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

# Configuration
MONGO_SERVICE="mongo"
COMPOSE_FILE="docker-compose-standalone.yaml"

# stop mongo container while we copy its volume
docker compose -f "$COMPOSE_FILE" stop "$MONGO_SERVICE"

# timestamp for filename
TIMESTAMP=$(date +"%Y-%m-%d-%H-%M")

# backup directory and retention (can be overridden via env)
BACKUP_DIR="${BACKUP_DIR:-backups}"
KEEP="${KEEP:-7}"

mkdir -p "$BACKUP_DIR"

BACKUP_FILE="$BACKUP_DIR/mongo-volume-backup-$TIMESTAMP.tar.gz"

sudo tar -czvpf "$BACKUP_FILE" mongo-volume

# rotate old backups: keep only the newest $KEEP files
if [ "$KEEP" -gt 0 ]; then
  # gather files sorted newest-first
  mapfile -t files < <(ls -1t "$BACKUP_DIR"/mongo-volume-backup-*.tar.gz 2>/dev/null || true)
  if [ "${#files[@]}" -gt "$KEEP" ]; then
    for f in "${files[@]:$KEEP}"; do
      echo "Removing old backup: $f"
      rm -f -- "$f"
    done
  fi
fi

# bring mongo container back up
docker compose -f "$COMPOSE_FILE" start "$MONGO_SERVICE"