#!/usr/bin/env bash
set -Eeuo pipefail
trap 'echo "[错误] 第 $LINENO 行执行失败：$BASH_COMMAND"' ERR

CONFIG_FILE="/etc/hysteria/config.yaml"
SERVICE_NAME="hysteria-server.service"
MASQUERADE_DEFAULT_URL="https://news.ycombinator.com/"

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() {
  openssl rand -base64 24 | tr -dc 'A-Za-z0-9' | head -c 24
  echo
}

generate_sub_prefix() {
  openssl rand -base64 32 | tr -dc 'a-z0-9' | head -c 8
  echo
}

get_public_ips() {
  local ipv4="" ipv6=""
  ipv4="$(curl -4 -fsSL https://api.ipify.org || true)"
  ipv6="$(curl -6 -fsSL https://api64.ipify.org || true)"
  printf '%s|%s\n' "$ipv4" "$ipv6"
}

wait_for_apt_lock() {
  local timeout="${1:-300}"
  local waited=0

  while pgrep -x apt >/dev/null 2>&1 \
     || pgrep -x apt-get >/dev/null 2>&1 \
     || pgrep -x dpkg >/dev/null 2>&1 \
     || pgrep -f unattended-upgrades >/dev/null 2>&1; do
    if (( waited == 0 )); then
      yellow "检测到 APT/DPKG 正被其他进程占用，正在等待..."
      ps -ef | grep -E 'apt|apt-get|dpkg|unattended' | grep -v grep || true
    fi

    if (( waited >= timeout )); then
      red "等待 APT 锁超时（${timeout} 秒）。"
      if confirm_yn "是否继续等待？"; then
        waited=0
      else
        return 1
      fi
    fi

    sleep 2
    waited=$((waited + 2))
  done

  return 0
}

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

  export DEBIAN_FRONTEND=noninteractive

  blue "==> 更新 APT 软件库"
  wait_for_apt_lock 300 || { red "APT 被占用，无法继续。"; exit 1; }
  apt update -y

  blue "==> 安装基础依赖"
  wait_for_apt_lock 300 || { red "APT 被占用，无法继续。"; exit 1; }
  apt install -y jq curl sed ufw openssl
}

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。"
}

cf_api() {
  local method="$1"
  local endpoint="$2"
  local token="$3"
  local data="${4:-}"

  if [[ -n "$data" ]]; then
    curl -fsSL -X "$method" "https://api.cloudflare.com/client/v4${endpoint}" \
      -H "Authorization: Bearer ${token}" \
      -H "Content-Type: application/json" \
      --data "$data"
  else
    curl -fsSL -X "$method" "https://api.cloudflare.com/client/v4${endpoint}" \
      -H "Authorization: Bearer ${token}" \
      -H "Content-Type: application/json"
  fi
}

get_cf_zone_id() {
  local main_domain="$1"
  local token="$2"
  local resp zone_id
  resp="$(cf_api GET "/zones?name=${main_domain}&status=active" "$token")"
  zone_id="$(printf '%s' "$resp" | jq -r '.result[0].id // empty')"

  if [[ -z "$zone_id" ]]; then
    red "未找到 Cloudflare Zone：${main_domain}"
    red "请确认主域名已接入 Cloudflare，且 API Token 对该 Zone 具有 DNS 编辑权限。"
    exit 1
  fi

  printf '%s\n' "$zone_id"
}

delete_existing_dns_record_if_needed() {
  local zone_id="$1"
  local full_domain="$2"
  local type="$3"
  local token="$4"
  local resp record_ids rid

  resp="$(cf_api GET "/zones/${zone_id}/dns_records?type=${type}&name=${full_domain}" "$token")"
  record_ids="$(printf '%s' "$resp" | jq -r '.result[].id // empty')"

  if [[ -n "$record_ids" ]]; then
    while IFS= read -r rid; do
      [[ -z "$rid" ]] && continue
      cf_api DELETE "/zones/${zone_id}/dns_records/${rid}" "$token" >/dev/null
    done <<< "$record_ids"
  fi
}

