#!/usr/bin/env bash
set -euo pipefail

SOURCE_DIR="${MARKDOWN_SOURCE_DIR:-./backend/content/posts}"
BACKUP_DIR="${BACKUP_DIR:-./backups/markdown}"
RETENTION_DAYS="${RETENTION_DAYS:-30}"
TIMESTAMP="$(date -u +%Y%m%dT%H%M%SZ)"
FILE_PATH="${BACKUP_DIR}/markdown-${TIMESTAMP}.tar.gz"

if [[ ! -d "${SOURCE_DIR}" ]]; then
  echo "Markdown source directory not found: ${SOURCE_DIR}" >&2
  exit 1
fi

mkdir -p "${BACKUP_DIR}"
tar -czf "${FILE_PATH}" -C "${SOURCE_DIR}" .
ln -sfn "$(basename "${FILE_PATH}")" "${BACKUP_DIR}/latest.tar.gz"
find "${BACKUP_DIR}" -type f -name 'markdown-*.tar.gz' -mtime +"${RETENTION_DAYS}" -delete

echo "Markdown backup written to ${FILE_PATH}"