frontend/src/components/InstallPrompt.jsx

import { useEffect, useState } from 'react'
import { Download } from 'lucide-react'

/**
 * Renders an "Install App" button when the browser fires the
 * beforeinstallprompt event (Chrome / Android). On iOS Safari the event
 * is never fired, so the button stays hidden.
 */
export default function InstallPrompt() {
  const [deferredPrompt, setDeferredPrompt] = useState(null)
  const [installed, setInstalled] = useState(false)

  useEffect(() => {
    const handler = (e) => {
      e.preventDefault()
      setDeferredPrompt(e)
    }
    window.addEventListener('beforeinstallprompt', handler)
    window.addEventListener('appinstalled', () => {
      setInstalled(true)
      setDeferredPrompt(null)
    })
    return () => window.removeEventListener('beforeinstallprompt', handler)
  }, [])

  if (!deferredPrompt || installed) return null

  const handleInstall = async () => {
    deferredPrompt.prompt()
    const { outcome } = await deferredPrompt.userChoice
    if (outcome === 'accepted') setInstalled(true)
    setDeferredPrompt(null)
  }

  return (
    <button
      onClick={handleInstall}
      className="flex items-center gap-2 rounded-lg border border-slate-600 bg-slate-800 px-3 py-1.5 text-sm font-medium text-slate-200 hover:bg-slate-700 transition-colors"
    >
      <Download size={15} />
      Install App
    </button>
  )
}