#!/bin/bash
#emacs: -*- mode: shell-script; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: t -*- 
#ex: set sts=4 ts=4 sw=4 noet:
#
# A helper to run/exec singularity images with sanitization:
#  - fake HOME with minimalistic .bashrc and .gitconfig
#  - dedicated /tmp /var/tmp
#  - cleansed environment variables
# while bind mounting (and starting from) current directory.
#
# COPYRIGHT: Yaroslav Halchenko 2019
#
# LICENSE: MIT
#
#  Permission is hereby granted, free of charge, to any person obtaining a copy
#  of this software and associated documentation files (the "Software"), to deal
#  in the Software without restriction, including without limitation the rights
#  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#  copies of the Software, and to permit persons to whom the Software is
#  furnished to do so, subject to the following conditions:
#
#  The above copyright notice and this permission notice shall be included in
#  all copies or substantial portions of the Software.
#
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
#  THE SOFTWARE.
#

set -eu

function info() {
	: #	echo -e "I: " "$@" >&2
}

#
# Generate $BHOME/.gitconfig if not present or missing required minimal user
# info based on the current one
#
function pass_git_config() {
	var="$1"
	default="$2"

	# git config reads without locking, but could lock for writing
	# so we might need to try multiple times setting the value
	value=$(git config "$var" || echo "$default")
	# shellcheck disable=SC2034
	for attempt in {1..5}; do
		git config -f "$BHOME/.gitconfig" "$var" >/dev/null \
			|| { git config -f "$BHOME/.gitconfig" "$var" "$value" 2>/dev/null && break; } \
			&& break
		# we failed - sleep a little. Alert: bashism!
		sleep 0."${RANDOM:0:1}"
	done
}

function readlink_f() {
	readlink -f "$1" 2> /dev/null || python -c 'import sys, os ; print(os.path.realpath(sys.argv[1]))' "$1"
}

info "PWD=$PWD"

thisfile=$(readlink_f "$0")
thisdir=$(dirname "$thisfile")
updir=$(dirname "$thisdir")
BHOME="$updir/binds/HOME"

cmd="${SINGULARITY_CMD:-$1}"; shift

if [ -n "${DATALAD_CONTAINER_NAME:-}" ]; then
	export SINGULARITYENV_DATALAD_CONTAINER_NAME="$DATALAD_CONTAINER_NAME"
	# for singularity -> apptainer migration and it seems that both are ok
	# see https://github.com/ReproNim/containers/issues/69
	export APPTAINERENV_DATALAD_CONTAINER_NAME="$DATALAD_CONTAINER_NAME"
fi

# fix non-writable matplotlib cache dir in apptainer https://github.com/ReproNim/containers/issues/97                                  
export SINGULARITYENV_MPLCONFIGDIR=/tmp/mpl-config
export APPTAINERENV_MPLCONFIGDIR=/tmp/mpl-config

# singularity bind mounts system /tmp, which might result in side-effects
# Create a dedicated temporary directory to be removed upon completion
# Mac's tmpdir (with default options) causes problems when a singularity 
# container in a docker container tries to create a socket in the 
# (double-bound) directory.  Shortening the name of the directory is one way 
# to fix the problem.  See https://github.com/ReproNim/containers/issues/57
if [ "$(uname -s)" = Darwin ]; then
    tmpdir=$(mktemp -d -t s)
else
    tmpdir=$(mktemp -d -t singtmp.XXXXXX)
fi

# To know what base would need to be mounted within docker
tmpbase=$(dirname "$tmpdir")
# Create new isolated /tmp to be bound mount
mkdir -p "$tmpdir/tmp"
info "created temp dir $tmpdir"
trap 'rm -fr "$tmpdir" && info "removed temp dir $tmpdir"' exit

pass_git_config "user.name" "ReproNim User"
pass_git_config "user.email" "nobody@example.com"

# Common arguments for the singularity run
SARGS=( -e -B "$PWD" -H "$BHOME" --pwd "$PWD" "$@" )

# Due to https://github.com/sylabs/singularity/issues/3949
# which was fixed only in v3.3.0-rc.1-431-g40331a5b1
# for now we need to avoid using `-c` in such cases and
# just create those needed bind points manually and bind mount
# /tmp manually (apparently -W is not in effect really without -c).
# TODO: make it also check/depend on current version of singularity
need_no_c=
for d in "$PWD" "$updir"; do
	d_normalized=$(readlink_f "$d")
	if [ "${d_normalized##/tmp/}" != "$d_normalized/" ]; then
		# we should create that one within our $tmpdir
		info "Creating $d and /var/tmp under $tmpdir"
		mkdir -p "$tmpdir$d" "$tmpdir/var/tmp"
		need_no_c=1
	fi
done

if [ -z "$need_no_c" ]; then
	SARGS=( -c "${SARGS[@]}" )
else
	SARGS=( -B "$tmpdir/tmp:/tmp" -B "$tmpdir/var/tmp:/var/tmp" "${SARGS[@]}" )
fi

SARGS=( -B "$updir/binds/zoneinfo/UTC:/etc/localtime" "${SARGS[@]}" )


# set -x
if hash singularity 2>/dev/null && [ -z "${REPRONIM_USE_DOCKER:-}" ]; then
	singularity "$cmd" -W "$tmpdir" "${SARGS[@]}"
else
	# we need to bind mount all bases without remapping
	DARGS=(
	--privileged
	--rm
	-e "UID=$(id -u)"
	-e "GID=$(id -g)"
	-v "$tmpbase:$tmpbase"
	-v "$PWD:$PWD"
	-v "$updir:$updir"
	-v "$BHOME:$BHOME"
	-w "$PWD")

	if [ -n "${REPRONIM_DOCKER_OPTS:-}" ]; then
		# ATM I do want to split all possible options into separate ones if provided,
		# shellcheck disable=SC2206
		DARGS=( ${REPRONIM_DOCKER_OPTS} "${DARGS[@]}" )
	fi

	# Even though we bind UTC zoneinfo via singularity -B, it does try to bind
	# it first itself, and if not present -- would fail.  So we do bind mount it
	# also into Docker environment to make sure that some /etc/localtime is available
	DARGS=( "${DARGS[@]}" -v "$updir/binds/zoneinfo/UTC:/etc/localtime" )

	docker run \
		   "${DARGS[@]}" \
		   repronim/containers:latest \
		   "$cmd" "${SARGS[@]}"
fi