Nearby: Fix race condition and lag when loading pin details, faster overlay management (#6047)

* temporary fixes part one

* temporary fixes part two

* temporary fixes part three

* temporary fixes part four

* temporary fixes part five

* reformatting

* remove code no longer in use

* Migrate NearbyParentFragmentPresenter to Kotlin

* Partially replace temporary experimental fixes

* Replace temporary experimental fixes part 2

* Replace temporary experimental fixes part 3

* Replace temporary fixes completely

* Fix caching and loading places in Nearby list

* Add place bookmarking logic, Remove all old code

* Nearby Presenter: Close channel properly

* Nearby pins now load starting from the center

Fixes #6049

* Add comments and javadoc for Nearby Presenter

* Fix warnings, Fix formatting, Add javadoc

* Pass unit tests

app/src/main/java/fr/free/nrw/commons/nearby/NearbyController.java

@@ -20,8 +20,8 @@ import timber.log.Timber;
 
 public class NearbyController extends MapController {
 
-    private static final int MAX_RESULTS = 1000;
     private final NearbyPlaces nearbyPlaces;
+    public static final int MAX_RESULTS = 1000;
     public static double currentLocationSearchRadius = 10.0; //in kilometers
     public static LatLng currentLocation; // Users latest fetched location
     public static LatLng latestSearchLocation; // Can be current and camera target on search this area button is used

app/src/main/java/fr/free/nrw/commons/nearby/contract/NearbyParentFragmentContract.java

@@ -2,11 +2,13 @@ package fr.free.nrw.commons.nearby.contract;
 
 import android.content.Context;
 import androidx.annotation.Nullable;
+import androidx.lifecycle.LifecycleCoroutineScope;
 import fr.free.nrw.commons.BaseMarker;
 import fr.free.nrw.commons.kvstore.JsonKvStore;
 import fr.free.nrw.commons.location.LatLng;
 import fr.free.nrw.commons.location.LocationServiceManager.LocationChangeType;
 import fr.free.nrw.commons.nearby.Label;
+import fr.free.nrw.commons.nearby.MarkerPlaceGroup;
 import fr.free.nrw.commons.nearby.Place;
 import java.util.List;
 
@@ -68,7 +70,7 @@ public interface NearbyParentFragmentContract {
 
         Context getContext();
 
-        void updateMapMarkers(List<BaseMarker> BaseMarkers);
+        void replaceMarkerOverlays(List<MarkerPlaceGroup> markerPlaceGroups);
 
         void filterOutAllMarkers();
 
@@ -127,5 +129,7 @@ public interface NearbyParentFragmentContract {
         void setCheckboxUnknown();
 
         void setAdvancedQuery(String query);
+
+        void toggleBookmarkedStatus(Place place);
     }
 }

app/src/main/java/fr/free/nrw/commons/nearby/fragments/NearbyParentFragment.java

@@ -23,8 +23,6 @@ import android.graphics.drawable.Drawable;
 import android.location.Location;
 import android.location.LocationManager;
 import android.net.Uri;
-import android.os.Build.VERSION;
-import android.os.Build.VERSION_CODES;
 import android.os.Bundle;
 import android.os.Environment;
 import android.os.Handler;
@@ -56,6 +54,7 @@ import androidx.appcompat.app.AlertDialog.Builder;
 import androidx.constraintlayout.widget.ConstraintLayout;
 import androidx.core.content.ContextCompat;
 import androidx.core.content.FileProvider;
+import androidx.lifecycle.LifecycleOwnerKt;
 import androidx.recyclerview.widget.DividerItemDecoration;
 import androidx.recyclerview.widget.GridLayoutManager;
 import androidx.recyclerview.widget.LinearLayoutManager;
@@ -110,16 +109,12 @@ import fr.free.nrw.commons.wikidata.WikidataEditListener;
 import io.reactivex.Completable;
 import io.reactivex.Observable;
 import io.reactivex.android.schedulers.AndroidSchedulers;
-import io.reactivex.disposables.Disposable;
 import io.reactivex.schedulers.Schedulers;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
 import java.util.Date;
 import java.util.List;
 import java.util.Locale;
@@ -155,6 +150,29 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
 
     FragmentNearbyParentBinding binding;
 
+    public final MapEventsOverlay mapEventsOverlay = new MapEventsOverlay(new MapEventsReceiver() {
+        @Override
+        public boolean singleTapConfirmedHelper(GeoPoint p) {
+            if (clickedMarker != null) {
+                clickedMarker.closeInfoWindow();
+            } else {
+                Timber.e("CLICKED MARKER IS NULL");
+            }
+            if (isListBottomSheetExpanded()) {
+                // Back should first hide the bottom sheet if it is expanded
+                hideBottomSheet();
+            } else if (isDetailsBottomSheetVisible()) {
+                hideBottomDetailsSheet();
+            }
+            return true;
+        }
+
+        @Override
+        public boolean longPressHelper(GeoPoint p) {
+            return false;
+        }
+    });
+
     @Inject
     LocationServiceManager locationManager;
     @Inject
@@ -217,7 +235,6 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
     private Runnable searchRunnable;
     private static final long SCROLL_DELAY = 800; // Delay for debounce of onscroll, in milliseconds.
 
-    private List<Place> updatedPlacesList;
     private LatLng updatedLatLng;
     private boolean searchable;
 
@@ -308,10 +325,6 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
      * WLM URL
      */
     public static final String WLM_URL = "https://commons.wikimedia.org/wiki/Commons:Mobile_app/Contributing_to_WLM_using_the_app";
-    /**
-     * Saves response of list of places for the first time
-     */
-    private List<Place> places = new ArrayList<>();
 
     @NonNull
     public static NearbyParentFragment newInstance() {
@@ -327,7 +340,7 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         view = binding.getRoot();
 
         initNetworkBroadCastReceiver();
-        presenter = new NearbyParentFragmentPresenter(bookmarkLocationDao);
+        presenter = new NearbyParentFragmentPresenter(bookmarkLocationDao, placesRepository, nearbyController);
         progressDialog = new ProgressDialog(getActivity());
         progressDialog.setCancelable(false);
         progressDialog.setMessage("Saving in progress...");
@@ -452,28 +465,7 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         binding.map.getOverlays().add(scaleBarOverlay);
         binding.map.getZoomController().setVisibility(Visibility.NEVER);
         binding.map.getController().setZoom(ZOOM_LEVEL);
-        binding.map.getOverlays().add(new MapEventsOverlay(new MapEventsReceiver() {
+        binding.map.getOverlays().add(mapEventsOverlay);
-            @Override
-            public boolean singleTapConfirmedHelper(GeoPoint p) {
-                if (clickedMarker != null) {
-                    clickedMarker.closeInfoWindow();
-                } else {
-                    Timber.e("CLICKED MARKER IS NULL");
-                }
-                if (isListBottomSheetExpanded()) {
-                    // Back should first hide the bottom sheet if it is expanded
-                    hideBottomSheet();
-                } else if (isDetailsBottomSheetVisible()) {
-                    hideBottomDetailsSheet();
-                }
-                return true;
-            }
-
-            @Override
-            public boolean longPressHelper(GeoPoint p) {
-                return false;
-            }
-        }));
 
         binding.map.addMapListener(new MapListener() {
             @Override
@@ -605,8 +597,7 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
                 return Unit.INSTANCE;
             },
             (place, isBookmarked) -> {
-                updateMarker(isBookmarked, place, null);
+                presenter.toggleBookmarkedStatus(place);
-                binding.map.invalidate();
                 return Unit.INSTANCE;
             },
             commonPlaceClickActions,
@@ -670,19 +661,7 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         registerNetworkReceiver();
         if (isResumed() && ((MainActivity) getActivity()).activeFragment == ActiveFragment.NEARBY) {
             if (locationPermissionsHelper.checkLocationPermission(getActivity())) {
-                if (lastFocusLocation == null && lastKnownLocation == null) {
+                locationPermissionGranted();
-                    locationPermissionGranted();
-                } else{
-                    if (updatedPlacesList != null) {
-                        if (!updatedPlacesList.isEmpty()) {
-                            loadPlacesDataAsync(updatedPlacesList, updatedLatLng);
-                        } else {
-                            updateMapMarkers(updatedPlacesList, getLastMapFocus(), false);
-                        }
-                    }else {
-                        locationPermissionGranted();
-                    }
-                }
             } else {
                 startMapWithoutPermission();
             }
@@ -973,7 +952,7 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
 
