import { NextRequest, NextResponse } from "next/server";
import { draftMode, cookies } from "next/headers";
import {
  fetchPreviewPage,
  resolvePreviewPath,
  PREVIEW_CONTENT_TYPE_COOKIE,
  PREVIEW_TOKEN_COOKIE,
} from "@/services/preview.service";
import type { WagtailPageSummary } from "@/types/wagtail";

/**
 * Wagtail 编辑器点击"预览"后会重定向到此路由（详见 wagtailcms/settings/base.py
 * 中 WAGTAIL_HEADLESS_PREVIEW.CLIENT_URLS）。校验 token 有效后开启 Next.js
 * Draft Mode 并重定向到对应内容的前端路由，由页面组件通过 getPreviewOrFallback
 * 拉取草稿数据渲染。
 */
export async function GET(request: NextRequest) {
  const contentType = request.nextUrl.searchParams.get("content_type");
  const token = request.nextUrl.searchParams.get("token");

  if (!contentType || !token) {
    return NextResponse.json(
      { error: "缺少 content_type 或 token 参数" },
      { status: 400 },
    );
  }

  // 先校验 token 是否有效并取回 slug，未开启 Draft Mode，避免暴露无效预览。
  const page = await fetchPreviewPage<WagtailPageSummary>(contentType, token);
  const path = page ? resolvePreviewPath(contentType, page) : null;

  if (!page || !path) {
    return NextResponse.json(
      { error: "预览链接无效或已过期" },
      { status: 404 },
    );
  }

  const draft = await draftMode();
  draft.enable();

  const isProduction = process.env.NODE_ENV === "production";
  const cookieStore = await cookies();
  const cookieOptions = {
    httpOnly: true,
    sameSite: "lax" as const,
    secure: isProduction,
    path: "/",
  };
  cookieStore.set(PREVIEW_CONTENT_TYPE_COOKIE, contentType, cookieOptions);
  cookieStore.set(PREVIEW_TOKEN_COOKIE, token, cookieOptions);

  return NextResponse.redirect(new URL(path, request.url));
}