#!/usr/bin/env bash
set -euo pipefail

TPROXY_PORT="${TPROXY_PORT:-7895}"
TPROXY_MARK="${TPROXY_MARK:-1}"
TPROXY_TABLE="${TPROXY_TABLE:-100}"
TPROXY_CHAIN="${TPROXY_CHAIN:-VPN_PROXY_TPROXY}"
BYPASS_CIDRS="${BYPASS_CIDRS:-0.0.0.0/8 10.0.0.0/8 100.64.0.0/10 127.0.0.0/8 169.254.0.0/16 172.16.0.0/12 192.168.0.0/16 224.0.0.0/4 240.0.0.0/4}"

log() {
  printf '[gateway-entrypoint] %s\n' "$*"
}

ipt() {
  iptables -w "$@"
}

cleanup_tproxy() {
  log "cleanup tproxy rules"
  ipt -t mangle -D PREROUTING -j "$TPROXY_CHAIN" 2>/dev/null || true
  ipt -t mangle -F "$TPROXY_CHAIN" 2>/dev/null || true
  ipt -t mangle -X "$TPROXY_CHAIN" 2>/dev/null || true
  ip rule del fwmark "$TPROXY_MARK" table "$TPROXY_TABLE" 2>/dev/null || true
  ip route flush table "$TPROXY_TABLE" 2>/dev/null || true
}

setup_tproxy() {
  log "setup tproxy on port ${TPROXY_PORT}, mark ${TPROXY_MARK}, table ${TPROXY_TABLE}"
  cleanup_tproxy

  ip rule add fwmark "$TPROXY_MARK" table "$TPROXY_TABLE" 2>/dev/null || true
  ip route replace local 0.0.0.0/0 dev lo table "$TPROXY_TABLE"

  ipt -t mangle -N "$TPROXY_CHAIN"
  # Пропускаем пакеты, адресованные самому хосту (ответы на исходящие соединения sing-box)
  ipt -t mangle -A "$TPROXY_CHAIN" -m addrtype --dst-type LOCAL -j RETURN
  ipt -t mangle -A "$TPROXY_CHAIN" -m mark --mark "$TPROXY_MARK" -j RETURN

  for cidr in $BYPASS_CIDRS; do
    ipt -t mangle -A "$TPROXY_CHAIN" -d "$cidr" -j RETURN
  done

  ipt -t mangle -A "$TPROXY_CHAIN" -p tcp -j TPROXY --on-port "$TPROXY_PORT" --tproxy-mark "$TPROXY_MARK/$TPROXY_MARK"
  ipt -t mangle -A "$TPROXY_CHAIN" -p udp -j TPROXY --on-port "$TPROXY_PORT" --tproxy-mark "$TPROXY_MARK/$TPROXY_MARK"
  ipt -t mangle -A PREROUTING -j "$TPROXY_CHAIN"
}

setup_tproxy

node /app/src/server/index.js &
APP_PID=$!

shutdown() {
  log "shutdown requested"
  kill "$APP_PID" 2>/dev/null || true
  wait "$APP_PID" 2>/dev/null || true
  cleanup_tproxy
}

trap 'shutdown; exit 0' SIGTERM SIGINT

wait "$APP_PID"
STATUS=$?
cleanup_tproxy
exit "$STATUS"