#!/bin/bash
# Copyright (c) 2024, William Hubbs
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 
# 1. Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. Neither the name of the copyright holder nor the names of its
#    contributors may be used to endorse or promote products derived from
#    this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

set -e
shopt -s lastpipe

if [[ -z $1 ]]; then
printf "%s\n" "no tarball name specified" >&2
exit 1
fi

if [[ ! -f go.mod ]]; then
printf "%s %s\n" "${PWD}" "does not contain a go project" >&2
exit 1
fi

work=$(mktemp -d -p '' dep-tarball-XXXXXX)
export GOMODCACHE="${work}"/go-mod
go mod download -modcacherw
mapfile -t mod_paths < <(find . -mindepth 2 -name go.mod -print)
for p in "${mod_paths[@]}"; do
	printf "entering %s\n" "${p%/go.mod}"
	pushd "${p%/go.mod}" > /dev/null
	go mod download -modcacherw
	popd > /dev/null
done
find "${GOMODCACHE}/cache/download" -type f -name '*.zip' -delete
(
cd "${work}"
XZ_OPT='-T0 -9' \
tar --owner 0 --group 0 --posix -acf "${1}"-deps.tar.xz go-mod
rm -fr go-mod
)
mv "${work}"/*xz .
rmdir "${work}"