     @Override
     public void updateListFragment(final List<Place> placeList) {
-        places = placeList;
+        adapter.clear();
         adapter.setItems(placeList);
         binding.bottomSheetNearby.noResultsMessage.setVisibility(
             placeList.isEmpty() ? View.VISIBLE : View.GONE);
@@ -1367,13 +1346,8 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
                             ? getTextBetweenParentheses(
                             updatedPlace.getLongDescription()) : updatedPlace.getLongDescription());
                     marker.showInfoWindow();
-                    for (int i = 0; i < updatedPlacesList.size(); i++) {
+                    presenter.handlePinClicked(updatedPlace);
-                        Place pl = updatedPlacesList.get(i);
+                    savePlaceToDatabase(place);
-                        if (pl.location == updatedPlace.location) {
-                            updatedPlacesList.set(i, updatedPlace);
-                            savePlaceToDatabase(place);
-                        }
-                    }
                     Drawable icon = ContextCompat.getDrawable(getContext(),
                         getIconFor(updatedPlace, isBookMarked));
                     marker.setIcon(icon);
@@ -1412,12 +1386,10 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
                         setProgressBarVisibility(false);
                         presenter.lockUnlockNearby(false);
                     } else {
-                        updateMapMarkers(nearbyPlacesInfo.placeList, nearbyPlacesInfo.currentLatLng,
+                        updateMapMarkers(nearbyPlacesInfo.placeList, searchLatLng, true);
-                            true);
                         lastFocusLocation = searchLatLng;
                         lastMapFocus = new GeoPoint(searchLatLng.getLatitude(),
                             searchLatLng.getLongitude());
-                        loadPlacesDataAsync(nearbyPlacesInfo.placeList, nearbyPlacesInfo.currentLatLng);
                     }
                 },
                 throwable -> {
@@ -1457,12 +1429,10 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
 
                         // curLatLng is used to calculate distance from the current location to the place
                         // and distance is later on populated to the place
-                        updateMapMarkers(nearbyPlacesInfo.placeList, nearbyPlacesInfo.currentLatLng,
+                        updateMapMarkers(nearbyPlacesInfo.placeList, searchLatLng, false);
-                            false);
                         lastMapFocus = new GeoPoint(searchLatLng.getLatitude(),
                             searchLatLng.getLongitude());
                         stopQuery();
-                        loadPlacesDataAsync(nearbyPlacesInfo.placeList, nearbyPlacesInfo.currentLatLng);
                     }
                 },
                 throwable -> {
@@ -1475,167 +1445,7 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
                 }));
     }
 
-    public void loadPlacesDataAsync(List<Place> placeList, LatLng curLatLng) {
+    public void savePlaceToDatabase(Place place) {
-        List<Place> places = new ArrayList<>(placeList);
-
-        // Instead of loading all pins in a single SPARQL query, we query in batches.
-        // This variable controls the number of pins queried per batch.
-        int batchSize = 3;
-
-        updatedLatLng = curLatLng;
-        updatedPlacesList = new ArrayList<>(placeList);
-
-        // Sorts the places by distance to ensure the nearest pins are ready for the user as soon
-        // as possible.
-        if (VERSION.SDK_INT >= VERSION_CODES.N) {
-            Collections.sort(places,
-                Comparator.comparingDouble(place -> place.getDistanceInDouble(getMapFocus())));
-        }
-        stopQuery = false;
-        processBatchesSequentially(places, batchSize, updatedPlacesList, curLatLng, 0);
-    }
-
-    /**
-     * Processes a list of places in batches sequentially. This method handles the asynchronous
-     * processing of places, updating the map markers and updates the list of updated places accordingly.
-     *
-     * @param places           The list of Place objects to be processed.
-     * @param batchSize        The size of each batch to be processed.
-     * @param updatedPlaceList The list of Place objects to be updated.
-     * @param curLatLng        The current location of the user.
-     * @param startIndex       The starting index for the current batch.
-     */
-    @SuppressLint("CheckResult")
-    private void processBatchesSequentially(List<Place> places, int batchSize,
-        List<Place> updatedPlaceList, LatLng curLatLng, int startIndex) {
-        if (startIndex >= places.size() || stopQuery) {
-            return;
-        }
-
-        int endIndex = Math.min(startIndex + batchSize, places.size());
-        List<Place> batch = places.subList(startIndex, endIndex);
-        for (int i = 0; i < batch.size(); i++) {
-            if (i == batch.size() - 1 && batch.get(i).name != "") {
-                processBatchesSequentially(places, batchSize, updatedPlaceList, curLatLng,
-                    endIndex + batchSize);
-                return;
-            }
-            if (batch.get(i).name == "") {
-                if (i == 0) {
-                    break;
-                }
-                processBatchesSequentially(places, batchSize, updatedPlaceList, curLatLng,
-                    endIndex + i);
-                return;
-            }
-        }
-
-        Disposable disposable = processBatch(batch, updatedPlaceList)
-            .subscribe(p -> {
-                if (stopQuery) {
-                    return;
-                }
-                if (!p.isEmpty() && p != updatedPlaceList) {
-                    synchronized (updatedPlaceList) {
-                        updatedPlaceList.clear();
-                        updatedPlaceList.addAll((Collection<? extends Place>) p);
-                    }
-                }
-                updateMapMarkers(new ArrayList<>(updatedPlaceList), curLatLng, false);
-                processBatchesSequentially(places, batchSize, updatedPlaceList, curLatLng, endIndex);
-            }, throwable -> {
-                Timber.e(throwable);
-                showErrorMessage(getString(R.string.error_fetching_nearby_places) + throwable.getLocalizedMessage());
-                setFilterState();
-            });
-
-        compositeDisposable.add(disposable);
-    }
-
-    /**
-     * Processes a batch of places, updating the provided place list with fetched or updated data.
-     * This method handles the asynchronous fetching and updating of places from the repository.
-     *
-     * @param batch     The batch of Place objects to be processed.
-     * @param placeList The list of Place objects to be updated.
-     * @return An Observable emitting the updated list of Place objects.
-     */
-    private Observable<List<?>> processBatch(List<Place> batch, List<Place> placeList) {
-        List<Place> toBeProcessed = new ArrayList<>();
-
-        List<Observable<Place>> placeObservables = new ArrayList<>();
-
-        for (Place place : batch) {
-            Observable<Place> placeObservable = Observable
-                .fromCallable(() -> {
-                    Place fetchedPlace = placesRepository.fetchPlace(place.entityID);
-                    return fetchedPlace != null ? fetchedPlace : place;
-                })
-                .subscribeOn(Schedulers.io())
-                .observeOn(AndroidSchedulers.mainThread())
-                .doOnNext(placeData -> {
-                    if (placeData.equals(place)) {
-                        toBeProcessed.add(place);
-                    } else {
-                        for (int i = 0; i < placeList.size(); i++) {
-                            Place pl = placeList.get(i);
-                            if (pl.location.equals(place.location)) {
-                                placeList.set(i, placeData);
-                                break;
-                            }
-                        }
-                    }
-                });
-
-            placeObservables.add(placeObservable);
-        }
-
-        return Observable.zip(placeObservables, objects -> toBeProcessed)
-            .flatMap(processedList -> {
-                if (processedList.isEmpty()) {
-                    return Observable.just(placeList);
-                }
-                return Observable.fromCallable(() -> nearbyController.getPlaces(processedList))
-                    .subscribeOn(Schedulers.io())
-                    .observeOn(AndroidSchedulers.mainThread())
-                    .map(places -> {
-                        if (stopQuery) {
-                            return Collections.emptyList();
-                        }
-                        if (places == null || places.isEmpty()) {
-                            return Collections.emptyList();
-                        } else {
-                            List<Place> updatedPlaceList = new ArrayList<>(placeList);
-                            for (Place place : places) {
-                                for (Place foundPlace : placeList) {
-                                    if (place.siteLinks.getWikidataLink()
-                                        .equals(foundPlace.siteLinks.getWikidataLink())) {
-                                        place.location = foundPlace.location;
-                                        place.distance = foundPlace.distance;
-                                        place.setMonument(foundPlace.isMonument());
-                                        int index = updatedPlaceList.indexOf(foundPlace);
-                                        if (index != -1) {
-                                            updatedPlaceList.set(index, place);
-                                            savePlaceToDatabase(place);
-                                        }
-                                        break;
-                                    }
-                                }
-                            }
-                            return updatedPlaceList;
-                        }
-                    })
-                    .onErrorReturn(throwable -> {
-                        Timber.e(throwable);
-                        showErrorMessage(getString(R.string.error_fetching_nearby_places) + " "
-                            + throwable.getLocalizedMessage());
-                        setFilterState();
-                        return Collections.emptyList();
-                    });
-            });
-    }
-
-    private void savePlaceToDatabase(Place place) {
         compositeDisposable.add(placesRepository
             .save(place)
             .subscribeOn(Schedulers.io())
@@ -1661,8 +1471,8 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
      */
     private void updateMapMarkers(final List<Place> nearbyPlaces, final LatLng curLatLng,
         final boolean shouldUpdateSelectedMarker) {
-        presenter.updateMapMarkers(nearbyPlaces, curLatLng, shouldUpdateSelectedMarker);
+        presenter.updateMapMarkers(nearbyPlaces, curLatLng,
-        setFilterState();
+            LifecycleOwnerKt.getLifecycleScope(getViewLifecycleOwner()));
     }
 
