#!/usr/bin/env bash
# SPDX-FileCopyrightText: 2026 Lukas Schaefer
# SPDX-License-Identifier: AGPL-3.0-or-later
#
# Print the newest Keep a Changelog version section (skips Unreleased).
# Usage: extract-latest-changelog.sh [CHANGELOG.md]

set -euo pipefail

changelog="${1:-CHANGELOG.md}"

if [[ ! -f "${changelog}" ]]; then
	echo "changelog not found: ${changelog}" >&2
	exit 1
fi

notes="$(awk '
	BEGIN { printing = 0 }

	# Version headings are "## …"; subsection headings are "### …".
	/^##[ \t]/ {
		if ($0 ~ /^##[ \t]+\[?[Uu]nreleased\]?/) {
			printing = 0
			next
		}
		if (printing) {
			exit
		}
		printing = 1
	}

	printing { print }
' "${changelog}")"

if [[ -z "${notes}" ]]; then
	echo "no version section found in ${changelog}" >&2
	exit 1
fi

# Trim trailing blank lines.
printf '%s\n' "${notes}" | awk '
	NF { seen = 1 }
	seen { lines[++n] = $0 }
	END {
		while (n > 0 && lines[n] ~ /^[ \t]*$/) {
			n--
		}
		for (i = 1; i <= n; i++) {
			print lines[i]
		}
	}
'