#!/bin/bash

if [ "$(id -u)" != "0" ]; then
    echo -e "\033[31mThis script requires superuser rights\033[0m"
    exit 0
fi

if [ "$#" -ne 1 ]; then
    echo "Usage: $0 <y/n>"
    exit 1
fi

if [ "$1" != "y" ] && [ "$1" != "n" ]; then
    echo "Invalid argument. Use 'y' to enable password authentication and 'n' to disable it"
    exit 1
fi

ENABLE_PASSWORD=$1
SSHD_CONFIG="/etc/ssh/sshd_config"

trap 'echo -e "\033[31mSomething went wrong\033[0m"; exit 1' ERR
set -e

echo "Backup $SSHD_CONFIG..."
cp $SSHD_CONFIG $SSHD_CONFIG.backup

if [ "$ENABLE_PASSWORD" == "y" ]; then
    sed -i 's/^#PasswordAuthentication yes/PasswordAuthentication yes/' $SSHD_CONFIG
    sed -i 's/^PasswordAuthentication no/PasswordAuthentication yes/' $SSHD_CONFIG
else
    sed -i 's/^#PasswordAuthentication yes/PasswordAuthentication no/' $SSHD_CONFIG
    sed -i 's/^PasswordAuthentication yes/PasswordAuthentication no/' $SSHD_CONFIG
fi

echo "Restart SSH for apply password $1"
systemctl daemon-reload
systemctl restart ssh

trap - ERR

if [ "$1" == "y" ]; then
    echo "Password authentication has been enabled"
else
    echo "Password authentication has been disabled"
fi