 
@@ -1899,13 +1709,6 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         }
     }
 
-    @Override
-    public void updateMapMarkers(final List<BaseMarker> BaseMarkers) {
-        if (binding.map != null) {
-            presenter.updateMapMarkersToController(BaseMarkers);
-        }
-    }
-
     @Override
     public void filterOutAllMarkers() {
         clearAllMarkers();
@@ -1925,8 +1728,11 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         final boolean displayExists = false;
         final boolean displayNeedsPhoto= false;
         final boolean displayWlm = false;
-        // Remove the previous markers before updating them
+        if (selectedLabels == null || selectedLabels.size() == 0) {
-        clearAllMarkers();
+            replaceMarkerOverlays(NearbyController.markerLabelList);
+            return;
+        }
+        final ArrayList<MarkerPlaceGroup> placeGroupsToShow = new ArrayList<>();
         for (final MarkerPlaceGroup markerPlaceGroup : NearbyController.markerLabelList) {
             final Place place = markerPlaceGroup.getPlace();
             // When label filter is engaged
@@ -1967,19 +1773,12 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
             }
 
             if (shouldUpdateMarker) {
-                updateMarker(markerPlaceGroup.getIsBookmarked(), place,
+                placeGroupsToShow.add(
-                    NearbyController.currentLocation);
+                    new MarkerPlaceGroup(markerPlaceGroup.getIsBookmarked(), place)
+                );
             }
         }
-        if (selectedLabels == null || selectedLabels.size() == 0) {
+        replaceMarkerOverlays(placeGroupsToShow);
-            ArrayList<BaseMarker> markerArrayList = new ArrayList<>();
-            for (final MarkerPlaceGroup markerPlaceGroup : NearbyController.markerLabelList) {
-                BaseMarker nearbyBaseMarker = new BaseMarker();
-                nearbyBaseMarker.setPlace(markerPlaceGroup.getPlace());
-                markerArrayList.add(nearbyBaseMarker);
-            }
-            addMarkersToMap(markerArrayList);
-        }
     }
 
     @Override
@@ -1987,18 +1786,6 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         return binding.map == null ? null : getMapFocus();
     }
 
-    /**
-     * Sets marker icon according to marker status. Sets title and distance.
-     *
-     * @param isBookmarked  true if place is bookmarked
-     * @param place
-     * @param currentLatLng current location
-     */
-    public void updateMarker(final boolean isBookmarked, final Place place,
-        @Nullable final LatLng currentLatLng) {
-        addMarkerToMap(place, isBookmarked);
-    }
-
     /**
      * Highlights nearest place when user clicks on home nearby banner
      *
@@ -2052,13 +1839,7 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         );
     }
 
-    /**
+    public Marker convertToMarker(Place place, Boolean isBookMarked) {
-     * Adds a marker representing a place to the map with optional bookmark icon.
-     *
-     * @param place        The Place object containing information about the location.
-     * @param isBookMarked A Boolean flag indicating whether the place is bookmarked or not.
-     */
-    private void addMarkerToMap(Place place, Boolean isBookMarked) {
         Drawable icon = ContextCompat.getDrawable(getContext(), getIconFor(place, isBookMarked));
         GeoPoint point = new GeoPoint(place.location.getLatitude(), place.location.getLongitude());
         Marker marker = new Marker(binding.map);
@@ -2094,22 +1875,27 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
             bottomSheetDetailsBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
             return true;
         });
-        binding.map.getOverlays().add(marker);
+        return marker;
     }
 
     /**
      * Adds multiple markers representing places to the map and handles item gestures.
      *
-     * @param nearbyBaseMarkers The list of Place objects containing information about the
+     * @param markerPlaceGroups The list of marker place groups containing the places and
-     *                          locations.
+     *                          their bookmarked status
      */
-    private void addMarkersToMap(List<BaseMarker> nearbyBaseMarkers) {
+    @Override
-
+    public void replaceMarkerOverlays(final List<MarkerPlaceGroup> markerPlaceGroups) {
-        for(int i = 0; i< nearbyBaseMarkers.size(); i++){
+        ArrayList<Marker> newMarkers = new ArrayList<>(markerPlaceGroups.size());
-            addMarkerToMap(nearbyBaseMarkers.get(i).getPlace(), false);
+        for (MarkerPlaceGroup markerPlaceGroup : markerPlaceGroups) {
+            newMarkers.add(
+                convertToMarker(markerPlaceGroup.getPlace(), markerPlaceGroup.getIsBookmarked()));
         }
+        clearAllMarkers();
+        binding.map.getOverlays().addAll(newMarkers);
     }
 
+
     /**
      * Extracts text between the first occurrence of '(' and its corresponding ')' in the input
      * string.
@@ -2400,7 +2186,6 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         binding.map.invalidate();
         GeoPoint geoPoint = mapCenter;
         if (geoPoint != null) {
-            List<Overlay> overlays = binding.map.getOverlays();
             ScaleDiskOverlay diskOverlay =
                 new ScaleDiskOverlay(this.getContext(),
                     geoPoint, 2000, UnitOfMeasure.foot);
@@ -2434,28 +2219,7 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         scaleBarOverlay.setBackgroundPaint(barPaint);
         scaleBarOverlay.enableScaleBar();
         binding.map.getOverlays().add(scaleBarOverlay);
-        binding.map.getOverlays().add(new MapEventsOverlay(new MapEventsReceiver() {
+        binding.map.getOverlays().add(mapEventsOverlay);
-            @Override
-            public boolean singleTapConfirmedHelper(GeoPoint p) {
-                if (clickedMarker != null) {
-                    clickedMarker.closeInfoWindow();
-                } else {
-                    Timber.e("CLICKED MARKER IS NULL");
-                }
-                if (isListBottomSheetExpanded()) {
-                    // Back should first hide the bottom sheet if it is expanded
-                    hideBottomSheet();
-                } else if (isDetailsBottomSheetVisible()) {
-                    hideBottomDetailsSheet();
-                }
-                return true;
-            }
-
-            @Override
-            public boolean longPressHelper(GeoPoint p) {
-                return false;
-            }
-        }));
         binding.map.setMultiTouchControls(true);
     }
 
