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

CONFIG_FILE="/etc/hysteria/config.yaml"
SERVICE_NAME="hysteria-server.service"

red()    { printf '\033[31m%s\033[0m\n' "$*"; }
green()  { printf '\033[32m%s\033[0m\n' "$*"; }
yellow() { printf '\033[33m%s\033[0m\n' "$*"; }
blue()   { printf '\033[36m%s\033[0m\n' "$*"; }

require_root() {
  if [[ "${EUID}" -ne 0 ]]; then
    red "请使用 root 运行此脚本。"
    exit 1
  fi
}

require_cmd() {
  command -v "$1" >/dev/null 2>&1 || {
    red "缺少命令: $1"
    exit 1
  }
}

prompt_nonempty() {
  local prompt="$1"
  local value=""
  while true; do
    read -r -p "$prompt" value
    if [[ -n "${value// }" ]]; then
      printf '%s' "$value"
      return 0
    fi
    yellow "输入不能为空，请重新输入。"
  done
}

confirm_yn() {
  local prompt="${1:-是否继续？}"
  local answer
  read -r -p "${prompt} [Y/n]: " answer
  case "${answer:-Y}" in
    Y|y|yes|YES|"") return 0 ;;
    N|n|no|NO) return 1 ;;
    *) yellow "输入无效，默认按 Y 处理。"; return 0 ;;
  esac
}

generate_password() {
  tr -dc 'A-Za-z0-9' </dev/urandom | head -c 24
}

get_server_ip() {
  local ipv4 ipv6
  ipv4="$(curl -4 -fsSL https://api.ipify.org || true)"
  ipv6="$(curl -6 -fsSL https://api64.ipify.org || true)"
  echo "${ipv4}|${ipv6}"
}

apt_update_and_install_base() {
  if ! confirm_yn "即将执行 apt update 并安装基础依赖 curl sed ufw，是否继续？"; then
    red "已取消。"
    exit 1
  fi

  blue "==> 更新 APT 软件库"
  export DEBIAN_FRONTEND=noninteractive
  apt update -y

  blue "==> 安装基础依赖"
  apt install -y curl sed ufw
}

disable_existing_firewalls() {
  if ! confirm_yn "即将关闭系统现有防火墙并清理规则，是否继续？"; then
    red "已取消关闭现有防火墙。"
    exit 1
  fi

  blue "==> 自动检测并关闭当前系统防火墙"

  if command -v ufw >/dev/null 2>&1; then
    yellow "检测到 UFW，正在关闭并重置"
    ufw disable || true
    yes | ufw reset || true
  fi

  if systemctl list-unit-files 2>/dev/null | grep -q '^firewalld\.service'; then
    yellow "检测到 firewalld，正在停止并禁用"
    systemctl stop firewalld || true
    systemctl disable firewalld || true
    systemctl mask firewalld || true
  fi

  if systemctl list-unit-files 2>/dev/null | grep -q '^nftables\.service'; then
    yellow "检测到 nftables，正在停止并禁用"
    systemctl stop nftables || true
    systemctl disable nftables || true
  fi

  if command -v nft >/dev/null 2>&1; then
    yellow "清空 nftables 规则"
    nft flush ruleset || true
  fi

  if command -v iptables >/dev/null 2>&1; then
    yellow "清空 iptables 规则"
    iptables -I INPUT 1 -p tcp --dport 22 -j ACCEPT || true
    iptables -F || true
    iptables -X || true
    iptables -Z || true
    iptables -P INPUT ACCEPT || true
    iptables -P FORWARD ACCEPT || true
    iptables -P OUTPUT ACCEPT || true
  else
    yellow "未检测到 iptables，跳过。"
  fi

  if command -v ip6tables >/dev/null 2>&1; then
    yellow "清空 ip6tables 规则"
    ip6tables -I INPUT 1 -p tcp --dport 22 -j ACCEPT || true
    ip6tables -F || true
    ip6tables -X || true
    ip6tables -Z || true
    ip6tables -P INPUT ACCEPT || true
    ip6tables -P FORWARD ACCEPT || true
    ip6tables -P OUTPUT ACCEPT || true
  else
    yellow "未检测到 ip6tables，跳过。"
  fi

  green "现有防火墙处理完成。"
}

configure_ufw() {
  if ! confirm_yn "即将配置并启用 UFW（开放 22/80/443 TCP 和 443 UDP），是否继续？"; then
    red "已取消 UFW 配置。"
    exit 1
  fi

  blue "==> 配置 UFW"

  if [[ -f /etc/default/ufw ]]; then
    sed -i 's/^IPV6=.*/IPV6=yes/' /etc/default/ufw || true
  fi

  ufw default deny incoming || true
  ufw default allow outgoing || true
  ufw allow 22/tcp || true
  ufw allow 80/tcp || true
  ufw allow 443/tcp || true
  ufw allow 443/udp || true
  yes | ufw enable || true

