#!/bin/bash
# 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; version 2 of the License.
#
# 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.

FORCE='n'
RUN=''
MAKEPKG_ARGS='-s --noconfirm'
REPACK=''
WORKDIR=$PWD

update_first='0'
clean_first='0'
install_pkg=''
add_to_db=0

chrootdir=''

APPNAME=$(basename "${0}")

default_copy=$USER
[[ -n $SUDO_USER ]] && default_copy=$SUDO_USER
[[ -z $default_copy || $default_copy = root ]] && default_copy=copy

usage() {
	echo "usage ${APPNAME} [options] -r <chrootdir> [--] [makepkg args]"
	echo ' Run this script in a PKGBUILD dir to build a package inside a'
	echo ' clean chroot. All unrecognized arguments passed to this script'
	echo ' will be passed to makepkg.'
	echo ''
	echo ' The chroot dir consists of the following directories:'
	echo ' <chrootdir>/{root, copy} but only "root" is required'
	echo ' by default. The working copy will be created as needed'
	echo ''
	echo 'The chroot "root" directory must be created via the following'
	echo 'command:'
	echo '    mkarchroot <chrootdir>/root base base-devel sudo'
	echo ''
	echo "Default makepkg args: $MAKEPKG_ARGS"
	echo ''
	echo 'Flags:'
	echo '-h         This help'
	echo '-c         Clean the chroot before building'
	echo '-u         Update the working copy of the chroot before building'
	echo '           This is useful for rebuilds without dirtying the pristine'
	echo '           chroot'
	echo '-d         Add the package to a local db at /repo after building'
	echo '-r <dir>   The chroot dir to use'
	echo '-I <pkg>   Install a package into the working copy of the chroot'
	echo '-l <copy>  The directory to use as the working copy of the chroot'
	echo '           Useful for maintaining multiple copies.'
	echo "           Default: $default_copy"
	exit 1
}

while getopts 'hcudr:I:l:' arg; do
	case "${arg}" in
		h) usage ;;
		c) clean_first=1 ;;
		u) update_first=1 ;;
		d) add_to_db=1 ;;
		r) chrootdir="$OPTARG" ;;
		I) install_pkg="$OPTARG" ;;
		l) copy="$OPTARG" ;;
		*) MAKEPKG_ARGS="$MAKEPKG_ARGS -$arg $OPTARG" ;;
	esac
done

# Canonicalize chrootdir, getting rid of trailing /
chrootdir=$(readlink -e "$chrootdir")

[[ -z $copy ]] && copy=$default_copy
copydir="$chrootdir/$copy"

# Pass all arguments after -- right to makepkg
MAKEPKG_ARGS="$MAKEPKG_ARGS ${*:$OPTIND}"

# See if -R was passed to makepkg
for arg in ${*:$OPTIND}; do
	if [ "$arg" = '-R' ]; then
		REPACK=1
		break;
	fi
done

if [ "$EUID" != '0' ]; then
	echo 'This script must be run as root.'
	exit 1
fi

if [ ! -f PKGBUILD -a -z "$install_pkg" ]; then
	echo 'This must be run in a directory containing a PKGBUILD.'
	exit 1
fi

if [ ! -d "$chrootdir" ]; then
	echo "No chroot dir defined, or invalid path '$chrootdir'"
	exit 1
fi

if [ ! -d "$chrootdir/root" ]; then
	echo 'Missing chroot dir root directory.'
	echo "Try using: mkarchroot $chrootdir/root base base-devel sudo"
	usage
fi

umask 0022

# Lock the chroot we want to use. We'll keep this lock until we exit.
# Note this is the same FD number as in mkarchroot
exec 9>"$copydir.lock"
if ! flock -n 9; then
	echo -n "locking chroot copy '$copy'..."
	flock 9
	echo "done"
fi

if [ ! -d "$copydir" -o "$clean_first" -eq "1" ]; then
	# Get a read lock on the root chroot to make
	# sure we don't clone a half-updated chroot
	exec 8>"$chrootdir/root.lock"

	if ! flock -sn 8; then
		echo -n "locking clean chroot..."
		flock -s 8
		echo "done"
	fi

	echo -n 'creating clean working copy...'
	use_rsync=false
	if type -P btrfs >/dev/null; then
		[ -d $copydir ] && btrfs subvolume delete "$copydir" &>/dev/null
		btrfs subvolume snapshot "$chrootdir/root" "$copydir" &>/dev/null || use_rsync=true
	else
		use_rsync=true
	fi

	if $use_rsync; then
		mkdir -p "$copydir"
		rsync -a --delete -q -W -x "$chrootdir/root/" "$copydir"
	fi
	echo 'done'

	# Drop the read lock again
	exec 8>&-
fi

if [ -n "$install_pkg" ]; then
	pkgname="$(basename "$install_pkg")"
	cp "$install_pkg" "$copydir/$pkgname"
	mkarchroot -r "pacman -U /$pkgname" "$copydir"
	ret=$?
	rm "$copydir/$pkgname"
	#exit early, we've done all we need to
	exit $ret
fi

if [ $update_first -eq 1 ]; then
	mkarchroot -u "$copydir"
fi

[ -d "$copydir/build" ] || mkdir "$copydir/build"

if [ "$REPACK" != "1" ]; then
	#Remove anything in there UNLESS -R (repack) was passed to makepkg
	rm -rf "$copydir/build/"*
fi

# read .makpekg.conf even if called via sudo
if [ -n "${SUDO_USER}" ]; then
	makepkg_conf="/$(eval echo ~${SUDO_USER})/.makepkg.conf"
else
	makepkg_conf="~/.makepkg.conf"
fi

