import { useEffect, useState } from "react"

export type PushObject = {
  /**
   * Boolean state indicating whether the user is subscribed to push notifications or not.
   */
  isSubscribed: boolean
  /**
   * The push subscription object
   */
  pushSubscription: PushSubscription | null
  /**
   * Request permission for push notifications
   * @returns The permission status of the push notifications
   */
  requestPermission: () => NotificationPermission
  /**
   * Utility to subscribe to push notifications
   * @param publicKey the public vapid key
   * @param callback a callback function to be called when the subscription is successful
   * @param errorCallback a callback function to be called if the subscription fails
   */
  subscribeToPush: (
    publicKey: string,
    callback?: (subscription: PushSubscription) => void,
    errorCallback?: (error: any) => void
  ) => void
  /**
   * Utility to unsubscribe from push notifications
   * @param callback a callback function to be called when the unsubscription is successful
   * @param errorCallback a callback function to be called if the unsubscription fails
   */
  unsubscribeFromPush: (
    callback?: () => void,
    errorCallback?: (error: any) => void
  ) => void
  /**
   * Boolean state indicating whether the user has allowed sending of push notifications or not.
   */
  canSendPush: boolean
}

/**
 * Push API hook - contains all your necessities for handling push notifications in the client
 */
export const usePush = (): PushObject => {
  const [swRegistration, setSWRegistration] =
    useState<ServiceWorkerRegistration | null>(null)
  const [isSubscribed, setIsSubscribed] = useState<boolean>(false)
  const [pushSubscription, setPushSubscription] =
    useState<PushSubscription | null>(null)
  const [canSendPush, setCanSendPush] = useState<boolean>(false)

  const requestPermission = () => {
    if (canSendPush) return "granted"

    Notification.requestPermission().then((permission) => {
      if (permission === "granted") {
        setCanSendPush(true)
        return permission
      } else {
        setCanSendPush(false)
        return permission
      }
    })

    return "default"
  }

  const subscribeToPush = (
    publicKey: string,
    callback?: (subscription: PushSubscription) => void,
    errorCallback?: (error: any) => void
  ) => {
    if (swRegistration === null || swRegistration.pushManager === undefined)
      return

    swRegistration.pushManager
      .subscribe({
        userVisibleOnly: true,
        applicationServerKey: publicKey,
      })
      .then(
        (subscription) => {
          setIsSubscribed(true)
          setPushSubscription(subscription)
          callback && callback(subscription)
        },
        (error) => {
          errorCallback && errorCallback(error)
        }
      )
  }

  const unsubscribeFromPush = (
    callback?: () => void,
    errorCallback?: (error: any) => void
  ) => {
    if (swRegistration === null || swRegistration.pushManager === undefined)
      return

    swRegistration.pushManager
      .getSubscription()
      .then((subscription) => {
        if (subscription) {
          subscription.unsubscribe().then(
            () => {
              setIsSubscribed(false)
              setPushSubscription(null)
              callback && callback()
            },
            (error) => {
              errorCallback && errorCallback(error)
            }
          )
        }
      })
      .catch((error) => {
        errorCallback && errorCallback(error)
      })
  }

  useEffect(() => {
    if (typeof window === "undefined") return

    const getRegistration = async () => {
      if ("serviceWorker" in navigator) {
        try {
          const _registration = await navigator.serviceWorker.getRegistration()
          setSWRegistration(_registration ?? null)
        } catch (err) {
          console.error("Error getting service worker registration:", err)
        }
      } else {
        console.warn("Service Workers are not supported in this browser.")
      }
    }

    const handleControllerChange = () => {
      getRegistration()
    }

    if ("serviceWorker" in navigator) {
      navigator.serviceWorker.addEventListener(
        "controllerchange",
        handleControllerChange
      )
    }

    getRegistration()

    return () => {
      if ("serviceWorker" in navigator) {
        navigator.serviceWorker.removeEventListener(
          "controllerchange",
          handleControllerChange
        )
      }
    }
  }, [])

  useEffect(() => {
    if (swRegistration && swRegistration.pushManager !== undefined) {
      swRegistration.pushManager.getSubscription().then((subscription) => {
        setIsSubscribed(!!subscription)
        setPushSubscription(subscription)
      })

      Notification.permission === "granted"
        ? setCanSendPush(true)
        : setCanSendPush(false)
    }
  }, [swRegistration])

  return {
    isSubscribed,
    pushSubscription,
    requestPermission,
    subscribeToPush,
    unsubscribeFromPush,
    canSendPush,
  }
}