import { defineStore } from 'pinia'
import { ref } from 'vue'

function urlBase64ToUint8Array(base64String: string): Uint8Array<ArrayBuffer> {
  const padding = '='.repeat((4 - (base64String.length % 4)) % 4)
  const base64 = (base64String + padding).replace(/-/g, '+').replace(/_/g, '/')
  const rawData = window.atob(base64)
  const buf = new ArrayBuffer(rawData.length)
  const outputArray = new Uint8Array<ArrayBuffer>(buf)
  for (let i = 0; i < rawData.length; ++i) {
    outputArray[i] = rawData.charCodeAt(i)
  }
  return outputArray
}

export const usePushStore = defineStore('push', () => {
  const isSupported = ref(
    'serviceWorker' in navigator && 'PushManager' in window && 'Notification' in window
  )
  const permission = ref<NotificationPermission>(
    'Notification' in window ? Notification.permission : 'denied'
  )
  const isSubscribed = ref(false)
  const loading = ref(false)
  const error = ref<string | null>(null)

  async function checkSubscription(): Promise<void> {
    if (!isSupported.value) return
    try {
      const reg = await navigator.serviceWorker.ready
      const sub = await reg.pushManager.getSubscription()
      isSubscribed.value = !!sub
    } catch {
      isSubscribed.value = false
    }
  }

  async function subscribe(): Promise<void> {
    if (!isSupported.value) {
      error.value = 'Push notifications not supported in this browser'
      return
    }
    loading.value = true
    error.value = null
    try {
      // Request permission
      permission.value = await Notification.requestPermission()
      if (permission.value !== 'granted') {
        error.value = 'Notification permission denied'
        return
      }

      // Fetch VAPID public key
      const resp = await fetch('/api/push/vapid-public-key')
      if (!resp.ok) {
        error.value = 'Push notifications not configured on server'
        return
      }
      const { publicKey } = await resp.json()

      // Register service worker
      const reg = await navigator.serviceWorker.register('/sw.js')
      await navigator.serviceWorker.ready

      // Subscribe
      const sub = await reg.pushManager.subscribe({
        userVisibleOnly: true,
        applicationServerKey: urlBase64ToUint8Array(publicKey),
      })

      // Save to server
      const saveResp = await fetch('/api/push/subscribe', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(sub.toJSON()),
      })
      if (!saveResp.ok) throw new Error('Failed to save subscription')
      isSubscribed.value = true
    } catch (e: unknown) {
      error.value = e instanceof Error ? e.message : 'Failed to subscribe'
    } finally {
      loading.value = false
    }
  }

  async function unsubscribe(): Promise<void> {
    loading.value = true
    error.value = null
    try {
      const reg = await navigator.serviceWorker.ready
      const sub = await reg.pushManager.getSubscription()
      if (sub) {
        await fetch('/api/push/subscribe', {
          method: 'DELETE',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ endpoint: sub.endpoint }),
        })
        await sub.unsubscribe()
      }
      isSubscribed.value = false
    } catch (e: unknown) {
      error.value = e instanceof Error ? e.message : 'Failed to unsubscribe'
    } finally {
      loading.value = false
    }
  }

  return { isSupported, permission, isSubscribed, loading, error, checkSubscription, subscribe, unsubscribe }
})