#!/usr/bin/env bash
set -eE
# Copyright (C) 2011-2012 Nicolás Reynolds <fauno@parabola.nu>
# Copyright (C) 2012-2013, 2015, 2017-2018 Luke Shumaker <lukeshu@parabola.nu>
#
# If you don't see m4_include(...) below, but see function definitions
# for msg() et al., then this is a generated file, and contains some
# code from librelib.  See the source distribution for full copyright
# information.
#
# License: GNU GPLv3+
#
# 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 3 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 Affero 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/>.

# Performs chroot cleanup smartly, it only removes the unneeded packages or
# leaves you with a clean system

# Library routines #############################################################

# Statically include various library routines to avoid having
# dependencies on outside files.
export TEXTDOMAIN='libretools'
export TEXTDOMAINDIR='/usr/share/locale'

if type gettext &>/dev/null; then
	_() { gettext "$@"; }
else
	_() { echo "$@"; }
fi

# Begin chcleanup.lib ##########################################################
m4_include(chcleanup.lib)
# End chcleanup.lib ############################################################

# User interface ###############################################################
DRYRUN=${DRYRUN:-false}
if [[ ! -f /.arch-chroot ]] && ! ${DRYRUN}; then
	error "(chcleanup): Must be run inside of a chroot"
	exit 1
fi

# Load configuration ###########################################################
CHROOTPKG=(base-devel)
# Note: the in-chroot pkgconfdir is non-configurable, this is
# intentionally hard-coded.
source /etc/libretools.d/chroot.conf
# If we're running makepkg
if [[ -f ./PKGBUILD ]]; then
	if [[ ! -f ./.SRCINFO || ./PKGBUILD -nt ./.SRCINFO ]]; then
		sudo -u "#$(stat -c %u -- ./PKGBUILD)" sh -c 'makepkg --printsrcinfo > .SRCINFO'
	fi
	CARCH="$(. /etc/makepkg.conf; printf '%s' "$CARCH")"
	mapfile -t DEPENDS < <(sed -nE "s/^\\s+(|make|check)depends(|_${CARCH}) = //p" < .SRCINFO)
else
	DEPENDS=()
fi

# Main #########################################################################

msg "Cleaning chroot..."

# Sync the local repo with pacman (a limited form of `pacman -Sy`)
cp /repo/repo.db /var/lib/pacman/sync/repo.db

# Setup the temporary directory
TEMPDIR="$(mktemp --tmpdir -d "${0##*/}.XXXXXXXXXX")"
trap "rm -rf -- ${TEMPDIR@Q}" EXIT

# Set up a scratch pacman DB
mkdir -- "$TEMPDIR/db" "$TEMPDIR/db/local" "$TEMPDIR/hooks"
cp -a -t "${TEMPDIR}/db" -- /var/lib/pacman/sync
{ echo /usr/share/libalpm/hooks; pacman-conf HookDir; } | while read -r dir; do
	for hook in "$dir"/*.hook; do
		ln -sfT -- /dev/null "$TEMPDIR/hooks/${hook##*/}"
	done
done
pacman=(pacman --dbpath="$TEMPDIR/db" --hookdir="$TEMPDIR/hooks")

# Do our best to preload the scratch DB with CHROOTPKG and
# CHROOTEXTRAPKG packages.  This is purely an optimization step.  The
# safety of this optimization assumes that none of CHROOTPKG,
# CHROOTEXTRAPKG, *or their dependancies* are virtual packages.  We
# don't include DEPENDS in this optimization, because this assumption
# doesn't hold for them.
while read -r pkg; do
	if [[ -d /var/lib/pacman/local/$pkg ]]; then
		cp -a -T -- "/var/lib/pacman/local/$pkg" "$TEMPDIR/db/local/$pkg"
	fi
done < <("${pacman[@]}" -Sp --print-format='%n-%v' -- "${CHROOTPKG[@]}" "${CHROOTEXTRAPKG[@]}")

# Get the full list of packages needed by dependencies, including the base system
msg2 "Creating a full list of packages..."
for var in CHROOTPKG CHROOTEXTRAPKG DEPENDS; do
	declare -n pkgsref="$var"
	if [[ $var = DEPENDS ]]; then
		mapfile -t pkgs < <("${pacman[@]}" -T -- "${pkgsref[@]}")
	else
		pkgs=("${pkgsref[@]}")
	fi
	if (( ${#pkgs[@]} == 0 )); then
		continue
	fi
	"${pacman[@]}" -S --dbonly --noscriptlet --needed --noconfirm -- "${pkgs[@]}" <&- >& "$TEMPDIR/pacman.txt" || ret=$?
	if (( ret != 0 )); then
		error "Could not create a full list of packages, exiting."
		plain "This is likely caused by a dependency that could not be found."
		sed 's/^/ > /' <"$TEMPDIR/pacman.txt" >&2
		exit $ret
	fi
done
"${pacman[@]}" -Qq >"$TEMPDIR/pkglist.txt"

# Diff installed packages against a clean chroot then remove leftovers
packages=($(comm -23 <(pacman -Qq | sort -u) \
                     <(sort -u "$TEMPDIR/pkglist.txt")))
if [[ ${#packages[@]} = 0 ]]; then
	msg2 "No packages to remove"
else
	msg2 "Removing %d packages" ${#packages[@]}

	if ${DRYRUN}; then
		echo "${packages[*]}"
	else
		# Only remove leftovers, -Rcs removes too much
		pacman --noconfirm -R --nosave "${packages[@]}"
	fi
fi

packages=($(comm -13 <(pacman -Qq | sort -u) \
                     <(sort -u "$TEMPDIR/pkglist.txt")))
if [[ ${#packages[@]} = 0 ]]; then
	msg2 "No packages to add"
else
	msg2 "Adding %d packages" ${#packages[@]}

	if ${DRYRUN}; then
		echo "${packages[*]}"
	else
		pacman --noconfirm -S "${packages[@]}"
	fi
fi