#!/bin/sh
set -eu

destination="${BACKUP_DESTINATION:-/backups}"
verify_dir="${BACKUP_OFFSITE_VERIFY_DIR:-/offsite-verify}"
remote="${RCLONE_ONEDRIVE_REMOTE:-onedrive}"
remote_path="${RCLONE_ONEDRIVE_PATH:-FleetOps/backups}"
interval="${BACKUP_OFFSITE_INTERVAL_SECONDS:-900}"
restore_drill_interval="${BACKUP_RESTORE_DRILL_INTERVAL_SECONDS:-604800}"
retention_days="${BACKUP_RETENTION_DAYS:-30}"

case "$destination" in ""|"/"|".") echo "Unsafe backup destination: $destination" >&2; exit 1;; esac
case "$verify_dir" in ""|"/"|".") echo "Unsafe off-site verify directory: $verify_dir" >&2; exit 1;; esac
case "$remote" in ""|*:*|*/*) echo "Rclone remote must be a configured remote name" >&2; exit 1;; esac
case "$remote_path" in ""|"/"|/*|*".."*) echo "Unsafe OneDrive backup path" >&2; exit 1;; esac
case "$interval:$restore_drill_interval:$retention_days" in *[!0-9:]*|:*|*:) echo "Off-site intervals and retention must be integers" >&2; exit 1;; esac
[ "$retention_days" -ge 1 ] || { echo "Off-site retention must be at least one day" >&2; exit 1; }
[ -f "${RCLONE_CONFIG:-/config/rclone/rclone.conf}" ] || {
  echo "Rclone configuration is missing" >&2
  exit 1
}

mkdir -p "$verify_dir"

while true; do
  latest="$(find "$destination" -maxdepth 1 -type f -name 'mobilityops-*.dump' | sort -r | head -n 1)"
  if [ -n "$latest" ] && [ -f "$latest.sha256" ]; then
    name="$(basename "$latest")"
    checksum_name="$name.sha256"
    remote_root="$remote:$remote_path"
    temporary_dump="$verify_dir/$name.partial"
    temporary_checksum="$verify_dir/$checksum_name.partial"
    verified_dump="$verify_dir/$name"

    rm -f "$temporary_dump" "$temporary_checksum"
    if rclone copyto "$latest" "$remote_root/$name" --checksum --retries 3 --low-level-retries 5 \
        && rclone copyto "$latest.sha256" "$remote_root/$checksum_name" --checksum --retries 3 --low-level-retries 5 \
        && rclone copyto "$remote_root/$name" "$temporary_dump" --retries 3 --low-level-retries 5 \
        && rclone copyto "$remote_root/$checksum_name" "$temporary_checksum" --retries 3 --low-level-retries 5 \
        && mv "$temporary_dump" "$verified_dump" \
        && mv "$temporary_checksum" "$verify_dir/$checksum_name" \
        && (cd "$verify_dir" && sha256sum -c "$checksum_name") \
        && pg_restore --list "$verified_dump" > /dev/null; then
      date -u +%Y-%m-%dT%H:%M:%SZ > "$destination/latest-offsite-success"
      drill_minutes=$((restore_drill_interval / 60))
      if [ ! -f "$destination/latest-offsite-restore-drill" ] \
          || ! find "$destination/latest-offsite-restore-drill" -mmin "-$drill_minutes" -print -quit | grep -q .; then
        if /opt/mobilityops/restore-drill-postgres.sh "$verified_dump"; then
          date -u +%Y-%m-%dT%H:%M:%SZ > "$destination/latest-offsite-restore-drill"
        else
          echo "Off-site restore drill failed for $name" >&2
        fi
      fi
      rclone delete "$remote_root" --min-age "${retention_days}d" \
        --include 'mobilityops-*.dump' --include 'mobilityops-*.dump.sha256' \
        --retries 3 --low-level-retries 5
      find "$verify_dir" -type f -mtime "+$retention_days" -delete
      echo "Verified OneDrive round trip: $remote_root/$name"
    else
      rm -f "$temporary_dump" "$temporary_checksum"
      echo "OneDrive backup synchronization failed for $name" >&2
    fi
  else
    echo "No verified local backup is available for OneDrive synchronization" >&2
  fi
  sleep "$interval"
done