import { useState, useCallback, useRef, useEffect } from "react";

export async function copyTextToClipboard(text: string): Promise<void> {
  if (typeof navigator !== "undefined" && navigator.clipboard?.writeText) {
    try {
      await navigator.clipboard.writeText(text);
      return;
    } catch {
      // Fall through to the selection-based copy path.
    }
  }
  if (fallbackCopyText(text)) return;
  throw new Error("Clipboard unavailable");
}

function fallbackCopyText(text: string): boolean {
  if (typeof document === "undefined" || !document.body) return false;

  const textarea = document.createElement("textarea");
  textarea.value = text;
  textarea.setAttribute("readonly", "");
  textarea.style.position = "fixed";
  textarea.style.top = "0";
  textarea.style.left = "-9999px";

  const selection = document.getSelection();
  const ranges: Range[] = [];
  if (selection) {
    for (let index = 0; index < selection.rangeCount; index += 1) {
      ranges.push(selection.getRangeAt(index).cloneRange());
    }
  }

  document.body.appendChild(textarea);
  textarea.select();

  try {
    return document.execCommand("copy");
  } catch {
    return false;
  } finally {
    textarea.remove();
    if (selection) {
      selection.removeAllRanges();
      for (const range of ranges) {
        selection.addRange(range);
      }
    }
  }
}

export function useCopyFeedback<T = string>(timeout = 2000) {
  const [copiedId, setCopiedId] = useState<T | null>(null);
  const timerRef = useRef<ReturnType<typeof setTimeout>>(undefined);

  useEffect(() => {
    return () => clearTimeout(timerRef.current);
  }, []);

  const copy = useCallback(
    (id: T, text: string) => {
      void copyTextToClipboard(text).catch(() => {
        // Keep the static surface usable when clipboard is unavailable.
      });
      clearTimeout(timerRef.current);
      setCopiedId(id);
      timerRef.current = setTimeout(() => setCopiedId(null), timeout);
    },
    [timeout],
  );

  return { copiedId, copy };
}