feat(shared-decks): redesign download screen in Compose

Co-Authored-By: Colby Cabrera <colbycabrera.wd@gmail.com>

Author: criticalAY

.idea/codeStyles/Project.xml

@@ -0,0 +1,36 @@
+// SPDX-FileCopyrightText: 2026 Ashish Yadav <mailtoashish693@gmail.com>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package com.ichi2.anki.shareddeck
+
+import android.text.format.Formatter
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.platform.LocalConfiguration
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import com.ichi2.anki.R
+
+@Composable
+internal fun rememberDownloadSizeRange(
+    downloadedBytes: Long,
+    totalBytes: Long,
+): String {
+    if (totalBytes <= 0 && downloadedBytes <= 0) return ""
+
+    val context = LocalContext.current
+    val configuration = LocalConfiguration.current
+
+    val downloadedFmt =
+        remember(downloadedBytes, configuration) {
+            Formatter.formatFileSize(context, downloadedBytes)
+        }
+
+    if (totalBytes <= 0) return downloadedFmt
+
+    val totalFmt =
+        remember(totalBytes, configuration) {
+            Formatter.formatFileSize(context, totalBytes)
+        }
+    return stringResource(R.string.progress_amount_bytes, downloadedFmt, totalFmt)
+}

AnkiDroid/src/main/java/com/ichi2/anki/shareddeck/DownloadSizeFormatter.kt

@@ -0,0 +1,63 @@
+// SPDX-FileCopyrightText: 2026 Colby Cabrera <colbycabrera.wd@gmail.com>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package com.ichi2.anki.shareddeck
+
+/**
+ * Calculates download speed using Exponential Moving Average (EMA) to smooth out fluctuations.
+ *
+ * @param alpha The smoothing factor. A value between 0 and 1. Higher values give more weight to
+ * current measurements. Default is 0.5 (averaging current and last speed).
+ */
+class DownloadSpeedCalculator(
+    private val alpha: Double = 0.5,
+) {
+    init {
+        require(alpha in 0.0..1.0) { "Alpha must be between 0.0 and 1.0" }
+    }
+
+    private var lastSmoothedSpeed: Double = 0.0
+    private var lastBytesDownloaded: Long = 0
+    private var lastTimeChecked: Long? = null
+
+    /**
+     * Updates the calculation with new data points.
+     *
+     * @param downloadedBytes Total bytes downloaded so far.
+     * @param currentTime Current time in milliseconds.
+     * @return The smoothed download speed in bytes per second.
+     */
+    fun update(
+        downloadedBytes: Long,
+        currentTime: Long,
+    ): Double {
+        val lastTime = lastTimeChecked
+        if (lastTime != null && currentTime > lastTime) {
+            val timeDiff = currentTime - lastTime
+            val bytesDiff = downloadedBytes - lastBytesDownloaded
+
+            if (bytesDiff >= 0) {
+                val instantSpeed = (bytesDiff * 1000.0) / timeDiff
+                lastSmoothedSpeed =
+                    if (lastSmoothedSpeed == 0.0 && instantSpeed > 0) {
+                        // Initialize with the first non-zero speed to avoid a slow ramp up from 0.
+                        instantSpeed
+                    } else {
+                        (lastSmoothedSpeed * (1 - alpha)) + (instantSpeed * alpha)
+                    }
+            }
+        }
+        lastBytesDownloaded = downloadedBytes
+        lastTimeChecked = currentTime
+        return lastSmoothedSpeed
+    }
+
+    /**
+     * Resets the internal state of the calculator.
+     */
+    fun reset() {
+        lastSmoothedSpeed = 0.0
+        lastBytesDownloaded = 0
+        lastTimeChecked = null
+    }
+}

AnkiDroid/src/main/java/com/ichi2/anki/shareddeck/DownloadSpeedCalculator.kt

@@ -18,7 +18,9 @@ package com.ichi2.anki.shareddeck
 
 import android.app.DownloadManager
 import android.content.Context
+import android.graphics.Color.TRANSPARENT
 import android.os.Bundle
+import android.util.TypedValue
 import android.view.Menu
 import android.view.MenuItem
 import android.webkit.CookieManager
@@ -225,7 +227,7 @@ class SharedDecksActivity : AnkiActivity(R.layout.activity_shared_decks) {
         supportActionBar?.setDisplayHomeAsUpEnabled(true)
         supportActionBar?.setDisplayShowHomeEnabled(true)
 
-        downloadManager = getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
+        downloadManager = getSystemService(DOWNLOAD_SERVICE) as DownloadManager
 
         binding.webView.settings.javaScriptEnabled = true
         binding.webView.loadUrl(resources.getString(R.string.shared_decks_url))
@@ -246,11 +248,24 @@ class SharedDecksActivity : AnkiActivity(R.layout.activity_shared_decks) {
                         SHARED_DECKS_DOWNLOAD_FRAGMENT,
                     ).addToBackStack(null)
                 }
+                supportActionBar?.title = ""
+                binding.webviewToolbar.setBackgroundColor(TRANSPARENT)
             }
         }
 
         binding.webView.webViewClient = webViewClient
         onBackPressedDispatcher.addCallback(onBackPressedCallback)
+
+        supportFragmentManager.addOnBackStackChangedListener {
+            if (supportFragmentManager.backStackEntryCount == 0) {
+                // Restore toolbar when returning to the webview
+                supportActionBar?.setTitle(R.string.download_deck)
+
+                val typedValue = TypedValue()
+                theme.resolveAttribute(R.attr.appBarColor, typedValue, true)
+                binding.webviewToolbar.setBackgroundColor(typedValue.data)
+            }
+        }
     }
 
     override fun onCreateOptionsMenu(menu: Menu): Boolean {