#!/bin/bash
# Authors : Simon Peter, Ismael Barros² <ismael@barros2.org>
# License : BSD http://en.wikipedia.org/wiki/BSD_license

set -e
# set -x

HERE=$(dirname $(readlink -f "${0}"))
export PATH=$HERE:$PATH

opt_shell=
while getopts "s" arg; do
	case $arg in
	s)
		opt_shell=1
		shift $((OPTIND-1))
		;;
      esac
done



OSIMAGE="$1"
APPIMAGE="$2"
[ ! "$APPIMAGE" ] && [ -f AppRun ] && APPIMAGE=.

usage() { echo "Usage: $0 <OS image> <AppImage|AppDir>"; }

[ -n "$OSIMAGE" ] || { usage; exit 1; }
[ -n "$APPIMAGE" ] || { usage; exit 1; }
[ -e "$APPIMAGE" ] || { echo "$APPIMAGE doesn't exist"; exit 1; }
[ -d "$APPIMAGE" ] && [ -f "$APPIMAGE/AppRun" ] && { echo "$APPIMAGE/AppRun doesn't exist"; exit 1; }

WORKDIR="$(mktemp -d /tmp/runInChroot.XXXXXXXXXX)"
MOUNTPOINT_UNION="$WORKDIR/union"
MOUNTPOINT_UNIONFS="$WORKDIR/unionfs"
MOUNTPOINT_ISO="$WORKDIR/iso"


trap atexit EXIT
atexit() {
	set +e
	echo "Cleaning up..."
	sudo umount -l "$APPIMAGE"
	sudo umount -l "$MOUNTPOINT_UNION/var/run"
	sudo umount -l "$MOUNTPOINT_UNION/var/lib/dbus"
	sudo umount -l "$MOUNTPOINT_UNION/etc/resolv.conf"
	sudo umount -l "$MOUNTPOINT_UNION/dev/pts"
	sudo umount -l "$MOUNTPOINT_UNION/sys/"
	sudo umount -l "$MOUNTPOINT_UNION/dev"
	sudo umount -l "$MOUNTPOINT_UNION/proc"
	#sudo umount "$MOUNTPOINT_UNION/boot"
#	fusermount -u "$MOUNTPOINT_UNION/automake" 2>/dev/null # Puppy
	#fusermount -u "$MOUNTPOINT_UNION"
	sudo umount -l "$MOUNTPOINT_UNION"
	killall unionfs # Just in case.
	sudo umount -l "$MOUNTPOINT_UNIONFS/root" 2>/dev/null
	fusermount -u "$MOUNTPOINT_ISO" 2>/dev/null
	fusermount -u "$MOUNTPOINT_ISO" 2>/dev/null
	fusermount -u "$MOUNTPOINT_ISO" 2>/dev/null
	rmdir "$MOUNTPOINT_UNIONFS/root" || ls "$MOUNTPOINT_UNIONFS/root"
	rm -rf "$MOUNTPOINT_UNIONFS/rw"
	rmdir "$MOUNTPOINT_UNIONFS" || ls "$MOUNTPOINT_UNIONFS"
	rmdir "$MOUNTPOINT_UNION" || ls "$MOUNTPOINT_UNION"
	#rmdir "$MOUNTPOINT_ISO" || ls "$MOUNTPOINT_ISO"
	rmdir "$WORKDIR" || ls "$WORKDIR"
}


mkdir -p "$MOUNTPOINT_UNIONFS/root" # Unionfs read-only
mkdir -p "$MOUNTPOINT_UNIONFS/rw" # Unionfs rw
mkdir -p "$MOUNTPOINT_UNION" # Overlay

# If ISO was specified, then mount it and find contained filesystem
if [ ${OSIMAGE##*.} == "iso" ] ; then
	ISO="$OSIMAGE"

	echo "Mounting ISO $ISO on $MOUNTPOINT_ISO"

	#mkdir -p "$MOUNTPOINT_ISO"
	#sudo mount -o loop,ro "$ISO" "$MOUNTPOINT_ISO"
	fuseiso -p "$ISO" "$MOUNTPOINT_ISO" -o allow_other

	# Ubuntu-like ISOs
	if [ -e "$MOUNTPOINT_ISO/casper/filesystem.squashfs" ] ; then
		SQUASHFS="$MOUNTPOINT_ISO/casper/filesystem.squashfs"

	# Fedora-like ISOs
	elif [ -e "$MOUNTPOINT_ISO/LiveOS/squashfs.img" ] ; then
		SQUASHFS="$MOUNTPOINT_ISO/LiveOS/ext3fs.img"
		#SQUASHFS="$MOUNTPOINT_ISO/LiveOS/squashfs.img"
		#sudo mount -o loop,ro "$MOUNTPOINT_ISO/LiveOS/squashfs.img" "$MOUNTPOINT_ISO" || exit 1
	
	else
		# OpenSUSE-like ISOs
		openSuseSquash="$(ls -1 "$MOUNTPOINT_ISO"/openSUSE-*-livecd* | head -n1)"
		if [ -e "$openSuseSquash" ] ; then
			SQUASHFS="$openSuseSquash"
			echo "Actually, OpenSUSE doesn't work for now, sorry!"
			exit 1
		else
			echo "Unknown distro"
			echo "Contents of $MOUNTPOINT_ISO:"
			ls -l "$MOUNTPOINT_ISO"
			exit 1
		fi
	fi
else
	SQUASHFS="$OSIMAGE"
fi

echo "Using SquashFS $SQUASHFS"
sudo mount -o loop,ro "$SQUASHFS" "$MOUNTPOINT_UNIONFS/root" || exit 1

