk/oss/gentoo/          #
###############################################################################

readonly VERSION="1.03"
readonly REVISION="$Revision$svnhack"
readonly CURRENT_VERSION="$VERSION - Revision$REVISION"

# safety bash settings
set -o nounset # no unset variables
set -o errexit # exit on any errors

####################
# set up variables #
####################

# program name-version-pid-(date in ns), should be rather unique
readonly TEMP_FOLDER="/tmp/lclsync-$VERSION-$$-$(date +%N)"
readonly IP_LIST="10.0.0.4 ibm server x56"
readonly AGE_THRESHOLD=14

BEST_IP=
BEST_IP_TIMESTAMP=0
LOCAL_TIMESTAMP=$(awk '{print $1}' /usr/portage/metadata/timestamp.x)
TREE_AGE=$(( $(( $(date +%s)-$LOCAL_TIMESTAMP )) / 3600 ))
SUDO=

VERBOSE_SWITCH=
ASK_SWITCH="-a"
QUIET_REDIRECT=

QUIET_FLAG="no"
FIRST_FLAG="no"
FORCE_FLAG="no"
WEBSYNC_FLAG="no"

DO_EVERYTHING="yes"
SYNC_FLAG=
UPDATE_FLAG=
DEPCLEAN_FLAG=
REVDEP_FLAG=
ECLEAN_FLAG=

####################
# set up constants #
####################

readonly RED="\033[1;31m"
readonly GREEN="\033[1;32m"
readonly AMBER="\033[0;33m"
readonly CYAN="\033[0;36m"
readonly VIOLET="\033[1;35m"
readonly WHITE="\033[1;37m"

readonly NO_COLOUR="\033[0m"

readonly TITLE_COLOUR=$WHITE
readonly QUESTION_COLOUR=$CYAN
readonly INFO_COLOUR="$AMBER"
readonly ERR_COLOUR="$RED"
readonly OK_COLOUR=$GREEN

#########################
# some helper functions #
#########################

function print_help {
# prints the help...
#if 
echo "Local Sync (for Gentoo) -- lclsync

Checks a list of local IPs for a more recent Gentoo portage tree 
and then syncs with it, performs an update world and depclean

See README for more information and examples.

Author: Graham Russell
Version: $CURRENT_VERSION

Switches:
-q quiet
-v verbose
-f force        -- does without asking,non-interactive
-s sync         -- syncs
-u update       -- updates
-d depclean     -- depclean
-r revdep       -- revdep-rebuilds
-e eclean       -- does an eclean
-1 first (1st)  -- syncs with the first LAN server with a newer portage tree
-a age          -- prints the age of your portage tree
-w webrsync     -- does an emerge-webrsync instead of the normal \"emerge --sync\"
-x debug mode   -- enters crazy debug mode
"
}

function lr_echo {
# argument format: lr_echo(text, colour, echo-flag)
# local rsync echo - wrapper function for echo
	if [[ $QUIET_FLAG != "yes" ]]
	then
		case "$#" in
			"0")
			echo
			;;
			"1")
			echo -e "${1}${NO_COLOUR}"
			;;
			"2")
			# works for lr_echo(text, colour) or lr_echo(text, echo-flag)
			echo -e $2 "${1}${NO_COLOUR}"
			;;
			"3")
			echo -e $3 "${2}${1}${NO_COLOUR}"
			;;
			*)
			lr_echo "Too many arguments given to lr_echo" $ERR_COLOUR
			;;
		esac
	else
		if [ $# -gt 1 ]
		then
			if [ $ERR_COLOUR == $2 ]
			then
				echo -e "$2$1$NO_COLOUR"
				return
			fi
		fi
	fi
}

function quit {
# cleans up temp folder
# saves peppering the script with rm and ensures the script doesn't litter
	local exit_colour=$OK_COLOUR

	trap "" SIGINT SIGTERM EXIT

	lr_echo "\nQuit...\n" $TITLE_COLOUR
	
	lr_echo "Cleaning up temp files..." $INFO_COLOUR
	rm -rf $VERBOSE_SWITCH $TEMP_FOLDER 

	if (( $1 != 0 )); then exit_colour=$ERR_COLOUR; fi
	lr_echo "Exiting with status $1" $exit_colour
	exit $1
}

function reset_trap {
# set up to trap ctrl-C and kill gracefully
	trap "lr_echo \"\n\n${ERR_COLOUR}AH! Caught SIGINT/TERM...\"; quit 1" SIGINT SIGTERM
	trap "quit $?" EXIT
}

function ask { 
# argument format: ask(question, action-if-yes, action-if-no)
# Questions should be phrased such that positive answer result in an action
	local answer

