First alpha release (#52)

* added __version__ to main.py
* package name changed from io.lbry.lbrynet to io.lbry.browser
* removed unnecessary WRITE_EXTERNAL_STORAGE permission from AndroidManifest template, buildozer.spec updates and some cleanup

src/main/java/io/lbry/browser/reactmodules/DownloadManagerModule.java

@@ -0,0 +1,121 @@
+package io.lbry.browser.reactmodules;
+
+import android.content.Context;
+import android.support.v4.app.NotificationCompat;
+import android.support.v4.app.NotificationManagerCompat;
+
+import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.react.bridge.ReactContextBaseJavaModule;
+import com.facebook.react.bridge.ReactMethod;
+
+import io.lbry.browser.R;
+
+import java.text.DecimalFormat;
+import java.util.HashMap;
+import java.util.Random;
+
+/**
+ * Created by akinwale on 3/15/18.
+ */
+
+public class DownloadManagerModule extends ReactContextBaseJavaModule {
+    private Context context;
+
+    private HashMap<Integer, NotificationCompat.Builder> builders = new HashMap<Integer, NotificationCompat.Builder>();
+
+    private HashMap<String, Integer> downloadIdNotificationIdMap = new HashMap<String, Integer>();
+
+    private static final int MAX_PROGRESS = 100;
+
+    private static final DecimalFormat DECIMAL_FORMAT = new DecimalFormat("#.##");
+
+    public DownloadManagerModule(ReactApplicationContext reactContext) {
+        super(reactContext);
+        this.context = reactContext;
+    }
+
+    private int generateNotificationId() {
+        return new Random().nextInt();
+    }
+
+    @Override
+    public String getName() {
+        return "LbryDownloadManager";
+    }
+
+    @ReactMethod
+    public void startDownload(String id, String fileName) {
+        NotificationManagerCompat notificationManager = NotificationManagerCompat.from(context);
+        NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
+        builder.setContentTitle(String.format("Downloading %s...", fileName))
+                .setSmallIcon(R.drawable.ic_file_download_black_24dp)
+                .setPriority(NotificationCompat.PRIORITY_LOW);
+
+        builder.setProgress(MAX_PROGRESS, 0, false);
+
+        int notificationId = generateNotificationId();
+        downloadIdNotificationIdMap.put(id, notificationId);
+
+        builders.put(notificationId, builder);
+        notificationManager.notify(notificationId, builder.build());
+    }
+
+    @ReactMethod
+    public void updateDownload(String id, String fileName, double progress, double writtenBytes, double totalBytes) {
+        if (!downloadIdNotificationIdMap.containsKey(id)) {
+            return;
+        }
+
+        int notificationId = downloadIdNotificationIdMap.get(id);
+        if (!builders.containsKey(notificationId)) {
+            return;
+        }
+
+        NotificationManagerCompat notificationManager = NotificationManagerCompat.from(context);
+        NotificationCompat.Builder builder = builders.get(notificationId);
+        builder.setProgress(MAX_PROGRESS, new Double(progress).intValue(), false);
+        builder.setContentText(String.format("%.0f%% (%s / %s)", progress, formatBytes(writtenBytes), formatBytes(totalBytes)));
+        builder.setOngoing(true);
+        notificationManager.notify(notificationId, builder.build());
+
+        if (progress == MAX_PROGRESS) {
+            builder.setContentTitle(String.format("Downloaded %s.", fileName));
+            builder.setOngoing(false);
+            downloadIdNotificationIdMap.remove(id);
+            builders.remove(notificationId);
+        }
+    }
+    
+    @ReactMethod
+    public void stopDownload(String id, String filename) {
+        if (!downloadIdNotificationIdMap.containsKey(id)) {
+            return;
+        }
+
+        int notificationId = downloadIdNotificationIdMap.get(id);
+        if (!builders.containsKey(notificationId)) {
+            return;
+        }
+        
+        NotificationManagerCompat notificationManager = NotificationManagerCompat.from(context);
+        NotificationCompat.Builder builder = builders.get(notificationId);
+        builder.setOngoing(false);
+        notificationManager.cancel(notificationId);
+
+        downloadIdNotificationIdMap.remove(id);
+        builders.remove(notificationId);
+    }
+
+    private String formatBytes(double bytes)
+    {
+        if (bytes < 1048576) { // < 1MB
+            return String.format("%s KB", DECIMAL_FORMAT.format(bytes / 1024.0));
+        }
+
+        if (bytes < 1073741824) { // < 1GB
+            return String.format("%s MB", DECIMAL_FORMAT.format(bytes / (1024.0 * 1024.0)));
+        }
+
+        return String.format("%s GB", DECIMAL_FORMAT.format(bytes / (1024.0 * 1024.0 * 1024.0)));
+    }
+}