import { init, Renderer } from "takumi-js/wasm/no-init";
import type { WorkerRequest, WorkerResult } from "./types";
import { renderExport } from "./render";

let rendererPromise: Promise<Renderer> | undefined;
async function getRenderer(origin: string) {
  rendererPromise ??= (async () => {
    const response = await fetch(new URL("/takumi.wasm", origin), {
      signal: AbortSignal.timeout(15000),
    });
    if (!response.ok) throw new Error("Unable to load image renderer");
    await init({ module_or_path: await response.arrayBuffer() });
    const renderer = new Renderer();
    try {
      const fonts = await Promise.all(
        [
          { name: "Anuphan", path: "/Anuphan.ttf" },
          { name: "Genshin Overview", path: "/zh-cn.ttf" },
          {
            name: "Kanit Overview",
            path: "/Kanit-SemiBold.ttf",
            weight: 600,
            style: "normal" as const,
          },
          {
            name: "Kanit Poster",
            path: "/Kanit-ExtraBoldItalic.ttf",
            weight: 800,
            style: "italic" as const,
          },
        ].map(async ({ path, ...descriptor }) => {
          const font = await fetch(new URL(path, origin), {
            signal: AbortSignal.timeout(15000),
          });
          if (!font.ok) throw new Error("Unable to load export fonts");
          return {
            ...descriptor,
            data: new Uint8Array(await font.arrayBuffer()),
          };
        }),
      );
      for (const font of fonts) await renderer.registerFont(font);
      return renderer;
    } catch (error) {
      renderer.free();
      throw error;
    }
  })().catch((error) => {
    rendererPromise = undefined;
    throw error;
  });
  return rendererPromise;
}
let queue = Promise.resolve();
self.onmessage = ({ data }: MessageEvent<WorkerRequest>) => {
  queue = queue.then(async () => {
    try {
      const renderer = await getRenderer(data.origin);
      const image = await renderExport(renderer, data.request, data.origin);
      const bytes = image.buffer as ArrayBuffer;
      self.postMessage({ id: data.id, bytes } satisfies WorkerResult, {
        transfer: [bytes],
      });
    } catch (error) {
      self.postMessage({
        id: data.id,
        error: error instanceof Error ? error.message : "Image export failed",
      } satisfies WorkerResult);
    }
  });
};