create_cf_dns_record() {
  local zone_id="$1"
  local full_domain="$2"
  local type="$3"
  local content="$4"
  local token="$5"
  local payload resp success

  payload="$(jq -nc \
    --arg type "$type" \
    --arg name "$full_domain" \
    --arg content "$content" \
    '{type:$type,name:$name,content:$content,ttl:120,proxied:false}')"

  resp="$(cf_api POST "/zones/${zone_id}/dns_records" "$token" "$payload")"
  success="$(printf '%s' "$resp" | jq -r '.success')"

  if [[ "$success" != "true" ]]; then
    red "创建 Cloudflare DNS 记录失败："
    printf '%s\n' "$resp" | jq .
    exit 1
  fi
}

create_cloudflare_dns_records() {
  local main_domain="$1"
  local sub_prefix="$2"
  local token="$3"
  local ip_info="$4"
  local ipv4="${ip_info%%|*}"
  local ipv6="${ip_info##*|}"
  local full_domain="${sub_prefix}.${main_domain}"
  local zone_id

  zone_id="$(get_cf_zone_id "$main_domain" "$token")"

  blue "==> 在 Cloudflare 中创建 DNS 记录"
  echo "Zone: ${main_domain}"
  echo "完整域名: ${full_domain}"

  if [[ -n "$ipv4" ]]; then
    delete_existing_dns_record_if_needed "$zone_id" "$full_domain" "A" "$token"
    create_cf_dns_record "$zone_id" "$full_domain" "A" "$ipv4" "$token"
    green "已创建 A 记录 -> ${ipv4}"
  fi

  if [[ -n "$ipv6" ]]; then
    delete_existing_dns_record_if_needed "$zone_id" "$full_domain" "AAAA" "$token"
    create_cf_dns_record "$zone_id" "$full_domain" "AAAA" "$ipv6" "$token"
    green "已创建 AAAA 记录 -> ${ipv6}"
  fi

  if [[ -z "$ipv4" && -z "$ipv6" ]]; then
    red "未获取到当前机器公网 IPv4/IPv6，无法创建 DNS 记录。"
    exit 1
  fi

  printf '%s\n' "$full_domain"
}

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 full_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:
    - ${full_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:
    - ${full_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

  chown root:root "${CONFIG_FILE}"
  chmod 644 "${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 full_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}@${full_domain}:443/?sni=${full_domain}&insecure=0"

  echo
  green "================= HY2 节点信息 ================="
  echo "域名: ${full_domain}"
  echo "端口: 443"
  echo "密码: ${password}"
  echo "伪装站点: ${proxy_url}"
  [[ -n "${ipv4}" ]] && echo "IPv4: ${ipv4}"
  [[ -n "${ipv6}" ]] && echo "IPv6: ${ipv6}"
  echo
  echo "代理链接:"
  echo "${share_link}"
  echo
  echo "hysteria 状态:"
  systemctl status "${SERVICE_NAME}" --no-pager -l | sed -n '1,8p'
  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、自动创建 Cloudflare DNS，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
  require_cmd jq
  require_cmd openssl

  local main_domain email cf_token password sub_prefix full_domain ip_info proxy_url

  main_domain="$(prompt_nonempty '请输入主域名（例如 example.com）: ')"
  email="$(prompt_nonempty '请输入 ACME 邮箱: ')"
  cf_token="$(prompt_nonempty '请输入 Cloudflare API Token: ')"

  password="$(generate_password)"
  sub_prefix="$(generate_sub_prefix)"
  ip_info="$(get_public_ips)"

  full_domain="$(create_cloudflare_dns_records "$main_domain" "$sub_prefix" "$cf_token" "$ip_info")"
  proxy_url="$MASQUERADE_DEFAULT_URL"

  echo
  green "自动生成的 Hysteria 域名: ${full_domain}"
  echo "默认伪装站点: ${proxy_url}"
  echo "随机密码: ${password}"
  echo

  disable_existing_firewalls
  configure_ufw
  install_hysteria2
  write_config "${full_domain}" "${email}" "${cf_token}" "${password}" "${proxy_url}"
  start_service
  show_result "${full_domain}" "${password}" "${proxy_url}" "${ip_info}"
}

main "$@"