import type { Middleware } from "@wrnexus/core";
import type { createStudioHandler } from "@wrnexus/design-studio/server";
import { studioAI } from "../lib/studio-ai.ts";
import { addStudioGuide, studioHelpScript } from "../lib/studio-guide.ts";

let studio: ReturnType<typeof createStudioHandler> | undefined;
let ai: ReturnType<typeof studioAI> | undefined;

const designStudio: Middleware = async (ctx, next) => {
  const url = new URL(ctx.req.url);
  if (url.pathname === "/design-studio")
    return new Response(null, {
      status: 308,
      headers: { location: "/design-studio/" },
    });
  if (!url.pathname.startsWith("/design-studio/")) return next();
  ai ??= studioAI(process.env.APIMART_API_KEY?.trim());
  const generated = await ai(ctx.req);
  if (generated) return generated;
  if (
    url.pathname === "/design-studio/site-help.js" &&
    ctx.req.method === "GET"
  )
    return new Response(studioHelpScript, {
      headers: {
        "content-type": "text/javascript",
        "cache-control": "no-store",
      },
    });
  // Load the installed package at runtime so its assets keep their package-relative URLs.
  const studioModule = import.meta.resolve("@wrnexus/design-studio/server");
  studio ??= import(studioModule)
    .then(({ createStudioHandler }) =>
      createStudioHandler({
        hosted: { basePath: "/design-studio" },
      }),
    )
    .catch((error) => {
      studio = undefined;
      throw error;
    });
  const response = await (await studio)(ctx.req);
  if (
    url.pathname === "/design-studio/" &&
    response.ok &&
    ctx.req.method === "GET"
  ) {
    const headers = new Headers(response.headers);
    headers.delete("content-length");
    return new Response(
      addStudioGuide(
        await response.text(),
        !!process.env.APIMART_API_KEY?.trim(),
      ),
      { status: response.status, headers },
    );
  }
  return response;
};

export default designStudio;