import { useEffect, useState } from "react";
import { describeAdapter } from "@plate-dyn/core";

export type WebGpuSupport =
  | { status: "checking" }
  | { status: "available"; adapter: string }
  | { status: "unavailable"; reason: string };

/**
 * Whether this browser exposes WebGPU, and on what. Asked once on the main
 * thread so the controls can say what a GPU run would use; the worker makes
 * its own device request when a run asks for it.
 */
export function useWebGpuSupport(): WebGpuSupport {
  const [support, setSupport] = useState<WebGpuSupport>({ status: "checking" });
  useEffect(() => {
    let alive = true;
    const set = (s: WebGpuSupport) => {
      if (alive) setSupport(s);
    };
    (async () => {
      try {
        const gpu = (navigator as { gpu?: GPU }).gpu;
        if (!gpu)
          return set({ status: "unavailable", reason: "this browser does not expose WebGPU" });
        const adapter = await gpu.requestAdapter();
        if (!adapter)
          return set({ status: "unavailable", reason: "no WebGPU adapter was offered" });
        set({ status: "available", adapter: describeAdapter(adapter) });
      } catch (e) {
        set({ status: "unavailable", reason: e instanceof Error ? e.message : String(e) });
      }
    })();
    return () => {
      alive = false;
    };
  }, []);
  return support;
}