#!/usr/bin/env bash 

set -eu
#set -x

DISK_NAME="DebianBuster-amd64.disk"
FOR_ROOT=0
USE_SUDO=0
UMOUNT=0

synopsis() {
	cat << EOF
Usage : `basename $0` [-h] [-r] [-i user] [-s] [-u]
EOF
}

help() {
	cat << EOF

`basename $0` exécute VDN dans un environnement proot en utilisant le disque :

$DISK
  
`synopsis`

-h      : affiche cette aide.
-u      : démontages seulement.

EOF
}

usage() {
	synopsis
	exit 1
}

args() {
	local opt
	while getopts "hrsi:u" opt; do
		case $opt in
			h) help; exit 0;;
			u) UMOUNT=1;;
			?) usage;;
		esac
	done
	shift $(($OPTIND - 1))
	[ $# -ne 0 ] && usage || :	
}

vdnMountProotForRoot() {

	key="$(cat $TMPDIR/vdn-key-$USER)"
	
	disp=$(cat $TMPDIR/vdn-display-$USER)
	
	d=$TMPDIR/vdn-chroot-$USER;
	
	if [ $UMOUNT = 0 ]; then
	
		mount | grep -q $d || mount -o loop,offset=$((2048*512)) $DISK $d
		
		for i in /dev /dev/pts /sys /proc /tmp; do
			mount | grep -q $d$i || { mount --bind $i $d$i; }
		done
		
		mount --bind $VDN_PATH $d/home/test/vdn

		#mount | grep $d
		
		chroot $d su - -s /bin/bash -c "export DISPLAY=":"$disp; \
		unset XAUTHORITY; rm -rf /home/test/.config/xfce4-session;  \
		rm -rf /home/test/.config/xfce4/terminal/; \
		xauth add \$DISPLAY . $key; \
		export NO_AT_BRIDGE=1; \
		xfce4-terminal --disable-server # 2> /dev/null;" test
		
		sleep 1
	fi
	
	for i in /tmp /proc /sys /dev/pts /dev; do
		mount | grep -q $d$i && { umount $d$i || { echo "umount lazy : $d$i"; umount -l $d$i; } ; } || :
	done
	
	mount | grep -q $d/home/test/vdn && { umount $d/home/test/vdn || umount -l $d/home/test/vdn; } || :
	mount | grep -q $d && { umount $d || umount -l $d; } || :
	
	m="$(mount | grep $d)"
	
	echo $m
}

vdnUmount() {
	set +e
	for i in $(mount | grep $TMPDIR/vdn-proot-$USER | cut -d ' ' -f 3 | tac); do
		fusermount -u $i
	done
	set -e
}

vdnMount() {
	
	[ ! -e $DISK ] && error "$DISK not found !" || :
	
	if [ ! -w $DISK ]; then
		error "$DISK doit être accessible en écriture !"
	fi

	
	# get display
	
	if [ -z $DISPLAY ]; then
		error "DISPLAY not set !"
	fi
	
	(rm -f $TMPDIR/vdn-display-$USER; umask 077 ; touch $TMPDIR/vdn-display-$USER)
	DISP=$(echo $DISPLAY | cut -d ':' -f 2 | cut -d '.' -f 1)
	echo $DISPLAY | cut -d ':' -f 2 >> $TMPDIR/vdn-display-$USER

	# get xauth key
	
	key=$(xauth list| grep $(uname -n) | grep $DISP | tail -n 1 | tr -s ' '  | cut -d ' ' -f 3)
	
	[ -n "$key" ] || error "Xauth key  is empty !"
	echo $key | egrep -q '^[[:xdigit:]]+$' ||  error "Bad xauth key ($key) !"
	
	(rm -f $TMPDIR/vdn-key-$USER; umask 077 ; touch $TMPDIR/vdn-key-$USER)
	
	echo $key >> $TMPDIR/vdn-key-$USER
	
	# mount (fuse)
	
	# 1 : offset (2048*512) 
	d=$TMPDIR/vdn-proot-$USER; 
	[ ! -d $d/offset ] && mkdir -p $d/offset || :
	$VDN_PATH/bin/bbfs $VDN_PATH/files $d/offset
	
	# 2 : mount part
	[ ! -d $d/part ] && mkdir -p $d/part1 || :
	$VDN_PATH/bin/ext4fuse $d/offset/$DISK_NAME $d/part1
	
	# 3 : proot
	# -b /etc/passwd -b /etc/group
	proot -b /proc -b /dev -b /sys  -b /dev/pts -b /home -b /tmp -b /etc \
		 -r $d/part1 /bin/bash
	
	echo "Done"
	
	

}

# Programme principal

VDN_PATH=$(readlink -f $(dirname $0)/..); . $VDN_PATH/bin/functions.sh

DISK=$VDN_PATH/files/$DISK_NAME

args "$@"

set -x

if [ $UMOUNT = 0 ]; then 
	vdnUmount
	trap vdnUmount 0
	vdnMount
else
	vdnUmount
fi