Improve emoji sticker suggestions.

There was a bug around some emoji being marked as 'obsolete' and
therefore not being found.

I also made a change so that you can use skin variations of emoji and
still find emoji tagged with the default yellow version of it.

Fixes #9471

app/src/main/java/org/thoughtcrime/securesms/components/emoji/EmojiUtil.java

@@ -0,0 +1,70 @@
+package org.thoughtcrime.securesms.components.emoji;
+
+import androidx.annotation.NonNull;
+
+import org.whispersystems.libsignal.util.Pair;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public final class EmojiUtil {
+
+  private static final Map<String, String> VARIATION_MAP = new HashMap<>();
+
+  static {
+    for (EmojiPageModel page : EmojiPages.DATA_PAGES) {
+      for (Emoji emoji : page.getDisplayEmoji()) {
+        for (String variation : emoji.getVariations()) {
+          VARIATION_MAP.put(variation, emoji.getValue());
+        }
+      }
+    }
+  }
+
+  public static final int MAX_EMOJI_LENGTH;
+  static {
+    int max = 0;
+    for (EmojiPageModel page : EmojiPages.DATA_PAGES) {
+      for (String emoji : page.getEmoji()) {
+        max = Math.max(max, emoji.length());
+      }
+    }
+    MAX_EMOJI_LENGTH = max;
+  }
+
+  private EmojiUtil() {}
+
+  /**
+   * This will return all ways we know of expressing a singular emoji. This is to aid in search,
+   * where some platforms may send an emoji we've locally marked as 'obsolete'.
+   */
+  public static @NonNull Set<String> getAllRepresentations(@NonNull String emoji) {
+    Set<String> out = new HashSet<>();
+
+    out.add(emoji);
+
+    for (Pair<String, String> pair : EmojiPages.OBSOLETE) {
+      if (pair.first().equals(emoji)) {
+        out.add(pair.second());
+      } else if (pair.second().equals(emoji)) {
+        out.add(pair.first());
+      }
+    }
+
+    return out;
+  }
+
+  /**
+   * When provided an emoji that is a skin variation of another, this will return the default yellow
+   * version. This is to aid in search, so using a variation will still find all emojis tagged with
+   * the default version.
+   *
+   * If the emoji has no skin variations, this function will return the original emoji.
+   */
+  public static @NonNull String getCanonicalRepresentation(@NonNull String emoji) {
+    String canonical = VARIATION_MAP.get(emoji);
+    return canonical != null ? canonical : emoji;
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/conversation/ConversationStickerViewModel.java

@@ -10,28 +10,29 @@
 import androidx.annotation.NonNull;
 import android.text.TextUtils;
 
+import org.thoughtcrime.securesms.components.emoji.EmojiUtil;
 import org.thoughtcrime.securesms.database.CursorList;
 import org.thoughtcrime.securesms.database.DatabaseContentProviders;
 import org.thoughtcrime.securesms.database.model.StickerRecord;
 import org.thoughtcrime.securesms.stickers.StickerSearchRepository;
 import org.thoughtcrime.securesms.util.CloseableLiveData;
 import org.thoughtcrime.securesms.util.Throttler;
 
-class ConversationStickerViewModel extends ViewModel {
+import java.util.List;
 
-  private static final int SEARCH_LIMIT = 10;
+class ConversationStickerViewModel extends ViewModel {
 
-  private final Application                                  application;
-  private final StickerSearchRepository                      repository;
-  private final CloseableLiveData<CursorList<StickerRecord>> stickers;
-  private final MutableLiveData<Boolean>                     stickersAvailable;
-  private final Throttler                                    availabilityThrottler;
-  private final ContentObserver                              packObserver;
+  private final Application                          application;
+  private final StickerSearchRepository              repository;
+  private final MutableLiveData<List<StickerRecord>> stickers;
+  private final MutableLiveData<Boolean>             stickersAvailable;
+  private final Throttler                            availabilityThrottler;
+  private final ContentObserver                      packObserver;
 
   private ConversationStickerViewModel(@NonNull Application application, @NonNull StickerSearchRepository repository) {
     this.application           = application;
     this.repository            = repository;
-    this.stickers              = new CloseableLiveData<>();
+    this.stickers              = new MutableLiveData<>();
     this.stickersAvailable     = new MutableLiveData<>();
     this.availabilityThrottler = new Throttler(500);
     this.packObserver          = new ContentObserver(new Handler()) {
@@ -44,7 +45,7 @@ public void onChange(boolean selfChange) {
     application.getContentResolver().registerContentObserver(DatabaseContentProviders.StickerPack.CONTENT_URI, true, packObserver);
   }
 
