#!/usr/bin/bash
#
# pacache - flexible pacman cache cleaning
#
# Copyright (C) 2011 Dave Reisner <dreisner@archlinux.org>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


# Expand to nothing if there are no matches
shopt -s nullglob
shopt -s extglob

declare -r myname='paccache'
declare -r myver='1.0.0'

declare -a cachedirs=() candidates=() cmdopts=() whitelist=() blacklist=()
declare -i delete=0 dryrun=0 filecount=0 move=0 totalsaved=0 verbose=0
declare    delim=$'\n' keep=3 movedir= scanarch=

QUIET=0
USE_COLOR='y'

plain() {
	(( QUIET )) && return
	local mesg=$1; shift
	printf "${BOLD}    ${mesg}${ALL_OFF}\n" "$@" >&1
}

msg() {
	(( QUIET )) && return
	local mesg=$1; shift
	printf "${GREEN}==>${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}\n" "$@" >&1
}

msg2() {
	(( QUIET )) && return
	local mesg=$1; shift
	printf "${BLUE}  ->${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}\n" "$@" >&1
}

ask() {
	local mesg=$1; shift
	printf "${BLUE}::${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}" "$@" >&1
}

warning() {
	local mesg=$1; shift
	printf "${YELLOW}==> $(gettext "WARNING:")${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}\n" "$@" >&2
}

error() {
	local mesg=$1; shift
	printf "${RED}==> $(gettext "ERROR:")${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}\n" "$@" >&2
}

# getopt-like parser
parseopts() {
	local opt= optarg= i= shortopts=$1
	local -a longopts=() unused_argv=()

	shift
	while [[ $1 && $1 != '--' ]]; do
		longopts+=("$1")
		shift
	done
	shift

	longoptmatch() {
		local o longmatch=()
		for o in "${longopts[@]}"; do
			if [[ ${o%:} = "$1" ]]; then
				longmatch=("$o")
				break
			fi
			[[ ${o%:} = "$1"* ]] && longmatch+=("$o")
		done

		case ${#longmatch[*]} in
			1)
				# success, override with opt and return arg req (0 == none, 1 == required)
				opt=${longmatch%:}
				if [[ $longmatch = *: ]]; then
					return 1
				else
					return 0
				fi ;;
			0)
				# fail, no match found
				return 255 ;;
			*)
				# fail, ambiguous match
				printf "paccache: $(gettext "option '%s' is ambiguous; possibilities:")" "--$1"
				printf " '%s'" "${longmatch[@]%:}"
				printf '\n'
				return 254 ;;
		esac >&2
	}

	while (( $# )); do
		case $1 in
			--) # explicit end of options
				shift
				break
				;;
			-[!-]*) # short option
				for (( i = 1; i < ${#1}; i++ )); do
					opt=${1:i:1}

					# option doesn't exist
					if [[ $shortopts != *$opt* ]]; then
						printf "paccache: $(gettext "invalid option") -- '%s'\n" "$opt" >&2
						OPTRET=(--)
						return 1
					fi

					OPTRET+=("-$opt")
					# option requires optarg
					if [[ $shortopts = *$opt:* ]]; then
						# if we're not at the end of the option chunk, the rest is the optarg
						if (( i < ${#1} - 1 )); then
							OPTRET+=("${1:i+1}")
							break
						# if we're at the end, grab the the next positional, if it exists
						elif (( i == ${#1} - 1 )) && [[ $2 ]]; then
							OPTRET+=("$2")
							shift
							break
						# parse failure
						else
							printf "paccache: $(gettext "option requires an argument") -- '%s'\n" "$opt" >&2
							OPTRET=(--)
							return 1
						fi
					fi
				done
				;;
			--?*=*|--?*) # long option
				IFS='=' read -r opt optarg <<< "${1#--}"
				longoptmatch "$opt"
				case $? in
					0)
						# parse failure
						if [[ $optarg ]]; then
							printf "paccache: $(gettext "option '%s' does not allow an argument")\n" "--$opt" >&2
							OPTRET=(--)
							return 1
						# --longopt
						else
							OPTRET+=("--$opt")
						fi
						;;
					1)
						# --longopt=optarg
						if [[ $optarg ]]; then
							OPTRET+=("--$opt" "$optarg")
						# --longopt optarg
						elif [[ $2 ]]; then
							OPTRET+=("--$opt" "$2" )
							shift
						# parse failure
						else
							printf "paccache: $(gettext "option '%s' requires an argument")\n" "--$opt" >&2
							OPTRET=(--)
							return 1
						fi
						;;
					254)
						# ambiguous option -- error was reported for us by longoptmatch()
						OPTRET=(--)
						return 1
						;;
					255)
						# parse failure
						printf "paccache: $(gettext "invalid option") '--%s'\n" "$opt" >&2
						OPTRET=(--)
						return 1
						;;
				esac
				;;
			*) # non-option arg encountered, add it as a parameter
				unused_argv+=("$1")
				;;
		esac
		shift
	done

