/**
 * Browser notification + in-app toast for generation task completions.
 * Falls back gracefully when Notification API is unavailable.
 */

import { toast } from "../components/toast/toastStore";

let permissionGranted = false;

async function requestPermission(): Promise<boolean> {
  if (permissionGranted) return true;
  if (typeof Notification === "undefined") return false;
  if (Notification.permission === "granted") { permissionGranted = true; return true; }
  if (Notification.permission === "denied") return false;
  try {
    const result = await Notification.requestPermission();
    permissionGranted = result === "granted";
    return permissionGranted;
  } catch {
    return false;
  }
}

export function notifyTaskCompleted(label: string, mode: "image" | "video" = "image") {
  const emoji = mode === "video" ? "🎬" : "🖼️";
  const title = `${emoji} ${label}生成完成`;
  const body = "点击返回查看生成结果";

  // Browser notification (background tab)
  if (typeof Notification !== "undefined" && Notification.permission === "granted") {
    try { new Notification(title, { body, icon: "/favicon.ico", tag: "gen-complete" }); } catch { /* */ }
  }

  // In-app toast
  dispatchGenToast(title);
}

// Use the existing toast system for in-app notifications
function dispatchGenToast(msg: string) {
  toast(msg, "success");
}

/** Call once on app init to pre-warm permission. */
export async function initNotificationPermission() {
  if (typeof Notification === "undefined") return;
  if (Notification.permission === "default") {
    // Don't prompt immediately — wait for first user interaction
    document.addEventListener("click", () => requestPermission(), { once: true });
  }
}