@@ -2510,21 +2274,14 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
     @Override
     public void onBottomSheetItemClick(@Nullable View view, int position) {
         BottomSheetItem item = dataList.get(position);
-        boolean isBookmarked = bookmarkLocationDao.findBookmarkLocation(selectedPlace);
         switch (item.getImageResourceId()) {
             case R.drawable.ic_round_star_border_24px:
-                bookmarkLocationDao.updateBookmarkLocation(selectedPlace);
+                presenter.toggleBookmarkedStatus(selectedPlace);
                 updateBookmarkButtonImage(selectedPlace);
-                isBookmarked = bookmarkLocationDao.findBookmarkLocation(selectedPlace);
-                updateMarker(isBookmarked, selectedPlace, locationManager.getLastLocation());
-                binding.map.invalidate();
                 break;
             case R.drawable.ic_round_star_filled_24px:
-                bookmarkLocationDao.updateBookmarkLocation(selectedPlace);
+                presenter.toggleBookmarkedStatus(selectedPlace);
                 updateBookmarkButtonImage(selectedPlace);
-                isBookmarked = bookmarkLocationDao.findBookmarkLocation(selectedPlace);
-                updateMarker(isBookmarked, selectedPlace, locationManager.getLastLocation());
-                binding.map.invalidate();
                 break;
             case R.drawable.ic_directions_black_24dp:
                 Utils.handleGeoCoordinates(this.getContext(), selectedPlace.getLocation());

app/src/main/java/fr/free/nrw/commons/nearby/presenter/NearbyParentFragmentPresenter.java

