/**
 * Native FCM push for the bundled Capacitor app (Phase B) — rings the device on a new chat DM when
 * the app is backgrounded/killed (the live WebSocket only covers an OPEN app; web-push doesn't reach
 * a native app).
 *
 * App-only + staff-only + fail-soft:
 *  - early-returns on the web build (__CAP_BUILD__ undefined) and the plugin is also dropped from the
 *    web bundle by the nuxt.config app:resolve hook;
 *  - @capacitor/push-notifications is DYNAMICALLY imported so the web build never loads it;
 *  - registers only once the user is eligible staff (useChatEligible — same gate as the chat socket);
 *  - any failure (no google-services.json, perm denied, …) is swallowed → native push just stays off.
 *
 * NOTE: the filename intentionally avoids the substring 'push-notifications' — the app:resolve drop
 * list strips that (it targets the WEB VAPID plugin 02.push-notifications.client.ts).
 */

// Injected by Vite only in the app build (see nuxt.config.ts).
declare const __CAP_BUILD__: boolean | undefined

export default defineNuxtPlugin(() => {
  if (typeof __CAP_BUILD__ === 'undefined') return   // web build → no-op
  if (!process.client) return
  if (useRuntimeConfig().public.chatEnabled !== true) return

  const eligible = useChatEligible()
  let registered = false

  const setup = async () => {
    if (registered || !eligible.value) return
    registered = true
    try {
      const { PushNotifications } = await import('@capacitor/push-notifications')

      // Token issued → persist it for this staff user (server resolves the user from the bearer).
      PushNotifications.addListener('registration', (token: any) => {
        $fetch('/api/push/register-native', {
          method: 'POST',
          body: { token: token?.value, platform: 'android' },
        }).catch((e: any) => console.warn('[native-push] token register failed:', e?.message))
      })

      PushNotifications.addListener('registrationError', (err: any) =>
        console.warn('[native-push] registration error:', err?.error))

      // Tap on a notification → open that conversation.
      PushNotifications.addListener('pushNotificationActionPerformed', (action: any) => {
        const sender = action?.notification?.data?.senderUserId
        navigateTo(sender ? `/chat?chat=${sender}` : '/chat')
      })

      // Foreground receipt is intentionally a no-op — the live WS already renders the message in-app.

      // High-importance channel so chat pushes can heads-up on Android 8+ (FCM targets channelId 'chat').
      try { await PushNotifications.createChannel({ id: 'chat', name: 'Chat', importance: 5, visibility: 1 }) } catch { /* iOS / unsupported */ }

      let perm = await PushNotifications.checkPermissions()
      if (perm.receive === 'prompt' || perm.receive === 'prompt-with-rationale') {
        perm = await PushNotifications.requestPermissions()
      }
      if (perm.receive !== 'granted') { registered = false; return } // allow a later retry

      await PushNotifications.register()
    } catch (e: any) {
      registered = false
      console.warn('[native-push] setup failed:', e?.message)
    }
  }

  // Register as soon as the user is eligible (immediately if already logged in, else after login).
  watch(eligible, (v) => { if (v) setup() }, { immediate: true })
})