#unionfs-fuse -o allow_other,use_ino,suid,dev,nonempty -ocow,chroot=$MOUNTPOINT_UNIONFS/,max_files=32768 /rw=RW:/root=RO $MOUNTPOINT_UNION
unionfs -o allow_other,use_ino,suid,dev,nonempty -o cow "$MOUNTPOINT_UNIONFS/rw"=RW:"$MOUNTPOINT_UNIONFS/root"=RO "$MOUNTPOINT_UNION" || exit 1

ls "$MOUNTPOINT_UNION/mnt" >/dev/null && MNT=/mnt
#ls "$MOUNTPOINT_UNION/automake" >/dev/null && MNT=/automake || echo "" # Puppy

if [ "x$MNT" == "x" ]; then
	echo "Could not find free mountpoint"
	exit 1
fi

if [ -f "$APPIMAGE" ] ; then # AppImage
	[[ "$(file "$APPIMAGE")" =~ ELF.*executable.*\ interpreter ]] || { echo "Unknown AppImage file type"; exit 1; }

	#RUNNABLE="/mnt/$(basename "$APPIMAGE")"
	#sudo mount --bind "$APPIMAGE" "$MOUNTPOINT_UNION/$UNNABLE"
	RUNNABLE="$(readlink -f "/$MNT/AppRun")"

	if [[ "$(file -k "$APPIMAGE")" =~ ISO\ 9660\ CD-ROM ]]; then
		echo "Mounting Type1 AppImage $APPIMAGE"
		sudo mount -o loop "$APPIMAGE" "$MOUNTPOINT_UNION/$MNT"
	else
		OFFSET=$(./"$APPIMAGE" --appimage-offset)
		[ "$OFFSET" -gt 0 ] || { echo "Could not find offset on $APPIMAGE"; exit 1; }
		echo "Mounting Type2 AppImage $APPIMAGE with offset $OFFSET"
		sudo mount -o loop "$APPIMAGE" "$MOUNTPOINT_UNION/$MNT" -o offset=$OFFSET
	fi
elif [ -d "$APPIMAGE" ] ; then # AppDir
	echo "Mounting AppDir $APPIMAGE"
	RUNNABLE="$(readlink -f "/$MNT/AppRun")"
	sudo mount --bind "$APPIMAGE" "$MOUNTPOINT_UNION/$MNT"
fi

cat > "$MOUNTPOINT_UNION/run.sh" <<EOF
#!/bin/sh

export PATH=/bin:/usr/bin
export HOME="/root" 
export LANG="en_EN.UTF-8"
# export QT_PLUGIN_PATH=./lib/qt4/plugins ###################### !!!

cat /etc/*release
echo ""

rm -rf /etc/pango
mkdir -p /etc/pango
pango-querymodules > '/etc/pango/pango.modules' 2>/dev/null # otherwise only squares instead of text
[ -f /si-chroot ] && ln -s /lib/ld-lsb.so.3 /lib/ld-linux.so.2

echo "*** ldd "$MNT"/usr/{bin,lib}"
LD_LIBRARY_PATH="$MNT/usr/lib:$MNT/lib/:$LD_LIBRARY_PATH" ldd "$MNT"/usr/{bin,lib}/* 2>/dev/null | grep "not found" | sort | uniq
echo ""

if [ "$opt_shell" ]; then
	DIR="$(dirname "$RUNNABLE")"
	echo "*** Opening shell on \${DIR}. Runnable is $(basename "$RUNNABLE")."
	cd "\$DIR"
	if [ -x /bin/bash ]; then /bin/bash
	elif [ -x /bin/sh ]; then /bin/sh
	else echo "No shell found"
	fi
else
	echo "*** Running ${RUNNABLE}..."
	./$RUNNABLE
	echo "*** $RUNNABLE finished with exit code $?"
fi
EOF

chmod a+x "$MOUNTPOINT_UNION/run.sh"
sudo mount -t proc proc "$MOUNTPOINT_UNION/proc"
sudo mount -t sysfs sys "$MOUNTPOINT_UNION/sys/"
sudo mount --bind /dev "$MOUNTPOINT_UNION/dev"
sudo mount --bind /dev/shm "$MOUNTPOINT_UNION/dev/shm"
sudo mount -t devpts pts "$MOUNTPOINT_UNION/dev/pts"
sudo mount --bind /var/run "$MOUNTPOINT_UNION/var/run" # pulse
#sudo mount --bind /tmp "$MOUNTPOINT_UNION/tmp" # pulse
sudo mount --bind /var/lib/dbus "$MOUNTPOINT_UNION/var/lib/dbus" # pulse (and more)
sudo mkdir "$MOUNTPOINT_UNION/root/.pulse" # pulse
sudo mount --bind ~/.pulse "$MOUNTPOINT_UNION/root/.pulse" # pulse
sudo touch "$MOUNTPOINT_UNION/etc/resolv.conf" || echo ""
sudo mount --bind /etc/resolv.conf "$MOUNTPOINT_UNION/etc/resolv.conf"
xhost local: # otherwise "cannot open display: :0.0"

echo
echo "=== Entering chroot $MOUNTPOINT_UNION"
echo
sudo chroot "$MOUNTPOINT_UNION" /run.sh # $MNT/AppRun
#cd "$MOUNTPOINT_UNION"
#sudo systemd-nspawn
echo
echo "=== Leaving chroot"
echo

exit $?