#!/bin/sh
#
# Copyright (c) 2009
# Dominic Fandrey <kamikaze@bsdforen.de>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

readonly name=distviper
readonly version=1.1

verbose=
demo=
quiet=
interactive=

# Determine portsdir
portsdir="$(make -V PORTSDIR -f /usr/share/mk/bsd.port.mk)"
if [ ! -d "$portsdir" ]; then
        echo "The PORTSDIR '$portsdir' is missing."
        exit 1
fi

# Determine distdir
distdir="$(make -V DISTDIR -f /usr/share/mk/bsd.port.mk)"
if [ ! -d "$distdir" ]; then
        echo "The DISTDIR '$distdir' is missing."
        exit 2
fi

# Extract file from distinfo.
extractFileCmd="sed -E -e 's/^[^(]*\(//1' -e 's/\).*$//1'"

# Display help.
printHelp() {
	echo "$name v$version
usage:	$name [-d] [-h] [-i] [-q] [-v] [fast|thorough]"
}

#
# Handle parameters.
#
# @param $1
#	The parameter to handle.
# @param $verbose
#	Is set to create verbose output.
# @param $demo
#	Is set to only print the output that would occur.
# @param $quiet
#	Is set to act without creating any output.
# @return
#	Returns 0 if the processed parameter was a valid parameter,
#	returns 1 if not.
#
readParams() {
	case "$1" in
		"-d" | "--demo")
			demo=1
			return 0
		;;
		"-h" | "--help")
			printHelp
			exit 0
		;;
		"-i" | "--interactive")
			interactive=-i
			return 0
		;;
		"-q" | "--quiet")
			quiet=1
			return 0
		;;
		"-v" | "--verbose")
			verbose=1
			return 0
		;;
		-? | --*)
			return 1
		;;
		-*)
			# Split parameters.
			# first parameter
			readParams "${1%${1#-?}}" || return $?
			# remaining parameters
			readParams "-${1#-?}"
			return $?
		;;
		*)
			return 1
		;;
	esac
}

#
# This algorithm outputs the distfiles of installed ports. If a port downloads
# a distfile through depending on the fetch target of another port, it
# is missed, in case that other port is not installed as well.
#
# @param $portsdir
#	The direcotry holding the ports tree.
#
getDistFiles_fast() {
	for port in $(pkg_info -qoa); {
		if [ -e "$portsdir/$port/distinfo" ]; then
			eval "$extractFileCmd '$portsdir/$port/distinfo'" | uniq
		fi
	}
}

#
# This algorithm outputs the distfiles of all ports.
#
# @param $portsdir
#	The direcotry holding the ports tree.
#
getDistFiles_thorough() {
	find -H "$portsdir" -type f -name distinfo | \
		eval "xargs $extractFileCmd" | uniq
}

# The current parameter processing stage.
stage=params

# The selected algorithm for finding distfiles to keep.
algorithm=thorough

# Parse the command line parameters.
for command; {
	# Read parameters until an unknown one is encountered.
	# In that case switch into command stage.
	if [ "$stage" = "params" ]; then
		if ! readParams "$command"; then
			stage=command
		fi
	fi

	# All parameters have been read, now either nothing or a mode
	# command should occur.
	if [ "$stage" = "command" ]; then
		stage=end
		case "$command" in
			thorough | fast)
				algorithm="$command"
			;;
			-*)
				echo "$name: Unknown parameter '$command'" \
					"encountered, exiting." 1>&2
				return 1
			;;
			*)
				echo "$name: Unknown command '$command'" \
					"encountered, exiting." 1>&2
				return 2
			;;
		esac
		# Skip everything following and continue with the next
		# argument.
		continue
	fi

	# Still being in the loop at this stage means unexpected parameters
	# have been encountered.
	if [ "$stage" = "end" ]; then
		echo "$name: The command '$command' is not allowed here, only" \
			"one command at a time is permitted." 1>&2
		return 3
	fi
}

# Check for inprobable options.
if [ -n "$interactive" -a -n "$demo" ]; then
	echo "$name: Interactive mode is ignored in demo mode." 1>&2
fi

test -n "$verbose" && echo "Create a list of up to date distfiles to keep" \
	"using a $algorithm algorithm:"

# Create the list of files to keep, using the selected algorithm.
keepFiles="$(eval "getDistFiles_$algorithm" | sort -u)"
if [ -n "$verbose" ]; then
	echo "$(($(echo "$keepFiles" | wc -l))) files recorded for keeping."
	echo "Search and delete outdated distfiles:"
fi

# Files before deletion.
filesCount="$(($(find -H "$distdir" -type f|wc -l)))"
filesDelete=0

# Seek and destroy files not in the $keepFiles list.
for file in $(find -H "$distdir" -type f); {
	file="${file#$distdir/}"

	if (echo "$keepFiles" | grep -qx "$file"); then
		test -n "$verbose" && echo "keep $file"
	else
		test -z "$quiet" && echo "delete $file"
		test -z "$demo" && rm $interactive "$distdir/$file"
		filesDelete=$(($filesDelete + 1))
	fi
}

# The number of deleted files
filesDeleted="$(($filesCount - $(find -H "$distdir" -type f|wc -l)))"

test -z "$demo" && find -H -d "$distdir" -type d -exec rmdir \{} \; 2> /dev/null

if [ -n "$verbose" ]; then
	echo "$filesDelete files were suggested for deletion."
	echo "$filesDeleted files of $filesCount have been removed."
fi

return 0