import type { Metadata } from "next";
import { cookies } from "next/headers";
import { Plus_Jakarta_Sans, Noto_Sans_SC, JetBrains_Mono } from "next/font/google";
import "./globals.css";
import Header from "@/components/Header";
import Footer from "@/components/Footer";
import Toaster from "@/components/Toaster";
import TipHost from "@/components/TipHost";
import AccountGuard from "@/components/AccountGuard";
import ThemeSync from "@/components/ThemeSync";
import RealtimeProvider from "@/components/RealtimeProvider";
import type { User } from "@/lib/api";
import { getMeCached, getPublicSettingsCached } from "@/lib/serverData";
import { TOKEN_COOKIE, authCookieHeader } from "@/lib/cookies";
import { accentStyleCSS } from "@/lib/theme";

// 构建期下载并自托管字体：同源加载 + 自动 preload + fallback 度量校正，
// 消除 F5 时 Google CDN 字体到达后整页"由粗变细"的 FOUT 闪动
const jakarta = Plus_Jakarta_Sans({
  subsets: ["latin"],
  weight: ["400", "500", "600", "700", "800"],
  variable: "--font-jakarta",
  display: "swap",
});

const notoSC = Noto_Sans_SC({
  // 须覆盖站内实际用到的字重：缺档时浏览器会伪粗（synthetic bold），中文在 2K 屏发虚发糊
  weight: ["400", "500", "600", "700", "800", "900"],
  variable: "--font-noto-sc",
  display: "swap",
});

const jetbrainsMono = JetBrains_Mono({
  subsets: ["latin"],
  weight: ["400", "500", "700"],
  variable: "--font-jetbrains",
  display: "swap",
});

export const metadata: Metadata = {
  title: {
    default: "姜十三论坛 · J13 FORUM",
    template: "%s · 姜十三论坛",
  },
  description: "姜十三论坛 - 技术分享与讨论社区",
  openGraph: {
    title: "姜十三论坛 · J13 FORUM",
    description: "姜十三论坛 - 技术分享与讨论社区",
    type: "website",
  },
};

export default async function RootLayout({
  children,
}: {
  children: React.ReactNode;
}) {
  const cookieStore = await cookies();
  // 浅色优先的设计系统，仅在显式选择暗色时挂 .dark
  const theme = cookieStore.get("j13-theme")?.value === "dark" ? "dark" : "light";

  // SSR 直出登录态（access 过期时 middleware 已先行轮转并注入请求头，见 middleware.ts），
  // 保证 F5 初始 HTML 中的右上角就是正确的用户区，而非先闪"登录/注册"。
  // 无 access cookie 即按游客渲染；客户端 Header 在 CSRF 可读时再静默校正一次。
  // 站点主题色（公开设置）：派生浅/暗两套 accent CSS 变量后随首屏 HTML 内联，
  // 覆盖 globals.css 默认令牌——无主题闪动（FOUC），后端不可用时降级为默认靛蓝
  const { accent } = await getPublicSettingsCached();
  const accentCSS = accentStyleCSS(accent || "");

  let user: User | null = null;
  let unread = 0;
  let chatUnread = 0;
  const hasAuthCookie = !!cookieStore.get(TOKEN_COOKIE)?.value;
  if (hasAuthCookie) {
    // 用户信息与未读数合并为一次请求；只转发最小化的 access cookie
    const me = await getMeCached(authCookieHeader(cookieStore) || undefined);
    user = me.user;
    unread = me.unread_count;
    chatUnread = me.chat_unread_count ?? 0;
  }

  return (
    <html
      lang="zh-CN"
      className={`${theme === "dark" ? "dark" : ""} ${jakarta.variable} ${notoSC.variable} ${jetbrainsMono.variable}`}
    >
      <body className="min-h-screen flex flex-col">
        {accentCSS ? (
          // React 托管的 SSR 主题节点；客户端换肤走 j13-accent-runtime，禁止对此外挂 remove
          <style
            id="j13-accent-vars"
            data-accent-source="ssr"
            dangerouslySetInnerHTML={{ __html: accentCSS }}
          />
        ) : null}
        <a href="#main" className="skip-link">
          跳到主要内容
        </a>
        <Header
          initialUser={user}
          initialUnread={unread}
          initialChatUnread={chatUnread}
          initialTheme={theme}
        />
        <main
          id="main"
          tabIndex={-1}
          className="flex-1 w-full max-w-[1440px] mx-auto px-4 sm:px-6 py-7 sm:py-9 outline-none"
        >
          {children}
        </main>
        <Footer />
        <Toaster />
        <TipHost />
        <AccountGuard />
        <ThemeSync initialAccent={accent || ""} />
        <RealtimeProvider userId={user ? user.id : null} />
      </body>
    </html>
  );
}