import OperationalBanner from "@/components/OperationalBanner";
import type { Metadata, Viewport } from "next";
import { cookies, headers } from "next/headers";
import { Plus_Jakarta_Sans, Noto_Sans_SC, JetBrains_Mono } from "next/font/google";
import "./globals.css";
import SiteBrandProvider from "@/components/SiteBrandProvider";
import SiteChrome from "@/components/SiteChrome";
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 VisitBeacon from "@/components/VisitBeacon";
import PostLinkProvider from "@/components/PostLinkProvider";
import CodeFoldProvider from "@/components/markdown/CodeFoldProvider";
import MotionProvider from "@/components/MotionProvider";
import CommentsPolicyProvider from "@/components/CommentsPolicyProvider";
import MessagesPolicyProvider from "@/components/MessagesPolicyProvider";
import type { User } from "@/lib/api";
import { getMeCached, getPublicSettingsCached } from "@/lib/serverData";
import { TOKEN_COOKIE, authCookieHeader } from "@/lib/cookies";
import { accentStyleCSS } from "@/lib/theme";
import { bgConfigFromSettings, bgStyleCSS } from "@/lib/bg";
import { levelVarsCSS } from "@/lib/levels";
import { siteDocumentTitle } from "@/lib/brand";
import { motionConfigFromSettings } from "@/lib/motion";
import { peekPublicMetaSnapshot, publishPublicMetaSnapshot } from "@/lib/publicMetaSnapshot";
import { metadataBaseURL } from "@/lib/siteUrl";

// 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",
});

// 必须同步：根 layout 若在此 await（拉设置 / headers），Next 流式 metadata
// 会在等待期把标签临时写成 localhost:3000，开发态 RSC/HMR 一密就来回闪。
export function generateMetadata(): Metadata {
  const settings = peekPublicMetaSnapshot();
  const name = settings.site_name || "姜十三论坛";
  const title = siteDocumentTitle(name, settings.site_slogan || "");
  const desc = settings.site_description || "姜十三论坛 - 技术分享与讨论社区";
  const keywords = settings.site_keywords?.length ? settings.site_keywords : undefined;
  const metadataBase = metadataBaseURL();
  return {
    ...(metadataBase ? { metadataBase } : {}),
    title: {
      default: title,
      template: `%s · ${name}`,
    },
    description: desc,
    keywords,
    // 固定地址：换图后浏览器/书签侧的 icon 链接不变
    ...(settings.favicon_url ? { icons: { icon: "/api/brand/favicon" } } : {}),
    openGraph: {
      title,
      description: desc,
      type: "website",
    },
  };
}

// 移动端键盘弹出时压缩布局高度（而非仅视觉平移），聊天输入框随 100dvh
// 收缩保持可见，配合聊天页锁视口布局；再叠加聚焦时 scrollIntoView 兜底
export const viewport: Viewport = {
  width: "device-width",
  initialScale: 1,
  interactiveWidget: "resizes-content",
};

export default async function RootLayout({
  children,
}: {
  children: React.ReactNode;
}) {
  const cookieStore = await cookies();
  const headerStore = await headers();
  // middleware 写入 x-pathname；供 SiteChrome SSR 初值（软导航靠客户端 pathname）
  const pathname = headerStore.get("x-pathname") || "";
  const isAdmin = pathname === "/admin" || pathname.startsWith("/admin/");

  // 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 settings = await getPublicSettingsCached();
  publishPublicMetaSnapshot(settings);
  const accent = settings.accent;
  const accentCSS = accentStyleCSS(accent || "");
  const bgCfg = bgConfigFromSettings(settings);
  const bgCSS = bgStyleCSS(bgCfg);
  const motionCfg = motionConfigFromSettings(settings);
  const motionHtmlClass = [
    !motionCfg.ui_animations ? "j13-reduce-motion" : "",
    motionCfg.ui_animations && !motionCfg.anim_chrome ? "j13-reduce-chrome" : "",
    bgCfg.bg_site_url ? "j13-has-site-bg" : "",
    bgCfg.bg_admin_url ? "j13-has-admin-bg" : "",
  ]
    .filter(Boolean)
    .join(" ");

  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"
      data-j13-chrome={isAdmin ? "admin" : "site"}
      data-lv-fx={settings.levels_fx === false ? "off" : "on"}
      className={`${theme === "dark" ? "dark" : ""} ${motionHtmlClass} ${jakarta.variable} ${notoSC.variable} ${jetbrainsMono.variable}`.trim()}
    >
      <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}
        {bgCSS ? (
          <style
            id="j13-bg-vars"
            data-bg-source="ssr"
            dangerouslySetInnerHTML={{ __html: bgCSS }}
          />
        ) : null}
        {/* 等级配色变量（--lv-N-fg/-bg，引用设计 token 随明暗主题切换）；恒渲染兼作兜底 */}
        <style
          id="j13-level-vars"
          data-level-source="ssr"
          dangerouslySetInnerHTML={{ __html: levelVarsCSS(settings.levels) }}
        />
        <a href="#main" className="skip-link">
          跳到主要内容
        </a>
        <SiteBrandProvider initial={settings}>
        <MotionProvider initial={motionCfg}>
          <CommentsPolicyProvider
            allowComments={settings.allow_comments !== false}
            requireLogin={settings.comments_require_login === true}
          >
            <MessagesPolicyProvider allowMessages={settings.allow_messages !== false}>
              <PostLinkProvider openInNewTab={settings.post_link_new_tab !== false}>
                <CodeFoldProvider
                  initialEnabled={settings.code_block_auto_fold}
                  initialFoldLines={settings.code_block_fold_lines}
                >
                  <SiteChrome
                    initialIsAdmin={isAdmin}
                    user={user}
                    unread={unread}
                    chatUnread={settings.allow_messages !== false ? chatUnread : 0}
                    theme={theme}
                  >
                    <OperationalBanner />
                    {children}
                  </SiteChrome>
                </CodeFoldProvider>
              </PostLinkProvider>
            </MessagesPolicyProvider>
          </CommentsPolicyProvider>
        </MotionProvider>
        </SiteBrandProvider>
        <Toaster />
        <TipHost />
        <AccountGuard />
        <ThemeSync initialAccent={accent || ""} initialBg={bgCfg} />
        <VisitBeacon />
        <RealtimeProvider userId={user ? user.id : null} />
      </body>
    </html>
  );
}