#!/bin/bash
set -euo pipefail

# Check for root privileges
if [ "$(id -u)" -ne 0 ]; then
    echo "[✗] Dieses Skript muss als root ausgeführt werden." >&2
    exit 1
fi

# Prompt for username input
read -p "Bitte geben Sie den Benutzernamen ein: " USERNAME

# Check if the username is not empty
if [ -z "$USERNAME" ]; then
    echo "[✗] Kein Benutzername eingegeben." >&2
    exit 1
fi

SSH_KEY_URL="https://skulldev.de/Skull-IT/trusted-ssh-keys/raw/branch/main/trusted-ssh-keys"

# Set SSH directory based on username
if [ "$USERNAME" = "root" ]; then
    SSH_DIR="/root/.ssh"
else
    SSH_DIR="/home/$USERNAME/.ssh"
fi

# Update package list and install necessary packages
echo "[+] Updating package list and installing essential packages..."
apt-get update
apt-get install -y wget openssh-server

# Setting up SSH directory and authorized keys
echo "[+] Setting up SSH directory..."
mkdir -p "$SSH_DIR"
wget -O "$SSH_DIR/authorized_keys" "$SSH_KEY_URL"
chown -R "$USERNAME:$USERNAME" "$SSH_DIR"
chmod 700 "$SSH_DIR"
chmod 600 "$SSH_DIR/authorized_keys"

# Configure SSH server to allow public key authentication
echo "[+] Configuring SSH server..."
SSH_CONFIG="/etc/ssh/sshd_config"
sed -i 's/^#PubkeyAuthentication yes/PubkeyAuthentication yes/' "$SSH_CONFIG"
sed -i 's/^PubkeyAuthentication no/PubkeyAuthentication yes/' "$SSH_CONFIG"
sed -i 's/^#AuthorizedKeysFile/AuthorizedKeysFile/' "$SSH_CONFIG"
sed -i 's/^PasswordAuthentication yes/PasswordAuthentication no/' "$SSH_CONFIG"

# Restart SSH service to apply changes
systemctl restart ssh

# Adding user to sudo group
echo "[+] Adding user to sudo group..."
apt-get install -y sudo
usermod -aG sudo "$USERNAME"

# Configuring passwordless sudo for the user
echo "[+] Configuring passwordless sudo for $USERNAME..."
echo "$USERNAME ALL=(ALL) NOPASSWD:ALL" | tee "/etc/sudoers.d/$USERNAME" > /dev/null
chmod 440 "/etc/sudoers.d/$USERNAME"

# Setting timezone
echo "[+] Setting timezone to Europe/Berlin..."
apt-get install -y tzdata
ln -sf /usr/share/zoneinfo/Europe/Berlin /etc/localtime

echo "[✓] Bootstrap complete."