#!/usr/bin/env bash
# Pull the SkateSpots Community Cordn state off the relay host, keep 30 daily
# snapshots locally, refresh the 0600 working copy, and optionally push the
# snapshot directory to restic when the normal relay backup is configured.
#
#   scripts/backup-community-state.sh
#   SKATESPOTS_COMMUNITY_HOST=skatespots-cvm scripts/backup-community-state.sh
set -euo pipefail

HOST="${SKATESPOTS_COMMUNITY_HOST:-skatespots-cvm}"
REMOTE_STATE="${SKATESPOTS_COMMUNITY_STATE:-/var/lib/skatespots-community/state.json}"
DEST="${SKATESPOTS_COMMUNITY_BACKUP_DIR:-$HOME/.backups/community}"
CONFIG_DIR="$HOME/.config/skatespots"

mkdir -p "$DEST" "$CONFIG_DIR"
chmod 700 "$DEST" "$CONFIG_DIR"

tmp="$(mktemp)"
trap 'rm -f "$tmp"' EXIT

scp -q "$HOST:$REMOTE_STATE" "$tmp"
# Refuse to rotate a valid backup out for an empty/corrupt download.
node -e 'const fs=require("fs");const s=JSON.parse(fs.readFileSync(process.argv[1],"utf8"));if(!s||typeof s!=="object")process.exit(1)' "$tmp"

stamp="$(date +%F)"
install -m 600 "$tmp" "$DEST/state-$stamp.json"
install -m 600 "$tmp" "$CONFIG_DIR/community-state.json"
echo "saved $DEST/state-$stamp.json"

# Keep 30 daily snapshots.
ls -1t "$DEST"/state-*.json 2>/dev/null | tail -n +31 | xargs -r rm -f

if [[ -f "$CONFIG_DIR/restic.env" ]] && command -v restic >/dev/null 2>&1; then
  set -a
  # shellcheck disable=SC1091
  . "$CONFIG_DIR/restic.env"
  set +a
  restic backup "$DEST" --tag community-state --host "$(hostname)"
  restic forget --tag community-state --keep-daily 30 --prune
else
  echo "restic not configured; local snapshots only"
fi