#!/bin/sh
# -*- mode: shell-script; sh-basic-offset: 8; tab-width: 8 -*-

case ${BASH_VERSION-} in *.*) PATH=/ shopt -s xpg_echo; esac
case ${ZSH_VERSION-} in *.*) PATH=/ emulate ksh; esac

set -u  # expanding unset variable makes non-interactive shell exit immediately
set -f  # disable pathname expansion by default -- makes e.g. eval more robust
set -e  # exit on error -- know potential false negatives and positives !
#et -x  # s/#/s/ may help debugging  (or run /bin/sh -x ... on command line)

LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8; export LANG LC_ALL

#PATH='/sbin:/usr/sbin:/bin:/usr/bin'; export PATH

# XXX If bash finds *this* script by searching PATH...
case $0 in */*) ;; *)
	echo "'$0' does not contain '/'s. try './$0'" >&2; exit 1
esac

saved_IFS=$IFS; readonly saved_IFS

warn () { for l; do echo "$l"; done; } >&2
die () { for l; do echo "$l"; done; exit 1; } >&2

x () { echo + "$@" >&2; "$@"; }
x_env () { echo + "$@" >&2; env "$@"; }
x_eval () { echo + "$*" >&2; eval "$*"; }
x_exec () { echo + "$@" >&2; exec "$@"; die "exec '$*' failed"; }

test $# -gt 0 || {
	exec >&2; echo
	echo Usage: $0 '(debian8|ubuntu1604)'
	echo
	echo After everything set up a user shell to the given container
	echo is started "(cwd='$HOME'; X11 should work)."
	echo
	echo If container is already running, new shell is started.
	echo If container exists but is not running it is restarted.
	echo If image exists but no container, new container is created.
	echo If image does not exist. It is built.
	echo Build files are stored in /root/.docker-setup/ in the container.
	echo
	exit 1
}

case $1
in debian|debian8)
	shift; set debian8 "$@"
	name='debian8-notmuch'
;; ubuntu|ubuntu16|ubuntu1604)
	shift; set ubuntu1604 "$@"
	name='ubuntu1604-notmuch'
;; *)
	die "'$1': unsupported container name"
esac

if status=`exec docker inspect -f '{{.State.Status}}' $name 2>&1`
then
	if test "$status" = running
	then x_exec docker exec -it "$name" /bin/bash --login
	else x_exec docker start -i "$name"
	fi
fi

run ()
{
	test -d /tmp/.X11-unix &&
		xv='-v /tmp/.X11-unix:/tmp/.X11-unix:ro' || xv=

	x_exec docker run -it -e DISPLAY -e _USER="$USER" --name "$name" \
		-h "$name" -v $HOME:/home/$USER ${v:+-v "$v"} --ipc=host "$name"
}

case $status in *parsing*error*.State.Status*) run; esac

# Here if above docker inspect -f '{{.State.Status}}' did not match above, but
# Error: No such image or container: ...

case $1
in debian8)
   FROM_HASH=1b01529cc499d51767c62f9fc8083043610546b4e050898809ec54e00dbb1a34
   FROM_REF=debian:8.5
;; ubuntu1604)
   FROM_HASH=42118e3df429f09ca581a9deb3df274601930e428e452f7e4e9f1833c56a100a
   FROM_REF=ubuntu:16.04
esac

TRUNC_HASH=${FROM_HASH%????????????????????????????????????????????????????}

rmtmps () { rm -rf _docker_wip; trap - 0; }
rmtmps
mkdir _docker_wip

# outcomment next line when debugging build
trap rmtmps 0 INT HUP TERM
exec 3>&1 > _docker_wip/Dockerfile.gen

cat <<EOF

# Ensure that FROM_REF & FROM_HASH are in sync; hash wins if not...
#FROM $FROM_REF (is $TRUNC_HASH...)
FROM $FROM_HASH

# Note: The result of docker build with this Dockerfile is not entirely
#       reproducable as packages installed from remote sources may get
#       updated...

ENV LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8

EOF

case $1 in debian*|ubuntu*)

cat <<'EOF'
# Set locale in a way that is both ubuntu and debian compatible
RUN set -xeu \
 && export DEBIAN_FRONTEND=noninteractive \
 && apt-get update && apt-get install -y -q locales \
 && if test -f /etc/locale.gen; then \
       sed -i '/en_US.UTF-8/ s/^. *//' /etc/locale.gen; fi \
 && locale-gen en_US.UTF-8 \
 && echo 'LANG="en_US.UTF-8"' > /etc/default/locale \
 && apt-get install -y -q build-essential git libxapian-dev libgmime-2.6-dev libtalloc-dev zlib1g-dev \
 && apt-get -y autoremove && apt-get -y clean # rm -rf /var/lib/apt/lists/

EOF

esac

# all containers (more may be added...)

cat <<'EOF'
RUN set -xeu \
 && chmod 755 /root \
 && exec 3>&1 >>/root/.bash_profile && echo \
 && echo 'test ! -f /root/.docker-setup/bash-as-user.sh ||' \
 && echo '    . /root/.docker-setup/bash-as-user.sh' \
 && exec >>/etc/bash.bashrc && echo \
 && echo '# emulate zsh printexitvalue (written from Dockerfile)' \
 && echo 'trap '\''echo -n bash: exit $? \\ \\ ; fc -nl -1 -1'\'' ERR' \
 && exec 1>&3 3>&- \
 && umask 077 \
 && mkdir -p /etc/sudoers.d \
 && echo '%root ALL= NOPASSWD: ALL' >/etc/sudoers.d/55-wheel-allmighty

ADD bash-as-user.sh Dockerfile.gen /root/.docker-setup/

CMD ["/bin/bash", "--login" ]

EOF

exec >&3 3>&-

cat >_docker_wip/bash-as-user.sh <<'EOF'
# This file is supposed to be loaded from /root/.bash_profile
# when bash is started as login shell (-l or --login).

user=${_USER-}
unset _USER

if test "$user" && test -d /home/"$user"
then
	case $user in *[!-a-z0-9_]*) exit 1; esac
	grep -q "^$user:" /etc/passwd || {
		duid=`exec stat -c %u /home/"$user"`
		useradd -d /home/"$user" -M -u $duid -U -G 0 -s /bin/bash \
			-c "user $user" "$user" 2>/dev/null || :
	}
fi

# Simple change user which may work as well as gosu(1) if not (better).
test -z "$user" || exec perl -e '
	my @user = getpwnam $ARGV[0];
	chdir $user[7];
	$ENV{HOME} = $user[7];
	$ENV{USER} = $ARGV[0];
	$( = $) = "$user[3] $user[3] 0";
	$< = $> = $user[2]; die "setting uids: $!\n" if $!;
	exec qw"/bin/bash --login";' "$user"
unset user
EOF

( cd _docker_wip
  # TIME is used by (GNU) /usr/bin/time (TIMEFORMAT by bash builtin)
  export TIME='%Us user, %Ss system, %P cpu, %E total (max resident mem %Mk)'
  export SHELL=/bin/sh
  x command time docker build -f Dockerfile.gen -t $name .
  x_exec docker history $name )

rmtmps
# run() does exec; auto-eliminating traps
run