  green "UFW 配置完成。"
}

install_hysteria2() {
  if ! confirm_yn "即将安装 Hysteria 2，是否继续？"; then
    red "已取消 Hysteria 2 安装。"
    exit 1
  fi

  blue "==> 安装 Hysteria 2"
  bash <(curl -fsSL https://get.hy2.sh/)
  green "Hysteria 2 安装完成。"
}

run_domain_selector() {
  if confirm_yn "是否执行外部域名筛选脚本？"; then
    blue "==> 执行域名筛选脚本"
    bash <(curl -sL https://raw.githubusercontent.com/ccxkai233/Domain_Selector/main/domain_check.sh) || true
  else
    yellow "已跳过域名筛选脚本。"
  fi
}

backup_existing_config() {
  if [[ -f "${CONFIG_FILE}" ]]; then
    local backup_file="${CONFIG_FILE}.bak.$(date +%Y%m%d_%H%M%S)"
    cp -a "${CONFIG_FILE}" "${backup_file}"
    yellow "检测到已有配置，已备份到: ${backup_file}"
  fi
}

write_config() {
  local domain="$1"
  local email="$2"
  local cf_token="$3"
  local password="$4"
  local proxy_url="$5"

  echo
  blue "==> 即将写入如下配置到 ${CONFIG_FILE}"
  cat <<EOF
listen: :443

acme:
  domains:
    - ${domain}
  email: ${email}
  type: dns
  dns:
    name: cloudflare
    config:
      cloudflare_api_token: ${cf_token}

auth:
  type: password
  password: ${password}

masquerade:
  type: proxy
  proxy:
    url: ${proxy_url}
    rewriteHost: true
EOF
  echo

  if ! confirm_yn "是否确认写入配置文件？"; then
    red "已取消写入配置。"
    exit 1
  fi

  mkdir -p /etc/hysteria
  backup_existing_config

  cat > "${CONFIG_FILE}" <<EOF
listen: :443

acme:
  domains:
    - ${domain}
  email: ${email}
  type: dns
  dns:
    name: cloudflare
    config:
      cloudflare_api_token: ${cf_token}

auth:
  type: password
  password: ${password}

masquerade:
  type: proxy
  proxy:
    url: ${proxy_url}
    rewriteHost: true
EOF

  chmod 600 "${CONFIG_FILE}"
  green "配置已写入 ${CONFIG_FILE}"
}

start_service() {
  if ! confirm_yn "是否启动并设置 Hysteria 服务开机自启？"; then
    red "已取消启动服务。"
    exit 1
  fi

  blue "==> 启动并设置开机自启"
  systemctl daemon-reload || true
  systemctl enable --now "${SERVICE_NAME}"
  systemctl restart "${SERVICE_NAME}"
  green "服务已启动。"
}

show_result() {
  local domain="$1"
  local password="$2"
  local proxy_url="$3"
  local ip_info="$4"
  local ipv4="${ip_info%%|*}"
  local ipv6="${ip_info##*|}"

  local share_link="hysteria2://${password}@${domain}:443/?sni=${domain}&insecure=0"

  echo
  green "================= HY2 节点信息 ================="
  echo "服务名: ${SERVICE_NAME}"
  echo "配置文件: ${CONFIG_FILE}"
  echo "域名: ${domain}"
  echo "端口: 443"
  echo "认证方式: password"
  echo "密码: ${password}"
  echo "伪装站点: ${proxy_url}"
  [[ -n "${ipv4}" ]] && echo "服务器 IPv4: ${ipv4}"
  [[ -n "${ipv6}" ]] && echo "服务器 IPv6: ${ipv6}"
  echo
  echo "代理链接:"
  echo "${share_link}"
  echo
  echo "systemd 状态:"
  systemctl --no-pager --full status "${SERVICE_NAME}" || true
  echo
  echo "最近日志:"
  journalctl --no-pager -n 30 -u "${SERVICE_NAME}" || true
  echo "================================================"
}

main() {
  require_root

  if ! confirm_yn "本脚本将更新软件源、关闭现有防火墙、配置 UFW、安装并配置 Hysteria 2，是否继续？"; then
    red "用户取消执行。"
    exit 1
  fi

  apt_update_and_install_base

  require_cmd curl
  require_cmd sed
  require_cmd systemctl
  require_cmd ufw

  local domain email cf_token password proxy_url ip_info

  domain="$(prompt_nonempty '请输入用于签发证书的域名: ')"
  email="$(prompt_nonempty '请输入 ACME 邮箱: ')"
  cf_token="$(prompt_nonempty '请输入 Cloudflare API Token: ')"
  password="$(generate_password)"

  disable_existing_firewalls
  configure_ufw
  install_hysteria2
  run_domain_selector

  proxy_url="$(prompt_nonempty '请输入最终用于 masquerade 的完整 URL（例如 https://example.com/）: ')"

  write_config "${domain}" "${email}" "${cf_token}" "${password}" "${proxy_url}"
  start_service

  ip_info="$(get_server_ip)"
  show_result "${domain}" "${password}" "${proxy_url}" "${ip_info}"
}

main "$@"