	# add end-of-opt terminator and any leftover positional parameters
	OPTRET+=('--' "${unused_argv[@]}" "$@")
	unset longoptmatch

	return 0
}


die() {
	error "$@"
	exit 1
}

# reads a list of files on stdin and prints out deletion candidates
pkgfilter() {
	# there's whitelist and blacklist parameters passed to this
	# script after the block of awk.

	awk -v keep="$1" -v scanarch="$2" '
	function basename(str) {
		sub(".*/", "", str);
		return str;
	}

	function parse_filename(filename,     parts, count, i, pkgname, arch) {

		count = split(basename(filename), parts, "-")

		i = 1
		pkgname = parts[i++]
		while (i <= count - 3) {
			pkgname = pkgname "-" parts[i++]
		}

		arch = substr(parts[count], 1, index(parts[count], ".") - 1)

		# filter on whitelist or blacklist
		if (wlen && !whitelist[pkgname]) return
		if (blen && blacklist[pkgname]) return

		if ("" == packages[pkgname,arch]) {
			packages[pkgname,arch] = filename
		} else {
			packages[pkgname,arch] = packages[pkgname,arch] SUBSEP filename
		}
	}

	BEGIN {
		# create whitelist
		wlen = ARGV[1]; delete ARGV[1]
		for (i = 2; i < 2 + wlen; i++) {
			whitelist[ARGV[i]] = 1
			delete ARGV[i]
		}

		# create blacklist
		blen = ARGV[i]; delete ARGV[i]
		while (i++ < ARGC) {
			blacklist[ARGV[i]] = 1
			delete ARGV[i]
		}

		# read package filenames
		while (getline < "/dev/stdin") {
			parse_filename($0)
		}

		for (pkglist in packages) {
			# idx[1,2] = idx[pkgname,arch]
			split(pkglist, idx, SUBSEP)

			# enforce architecture match if specified
			if (!scanarch || scanarch == idx[2]) {
				count = split(packages[idx[1], idx[2]], pkgs, SUBSEP)
				for(i = 1; i <= count - keep; i++) {
					print pkgs[i]
				}
			}
		}
	}' "${@:3}"
}

size_to_human() {
	awk -v size="$1" '
	BEGIN {
		suffix[1] = "B"
		suffix[2] = "KiB"
		suffix[3] = "MiB"
		suffix[4] = "GiB"
		suffix[5] = "TiB"
		suffix[6] = "PiB"
		suffix[7] = "EiB"
		count = 1

		while (size > 1024) {
			size /= 1024
			count++
		}

		sizestr = sprintf("%.2f", size)
		sub(/\.?0+$/, "", sizestr)
		printf("%s %s", sizestr, suffix[count])
	}'
}


runcmd() {
	"$@"
}

summarize() {
	(( QUIET )) && return

	local -i filecount=$1; shift
	local seenarch= seen= arch= name=
	local -r pkg_re='(.+)-[^-]+-[0-9]+-([^.]+)\.pkg.*'

