#/bin/bash
#
# This script is used to Create a User Account with SUDO Privileges!!!,
# Display the Password and force the User to change that Password upon the first Login!
#
# Version: 1.0
# Author:  ham5ter@ham5ter.de
# Date:    02.08.2016


main(){
	# Default values.  These Values can be overwritten with Comandline Arguments
	FORCE_PASSWORD_CHANGE=true
	ADD_TO_SUDO_GROUP=true
	# Parse arguments
	parse_arguments $@
	# Add the User
	if id -u "$1" >/dev/null 2>&1; then
    echo "Error: The User \"$USERNAME\" already exists!"
	  exit 1
	else
	  adduser --disabled-password --gecos "" $USERNAME
	fi
	# Add the User to the SUDO Group
	if [ "$ADD_TO_SUDO_GROUP" = true ] ; then
	  usermod -aG sudo $USERNAME
	fi
	# Set the Password
	if [ "$USE_PASSWORD" = true ] ; then
	  PASSWORD_OF_THE_NEW_USER=$PROVIDED_PASSWORD
	else
	  PASSWORD_OF_THE_NEW_USER=$(genpasswd)
	fi
	# Force Password Change on Login!
	echo $USERNAME:$PASSWORD_OF_THE_NEW_USER | chpasswd
	if [ "$FORCE_PASSWORD_CHANGE" = true ] ; then
	  chage -d 0 $1
	fi
	# Display Informations
  echo ""
  echo "###"
  echo "# The Password for the Account \"$USERNAME\" is: \"$PASSWORD_OF_THE_NEW_USER\""
  echo "###"
}

genpasswd() {
  local l=$1
  [ "$l" == "" ] && l=16
  tr -dc A-Za-z0-9_ < /dev/urandom | head -c ${l} | xargs
}

usage() {
  cat 1>&2 <<EOF
Usage $(basename $0) USERNAME [OPTIONS]
This script is used to Create a User Account with SUDO Privileges.
  -v|--verbose       Make the Script verbose.
  -h|--help          Print this help message.
  -p|--password <p>  Set the Password of the new user to <p>.
  -n|--no-reset      Dont ask the user to change his Password.
  -s|--no-sudo       Dont add the user to the sudo Group.
EOF
}

parse_arguments(){
  if [ $# -eq 0 ]; then
  	echo "Error: Missing Argument"
  	usage
    exit 1
  fi
  PARAMS=""
  while (( "$#" )); do
    case "$1" in
      -v|--verbose)
        set -e
        set -x
        shift 1
        ;;
      -h|--help)
        usage
        exit 0
      ;;
      -n|--no-reset)
        FORCE_PASSWORD_CHANGE=false
        shift 1
      ;;
      -s|--no-sudo)
        ADD_TO_SUDO_GROUP=false
        shift 1
      ;;
      -p|--password)
	      PROVIDED_PASSWORD=$2
	      USE_PASSWORD=true
	      shift 2
      ;;
      --) # end Argument parsing
        shift
        break
        ;;
      -*|--*=) # unsupported Argument
        echo "Error: Unsupported Argument '$1'" >&2
        usage
        exit 1
      ;;
      *) # preserve positional Arguments
        USERNAME="$PARAMS$1"
        shift
      ;;
    esac
  done
}

main "$@"