# Get SRC/PKGDEST from makepkg.conf
if [ -f "${makepkg_conf}" ]; then
	eval $(grep '^SRCDEST=' "${makepkg_conf}")
	eval $(grep '^PKGDEST=' "${makepkg_conf}")

	eval $(grep '^MAKEFLAGS=' "${makepkg_conf}")
	eval $(grep '^PACKAGER=' "${makepkg_conf}")
fi
[ -z "${SRCDEST}" ] && eval $(grep '^SRCDEST=' /etc/makepkg.conf)
[ -z "${PKGDEST}" ] && eval $(grep '^PKGDEST=' /etc/makepkg.conf)

[ -d "$copydir/pkgdest" ] || mkdir "$copydir/pkgdest"
if ! grep 'PKGDEST="/pkgdest"' "$copydir/etc/makepkg.conf" >/dev/null 2>&1; then
	echo 'PKGDEST="/pkgdest"' >> "$copydir/etc/makepkg.conf"
fi

[ -d "$copydir/srcdest" ] || mkdir "$copydir/srcdest"
if ! grep 'SRCDEST="/srcdest"' "$copydir/etc/makepkg.conf" >/dev/null 2>&1; then
	echo 'SRCDEST="/srcdest"' >> "$copydir/etc/makepkg.conf"
fi
[ -z "${MAKEFLAGS}" ] && eval $(grep '^MAKEFLAGS=' /etc/makepkg.conf)
if [ -n "${MAKEFLAGS}" ]; then 
  sed -i '/^MAKEFLAGS=/d' "$copydir/etc/makepkg.conf"
  echo "MAKEFLAGS='${MAKEFLAGS}'" >> "$copydir/etc/makepkg.conf"
fi
[ -z "${PACKAGER}" ] && eval $(grep '^PACKAGER=' /etc/makepkg.conf)
if [ -n "${PACKAGER}" ]; then 
  sed -i '/^PACKAGER=/d' "$copydir/etc/makepkg.conf"
  echo "PACKAGER='${PACKAGER}'" >> "$copydir/etc/makepkg.conf"
fi

# Set target CARCH as it might be used within the PKGBUILD to select correct sources
eval $(grep '^CARCH=' "$copydir/etc/makepkg.conf")
export CARCH
# Copy PKGBUILD and sources
source=($(. PKGBUILD; echo ${source[@]}))
cp PKGBUILD "$copydir/build/"
for f in ${source[@]}; do
	basef=$(echo $f | sed 's|::.*||' | sed 's|^.*://.*/||g')
	if [ -f "$basef" ]; then
		cp "$basef" "$copydir/srcdest/"
	elif [ -f "$SRCDEST/$basef" ]; then
		cp "$SRCDEST/$basef" "$copydir/srcdest/"
	fi
done

( . PKGBUILD
for i in 'changelog' 'install'; do
	filelist=$(sed -n "s/^[[:space:]]*$i=//p" PKGBUILD)
	for file in $filelist; do
		# evaluate any bash variables used
		eval file=${file}
		if [[ -f "$file" ]]; then
			cp "$file" "$copydir/build/"
		fi
	done
done
)

chown -R nobody "$copydir/build"
chown -R nobody "$copydir/srcdest"
chown -R nobody "$copydir/pkgdest"

echo 'nobody ALL = NOPASSWD: /usr/bin/pacman' > "$copydir/etc/sudoers.d/nobody-pacman"
chmod 440 "$copydir/etc/sudoers.d/nobody-pacman"

#This is a little gross, but this way the script is recreated every time in the
#working copy
(cat <<EOF
#!/bin/bash
export LANG=C
cd /build
export HOME=/build
sudo -u nobody makepkg $MAKEPKG_ARGS || touch BUILD_FAILED
[ -f BUILD_FAILED ] && exit 1
which namcap &>/dev/null && namcap /build/PKGBUILD /pkgdest/*.pkg.tar.* > /build/namcap.log
exit 0
EOF
) > "$copydir/chrootbuild"
chmod +x "$copydir/chrootbuild"

if mkarchroot -r "/chrootbuild" "$copydir"; then
	for pkgfile in "${copydir}"/pkgdest/*.pkg.tar.*; do
		[ -e "$pkgfile" ] || continue
		if [ "$add_to_db" -eq "1" ]; then
			mkdir -p "${copydir}/repo"
			pushd "${copydir}/repo" >/dev/null
			cp "$pkgfile" .
			repo-add repo.db.tar.gz "$(basename "$pkgfile")"
			popd >/dev/null
		fi

		if [ -d "$PKGDEST" ]; then
			mv "$pkgfile" "${PKGDEST}"
		else
			mv "$pkgfile" "${WORKDIR}"
		fi
	done

	for l in "${copydir}"/build/{namcap,*-{build,package,package_*}}.log; do
		[ -f "$l" ] && mv "$l" "${WORKDIR}"
	done
else
	#just in case. We returned 1, make sure we fail
	touch "${copydir}/build/BUILD_FAILED"
fi

for f in "${copydir}"/srcdest/*; do
	[ -e "$f" ] || continue
	if [ -d "$SRCDEST" ]; then
		mv "$f" "${SRCDEST}"
	else
		mv "$f" "${WORKDIR}"
	fi
done

if [ -e "${copydir}/build/BUILD_FAILED" ]; then
	echo "Build failed, check $copydir/build"
	rm "${copydir}/build/BUILD_FAILED"
	exit 1
fi