DownloadWorker: Progress improvements

* Handle split apk download progress
* Also share download speed and time remaining

Signed-off-by: Aayush Gupta <aayushgupta219@gmail.com>

app/src/main/java/com/aurora/extensions/InputStream.kt

@@ -1,24 +1,37 @@
 package com.aurora.extensions
 
+import com.aurora.store.data.model.DownloadInfo
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOn
 import java.io.InputStream
 import java.io.OutputStream
+import kotlinx.coroutines.flow.distinctUntilChangedBy
+import kotlin.concurrent.fixedRateTimer
 
-fun InputStream.copyTo(out: OutputStream, streamSize: Long): Flow<Int> {
+fun InputStream.copyTo(out: OutputStream, streamSize: Long): Flow<DownloadInfo> {
     return flow {
         var bytesCopied: Long = 0
         val buffer = ByteArray(DEFAULT_BUFFER_SIZE)
         var bytes = read(buffer)
+
+        var lastTotalBytesRead = 0L
+        var speed: Long = 0
+        @Suppress("KotlinConstantConditions") // False-positive for bytesCopied always being zero
+        val timer = fixedRateTimer("timer", true, 0L, 1000) {
+            val totalBytesRead = bytesCopied
+            speed = totalBytesRead - lastTotalBytesRead
+            lastTotalBytesRead = totalBytesRead
+        }
+
         while (bytes >= 0) {
             out.write(buffer, 0, bytes)
             bytesCopied += bytes
-            bytes = read(buffer)
             // Emit stream progress in percentage
-            emit((bytesCopied * 100 / streamSize).toInt())
+            emit(DownloadInfo((bytesCopied * 100 / streamSize).toInt(), bytesCopied, speed))
+            bytes = read(buffer)
         }
-    }.flowOn(Dispatchers.IO).distinctUntilChanged()
+        timer.cancel()
+    }.flowOn(Dispatchers.IO).distinctUntilChangedBy { it.progress }
 }

app/src/main/java/com/aurora/store/data/model/DownloadInfo.kt

@@ -0,0 +1,7 @@
+package com.aurora.store.data.model
+
+data class DownloadInfo(
+    val progress: Int = 0,
+    val bytesCopied: Long = 0,
+    val speed: Long = 0
+)

app/src/main/java/com/aurora/store/data/work/DownloadWorker.kt

@@ -22,6 +22,7 @@ import com.aurora.extensions.copyAndRemove
 import com.aurora.gplayapi.data.models.App
 import com.aurora.gplayapi.helpers.PurchaseHelper
 import com.aurora.store.AuroraApplication
+import com.aurora.store.data.model.DownloadInfo
 import com.aurora.store.data.model.DownloadStatus
 import com.aurora.store.data.model.Request
 import com.aurora.store.data.network.HttpClient
@@ -39,6 +40,7 @@ import kotlinx.coroutines.flow.update
 import kotlin.io.path.ExperimentalPathApi
 import kotlin.io.path.createDirectories
 import kotlin.io.path.deleteRecursively
+import kotlin.properties.Delegates
 import com.aurora.gplayapi.data.models.File as GPlayFile
 
 class DownloadWorker(private val appContext: Context, workerParams: WorkerParameters) :
@@ -47,6 +49,8 @@ class DownloadWorker(private val appContext: Context, workerParams: WorkerParame
     companion object {
         const val DOWNLOAD_WORKER = "DOWNLOAD_WORKER"
         const val DOWNLOAD_PROGRESS = "DOWNLOAD_PROGRESS"
+        const val DOWNLOAD_TIME = "DOWNLOAD_TIME"
+        const val DOWNLOAD_SPEED = "DOWNLOAD_SPEED"
 
         fun enqueueApp(app: App) {
             AuroraApplication.enqueuedDownloads.update { it.copyAndAdd(app) }
@@ -73,6 +77,10 @@ class DownloadWorker(private val appContext: Context, workerParams: WorkerParame
     private lateinit var notificationManager: NotificationManager
     private var downloading = false
 
+    private var totalBytes by Delegates.notNull<Long>()
+    private var totalProgress = 0
+    private var downloadedBytes = 0L
+
     private val TAG = DownloadWorker::class.java.simpleName
     private val notificationID = 200
 
@@ -105,6 +113,7 @@ class DownloadWorker(private val appContext: Context, workerParams: WorkerParame
         }
 
         // Download and verify all files exists
+        totalBytes = files.sumOf { it.size }
         PathUtil.getAppDownloadDir(appContext, app.packageName, app.versionCode).createDirectories()
 
         val requestList = getDownloadRequest(files)
@@ -196,10 +205,30 @@ class DownloadWorker(private val appContext: Context, workerParams: WorkerParame
         }
     }
 
-    private suspend fun onProgress(progress: Int) {
+    private suspend fun onProgress(downloadInfo: DownloadInfo) {
         if (!isStopped) {
-            setProgress(Data.Builder().putInt(DOWNLOAD_PROGRESS, progress).build())
+            val progress = ((downloadedBytes + downloadInfo.bytesCopied) * 100 / totalBytes).toInt()
-            notifyStatus(DownloadStatus.DOWNLOADING, progress, notificationID)
+
+            // Individual file progress can be negligible in contrast to total progress
+            // Only notify the UI if progress is greater to avoid being rate-limited by Android
+            if (progress > totalProgress) {
+                val bytesRemaining = totalBytes - (downloadedBytes + downloadInfo.bytesCopied)
+                val speed = if (downloadInfo.speed == 0L) 1 else downloadInfo.speed
+
+                if (downloadInfo.progress == 100) {
+                    downloadedBytes += downloadInfo.bytesCopied
+                }
+
+                val data = Data.Builder()
+                    .putInt(DOWNLOAD_PROGRESS, progress)
+                    .putLong(DOWNLOAD_SPEED, downloadInfo.speed)
+                    .putLong(DOWNLOAD_TIME, bytesRemaining / speed * 1000)
+                    .build()
+
+                setProgress(data)
+                notifyStatus(DownloadStatus.DOWNLOADING, progress, notificationID)
+                totalProgress = progress
+            }
         }
     }