#!/usr/bin/env bash
#
# Backup a folder with a timestamp
# Usage: x-backup-folder folder_to_backup [filename]
# If filename is not provided, folder_to_backup will be used
#
# Example: x-backup-folder ~/Documents/MyFolder
#
# Copyright (c) 2022 Ismo Vuorinen. All Rights Reserved.
# Licensed under the MIT license.

set -euo pipefail

# Enable verbosity with VERBOSE=1
VERBOSE="${VERBOSE:-0}"

# Function to print usage information
usage()
{
  echo "Usage: $0 folder_to_backup [filename]"
  exit 1
}

# Function to print messages if VERBOSE is enabled
# $1 - message (string)
msg()
{
  [[ "$VERBOSE" -eq 1 ]] && echo "$1"
}

# Function to print error messages and exit
# $1 - error message (string)
msg_err()
{
  echo "(!) ERROR: $1" >&2
  exit 1
}

# Function to sanitize the filename
# $1 - filename (string)
sanitize_filename()
{
  local filename=$1
  echo "$filename" | tr '/' '_' | iconv -t ascii//TRANSLIT | sed -r 's/[^a-zA-Z0-9]+/_/g' | sed -r 's/^_+|_+$//g'
}

# Function to backup the directory
# $1 - directory to backup (string)
# $2 - filename prefix (string)
backup_directory()
{
  local directory=$1
  local filename=$2

  local sanitized_filename
  sanitized_filename=$(sanitize_filename "$filename")

  local timestamp
  timestamp=$(date "+%Y%m%d_%H%M%S")
  local filename_timestamp="${sanitized_filename}_${timestamp}"

  msg "Backing up directory '$directory' to '${filename_timestamp}.tar.gz'"

  tar cvzf "${filename_timestamp}.tar.gz" "${directory}/"

  msg "Backup completed and saved to '${filename_timestamp}.tar.gz'"
}

# Main function
main()
{
  if [ "$#" -lt 1 ] || [ "$#" -gt 2 ]; then
    usage
  fi

  local directory=$1
  local filename=${2:-$directory}

  if [ -z "$directory" ]; then
    msg_err "DIRECTORY (first argument) is missing"
  fi

  backup_directory "$directory" "$filename"
}

main "$@"