	# force defaults questions to yes
	if [[ $FORCE_FLAG == "yes" ]]
	then
		eval "$2"
	# defaults to no in quiet mode
	elif [[ $QUIET_FLAG == "yes" ]]
	then
		eval "$3"
	else
		# asks user the question and takes appropriate action
		echo -e -n "\n${QUESTION_COLOUR}$1${NO_COLOUR} [${GREEN}Yes${NO_COLOUR}/${RED}No${NO_COLOUR}/Quit] "
		read answer
		lr_echo
		if echo $answer|grep -iq '^y'    # yes
		then
			eval "$2"
		elif echo $answer| grep -iq '^q' # quit
		then
			quit 0
		else                             # no (and everything else)
			eval "$3"
		fi
	fi
}

function sync {
# function to sync the portage tree
	local sync_cmd="emerge --sync"
	if [[ $WEBSYNC_FLAG == "yes" ]]
	then
		sync_cmd="emerge-webrsync"
		if which emerge-delta-webrsync > /dev/null
		then
			lr_echo "apparently you have \"emerge-delta-webrsync\" installed, using it." $INFO_COLOUR
			sync_cmd="emerge-delta-webrsync"
		fi
	fi
	# sets up a new trap to ensure rsyncd gets started again
	trap "$SUDO /etc/init.d/rsyncd start; quit 1" INT TERM EXIT

	# prevents other people syncing with partial trees
	eval "$SUDO /etc/init.d/rsyncd stop $QUIET_REDIRECT"
	if [ $# -gt 0 ] && [[ $1 != " " ]]
	then
		export SYNC="rsync://$1/gentoo-portage"
		eval "$SUDO emerge --sync $QUIET_REDIRECT"
		unset SYNC
	else
		eval "$SUDO $sync_cmd $QUIET_REDIRECT"
	fi
	eval "$SUDO /etc/init.d/rsyncd start $QUIET_REDIRECT"
	reset_trap
}

######################
# process parameters #
######################

# Based on http://www.ibm.com/developerworks/library/l-bash-parameters.html
while getopts "fqvsudre1ahxw" optname
do
	case "$optname" in
		"f")
		FORCE_FLAG="yes";ASK_SWITCH=;
		;;
		"q")
		if [ ! -z $VERBOSE_SWITCH ]
		then
			echo "${RED}What are you doing? Verbose cancels out quiet!${NO_COLOUR}"
			sleep 2
		else
			QUIET_REDIRECT="> /dev/null" # hides output, but prints errors
			QUIET_FLAG="yes"
		fi
		;;
		"v")
		echo "Verbose flag on";
		if [[ $QUIET_FLAG == "yes" ]]
		then
			echo "${RED}What are you doing? Verbose cancels out quiet!${NO_COLOUR}"
			sleep 2
			QUIET_REDIRECT=
			QUIET_FLAG="no"
		fi
		VERBOSE_SWITCH="-v"
		;;
		"s")
		SYNC_FLAG="yes";     DO_EVERYTHING="no"
		;;
		"u")
		UPDATE_FLAG="yes";   DO_EVERYTHING="no"
		;;
		"d")
		DEPCLEAN_FLAG="yes"; DO_EVERYTHING="no"
		;;
		"r")
		REVDEP_FLAG="yes";   DO_EVERYTHING="no"
		;;
		"e")
		ECLEAN_FLAG="yes";   DO_EVERYTHING="no"
		;;
		"1")
		FIRST_FLAG="yes";
		;;
		"a")
		echo "Your portage tree is ~$TREE_AGE hour(s) old"; exit 1
		;;
		"h")
		print_help; exit 0;
		;;
		"x")
		set -x; # crazy debug mode
		;;
		"w")
		WEBSYNC_FLAG="yes"
		;;
		"?")
		print_help
		exit 1
		;;
		":")
		echo "No argument value for option $optarg"
		exit 1
		;;
		*)
		# Should not occur
		echo "Unknown error while processing options, bailing..."; exit 1;
		;;
	esac
done

##################
# main functions #
##################

function sync_main {
	local ip best_timestamp last_time older_by

	lr_echo "\nSynchronise tree...\n" $TITLE_COLOUR

	for ip in $IP_LIST
	do
		lr_echo "Checking $ip..." "-n"
		#  ping IP, once, timeout 1 sec, no lookup of symbolic names
		if ping $ip -c 1 -w 1 -n >/dev/null
		then
			#############################################
			# check time stamp of computers in the list #
			#############################################

			# ensure a clean temp file environment
			rm -rf $VERBOSE_SWITCH $TEMP_FOLDER
			mkdir -p $VERBOSE_SWITCH $TEMP_FOLDER

			# ensures we cope if rsync isn't running on the IP
			set +e
			rsync rsync://$ip/gentoo-portage/metadata/timestamp.x $TEMP_FOLDER > /dev/null 2>&1 \
				|| \
				{ lr_echo "...rsync down?" $INFO_COLOUR; continue; }
			set -e

			best_timestamp=$(awk '{print $1}' $TEMP_FOLDER/timestamp.x)

			lr_echo "...${OK_COLOUR}ok"

