#!/usr/bin/env bash
# Apt-P2P Clean
#
# Douglas Thrift
#
# $Id$

#  Copyright 2010 Douglas Thrift
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

function usage()
{
	cat <<-EOF
	Usage: $program [options]

	Options:
	  -a ARCHIVE, --archive=ARCHIVE   set the APT archive directory (default:
	                                  $_apt_archive)
	  -c CACHE, --cache=CACHE         set the Apt-P2P cache directory (default:
	                                  $_apt_p2p_cache)
	  -e, --execute                   clean up the Apt-P2P cache
	  -h, --help                      show this help message and exit
	  -n, --no-execute                show what would be done to clean up the
	                                  Apt-P2P cache
	  -v, --version                   show version information and exit
	EOF
	exit $@
}

function version()
{
	echo "$program $version"
	exit
}

program=`basename $0`
version='1.0.4'
apt_p2p_cache='/var/cache/apt-p2p/cache'
_apt_p2p_cache="$apt_p2p_cache"
apt_archive='/var/cache/apt/archives'
_apt_archive="$apt_archive"
args=`getopt -l 'archive:,cache:,execute,help,no-execute,version' -n "$program" -o 'a:c:ehnv' -- "$@"`
value=$?

[[ $value != 0 ]] && usage $value

eval set -- "$args"
unset args

until [[ "$1" == -- ]]; do
	value=1

	case "$1" in
	(-a|--archive)
		apt_archive="$2"
		value=2
		;;
	(-c|--cache)
		apt_p2p_cache="$2"
		value=2
		;;
	(-e|--execute)
		execute=1
		;;
	(-h|--help)
		usage
		;;
	(-n|--no-execute)
		execute=0
		;;
	(-v|--version)
		version
		;;
	esac

	shift $value
done

[[ -z $execute ]] && usage

unset value
set -e

for directory in "$apt_p2p_cache" "$apt_archive"; do
	if [[ ! -r "$directory" ]] || [[ ! -x "$directory" ]]; then
		echo "$program: $directory: Permission denied" 1>&2
		exit 1
	fi
done

if [[ $execute -eq 1 ]]; then
	echo 'Removing files:'
else
	echo 'Would remove files:'
fi

find "$apt_p2p_cache" -name '*.deb' | (
	freed=0
	
	while read deb; do
		_deb="${deb##*/}"
		_deb="${_deb//%7e/~}"

		if [[ ! -f "$apt_archive/$_deb" ]]; then
			if dpkg-deb -W $deb >/dev/null 2>&1; then
				_deb=`dpkg-deb -W --showformat='${Package}_${Version}_${Architecture}.deb' $deb`
			fi

			if [[ ! -f "$apt_archive/${_deb//:/%3a}" ]]; then
				# XXX: '|| true' because bash believes ((freed += 0)) is bad
				((freed += `du -B 1 $deb | cut -f 1`)) || true

				echo " $_deb"

				[[ $execute -eq 1 ]] && rm -f "$deb"
			fi
		fi
	done

	if [[ $execute -eq 1 ]]; then
		[[ $freed != 0 ]] && invoke-rc.d apt-p2p restart

		echo -n 'Freed'
	else
		echo -n 'Would free'
	fi

	echo " `bc <<-EOF
	freed=$freed
	scale=1
	if (freed >= 1024 ^ 3) print freed / 1024 ^ 3, "G" else if (freed >= 1024 ^ 2) print freed / 1024 ^ 2, "M" else if (freed >= 1024) print freed / 1024, "K" else freed
	EOF`B of disk space"
)

# Clean up the Apt-P2P cache