@@ -1,368 +0,0 @@
-package fr.free.nrw.commons.nearby.presenter;
-
-import static fr.free.nrw.commons.location.LocationServiceManager.LocationChangeType.CUSTOM_QUERY;
-import static fr.free.nrw.commons.location.LocationServiceManager.LocationChangeType.LOCATION_SIGNIFICANTLY_CHANGED;
-import static fr.free.nrw.commons.location.LocationServiceManager.LocationChangeType.LOCATION_SLIGHTLY_CHANGED;
-import static fr.free.nrw.commons.location.LocationServiceManager.LocationChangeType.MAP_UPDATED;
-import static fr.free.nrw.commons.location.LocationServiceManager.LocationChangeType.SEARCH_CUSTOM_AREA;
-import static fr.free.nrw.commons.nearby.CheckBoxTriStates.CHECKED;
-import static fr.free.nrw.commons.nearby.CheckBoxTriStates.UNCHECKED;
-import static fr.free.nrw.commons.nearby.CheckBoxTriStates.UNKNOWN;
-import static fr.free.nrw.commons.wikidata.WikidataConstants.PLACE_OBJECT;
-
-import android.location.Location;
-import androidx.annotation.MainThread;
-import androidx.annotation.Nullable;
-import fr.free.nrw.commons.BaseMarker;
-import fr.free.nrw.commons.bookmarks.locations.BookmarkLocationsDao;
-import fr.free.nrw.commons.kvstore.JsonKvStore;
-import fr.free.nrw.commons.location.LatLng;
-import fr.free.nrw.commons.location.LocationServiceManager.LocationChangeType;
-import fr.free.nrw.commons.location.LocationUpdateListener;
-import fr.free.nrw.commons.nearby.CheckBoxTriStates;
-import fr.free.nrw.commons.nearby.Label;
-import fr.free.nrw.commons.nearby.MarkerPlaceGroup;
-import fr.free.nrw.commons.nearby.NearbyController;
-import fr.free.nrw.commons.nearby.Place;
-import fr.free.nrw.commons.nearby.contract.NearbyParentFragmentContract;
-import fr.free.nrw.commons.utils.LocationUtils;
-import fr.free.nrw.commons.wikidata.WikidataEditListener;
-import java.lang.reflect.Proxy;
-import java.util.List;
-import timber.log.Timber;
-
-public class NearbyParentFragmentPresenter
-    implements NearbyParentFragmentContract.UserActions,
-    WikidataEditListener.WikidataP18EditListener,
-    LocationUpdateListener {
-
-    private boolean isNearbyLocked;
-    private LatLng currentLatLng;
-
-    private boolean placesLoadedOnce;
-
-    BookmarkLocationsDao bookmarkLocationDao;
-
-    private @Nullable String customQuery;
-
-    private static final NearbyParentFragmentContract.View DUMMY = (NearbyParentFragmentContract.View) Proxy.newProxyInstance(
-        NearbyParentFragmentContract.View.class.getClassLoader(),
-        new Class[]{NearbyParentFragmentContract.View.class}, (proxy, method, args) -> {
-            if (method.getName().equals("onMyEvent")) {
-                return null;
-            } else if (String.class == method.getReturnType()) {
-                return "";
-            } else if (Integer.class == method.getReturnType()) {
-                return Integer.valueOf(0);
-            } else if (int.class == method.getReturnType()) {
-                return 0;
-            } else if (Boolean.class == method.getReturnType()) {
-                return Boolean.FALSE;
-            } else if (boolean.class == method.getReturnType()) {
-                return false;
-            } else {
-                return null;
-            }
-        }
-    );
-    private NearbyParentFragmentContract.View nearbyParentFragmentView = DUMMY;
-
-
-    public NearbyParentFragmentPresenter(BookmarkLocationsDao bookmarkLocationDao) {
-        this.bookmarkLocationDao = bookmarkLocationDao;
-    }
-
-    @Override
-    public void attachView(NearbyParentFragmentContract.View view) {
-        this.nearbyParentFragmentView = view;
-    }
-
-    @Override
-    public void detachView() {
-        this.nearbyParentFragmentView = DUMMY;
-    }
-
-    @Override
-    public void removeNearbyPreferences(JsonKvStore applicationKvStore) {
-        Timber.d("Remove place objects");
-        applicationKvStore.remove(PLACE_OBJECT);
-    }
-
-    public void initializeMapOperations() {
-        lockUnlockNearby(false);
-        updateMapAndList(LOCATION_SIGNIFICANTLY_CHANGED);
-        nearbyParentFragmentView.setCheckBoxAction();
-    }
-
-    /**
-     * Sets click listeners of FABs, and 2 bottom sheets
-     */
-    @Override
-    public void setActionListeners(JsonKvStore applicationKvStore) {
-        nearbyParentFragmentView.setFABPlusAction(v -> {
-            if (applicationKvStore.getBoolean("login_skipped", false)) {
-                // prompt the user to login
-                nearbyParentFragmentView.displayLoginSkippedWarning();
-            } else {
-                nearbyParentFragmentView.animateFABs();
-            }
-        });
-
-        nearbyParentFragmentView.setFABRecenterAction(v -> {
-            nearbyParentFragmentView.recenterMap(currentLatLng);
-        });
-
-    }
-
-    @Override
-    public boolean backButtonClicked() {
-        if (nearbyParentFragmentView.isAdvancedQueryFragmentVisible()) {
-            nearbyParentFragmentView.showHideAdvancedQueryFragment(false);
-            return true;
-        } else if (nearbyParentFragmentView.isListBottomSheetExpanded()) {
-            // Back should first hide the bottom sheet if it is expanded
-            nearbyParentFragmentView.listOptionMenuItemClicked();
-            return true;
-        } else if (nearbyParentFragmentView.isDetailsBottomSheetVisible()) {
-            nearbyParentFragmentView.setBottomSheetDetailsSmaller();
-            return true;
-        }
-        return false;
-    }
-
-    public void markerUnselected() {
-        nearbyParentFragmentView.hideBottomSheet();
-    }
-
-    /**
-     * Nearby updates takes time, since they are network operations. During update time, we don't
-     * want to get any other calls from user. So locking nearby.
-     *
-     * @param isNearbyLocked true means lock, false means unlock
-     */
-    @Override
-    public void lockUnlockNearby(boolean isNearbyLocked) {
-        this.isNearbyLocked = isNearbyLocked;
-        if (isNearbyLocked) {
-            nearbyParentFragmentView.disableFABRecenter();
-        } else {
-            nearbyParentFragmentView.enableFABRecenter();
-        }
-    }
-
-    /**
-     * This method should be the single point to update Map and List. Triggered by location changes
-     *
-     * @param locationChangeType defines if location changed significantly or slightly
-     */
-    @Override
-    public void updateMapAndList(LocationChangeType locationChangeType) {
-        Timber.d("Presenter updates map and list");
-        if (isNearbyLocked) {
-            Timber.d("Nearby is locked, so updateMapAndList returns");
-            return;
-        }
-
-        if (!nearbyParentFragmentView.isNetworkConnectionEstablished()) {
-            Timber.d("Network connection is not established");
-            return;
-        }
-
-        LatLng lastLocation = nearbyParentFragmentView.getLastMapFocus();
-        if (nearbyParentFragmentView.getMapCenter() != null) {
-            currentLatLng = nearbyParentFragmentView.getMapCenter();
-        } else {
-            currentLatLng = lastLocation;
-        }
-        if (currentLatLng == null) {
-            Timber.d("Skipping update of nearby places as location is unavailable");
-            return;
-        }
-
-        /**
-         * Significant changed - Markers and current location will be updated together
-         * Slightly changed - Only current position marker will be updated
-         */
