#!/usr/bin/env bash
# Backs up plugins, config, worlds, and settings from MINECRAFT_SERVER_PATH
# to MINECRAFT_BACKUP_PATH/backup-<timestamp>[-label].tar.bz2.
#
# Usage: backup-server.sh [-f|--force] [label]
#   -f  Back up even if the server is running (worlds may be inconsistent).

set -euo pipefail

TOOLS_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$TOOLS_DIR/.." && pwd)"
if [[ ! -r "$PROJECT_ROOT/.env" ]]; then
  echo "Error: $PROJECT_ROOT/.env is missing or unreadable. Copy .env.example to .env and set its values." >&2
  exit 1
fi
load_project_env() {
  local env_line env_key env_value first_char last_char
  while IFS= read -r env_line || [[ -n "$env_line" ]]; do
    env_line="${env_line%$'\r'}"
    [[ "$env_line" =~ ^[[:space:]]*(#|$) ]] && continue
    [[ "$env_line" == *=* ]] || continue

    env_key="${env_line%%=*}"
    env_value="${env_line#*=}"
    env_key="${env_key#"${env_key%%[![:space:]]*}"}"
    env_key="${env_key%"${env_key##*[![:space:]]}"}"
    [[ "$env_key" =~ ^[A-Za-z_][A-Za-z0-9_]*$ ]] || continue
    env_value="${env_value#"${env_value%%[![:space:]]*}"}"
    env_value="${env_value%"${env_value##*[![:space:]]}"}"

    if (( ${#env_value} >= 2 )); then
      first_char="${env_value:0:1}"
      last_char="${env_value:$((${#env_value} - 1)):1}"
      if [[ "$first_char" == "$last_char" && ( "$first_char" == '"' || "$first_char" == "'" ) ]]; then
        env_value="${env_value:1:$((${#env_value} - 2))}"
      fi
    fi

    if [[ -z "${!env_key:-}" ]]; then
      export "$env_key=$env_value"
    fi
  done < "$PROJECT_ROOT/.env"
}
load_project_env

MINECRAFT_SERVER_PATH="${MINECRAFT_SERVER_PATH:-MCServer}"
MINECRAFT_SERVER_PATH="${MINECRAFT_SERVER_PATH/#\~/$HOME}"
[[ "$MINECRAFT_SERVER_PATH" == /* ]] || MINECRAFT_SERVER_PATH="$PROJECT_ROOT/$MINECRAFT_SERVER_PATH"
MINECRAFT_BACKUP_PATH="${MINECRAFT_BACKUP_PATH:-backups}"
MINECRAFT_BACKUP_PATH="${MINECRAFT_BACKUP_PATH/#\~/$HOME}"
[[ "$MINECRAFT_BACKUP_PATH" == /* ]] || MINECRAFT_BACKUP_PATH="$PROJECT_ROOT/$MINECRAFT_BACKUP_PATH"

FORCE=false
LABEL=""
for arg in "$@"; do
  case "$arg" in
    -f|--force) FORCE=true ;;
    -h|--help) sed -n '2,7p' "$0"; exit 0 ;;
    -*) echo "Unknown option: $arg" >&2; exit 1 ;;
    *) LABEL="$arg" ;;
  esac
done

[[ -d "$MINECRAFT_SERVER_PATH" ]] || { echo "Error: $MINECRAFT_SERVER_PATH does not exist." >&2; exit 1; }

if pgrep -f "java.*paper-.*\.jar" >/dev/null && ! $FORCE; then
  echo "Error: the server is running. Stop it first (tools/stop-server.sh) or pass --force." >&2
  exit 1
fi

cd "$MINECRAFT_SERVER_PATH"
shopt -s nullglob

ITEMS=()
[[ -d plugins ]] && ITEMS+=(plugins)
[[ -d config ]] && ITEMS+=(config)
for dir in */; do
  dir="${dir%/}"
  [[ -f "$dir/level.dat" ]] && ITEMS+=("$dir")
done
for f in *.yml *.yaml *.json *.properties eula.txt; do
  ITEMS+=("$f")
done

if (( ${#ITEMS[@]} == 0 )); then
  echo "Error: nothing to back up in $MINECRAFT_SERVER_PATH." >&2
  exit 1
fi

# Keep labels filename-safe.
LABEL="${LABEL//[^A-Za-z0-9._-]/_}"
NAME="backup-$(date +%Y%m%d-%H%M%S)${LABEL:+-$LABEL}.tar.bz2"
mkdir -p "$MINECRAFT_BACKUP_PATH"
ARCHIVE="$MINECRAFT_BACKUP_PATH/$NAME"

echo "Backing up: ${ITEMS[*]}"
trap 'rm -f "$ARCHIVE.part"' EXIT
tar --exclude 'plugins/.paper-remapped' --exclude '*/session.lock' \
  -cjf "$ARCHIVE.part" "${ITEMS[@]}"
mv "$ARCHIVE.part" "$ARCHIVE"
trap - EXIT

echo "Created $ARCHIVE ($(du -h "$ARCHIVE" | awk '{print $1}'))"