			# move to next IP if it's not better than current best
			if [ $BEST_IP_TIMESTAMP -gt $best_timestamp ]; then continue; fi

			BEST_IP_TIMESTAMP=$best_timestamp
			BEST_IP=$ip

			if [[ $FIRST_FLAG == "yes" ]]
			then
				if [ $BEST_IP_TIMESTAMP -gt $LOCAL_TIMESTAMP ]
				then
					# stop checking the rest of the IPs if we
					# find a local sever with a newer tree
					break
				fi
			fi
		else
			# ping failed
			lr_echo "...${ERR_COLOUR}off"
		fi
	done

	lr_echo

	# sync with the most up-to date (best) local server
	if [ $BEST_IP_TIMESTAMP -ne 0 -a $BEST_IP_TIMESTAMP -gt $LOCAL_TIMESTAMP ]
	then
		# calculate a new age
		BEST_TREE_AGE=$(( $(($(date +%s) - $BEST_IP_TIMESTAMP)) / $((3600)) ))
	
		lr_echo "Younger tree (~$BEST_TREE_AGE hour(s)) found on $BEST_IP" $INFO_COLOUR
		# if sync is successful update the local time-stamp/tree age
		ask "Do you want to sync. with this tree? " \
		    "sync $BEST_IP && \
		     LOCAL_TIMESTAMP=$BEST_IP_TIMESTAMP && \
		     TREE_AGE=$BEST_TREE_AGE" \
		    " "
	else
		lr_echo "You have the youngest tree (~$TREE_AGE hours(s) old) available locally" $OK_COLOUR
	fi

	if [[ $FORCE_FLAG == "yes" ]]
	then 
		sync
		return
	fi

	# check if the tree is too old
	if (( $TREE_AGE > $AGE_THRESHOLD ))
	then
		older_by=$(( $TREE_AGE - $AGE_THRESHOLD ))
		lr_echo "Your tree is $older_by hour(s) older than the threshold." $INFO_COLOUR
		# sync if forced
		ask "Shall I perform an external sync.? " \ 
		"sync" \ 
		"echo" 
	else
		lr_echo "Not externally sync'ing, your tree younger than the threshold." $INFO_COLOUR
	fi
}

function update {
	lr_echo "Update packages..." $TITLE_COLOUR

	ask "emerge $ASK_SWITCH -vuDN world? " \
	    "$SUDO emerge $ASK_SWITCH -vuDN world $QUIET_REDIRECT " \
	    ""
}

function depclean {
	lr_echo "Clean packages..." $TITLE_COLOUR
	
	ask "emerge $ASK_SWITCH --depclean? " \
	    "$SUDO emerge $ASK_SWITCH --depclean $QUIET_REDIRECT " \
	    ""
}

function revdep {
	lr_echo "Check for missing dependencies..." $TITLE_COLOUR

	ask "revdep-rebuild (recommended after a depclean)? " \
	    "$SUDO revdep-rebuild $QUIET_REDIRECT " \
	    ""
}

function ecleandist {
	lr_echo "Clean installation files..." $TITLE_COLOUR

	ask "eclean-dist -pdn? " \
	    "$SUDO eclean-dist -pdn $QUIET_REDIRECT " \
	    "exit"

	ask "Perform the above actions with: eclean-dist -idn? " \
	    "$SUDO eclean-dist -idn" \
	    "exit"
}

########
# main #
########

reset_trap

# make sure we are interactive unless forced
if [ ! -t 0 -a $FORCE_FLAG != "yes" ]
then
	lr_echo "Terminal is non-interactive and force (-f) is not specified." $ERR_COLOUR
	touch lclsync_error.log
	echo -e "$(date):\nError when running $0:" > lclsync_error.log
	echo "Terminal wasn't interactive and -f wasn't specified" >> lclsync_error.log
	quit 1
fi

# check user is root, else set SUDO variable to sudo so things that need to be
# run as root are.
if [[ $(id -nu) != "root" ]]
then
	lr_echo "You are not root." $ERR_COLOUR
	lr_echo "This program runs sudo and may ask for your password..." $INFO_COLOUR
	sudo -v
	SUDO="sudo"
fi

# banner
lr_echo "
--------------------------------------
- lclsync (Local Sync) -- for Gentoo -
--------------------------------------" $TITLE_COLOUR

if [[ $DO_EVERYTHING == "yes" ]]
then
	sync_main
	update
	depclean
	revdep
	ecleandist
else
	if [[ $SYNC_FLAG     == "yes" ]]; then sync_main;  fi
	if [[ $UPDATE_FLAG   == "yes" ]]; then update;     fi
	if [[ $DEPCLEAN_FLAG == "yes" ]]; then depclean;   fi
	if [[ $REVDEP_FLAG   == "yes" ]]; then revdep;     fi
	if [[ $ECLEAN_FLAG   == "yes" ]]; then ecleandist; fi
fi

exit 0