feat(Sync for Reddit): Add Fix video downloads patch (#710)

Author: 1fexd

app/src/main/java/app/revanced/integrations/syncforreddit/FixRedditVideoDownloadPatch.java

@@ -0,0 +1,77 @@
+package app.revanced.integrations.syncforreddit;
+
+import android.util.Pair;
+import androidx.annotation.Nullable;
+import org.w3c.dom.Element;
+import org.xml.sax.SAXException;
+
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+
+/**
+ * @noinspection unused
+ */
+public class FixRedditVideoDownloadPatch {
+    private static @Nullable Pair<Integer, String> getBestMpEntry(Element element) {
+        var representations = element.getElementsByTagName("Representation");
+        var entries = new ArrayList<Pair<Integer, String>>();
+
+        for (int i = 0; i < representations.getLength(); i++) {
+            Element representation = (Element) representations.item(i);
+            var bandwidthStr = representation.getAttribute("bandwidth");
+            try {
+                var bandwidth = Integer.parseInt(bandwidthStr);
+                var baseUrl = representation.getElementsByTagName("BaseURL").item(0);
+                if (baseUrl != null) {
+                    entries.add(new Pair<>(bandwidth, baseUrl.getTextContent()));
+                }
+            } catch (NumberFormatException ignored) {
+            }
+        }
+
+        if (entries.isEmpty()) {
+            return null;
+        }
+
+        Collections.sort(entries, (e1, e2) -> e2.first - e1.first);
+        return entries.get(0);
+    }
+
+    private static String[] parse(byte[] data) throws ParserConfigurationException, IOException, SAXException {
+        var adaptionSets = DocumentBuilderFactory
+                .newInstance()
+                .newDocumentBuilder()
+                .parse(new ByteArrayInputStream(data))
+                .getElementsByTagName("AdaptationSet");
+
+        String videoUrl = null;
+        String audioUrl = null;
+
+        for (int i = 0; i < adaptionSets.getLength(); i++) {
+            Element element = (Element) adaptionSets.item(i);
+            var contentType = element.getAttribute("contentType");
+            var bestEntry = getBestMpEntry(element);
+            if (bestEntry == null) continue;
+
+            if (contentType.equalsIgnoreCase("video")) {
+                videoUrl = bestEntry.second;
+            } else if (contentType.equalsIgnoreCase("audio")) {
+                audioUrl = bestEntry.second;
+            }
+        }
+
+        return new String[]{videoUrl, audioUrl};
+    }
+
+    public static String[] getLinks(byte[] data) {
+        try {
+            return parse(data);
+        } catch (ParserConfigurationException | IOException | SAXException e) {
+            return new String[]{null, null};
+        }
+    }
+}