"use client";

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

type BeforeInstallPromptEvent = Event & {
  prompt: () => Promise<void>;
  userChoice: Promise<{ outcome: "accepted" | "dismissed" }>;
};

export const PWAInstallPrompt = (): JSX.Element | null => {
  const [deferred, setDeferred] = useState<BeforeInstallPromptEvent | null>(
    null
  );
  const [isInstalled, setIsInstalled] = useState<boolean>(false);

  useEffect(() => {
    if (typeof window === "undefined") return;
    const onBeforeInstallPrompt = (e: Event) => {
      setDeferred(e as BeforeInstallPromptEvent);
    };
    const onAppInstalled = () => {
      setDeferred(null);
      setIsInstalled(true);
    };
    window.addEventListener("beforeinstallprompt", onBeforeInstallPrompt);
    window.addEventListener("appinstalled", onAppInstalled);
    if (window.matchMedia("(display-mode: standalone)").matches) {
      setIsInstalled(true);
    }
    return () => {
      window.removeEventListener("beforeinstallprompt", onBeforeInstallPrompt);
      window.removeEventListener("appinstalled", onAppInstalled);
    };
  }, []);

  const onInstall = useCallback(async () => {
    if (!deferred) return;
    try {
      await deferred.prompt();
      const choice = await deferred.userChoice;
      if (choice.outcome === "accepted") {
        setDeferred(null);
      }
    } catch (_err) { }
  }, [deferred]);

  if (isInstalled || !deferred) return null;

  return (
    <button
      className="px-3 py-2 ascii-border bg-background0 hover:bg-background1 transition-colors terminal-font text-sm"
      onClick={onInstall}
    >
      Install
    </button>
  );
};