#!/bin/bash
# =====================================================
# Proxmox VE: Linux Bridge erstellen
# =====================================================

# ---- Standardwerte ----
DEFAULT_BRIDGE="xx_vmbrmgt"
DEFAULT_BRIDGE_IP="10.60.10.1/24"
DEFAULT_NAT_SUBNET="10.60.10.0/24"
DEFAULT_OUT_IF="vmbr0"
INTERFACES_FILE="/etc/network/interfaces"

# ---- Farben / Layout ----
BOLD="\033[1m"
GREEN="\033[32m"
CYAN="\033[36m"
YELLOW="\033[33m"
RED="\033[31m"
RESET="\033[0m"
INDENT="      "

# ---- Root Check ----
if [[ $EUID -ne 0 ]]; then
    echo -e "${BOLD}${RED}${INDENT}Bitte als Root ausführen!${RESET}"
    exit 1
fi

# ---- Header ----
echo -e "${CYAN}${BOLD}${INDENT}==========================================${RESET}"
echo -e "${CYAN}${BOLD}${INDENT}           Linux Bridge erstellen          ${RESET}"
echo -e "${CYAN}${BOLD}${INDENT}==========================================${RESET}"

# ---- Eingaben ----
read -p "${INDENT}Bridge Name (Default: $DEFAULT_BRIDGE): " BRIDGE_NAME
BRIDGE_NAME="${BRIDGE_NAME:-$DEFAULT_BRIDGE}"

read -p "${INDENT}Bridge IP (Default: $DEFAULT_BRIDGE_IP): " BRIDGE_IP
BRIDGE_IP="${BRIDGE_IP:-$DEFAULT_BRIDGE_IP}"

read -p "${INDENT}Subnet für NAT (Default: $DEFAULT_NAT_SUBNET): " NAT_SUBNET
NAT_SUBNET="${NAT_SUBNET:-$DEFAULT_NAT_SUBNET}"

read -p "${INDENT}Physisches Ausgangsinterface (Default: $DEFAULT_OUT_IF): " OUT_IF
OUT_IF="${OUT_IF:-$DEFAULT_OUT_IF}"

# ---- Zusammenfassung ----
echo -e "\n${CYAN}${BOLD}${INDENT}==========================================${RESET}"
echo -e "${CYAN}${BOLD}${INDENT}             Zusammenfassung               ${RESET}"
echo -e "${CYAN}${BOLD}${INDENT}==========================================${RESET}"
echo -e "${INDENT}Bridge Name      : ${CYAN}$BRIDGE_NAME${RESET}"
echo -e "${INDENT}Bridge IP        : ${CYAN}$BRIDGE_IP${RESET}"
echo -e "${INDENT}NAT Subnet       : ${CYAN}$NAT_SUBNET${RESET}"
echo -e "${INDENT}Ausgangsinterface: ${CYAN}$OUT_IF${RESET}"
echo -e "${CYAN}${BOLD}${INDENT}==========================================${RESET}"

read -p "${INDENT}Mit Enter bestätigen und Bridge erstellen..." _

# ---- Backup der interfaces-Datei ----
echo -e "\n${INDENT}==> Backup der interfaces-Datei..."
cp "$INTERFACES_FILE" "${INTERFACES_FILE}.bak.$(date +%Y%m%d-%H%M)"
echo -e "${INDENT}Backup erstellt: ${CYAN}${INTERFACES_FILE}.bak.${RESET}"

# ---- Bridge in interfaces eintragen ----
echo -e "${INDENT}==> Bridge $BRIDGE_NAME in $INTERFACES_FILE eintragen..."
cat <<EOF >> "$INTERFACES_FILE"

# --------------------------------------------------
# VM Bridge $BRIDGE_NAME
auto $BRIDGE_NAME
iface $BRIDGE_NAME inet static
        address $BRIDGE_IP
        bridge-ports none
        bridge-stp off
        bridge-fd 0
        post-up echo 1 > /proc/sys/net/ipv4/ip_forward
        post-up iptables -t nat -A POSTROUTING -s '$NAT_SUBNET' -o $OUT_IF -j MASQUERADE
        post-down iptables -t nat -F
EOF

# ---- Bridge aktivieren ----
echo -e "${INDENT}==> Bridge $BRIDGE_NAME aktivieren..."
ifup $BRIDGE_NAME

# ---- Fertig ----
echo -e "${GREEN}${BOLD}${INDENT}✔ Bridge $BRIDGE_NAME ist jetzt aktiv und konfiguriert!${RESET}\n"