-  @NonNull LiveData<CursorList<StickerRecord>> getStickerResults() {
+  @NonNull LiveData<List<StickerRecord>> getStickerResults() {
     return stickers;
   }
 
@@ -54,7 +55,7 @@ public void onChange(boolean selfChange) {
   }
 
   void onInputTextUpdated(@NonNull String text) {
-    if (TextUtils.isEmpty(text) || text.length() > SEARCH_LIMIT) {
+    if (TextUtils.isEmpty(text) || text.length() > EmojiUtil.MAX_EMOJI_LENGTH) {
       stickers.setValue(CursorList.emptyList());
     } else {
       repository.searchByEmoji(text, stickers::postValue);
@@ -63,7 +64,6 @@ void onInputTextUpdated(@NonNull String text) {
 
   @Override
   protected void onCleared() {
-    stickers.close();
     application.getContentResolver().unregisterContentObserver(packObserver);
   }
 

app/src/main/java/org/thoughtcrime/securesms/database/StickerDatabase.java

@@ -30,6 +30,8 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.UnsupportedEncodingException;
+import java.net.URLEncoder;
 import java.util.List;
 
 public class StickerDatabase extends Database {

app/src/main/java/org/thoughtcrime/securesms/stickers/StickerSearchRepository.java

@@ -4,14 +4,20 @@
 import android.database.Cursor;
 import androidx.annotation.NonNull;
 
+import org.thoughtcrime.securesms.components.emoji.EmojiUtil;
 import org.thoughtcrime.securesms.database.AttachmentDatabase;
 import org.thoughtcrime.securesms.database.CursorList;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.database.StickerDatabase;
+import org.thoughtcrime.securesms.database.StickerDatabase.StickerRecordReader;
 import org.thoughtcrime.securesms.database.model.StickerPackRecord;
 import org.thoughtcrime.securesms.database.model.StickerRecord;
 import org.thoughtcrime.securesms.util.concurrent.SignalExecutors;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
 public final class StickerSearchRepository {
 
   private final StickerDatabase    stickerDatabase;
@@ -22,15 +28,22 @@ public StickerSearchRepository(@NonNull Context context) {
     this.attachmentDatabase = DatabaseFactory.getAttachmentDatabase(context);
   }
 
-  public void searchByEmoji(@NonNull String emoji, @NonNull Callback<CursorList<StickerRecord>> callback) {
+  public void searchByEmoji(@NonNull String emoji, @NonNull Callback<List<StickerRecord>> callback) {
     SignalExecutors.BOUNDED.execute(() -> {
-      Cursor cursor = stickerDatabase.getStickersByEmoji(emoji);
+      String              searchEmoji = EmojiUtil.getCanonicalRepresentation(emoji);
+      List<StickerRecord> out         = new ArrayList<>();
+      Set<String>         possible    = EmojiUtil.getAllRepresentations(searchEmoji);
 
-      if (cursor != null) {
-        callback.onResult(new CursorList<>(cursor, new StickerModelBuilder()));
-      } else {
-        callback.onResult(CursorList.emptyList());
+      for (String candidate : possible) {
+        try (StickerRecordReader reader = new StickerRecordReader(stickerDatabase.getStickersByEmoji(candidate))) {
+          StickerRecord record = null;
+          while ((record = reader.getNext()) != null) {
+            out.add(record);
+          }
+        }
       }
+
+      callback.onResult(out);
     });
   }
 
@@ -49,14 +62,7 @@ public void getStickerFeatureAvailability(@NonNull Callback<Boolean> callback) {
   private static class StickerModelBuilder implements CursorList.ModelBuilder<StickerRecord> {
     @Override
     public StickerRecord build(@NonNull Cursor cursor) {
-      return new StickerDatabase.StickerRecordReader(cursor).getCurrent();
-    }
-  }
-
-  private static class StickerPackModelBuilder implements CursorList.ModelBuilder<StickerPackRecord> {
-    @Override
-    public StickerPackRecord build(@NonNull Cursor cursor) {
-      return new StickerDatabase.StickerPackRecordReader(cursor).getCurrent();
+      return new StickerRecordReader(cursor).getCurrent();
     }
   }