	if (( delete )); then
		printf -v output 'finished: %d packages removed' "$filecount"
	elif (( move )); then
		printf -v output "finished: %d packages moved to '%s'" "$filecount" "$movedir"
	elif (( dryrun )); then
		if (( verbose )); then
			msg "Candidate packages:"
			while read -r pkg; do
				if (( verbose >= 3 )); then
					[[ $pkg =~ $pkg_re ]] && name=${BASH_REMATCH[1]} arch=${BASH_REMATCH[2]}
					if [[ -z $seen || $seenarch != "$arch" || $seen != "$name" ]]; then
						seen=$name seenarch=$arch
						printf '%s (%s):\n' "${name##*/}" "$arch"
					fi
					printf '  %s\n' "${pkg##*/}"
				elif (( verbose >= 2 )); then
					printf "%s$delim" "$pkg"
				else
					printf "%s$delim" "${pkg##*/}"
				fi
			done < <(printf '%s\n' "$@" | pacsort --files)
		fi
		printf -v output 'finished dry run: %d candidates' "$filecount"
	fi

	echo
	msg "$output (disk space saved: %s)" "$(size_to_human "$totalsaved")"
}

usage() {
	cat <<EOF
${myname} v${myver}

A flexible pacman cache cleaning utility.

Usage: ${myname} <operation> [options] [targets...]

  Operations:
    -d, --dryrun          perform a dry run, only finding candidate packages.
    -m, --move <dir>      move candidate packages to "dir".
    -r, --remove          remove candidate packages.

  Options:
    -a, --arch <arch>     scan for "arch" (default: all architectures).
    -c, --cachedir <dir>  scan "dir" for packages. can be used more than once.
                          (default: read from /etc/pacman.conf).
    -f, --force           apply force to mv(1) and rm(1) operations.
    -h, --help            display this help message and exit.
    -i, --ignore <pkgs>   ignore "pkgs", comma-separated. Alternatively, specify
                          "-" to read package names from stdin, newline-
                          delimited.
    -k, --keep <num>      keep "num" of each package in the cache (default: 3).
        --nocolor         remove color from output.
    -q, --quiet           minimize output
    -u, --uninstalled     target uninstalled packages.
    -v, --verbose         increase verbosity. specify up to 3 times.
    -z, --null            use null delimiters for candidate names (only with -v
                          and -vv).

EOF
}

version() {
	printf "%s %s\n" "$myname" "$myver"
	echo 'Copyright (C) 2011 Dave Reisner <dreisner@archlinux.org>'
}

OPT_SHORT=':a:c:dfhi:k:m:qrsuVvz'
OPT_LONG=('arch:' 'cachedir:' 'dryrun' 'force' 'help' 'ignore:' 'keep:' 'move'
          'nocolor' 'quiet' 'remove' 'uninstalled' 'version' 'verbose' 'null')

if ! parseopts "$OPT_SHORT" "${OPT_LONG[@]}" -- "$@"; then
	exit 1
fi
set -- "${OPTRET[@]}"
unset OPT_SHORT OPT_LONG OPTRET

while :; do
	case $1 in
		-a|--arch)
			scanarch=$2
			shift ;;
		-c|--cachedir)
			cachedirs+=("$2")
			shift ;;
		-d|--dryrun)
			dryrun=1 ;;
		-f|--force)
			cmdopts=(-f) ;;
		-h|--help)
			usage
			exit 0 ;;
		-i|--ignore)
			if [[ $2 = '-' ]]; then
				[[ ! -t 0 ]] && IFS=$'\n' read -r -d '' -a ign
			else
				IFS=',' read -r -a ign <<< "$2"
			fi
			blacklist+=("${ign[@]}")
			unset i ign
			shift ;;
		-k|--keep)
			keep=$2
			if [[ -z $keep || -n ${keep//[0-9]/} ]]; then
				die 'argument to option -k must be a non-negative integer'
			else
				keep=$(( 10#$keep ))
			fi
			shift ;;
		-m|--move)
			move=1 movedir=$2
			shift ;;
		--nocolor)
			USE_COLOR='n' ;;
		-q|--quiet)
			QUIET=1 ;;
		-r|--remove)
			delete=1 ;;
		-u|--uninstalled)
			IFS=$'\n' read -r -d '' -a ign < <(pacman -Qq)
			# pacman -Qq may exit with an error, thus making ign an empty array
			(( ${#ign[@]} )) || die 'failed to retrieve the list of installed packages'
			blacklist+=("${ign[@]}")
			unset ign ;;
		-V|--version)
			version
			exit 0 ;;
		-v|--verbose)
			(( ++verbose )) ;;
		-z|--null)
			delim='\0' ;;
		--)
			shift
			break 2 ;;
	esac
	shift
done

