Add user cache

Users that were loaded from the network are now kept in a cache and only
discarded when the app is closed. This means, that if a user navigates
away from the map and then comes back to it no more loading needs to be
done for the previously loaded areas.
Also, the loading is area aware. That means that for overlapping areas
requests are now only made for the non-loaded parts.

Fixes: #101

app/src/main/java/fi/bitrite/android/ws/ui/MapFragment.java

@@ -10,6 +10,7 @@
 import android.graphics.drawable.Drawable;
 import android.location.Location;
 import android.os.Bundle;
+import android.os.Handler;
 import android.preference.PreferenceManager;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
@@ -64,14 +65,14 @@
 import fi.bitrite.android.ws.repository.FavoriteRepository;
 import fi.bitrite.android.ws.repository.Resource;
 import fi.bitrite.android.ws.repository.SettingsRepository;
-import fi.bitrite.android.ws.repository.UserRepository;
 import fi.bitrite.android.ws.ui.listadapter.UserListAdapter;
 import fi.bitrite.android.ws.ui.util.NavigationController;
 import fi.bitrite.android.ws.ui.util.UserMarker;
 import fi.bitrite.android.ws.ui.util.UserMarkerClusterer;
 import fi.bitrite.android.ws.util.LocationManager;
 import fi.bitrite.android.ws.util.LoggedInUserHelper;
 import fi.bitrite.android.ws.util.Tools;
+import fi.bitrite.android.ws.util.UserRegionalCache;
 import io.reactivex.Completable;
 import io.reactivex.Observable;
 import io.reactivex.android.schedulers.AndroidSchedulers;
@@ -83,7 +84,7 @@ public class MapFragment extends BaseFragment {
     private static final String TAG = "MapFragment";
 
     @Inject LoggedInUserHelper mLoggedInUserHelper;
-    @Inject UserRepository mUserRepository;
+    @Inject UserRegionalCache mUserRegionalCache;
     @Inject FavoriteRepository mFavoriteRepository;
     @Inject SettingsRepository mSettingsRepository;
 
@@ -163,8 +164,6 @@ public void onCreate(Bundle savedInstanceState) {
         mMarkerClusterer.setSingleLocationMarkerFactory(singleLocationMarkerFactory);
         mMarkerClusterer.setMultiLocationMarkerFactory(multiLocationMarkerFactory);
         mMarkerClusterer.setOnClusterClickListener(this::onClusterClick);
-
-        loadOfflineUsers();
     }
 
     @Nullable
@@ -229,6 +228,9 @@ public boolean onZoom(ZoomEvent event) {
             doInitialMapMove();
         });
 
+        loadOfflineUsers();
+        loadCachedUsers();
+
         return view;
     }
 
@@ -440,10 +442,12 @@ private void fetchUsersForCurrentMapPosition() {
         if (mLastPosition.zoom < getResources().getInteger(R.integer.map_zoom_min_load)) {
             sendMessage(R.string.users_dont_load);
         } else {
-            sendMessage(R.string.loading_users);
+            Handler handler = new Handler();
+            Runnable r = () -> sendMessage(R.string.loading_users);
+            handler.postDelayed(r, 500);
 
             getResumePauseDisposable().add(
-                    mUserRepository.searchByLocation(mMap.getBoundingBox())
+                    mUserRegionalCache.searchByLocation(mMap.getBoundingBox())
                             .observeOn(AndroidSchedulers.mainThread())
                             .subscribe(searchResult -> {
                                 if (searchResult.isEmpty()) {
@@ -456,9 +460,10 @@ private void fetchUsersForCurrentMapPosition() {
                                 mMarkerClusterer.invalidate();
                                 mMap.invalidate();
                             }, throwable -> {
+                                handler.removeCallbacks(r);
                                 // TODO(saemy): Error handling.
                                 Log.e(TAG, throwable.getMessage());
-                            }));
+                            }, () -> handler.removeCallbacks(r)));
         }
 
     }
@@ -468,21 +473,24 @@ private void loadOfflineUsers() {
         mLoadOfflineUserDisposable = Observable.merge(mFavoriteRepository.getFavorites())
                 .filter(Resource::hasData)
                 .map(userResource -> userResource.data)
+                // Users pop up twice as one is the error since we might not be able to load it
+                // from the network.
+                .filter(user -> mOfflineUserIds.add(user.id))
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe(user -> {
-                    // Users pop up twice as one is the error since we might not be able to load it
-                    // from the network.
-                    boolean added = mOfflineUserIds.add(user.id);
-                    if (!added) {
-                        return;
-                    }
-
                     addUserToCluster(user);
                     mMarkerClusterer.invalidate();
                 });
         getCreateDestroyDisposable().add(mLoadOfflineUserDisposable);
     }
 
+    private void loadCachedUsers() {
+        for (UserSearchByLocationResponse.User user : mUserRegionalCache.getAllCached()) {
+            addUserToCluster(user.toSimpleUser());
+        }
+        mMarkerClusterer.invalidate();
+    }
+
     private void addUserToCluster(SimpleUser user) {
         // Only add to the cluster if it wasn't before or when its location changed.
         final Marker existingMarker = mClusteredUsers.get(user.id);