#!/bin/bash
set -e

# Script to add a new VPN client
# Usage: ./add-client.sh <client_name>
#
# Configuration is loaded from .env file or /etc/wireguard/vpn.conf

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# Try to load from .env in project directory (for development)
if [ -f "${SCRIPT_DIR}/../.env" ]; then
    source "${SCRIPT_DIR}/../.env"
# Or from deployed config
elif [ -f "/etc/wireguard/vpn.conf" ]; then
    source "/etc/wireguard/vpn.conf"
fi

# Default values
: "${RU_VDS_IP:=176.124.216.197}"
: "${WG_CLIENT_PORT:=51820}"
: "${USER_VPN_GATEWAY:=10.10.0.1}"
: "${WG_KEEPALIVE:=25}"

if [ "$EUID" -ne 0 ]; then
    echo "ERROR: Please run as root"
    exit 1
fi

if [ -z "$1" ]; then
    echo "Usage: $0 <client_name>"
    echo "Example: $0 phone"
    exit 1
fi

CLIENT_NAME="$1"
KEYS_DIR="/etc/wireguard/keys"
CLIENTS_DIR="/etc/wireguard/clients"
WG_INTERFACE="wg0"

# Check if client already exists
if [ -f "${KEYS_DIR}/client_${CLIENT_NAME}.key" ]; then
    echo "ERROR: Client '${CLIENT_NAME}' already exists"
    exit 1
fi

echo "Adding new VPN client: ${CLIENT_NAME}"
echo ""

# Extract network prefix from gateway IP (e.g., 10.10.0 from 10.10.0.1)
NETWORK_PREFIX=$(echo "$USER_VPN_GATEWAY" | sed 's/\.[0-9]*$//')

# Find next available IP
USED_IPS=$(wg show ${WG_INTERFACE} allowed-ips 2>/dev/null | grep -oP "${NETWORK_PREFIX//./\\.}\.\K[0-9]+" | sort -n)
NEXT_IP=2
for ip in $USED_IPS; do
    if [ $ip -ge $NEXT_IP ]; then
        NEXT_IP=$((ip + 1))
    fi
done

if [ $NEXT_IP -gt 254 ]; then
    echo "ERROR: No available IPs in ${NETWORK_PREFIX}.0/24 range"
    exit 1
fi

CLIENT_IP="${NETWORK_PREFIX}.${NEXT_IP}"

echo "[1/5] Generating client keys..."
wg genkey | tee "${KEYS_DIR}/client_${CLIENT_NAME}.key" | wg pubkey > "${KEYS_DIR}/client_${CLIENT_NAME}.pub"
chmod 600 "${KEYS_DIR}/client_${CLIENT_NAME}."*

CLIENT_PRIVATE_KEY=$(cat "${KEYS_DIR}/client_${CLIENT_NAME}.key")
CLIENT_PUBLIC_KEY=$(cat "${KEYS_DIR}/client_${CLIENT_NAME}.pub")
SERVER_PUBLIC_KEY=$(cat "${KEYS_DIR}/server.pub")

echo "[2/5] Adding peer to WireGuard interface..."
wg set ${WG_INTERFACE} peer ${CLIENT_PUBLIC_KEY} allowed-ips ${CLIENT_IP}/32

echo "[3/5] Saving WireGuard configuration..."
wg-quick save ${WG_INTERFACE}

echo "[4/5] Creating client configuration file..."
mkdir -p ${CLIENTS_DIR}

cat > "${CLIENTS_DIR}/${CLIENT_NAME}.conf" << EOF
[Interface]
PrivateKey = ${CLIENT_PRIVATE_KEY}
Address = ${CLIENT_IP}/32
DNS = ${USER_VPN_GATEWAY}

[Peer]
PublicKey = ${SERVER_PUBLIC_KEY}
Endpoint = ${RU_VDS_IP}:${WG_CLIENT_PORT}
AllowedIPs = 0.0.0.0/0
PersistentKeepalive = ${WG_KEEPALIVE}
EOF

chmod 600 "${CLIENTS_DIR}/${CLIENT_NAME}.conf"

echo "[5/5] Generating QR code..."
echo ""
echo "========================================="
echo "Client added successfully!"
echo "========================================="
echo ""
echo "Client name: ${CLIENT_NAME}"
echo "Client IP: ${CLIENT_IP}"
echo ""
echo "Configuration file: ${CLIENTS_DIR}/${CLIENT_NAME}.conf"
echo ""
echo "QR Code (scan with WireGuard mobile app):"
echo ""
qrencode -t ansiutf8 < "${CLIENTS_DIR}/${CLIENT_NAME}.conf"
echo ""
echo "Or copy the configuration from:"
echo "  cat ${CLIENTS_DIR}/${CLIENT_NAME}.conf"
echo ""