-        if (locationChangeType.equals(CUSTOM_QUERY)) {
-            Timber.d("ADVANCED_QUERY_SEARCH");
-            lockUnlockNearby(true);
-            nearbyParentFragmentView.setProgressBarVisibility(true);
-            LatLng updatedLocationByUser = LocationUtils.deriveUpdatedLocationFromSearchQuery(
-                customQuery);
-            if (updatedLocationByUser == null) {
-                updatedLocationByUser = lastLocation;
-            }
-            nearbyParentFragmentView.populatePlaces(updatedLocationByUser, customQuery);
-        } else if (locationChangeType.equals(LOCATION_SIGNIFICANTLY_CHANGED)
-            || locationChangeType.equals(MAP_UPDATED)) {
-            lockUnlockNearby(true);
-            nearbyParentFragmentView.setProgressBarVisibility(true);
-            nearbyParentFragmentView.populatePlaces(nearbyParentFragmentView.getMapCenter());
-        } else if (locationChangeType.equals(SEARCH_CUSTOM_AREA)) {
-            Timber.d("SEARCH_CUSTOM_AREA");
-            lockUnlockNearby(true);
-            nearbyParentFragmentView.setProgressBarVisibility(true);
-            nearbyParentFragmentView.populatePlaces(nearbyParentFragmentView.getMapFocus());
-        } else { // Means location changed slightly, ie user is walking or driving.
-            Timber.d("Means location changed slightly");
-        }
-    }
-
-    /**
-     * Populates places for custom location, should be used for finding nearby places around a
-     * location where you are not at.
-     *
-     * @param nearbyPlaces This variable has placeToCenter list information and distances.
-     */
-    public void updateMapMarkers(List<Place> nearbyPlaces, LatLng currentLatLng,
-        boolean shouldTrackPosition) {
-        if (null != nearbyParentFragmentView) {
-            nearbyParentFragmentView.clearAllMarkers();
-            List<BaseMarker> baseMarkers = NearbyController
-                .loadAttractionsFromLocationToBaseMarkerOptions(currentLatLng,
-                    // Curlatlang will be used to calculate distances
-                    nearbyPlaces);
-            nearbyParentFragmentView.updateMapMarkers(baseMarkers);
-            lockUnlockNearby(false); // So that new location updates wont come
-            nearbyParentFragmentView.setProgressBarVisibility(false);
-            nearbyParentFragmentView.updateListFragment(nearbyPlaces);
-        }
-    }
-
-    /**
-     * Some centering task may need to wait for map to be ready, if they are requested before map is
-     * ready. So we will remember it when the map is ready
-     */
-    private void handleCenteringTaskIfAny() {
-        if (!placesLoadedOnce) {
-            placesLoadedOnce = true;
-            nearbyParentFragmentView.centerMapToPlace(null);
-        }
-    }
-
-    @Override
-    public void onWikidataEditSuccessful() {
-        updateMapAndList(MAP_UPDATED);
-    }
-
-    @Override
-    public void onLocationChangedSignificantly(LatLng latLng) {
-        Timber.d("Location significantly changed");
-        updateMapAndList(LOCATION_SIGNIFICANTLY_CHANGED);
-    }
-
-    @Override
-    public void onLocationChangedSlightly(LatLng latLng) {
-        Timber.d("Location significantly changed");
-        updateMapAndList(LOCATION_SLIGHTLY_CHANGED);
-    }
-
-    @Override
-    public void onLocationChangedMedium(LatLng latLng) {
-        Timber.d("Location changed medium");
-    }
-
-    @Override
-    public void filterByMarkerType(List<Label> selectedLabels, int state,
-        boolean filterForPlaceState, boolean filterForAllNoneType) {
-        if (filterForAllNoneType) {// Means we will set labels based on states
-            switch (state) {
-                case UNKNOWN:
-                    // Do nothing
-                    break;
-                case UNCHECKED:
-                    //TODO
-                    nearbyParentFragmentView.filterOutAllMarkers();
-                    nearbyParentFragmentView.setRecyclerViewAdapterItemsGreyedOut();
-                    break;
-                case CHECKED:
-                    // Despite showing all labels NearbyFilterState still should be applied
-                    nearbyParentFragmentView.filterMarkersByLabels(selectedLabels,
-                        filterForPlaceState, false);
-                    nearbyParentFragmentView.setRecyclerViewAdapterAllSelected();
-                    break;
-            }
-        } else {
-            nearbyParentFragmentView.filterMarkersByLabels(selectedLabels,
-                filterForPlaceState, false);
-        }
-    }
-
-    @Override
-    @MainThread
-    public void updateMapMarkersToController(List<BaseMarker> baseMarkers) {
-        NearbyController.markerLabelList.clear();
-        for (int i = 0; i < baseMarkers.size(); i++) {
-            BaseMarker nearbyBaseMarker = baseMarkers.get(i);
-            NearbyController.markerLabelList.add(
-                new MarkerPlaceGroup(
-                    bookmarkLocationDao.findBookmarkLocation(nearbyBaseMarker.getPlace()),
-                    nearbyBaseMarker.getPlace()));
-        }
-    }
-
-    @Override
-    public void setCheckboxUnknown() {
-        nearbyParentFragmentView.setCheckBoxState(CheckBoxTriStates.UNKNOWN);
-    }
-
-    @Override
-    public void setAdvancedQuery(String query) {
-        this.customQuery = query;
-    }
-
-    @Override
-    public void searchViewGainedFocus() {
-        if (nearbyParentFragmentView.isListBottomSheetExpanded()) {
-            // Back should first hide the bottom sheet if it is expanded
-            nearbyParentFragmentView.hideBottomSheet();
-        } else if (nearbyParentFragmentView.isDetailsBottomSheetVisible()) {
-            nearbyParentFragmentView.hideBottomDetailsSheet();
-        }
-    }
-
-    /**
-     * Initiates a search for places within the area. Depending on whether the search
-     * is close to the current location, the map and list are updated
-     * accordingly.
-     */
-    public void searchInTheArea(){
-        if (searchCloseToCurrentLocation()) {
-            updateMapAndList(LOCATION_SIGNIFICANTLY_CHANGED);
-        } else {
-            updateMapAndList(SEARCH_CUSTOM_AREA);
-        }
-    }
-
-    /**
-     * Returns true if search this area button is used around our current location, so that we can
-     * continue following our current location again
-     *
-     * @return Returns true if search this area button is used around our current location
-     */
-    public boolean searchCloseToCurrentLocation() {
-        if (null == nearbyParentFragmentView.getLastMapFocus()) {
-            return true;
-        }
-        //TODO
-        Location mylocation = new Location("");
-        Location dest_location = new Location("");
-        dest_location.setLatitude(nearbyParentFragmentView.getMapFocus().getLatitude());
-        dest_location.setLongitude(nearbyParentFragmentView.getMapFocus().getLongitude());
-        mylocation.setLatitude(nearbyParentFragmentView.getLastMapFocus().getLatitude());
-        mylocation.setLongitude(nearbyParentFragmentView.getLastMapFocus().getLongitude());
-        Float distance = mylocation.distanceTo(dest_location);
-
-        if (distance > 2000.0 * 3 / 4) {
-            return false;
-        } else {
-            return true;
-        }
-    }
-
-    public void onMapReady() {
-        if (null != nearbyParentFragmentView) {
-            initializeMapOperations();
-        }
-    }
-}

