/**
 * @file clipboard.ts
 * @description `copyText(text)` — the one copy path for every "Copy …" action.
 * Uses the async Clipboard API when it exists and falls back to a hidden
 * textarea + `execCommand("copy")`, because `navigator.clipboard` is undefined
 * on a non-secure origin such as `http://<lan-ip>:4820`. Reports the outcome as
 * a toast, so a copy is never silent. `writeClipboard(text)` is the same two
 * paths with no toast, for a copy the user did not click (a terminal
 * selection); it hands the focus back to wherever it was.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import i18n from "../i18n";
import { toast } from "./toast";

function fallbackCopy(text: string): boolean {
  // Selecting the textarea moves the focus: give it back (a terminal keeps typing).
  const was = document.activeElement as HTMLElement | null;
  const ta = document.createElement("textarea");
  ta.value = text;
  ta.setAttribute("readonly", "");
  ta.style.position = "fixed";
  ta.style.opacity = "0";
  document.body.appendChild(ta);
  ta.select();
  try {
    return document.execCommand("copy");
  } catch {
    return false;
  } finally {
    ta.remove();
    was?.focus?.({ preventScroll: true });
  }
}

/** Copy `text` silently: the Clipboard API, else the textarea path. */
export async function writeClipboard(text: string): Promise<boolean> {
  try {
    if (navigator.clipboard?.writeText) {
      await navigator.clipboard.writeText(text);
      return true;
    }
  } catch {
    /* fall through to the textarea path */
  }
  return fallbackCopy(text);
}

/**
 * Copy text to the clipboard and toast the result.
 * @param quiet Skip the success toast (the caller shows its own feedback).
 * @returns Whether the copy succeeded.
 */
export async function copyText(text: string, quiet = false): Promise<boolean> {
  const ok = await writeClipboard(text);
  if (!ok) toast.error(i18n.t("common:copyFailed"));
  else if (!quiet) toast.success(i18n.t("common:copied"));
  return ok;
}