"use client";

import { useEffect, useState } from "react";
import { X, Download } from "lucide-react";
import { Button } from "@/components/ui/button";

const DISMISSED_KEY = "epicure:install-prompt-dismissed";

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

/** Only fires on Chromium-based browsers (Chrome/Edge/Android) — Safari and
 * Firefox never dispatch beforeinstallprompt, so this banner simply never
 * appears there, which is the correct behavior (no fallback UI to build). */
export function InstallPrompt() {
  const [deferredEvent, setDeferredEvent] = useState<BeforeInstallPromptEvent | null>(null);
  const [dismissed, setDismissed] = useState(() => typeof localStorage !== "undefined" && localStorage.getItem(DISMISSED_KEY) === "true");

  useEffect(() => {
    function handler(e: Event) {
      e.preventDefault();
      setDeferredEvent(e as BeforeInstallPromptEvent);
    }
    window.addEventListener("beforeinstallprompt", handler);
    return () => window.removeEventListener("beforeinstallprompt", handler);
  }, []);

  function dismiss() {
    localStorage.setItem(DISMISSED_KEY, "true");
    setDismissed(true);
  }

  async function install() {
    if (!deferredEvent) return;
    await deferredEvent.prompt();
    await deferredEvent.userChoice;
    setDeferredEvent(null);
  }

  if (!deferredEvent || dismissed) return null;

  return (
    <div className="fixed bottom-4 left-1/2 z-50 flex w-[calc(100%-2rem)] max-w-sm -translate-x-1/2 items-center gap-3 rounded-lg border bg-background p-3 shadow-lg">
      <Download className="h-5 w-5 shrink-0 text-muted-foreground" />
      <div className="min-w-0 flex-1">
        <p className="text-sm font-medium">Install Epicure</p>
        <p className="text-xs text-muted-foreground">Add to your home screen for quick access.</p>
      </div>
      <Button type="button" size="sm" onClick={() => { void install(); }}>
        Install
      </Button>
      <button type="button" onClick={dismiss} aria-label="Dismiss" className="text-muted-foreground hover:text-foreground">
        <X className="h-4 w-4" />
      </button>
    </div>
  );
}