app/src/main/java/fr/free/nrw/commons/nearby/presenter/NearbyParentFragmentPresenter.kt

@@ -0,0 +1,597 @@
+package fr.free.nrw.commons.nearby.presenter
+
+import android.location.Location
+import android.view.View
+import androidx.annotation.MainThread
+import androidx.lifecycle.LifecycleCoroutineScope
+import fr.free.nrw.commons.BaseMarker
+import fr.free.nrw.commons.bookmarks.locations.BookmarkLocationsDao
+import fr.free.nrw.commons.kvstore.JsonKvStore
+import fr.free.nrw.commons.location.LatLng
+import fr.free.nrw.commons.location.LocationServiceManager.LocationChangeType
+import fr.free.nrw.commons.location.LocationUpdateListener
+import fr.free.nrw.commons.nearby.CheckBoxTriStates
+import fr.free.nrw.commons.nearby.Label
+import fr.free.nrw.commons.nearby.MarkerPlaceGroup
+import fr.free.nrw.commons.nearby.NearbyController
+import fr.free.nrw.commons.nearby.Place
+import fr.free.nrw.commons.nearby.PlacesRepository
+import fr.free.nrw.commons.nearby.contract.NearbyParentFragmentContract
+import fr.free.nrw.commons.utils.LocationUtils
+import fr.free.nrw.commons.wikidata.WikidataConstants.PLACE_OBJECT
+import fr.free.nrw.commons.wikidata.WikidataEditListener.WikidataP18EditListener
+import io.reactivex.schedulers.Schedulers
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.ensureActive
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import timber.log.Timber
+import java.lang.reflect.InvocationHandler
+import java.lang.reflect.Method
+import java.lang.reflect.Proxy
+import java.util.concurrent.CopyOnWriteArrayList
+
+class NearbyParentFragmentPresenter
+    (
+    val bookmarkLocationDao: BookmarkLocationsDao,
+    val placesRepository: PlacesRepository,
+    val nearbyController: NearbyController
+) :
+    NearbyParentFragmentContract.UserActions,
+    WikidataP18EditListener, LocationUpdateListener {
+
+    private var isNearbyLocked = false
+    private var currentLatLng: LatLng? = null
+
+    private var placesLoadedOnce = false
+
+    private var customQuery: String? = null
+
+    private var nearbyParentFragmentView: NearbyParentFragmentContract.View = DUMMY
+
+    private val clickedPlaces = CopyOnWriteArrayList<Place>()
+
+    /**
+     * used to tell the asynchronous place detail loading job that a pin was clicked
+     * so as to prevent it from turning grey on the next pin detail update
+     *
+     * @param place the place whose details have already been loaded because clicked pin
+     */
+    fun handlePinClicked(place: Place) {
+        clickedPlaces.add(place)
+    }
+
+    // the currently running job for async loading of pin details, cancelled when new pins are come
+    private var loadPlacesDataAyncJob: Job? = null
+
+    /**
+     * - **batchSize**: number of places to fetch details of in a single request
+     * - **connnectionCount**: number of parallel requests
+     */
+    private object LoadPlacesAsyncOptions {
+        const val BATCH_SIZE = 3
+        const val CONNECTION_COUNT = 3
+    }
+
+    private var schedulePlacesUpdateJob: Job? = null
+
+    /**
+     * - **skippedCount**: stores the number of updates skipped
+     * - **skipLimit**: maximum number of consecutive updates that can be skipped
+     * - **skipDelayMs**: The delay (in milliseconds) to wait for a new update.
+     *
+     * @see schedulePlacesUpdate
+     */
+    private object SchedulePlacesUpdateOptions {
+        var skippedCount = 0
+        const val SKIP_LIMIT = 3
+        const val SKIP_DELAY_MS = 500L
+    }
+
+    // used to tell the asynchronous place detail loading job that the places' bookmarked status
+    // changed so as to prevent inconsistencies
+    private var bookmarkChangedPlaces = CopyOnWriteArrayList<Place>()
+
+    /**
+     * Schedules a UI update for the provided list of `MarkerPlaceGroup` objects. Since, the update
+     * is performed on the main thread, it waits for a `SchedulePlacesUpdateOptions.skipDelayMs`
+     * to see if a new update comes, and if one does, it discards the scheduled UI update.
+     *
+     * @param markerPlaceGroups The new list of `MarkerPlaceGroup` objects. If the list is empty, no
+     *                          update will be performed.
+     *
+     * @see SchedulePlacesUpdateOptions
+     */
+    private suspend fun schedulePlacesUpdate(markerPlaceGroups: List<MarkerPlaceGroup>) =
+        withContext(Dispatchers.Main) {
+            if (markerPlaceGroups.isEmpty()) return@withContext
+            schedulePlacesUpdateJob?.cancel()
+            schedulePlacesUpdateJob = launch {
+                if (SchedulePlacesUpdateOptions.skippedCount++
+                    < SchedulePlacesUpdateOptions.SKIP_LIMIT
+                ) {
+                    delay(SchedulePlacesUpdateOptions.SKIP_DELAY_MS)
+                }
+                SchedulePlacesUpdateOptions.skippedCount = 0
+                updatePlaceGroupsToControllerAndRender(markerPlaceGroups)
+            }
+        }
+
+    /**
+     * Handles the user action of toggling the bookmarked status of a given place. Updates the
+     * bookmark status in the database, updates the UI to reflect the new state.
+     *
+     * @param place The place whose bookmarked status is to be toggled. If the place is `null`,
+     *              the operation is skipped.
+     */
+    override fun toggleBookmarkedStatus(place: Place?) {
+        if (place == null) return
+        val nowBookmarked = bookmarkLocationDao.updateBookmarkLocation(place)
+        bookmarkChangedPlaces.add(place)
+        val placeIndex =
+            NearbyController.markerLabelList.indexOfFirst { it.place.location == place.location }
+        NearbyController.markerLabelList[placeIndex] = MarkerPlaceGroup(
+            nowBookmarked,
+            NearbyController.markerLabelList[placeIndex].place
+        )
+        nearbyParentFragmentView.setFilterState()
+    }
+
+    override fun attachView(view: NearbyParentFragmentContract.View) {
+        this.nearbyParentFragmentView = view
+    }
+
+    override fun detachView() {
+        this.nearbyParentFragmentView = DUMMY
+    }
+
+    override fun removeNearbyPreferences(applicationKvStore: JsonKvStore) {
+        Timber.d("Remove place objects")
+        applicationKvStore.remove(PLACE_OBJECT)
+    }
+
+    fun initializeMapOperations() {
+        lockUnlockNearby(false)
+        updateMapAndList(LocationChangeType.LOCATION_SIGNIFICANTLY_CHANGED)
+        nearbyParentFragmentView.setCheckBoxAction()
+    }
+
+    /**
+     * Sets click listeners of FABs, and 2 bottom sheets
+     */
+    override fun setActionListeners(applicationKvStore: JsonKvStore?) {
+        nearbyParentFragmentView.setFABPlusAction(View.OnClickListener { v: View? ->
+            if (applicationKvStore != null && applicationKvStore.getBoolean(
+                    "login_skipped", false
+                )
+            ) {
+                // prompt the user to login
+                nearbyParentFragmentView.displayLoginSkippedWarning()
+            } else {
+                nearbyParentFragmentView.animateFABs()
+            }
+        })
+
+        nearbyParentFragmentView.setFABRecenterAction(View.OnClickListener { v: View? ->
+            nearbyParentFragmentView.recenterMap(currentLatLng)
+        })
+    }
+
+    override fun backButtonClicked(): Boolean {
+        if (nearbyParentFragmentView.isAdvancedQueryFragmentVisible()) {
+            nearbyParentFragmentView.showHideAdvancedQueryFragment(false)
+            return true
+        } else if (nearbyParentFragmentView.isListBottomSheetExpanded()) {
+            // Back should first hide the bottom sheet if it is expanded
+            nearbyParentFragmentView.listOptionMenuItemClicked()
+            return true
+        } else if (nearbyParentFragmentView.isDetailsBottomSheetVisible()) {
+            nearbyParentFragmentView.setBottomSheetDetailsSmaller()
+            return true
+        }
+        return false
+    }
+
+    fun markerUnselected() {
+        nearbyParentFragmentView.hideBottomSheet()
+    }
+
+    /**
+     * Nearby updates takes time, since they are network operations. During update time, we don't
+     * want to get any other calls from user. So locking nearby.
+     *
+     * @param isNearbyLocked true means lock, false means unlock
+     */
+    override fun lockUnlockNearby(isNearbyLocked: Boolean) {
+        this.isNearbyLocked = isNearbyLocked
+        if (isNearbyLocked) {
+            nearbyParentFragmentView.disableFABRecenter()
+        } else {
+            nearbyParentFragmentView.enableFABRecenter()
+        }
+    }
+
+    /**
+     * This method should be the single point to update Map and List. Triggered by location changes
+     *
+     * @param locationChangeType defines if location changed significantly or slightly
+     */
+    override fun updateMapAndList(locationChangeType: LocationChangeType?) {
+        Timber.d("Presenter updates map and list")
+        if (isNearbyLocked) {
+            Timber.d("Nearby is locked, so updateMapAndList returns")
+            return
+        }
+
+        if (!nearbyParentFragmentView.isNetworkConnectionEstablished()) {
+            Timber.d("Network connection is not established")
+            return
+        }
+
+        val lastLocation = nearbyParentFragmentView.getLastMapFocus()
+        currentLatLng = if (nearbyParentFragmentView.getMapCenter() != null) {
+            nearbyParentFragmentView.getMapCenter()
+        } else {
+            lastLocation
+        }
+        if (currentLatLng == null) {
+            Timber.d("Skipping update of nearby places as location is unavailable")
+            return
+        }
+
+        /**
+         * Significant changed - Markers and current location will be updated together
+         * Slightly changed - Only current position marker will be updated
+         */
+        if (locationChangeType == LocationChangeType.CUSTOM_QUERY) {
+            Timber.d("ADVANCED_QUERY_SEARCH")
+            lockUnlockNearby(true)
+            nearbyParentFragmentView.setProgressBarVisibility(true)
+            var updatedLocationByUser = LocationUtils.deriveUpdatedLocationFromSearchQuery(
+                customQuery!!
+            )
+            if (updatedLocationByUser == null) {
+                updatedLocationByUser = lastLocation
+            }
+            nearbyParentFragmentView.populatePlaces(updatedLocationByUser, customQuery)
+        } else if (locationChangeType == LocationChangeType.LOCATION_SIGNIFICANTLY_CHANGED
+            || locationChangeType == LocationChangeType.MAP_UPDATED
+        ) {
+            lockUnlockNearby(true)
+            nearbyParentFragmentView.setProgressBarVisibility(true)
+            nearbyParentFragmentView.populatePlaces(nearbyParentFragmentView.getMapCenter())
+        } else if (locationChangeType == LocationChangeType.SEARCH_CUSTOM_AREA) {
+            Timber.d("SEARCH_CUSTOM_AREA")
+            lockUnlockNearby(true)
+            nearbyParentFragmentView.setProgressBarVisibility(true)
+            nearbyParentFragmentView.populatePlaces(nearbyParentFragmentView.getMapFocus())
+        } else { // Means location changed slightly, ie user is walking or driving.
+            Timber.d("Means location changed slightly")
