LibreTube/app/src/main/java/com/github/libretube/util/NotificationHelper.kt

package com.github.libretube.util

import android.app.PendingIntent
import android.content.Context
import android.content.Intent
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat
import androidx.work.Constraints
import androidx.work.ExistingPeriodicWorkPolicy
import androidx.work.NetworkType
import androidx.work.PeriodicWorkRequest
import androidx.work.WorkManager
import com.github.libretube.PUSH_CHANNEL_ID
import com.github.libretube.PUSH_NOTIFICATION_ID
import com.github.libretube.R
import com.github.libretube.activities.MainActivity
import com.github.libretube.api.RetrofitInstance
import com.github.libretube.api.SubscriptionHelper
import com.github.libretube.preferences.PreferenceHelper
import com.github.libretube.preferences.PreferenceKeys
import kotlinx.coroutines.async
import kotlinx.coroutines.runBlocking
import java.util.concurrent.TimeUnit

object NotificationHelper {
    fun enqueueWork(
        context: Context,
        existingPeriodicWorkPolicy: ExistingPeriodicWorkPolicy
    ) {
        // get the notification preferences
        PreferenceHelper.setContext(context)
        val notificationsEnabled = PreferenceHelper.getBoolean(
            PreferenceKeys.NOTIFICATION_ENABLED,
            true
        )

        val checkingFrequency = PreferenceHelper.getString(
            PreferenceKeys.CHECKING_FREQUENCY,
            "60"
        ).toLong()

        val uniqueWorkName = "NotificationService"

        // schedule the work manager request if logged in and notifications enabled
        if (notificationsEnabled && PreferenceHelper.getToken() != "") {
            // required network type for the work
            val networkType = when (
                PreferenceHelper.getString(PreferenceKeys.REQUIRED_NETWORK, "all")
            ) {
                "all" -> NetworkType.CONNECTED
                "wifi" -> NetworkType.UNMETERED
                "metered" -> NetworkType.METERED
                else -> NetworkType.CONNECTED
            }

            // requirements for the work
            // here: network needed to run the task
            val constraints = Constraints.Builder()
                .setRequiredNetworkType(networkType)
                .build()

            // create the worker
            val notificationWorker = PeriodicWorkRequest.Builder(
                NotificationWorker::class.java,
                checkingFrequency,
                TimeUnit.MINUTES
            )
                .setConstraints(constraints)
                .build()

            // enqueue the task
            WorkManager.getInstance(context)
                .enqueueUniquePeriodicWork(
                    uniqueWorkName,
                    existingPeriodicWorkPolicy,
                    notificationWorker
                )
        } else {
            // cancel the work if notifications are disabled or the user is not logged in
            WorkManager.getInstance(context)
                .cancelUniqueWork(uniqueWorkName)
        }
    }

    /**
     * check whether new streams are available in subscriptions
     */
    fun checkForNewStreams(context: Context): Boolean {
        var result = true

        val token = PreferenceHelper.getToken()
        runBlocking {
            val task = async {
                if (token != "") RetrofitInstance.authApi.getFeed(token)
                else RetrofitInstance.authApi.getUnauthenticatedFeed(
                    SubscriptionHelper.getFormattedLocalSubscriptions()
                )
            }
            // fetch the users feed
            val videoFeed = try {
                task.await()
            } catch (e: Exception) {
                result = false
                return@runBlocking
            }

            val lastSeenStreamId = PreferenceHelper.getLatestVideoId()
            val latestFeedStreamId = videoFeed[0].url.toID()

            // first time notifications enabled
            if (lastSeenStreamId == "") PreferenceHelper.setLatestVideoId(lastSeenStreamId)
            else if (lastSeenStreamId != latestFeedStreamId) {
                // get the index of the last user-seen video
                var newStreamIndex = -1
                videoFeed.forEachIndexed { index, stream ->
                    if (stream.url?.toID() == lastSeenStreamId) {
                        newStreamIndex = index
                    }
                }
                if (newStreamIndex == -1) return@runBlocking
                val (title, description) = when (newStreamIndex) {
                    // only one new stream available
                    1 -> {
                        Pair(videoFeed[0].title, videoFeed[0].uploaderName)
                    }
                    else -> {
                        Pair(
                            // return the amount of new streams as title
                            context.getString(
                                R.string.new_streams_count,
                                newStreamIndex.toString()
                            ),
                            // return the first few uploader as description
                            context.getString(
                                R.string.new_streams_by,
                                videoFeed[0].uploaderName + ", " + videoFeed[1].uploaderName + ", " + videoFeed[2].uploaderName
                            )
                        )
                    }
                }
                // save the id of the last recent video for the next time it's running
                PreferenceHelper.setLatestVideoId(videoFeed[0].url.toID())
                createNotification(context, title!!, description!!)
            }
        }
        // return whether the work succeeded
        return result
    }

    /**
     * Notification that is created when new streams are found
     */
    fun createNotification(context: Context, title: String, description: String) {
        val intent = Intent(context, MainActivity::class.java).apply {
            flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
        }
        val pendingIntent: PendingIntent = PendingIntent.getActivity(
            context,
            0,
            intent,
            PendingIntent.FLAG_IMMUTABLE
        )

        val builder = NotificationCompat.Builder(context, PUSH_CHANNEL_ID)
            .setContentTitle(title)
            .setSmallIcon(R.drawable.ic_bell)
            .setContentText(description)
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            // Set the intent that will fire when the user taps the notification
            .setContentIntent(pendingIntent)
            .setAutoCancel(true)
        with(NotificationManagerCompat.from(context)) {
            // notificationId is a unique int for each notification that you must define
            notify(PUSH_NOTIFICATION_ID, builder.build())
        }
    }
}