# check if messages are to be printed using color
unset ALL_OFF BOLD BLUE GREEN RED YELLOW
if [[ -t 2 && ! $USE_COLOR = "n" ]]; then
	# prefer terminal safe colored and bold text when tput is supported
	if tput setaf 0 &>/dev/null; then
		ALL_OFF="$(tput sgr0)"
		BOLD="$(tput bold)"
		BLUE="${BOLD}$(tput setaf 4)"
		GREEN="${BOLD}$(tput setaf 2)"
		RED="${BOLD}$(tput setaf 1)"
		YELLOW="${BOLD}$(tput setaf 3)"
	else
		ALL_OFF="\e[1;0m"
		BOLD="\e[1;1m"
		BLUE="${BOLD}\e[1;34m"
		GREEN="${BOLD}\e[1;32m"
		RED="${BOLD}\e[1;31m"
		YELLOW="${BOLD}\e[1;33m"
	fi
fi
readonly ALL_OFF BOLD BLUE GREEN RED YELLOW


# setting default cachedirs
if [[ -z $cachedirs ]]; then
	cachedirs=($(pacman-conf CacheDir))
fi

# remaining args are a whitelist
whitelist=("$@")

# sanity checks
case $(( dryrun+delete+move )) in
	0) die "no operation specified (use -h for help)" ;;
	[^1]) die "only one operation may be used at a time" ;;
esac

[[ $movedir && ! -d $movedir ]] &&
	die "destination directory '%s' does not exist or is not a directory" "$movedir"

if (( move || delete )); then
	# make it an absolute path since we're about to chdir
	[[ $movedir && ${movedir:0:1} != '/' ]] && movedir=$PWD/$movedir
fi

for cachedir in "${cachedirs[@]}"; do
	[[ -d $cachedir ]] ||
		die "cachedir '%s' does not exist or is not a directory" "$cachedir"

	# unlikely that this will fail, but better make sure
	pushd "$cachedir" &>/dev/null || die "failed to chdir to '%s'" "$cachedir"

	# note that these results are returned in an arbitrary order from awk, but
	# they'll be resorted (in summarize) iff we have a verbosity level set.
	IFS=$'\n' read -r -d '' -a cand < \
		<(printf '%s\n' "$PWD"/*.pkg.tar!(*.sig) | pacsort --files |
			pkgfilter "$keep" "$scanarch" \
				"${#whitelist[*]}" "${whitelist[@]}" \
				"${#blacklist[*]}" "${blacklist[@]}")

	candidates+=("${cand[@]}")
	unset cand

	popd &>/dev/null
done

if (( ! ${#candidates[*]} )); then
	msg 'no candidate packages found for pruning'
	exit 0
fi

# grab this prior to signature scavenging
pkgcount=${#candidates[*]}

# copy the list, merging in any found sigs
for cand in "${candidates[@]}"; do
	candtemp+=("$cand")
	[[ -f $cand.sig ]] && candtemp+=("$cand.sig")
done
candidates=("${candtemp[@]}")
unset candtemp

# do this before we destroy anything
totalsaved=$(stat -c %s "${candidates[@]}" | awk '{ sum += $1 } END { print sum }')

# Exit immediately if a pipeline returns non-zero.
set -o errexit

# crush. kill. destroy.
(( verbose )) && cmdopts+=(-v)
if (( delete )); then
	printf '%s\0' "${candidates[@]}" | runcmd xargs -0 rm "${cmdopts[@]}"
elif (( move )); then
	printf '%s\0' "${candidates[@]}" | runcmd xargs -0 mv "${cmdopts[@]}" -t "$movedir"
fi

summarize "$pkgcount" "${candidates[@]}"

# vim: set noet: