middleware.ts

import { type NextRequest, NextResponse } from "next/server";
import { fetchAnimeTitleById } from "./app/_lib/graphql/fetchers/animeFetcherById";
import { generateSlug } from "./app/_lib/helpers/slugGenerator";

export async function middleware(request: NextRequest) {
  const response = NextResponse.next();

  const theme = request.cookies.get("theme")?.value || "light";
  console.log("middleware: theme", request.cookies.get("theme")?.value);
  response.cookies.set("theme", theme, { path: "/" });

  //redirect on the anime preview page based on the preferred title language
  if (request.nextUrl.pathname.startsWith("/anime/")) {
    const url = request.nextUrl.clone();
    const pathname = url.pathname;

    // Check if the URL matches the anime page pattern
    const animeRegex = /^\/anime\/\d+(\/.+)?$/;
    if (!animeRegex.test(pathname)) {
      return NextResponse.next(); // Allow other routes to pass through
    }

    // Simulate fetching user's language preference (e.g., from cookies)
    const userLanguage =
      request.cookies.get("user-language")?.value || "english"; // Default to English

    console.log("user language", userLanguage);

    // Parse the ID and slug from the URL
    const segments = pathname.split("/");
    console.log("segments", segments);
    const id = segments[2];
    const slug = segments[3];

    console.log("middleware: current title slug", slug);

    // Generate the appropriate slug for the language

    const titles = await fetchAnimeTitleById({ mediaId: +id });

    let preferredTitle: string | undefined;

    switch (userLanguage) {
      case "english":
        preferredTitle = titles?.english || titles?.romaji;
        break;
      case "native":
      case "romaji":
        preferredTitle = titles?.romaji;
        break;

      case "userPreferred":
        preferredTitle = titles?.userPreferred;
        break;
      default: // Handle unsupported languages or fallback
        preferredTitle = titles?.english; // Or another default
        break;
    }

    const redirectSlug = generateSlug(preferredTitle || ""); // Handle potential undefined

    console.log("middleware: desired title slug", redirectSlug);

    // Redirect to the language-specific page if necessary
    if (slug !== redirectSlug) {
      url.pathname = `/anime/${id}/${redirectSlug}`;
      return NextResponse.redirect(url);
    }
  }

  return response; // Continue if no redirection is needed
}