#!/bin/sh

# Copyright © 2024, 2025  Mattias Andrée (m@maandree.se)
# 
# Copying and distribution of this script, with or without modification,
# are permitted in any medium without royalty provided the copyright
# notice and this notice are preserved.  This script is offered as-is,
# without any warranty.


set -e

if ! test $# = 2 || test -t 0 || test -t 1; then
	printf 'usage: %s tarball git-dir < version-info-file > checksum-listing\n' "$0" >&2
	exit 1
fi

tarball="$1"
gitdir="$2"

urls="$(grep '^Tarball: ' | cut -d ' ' -f 2 | grep -v '^https://maandree.se/static/')"

workdir="$$.tmpdir"
rm -rf -- "${workdir}"

refdir="${workdir}/reference"
mkdir -p -- "${refdir}"
gunzip < "${tarball}" | (cd "${refdir}" && tar -x)
if test "$(printf '%s\n' "${refdir}"/* | wc -l)" = 1; then
	refdir="$(printf '%s\n' "${refdir}"/*)"
fi

ln -s -- "$(cd -- "${gitdir}" && pwd)" "${workdir}/gitdir"

add_dirs () {
	while read f; do
		printf '%s\n' "$f"
		while :; do
			d="$(printf '%s\n' "$f" | sed 's|/[^/]*$||')"
			if test "$d" = "$f"; then
				break
			fi
			printf '%s\n' "$d"
			f="$d"
		done
	done
}

gitfiles="$( (cd -- "${gitdir}" && git ls-files) | add_dirs | sort -u | tee -- "${workdir}/gitfiles")"
test -n "${gitfiles}"
tarfiles="$( (cd -- "${refdir}" && find) | sed 's/^\.\///' | sed '/^\.$/d' | add_dirs | sort -u | tee -- "${workdir}/tarfiles")"
test -n "${tarfiles}"
diff -u -- "${workdir}/gitfiles" "${workdir}/tarfiles" >&2
# the following line makes the safe assumption that $workdir (and $refdir) does not contain {}
xargs -I {} diff -u "${refdir}"/{} "${workdir}/gitdir"/{} < "${workdir}/gitfiles" >&2

getandcheck () {
	url="$1"
	number="$2"
	curl -sL -- "${url}" > "${workdir}/downloaded-${number}.tar.gz"
	checkdir="${workdir}/downloaded"
	rm -rf -- "${checkdir}"
	mkdir -p -- "${checkdir}"
	gunzip < "${workdir}/downloaded-${number}.tar.gz" | (cd "${checkdir}" && tar -x)
	if test "$(printf '%s\n' "${checkdir}"/* | wc -l)" = 1; then
		checkdir="$(printf '%s\n' "${checkdir}"/*)"
	fi
	diff -ur -- "${refdir}" "${checkdir}" >&2
	rm -rf -- "${checkdir}"
}

nr=1
for url in $urls; do
	getandcheck "${url}" $(( nr++ ))
done

genfor () {
	tool="$1"
	name="$2"
	sum="$(${tool} < "${tarball}" | cut -d ' ' -f 1)"
	sums="$(printf '%s checksum: %s\n' "${name}" "${sum}")"
	number=1
	for url in $urls; do
		sum="$($tool < "${workdir}/downloaded-${number}.tar.gz" | cut -d ' ' -f 1)"
		test -n "$sum"
		sums="$(printf '%s\n%s checksum: %s\n' "${sums}" "${name}" "${sum}")"
		: $(( number++ ))
	done
	printf '%s\n' "${sums}" | sort -u
}

genfor sha224sum SHA224
genfor sha256sum SHA256
genfor sha384sum SHA384
genfor sha512sum SHA512
genfor sha512-224sum SHA512/224
genfor sha512-256sum SHA512/256
genfor sha3-224sum SHA3-224
genfor sha3-256sum SHA3-256
genfor sha3-384sum SHA3-384
genfor sha3-512sum SHA3-512
genfor b2sum BLAKE2b

rm -rf -- "${workdir}"