+        }
+    }
+
+    /**
+     * Update places on the map, and asynchronously load their details from cache and Wikidata query
+     *
+     * @param nearbyPlaces This variable has the list of placecs
+     * @param scope the lifecycle scope of `nearbyParentFragment`'s `viewLifecycleOwner`
+     */
+    fun updateMapMarkers(
+        nearbyPlaces: List<Place>?, currentLatLng: LatLng,
+        scope: LifecycleCoroutineScope?
+    ) {
+        val nearbyPlaceGroups = nearbyPlaces?.sortedBy { it.getDistanceInDouble(currentLatLng) }
+                ?.take(NearbyController.MAX_RESULTS)
+                ?.map {
+                    // currently only the place's location is known but bookmarks are stored by name
+                    MarkerPlaceGroup(
+                        false,
+                        it
+                    )
+                }
+                ?: return
+
+        loadPlacesDataAyncJob?.cancel()
+        lockUnlockNearby(false) // So that new location updates wont come
+        nearbyParentFragmentView.setProgressBarVisibility(false)
+
+        updatePlaceGroupsToControllerAndRender(nearbyPlaceGroups)
+
+        loadPlacesDataAyncJob = scope?.launch(Dispatchers.IO) {
+            // clear past clicks and bookmarkChanged queues
+            clickedPlaces.clear()
+            bookmarkChangedPlaces.clear()
+            var clickedPlacesIndex = 0
+            var bookmarkChangedPlacesIndex = 0
+
+            val updatedGroups = nearbyPlaceGroups.toMutableList()
+            // first load cached places:
+            val indicesToUpdate = mutableListOf<Int>()
+            for (i in 0..updatedGroups.lastIndex) {
+                val repoPlace = placesRepository.fetchPlace(updatedGroups[i].place.entityID)
+                if (repoPlace != null && repoPlace.name != ""){
+                    updatedGroups[i] = MarkerPlaceGroup(
+                        bookmarkLocationDao.findBookmarkLocation(repoPlace),
+                        repoPlace
+                    )
+                } else {
+                    indicesToUpdate.add(i)
+                }
+            }
+            if (indicesToUpdate.size < updatedGroups.size) {
+                schedulePlacesUpdate(updatedGroups)
+            }
+            // channel for lists of indices of places, each list to be fetched in a single request
+            val fetchPlacesChannel = Channel<List<Int>>(Channel.UNLIMITED)
+            var totalBatches = 0
+            for (i in indicesToUpdate.indices step LoadPlacesAsyncOptions.BATCH_SIZE) {
+                ++totalBatches
+                fetchPlacesChannel.send(
+                    indicesToUpdate.slice(
+                        i until (i + LoadPlacesAsyncOptions.BATCH_SIZE).coerceAtMost(
+                            indicesToUpdate.size
+                        )
+                    )
+                )
+            }
+            fetchPlacesChannel.close()
+            val collectResults = Channel<List<Pair<Int, MarkerPlaceGroup>>>(totalBatches)
+            repeat(LoadPlacesAsyncOptions.CONNECTION_COUNT) {
+                launch(Dispatchers.IO) {
+                    for (indices in fetchPlacesChannel) {
+                        ensureActive()
+                        try {
+                            val fetchedPlaces =
+                                nearbyController.getPlaces(indices.map { updatedGroups[it].place })
+                            collectResults.send(
+                                fetchedPlaces.mapIndexed { index, place ->
+                                    Pair(indices[index], MarkerPlaceGroup(
+                                        bookmarkLocationDao.findBookmarkLocation(place),
+                                        place
+                                    ))
+                                }
+                            )
+                        } catch (e: Exception) {
+                            Timber.tag("NearbyPinDetails").e(e)
+                            collectResults.send(indices.map { Pair(it, updatedGroups[it]) })
+                        }
+                    }
+                }
+            }
+            var collectCount = 0
+            for (resultList in collectResults) {
+                for ((index, fetchedPlaceGroup) in resultList) {
+                    val existingPlace = updatedGroups[index].place
+                    val finalPlaceGroup = MarkerPlaceGroup(
+                        fetchedPlaceGroup.isBookmarked,
+                        fetchedPlaceGroup.place.apply {
+                            location = existingPlace.location
+                            distance = existingPlace.distance
+                            isMonument = existingPlace.isMonument
+                        }
+                    )
+                    updatedGroups[index] = finalPlaceGroup
+                    placesRepository
+                        .save(finalPlaceGroup.place)
+                        .subscribeOn(Schedulers.io())
+                        .subscribe()
+                }
+                // handle any places clicked
+                if (clickedPlacesIndex < clickedPlaces.size) {
+                    val clickedPlacesBacklog = hashMapOf<LatLng, Place>()
+                    while (clickedPlacesIndex < clickedPlaces.size) {
+                        clickedPlacesBacklog.put(
+                            clickedPlaces[clickedPlacesIndex].location,
+                            clickedPlaces[clickedPlacesIndex]
+                        )
+                        ++clickedPlacesIndex
+                    }
+                    for ((index, group) in updatedGroups.withIndex()) {
+                        if (clickedPlacesBacklog.containsKey(group.place.location)) {
+                            updatedGroups[index] = MarkerPlaceGroup(
+                                updatedGroups[index].isBookmarked,
+                                clickedPlacesBacklog[group.place.location]
+                            )
+                        }
+                    }
+                }
+                // handle any bookmarks toggled
+                if (bookmarkChangedPlacesIndex < bookmarkChangedPlaces.size) {
+                    val bookmarkChangedPlacesBacklog = hashMapOf<LatLng, Place>()
+                    while (bookmarkChangedPlacesIndex < bookmarkChangedPlaces.size) {
+                        bookmarkChangedPlacesBacklog.put(
+                            bookmarkChangedPlaces[bookmarkChangedPlacesIndex].location,
+                            bookmarkChangedPlaces[bookmarkChangedPlacesIndex]
+                        )
+                        ++bookmarkChangedPlacesIndex
+                    }
+                    for ((index, group) in updatedGroups.withIndex()) {
+                        if (bookmarkChangedPlacesBacklog.containsKey(group.place.location)) {
+                            updatedGroups[index] = MarkerPlaceGroup(
+                                bookmarkLocationDao
+                                    .findBookmarkLocation(updatedGroups[index].place),
+                                updatedGroups[index].place
+                            )
+                        }
+                    }
+                }
+                schedulePlacesUpdate(updatedGroups)
+                if (++collectCount == totalBatches) {
+                    break
+                }
+            }
+            collectResults.close()
+        }
+    }
+
+    /**
+     * Some centering task may need to wait for map to be ready, if they are requested before map is
+     * ready. So we will remember it when the map is ready
+     */
+    private fun handleCenteringTaskIfAny() {
+        if (!placesLoadedOnce) {
+            placesLoadedOnce = true
+            nearbyParentFragmentView.centerMapToPlace(null)
+        }
+    }
+
+    override fun onWikidataEditSuccessful() {
+        updateMapAndList(LocationChangeType.MAP_UPDATED)
+    }
+
+    override fun onLocationChangedSignificantly(latLng: LatLng) {
+        Timber.d("Location significantly changed")
+        updateMapAndList(LocationChangeType.LOCATION_SIGNIFICANTLY_CHANGED)
+    }
+
+    override fun onLocationChangedSlightly(latLng: LatLng) {
+        Timber.d("Location significantly changed")
+        updateMapAndList(LocationChangeType.LOCATION_SLIGHTLY_CHANGED)
+    }
+
+    override fun onLocationChangedMedium(latLng: LatLng) {
+        Timber.d("Location changed medium")
+    }
+
+    override fun filterByMarkerType(
+        selectedLabels: List<Label?>?, state: Int,
+        filterForPlaceState: Boolean, filterForAllNoneType: Boolean
+    ) {
+        if (filterForAllNoneType) { // Means we will set labels based on states
+            when (state) {
+                CheckBoxTriStates.UNKNOWN -> {}
+                CheckBoxTriStates.UNCHECKED -> {
+                    //TODO
+                    nearbyParentFragmentView.filterOutAllMarkers()
+                    nearbyParentFragmentView.setRecyclerViewAdapterItemsGreyedOut()
+                }
+
+                CheckBoxTriStates.CHECKED -> {
+                    // Despite showing all labels NearbyFilterState still should be applied
+                    nearbyParentFragmentView.filterMarkersByLabels(
+                        selectedLabels,
+                        filterForPlaceState, false
+                    )
+                    nearbyParentFragmentView.setRecyclerViewAdapterAllSelected()
+                }
+            }
+        } else {
+            nearbyParentFragmentView.filterMarkersByLabels(
+                selectedLabels,
+                filterForPlaceState, false
+            )
+        }
+    }
+
+    @MainThread
+    override fun updateMapMarkersToController(baseMarkers: MutableList<BaseMarker>) {
+        NearbyController.markerLabelList.clear()
+        for (i in baseMarkers.indices) {
+            val nearbyBaseMarker = baseMarkers[i]
+            NearbyController.markerLabelList.add(
+                MarkerPlaceGroup(
+                    bookmarkLocationDao.findBookmarkLocation(nearbyBaseMarker.place),
+                    nearbyBaseMarker.place
+                )
+            )
+        }
+    }
+
+    /**
+     * Sends the supplied markerPlaceGroups to `NearbyController` and nearby list fragment,
+     * and tells nearby parent fragment to filter the updated values to be rendered as overlays
+     * on the map
+     *
+     * @param markerPlaceGroups the new/updated list of places along with their bookmarked status
+     */
+    @MainThread
+    private fun updatePlaceGroupsToControllerAndRender(markerPlaceGroups: List<MarkerPlaceGroup>) {
+        NearbyController.markerLabelList.clear()
+        NearbyController.markerLabelList.addAll(markerPlaceGroups)
+        nearbyParentFragmentView.setFilterState()
+        nearbyParentFragmentView.updateListFragment(markerPlaceGroups.map { it.place })
+    }
+
+    override fun setCheckboxUnknown() {
+        nearbyParentFragmentView.setCheckBoxState(CheckBoxTriStates.UNKNOWN)
+    }
+
+    override fun setAdvancedQuery(query: String) {
+        this.customQuery = query
+    }
+
+    override fun searchViewGainedFocus() {
+        if (nearbyParentFragmentView.isListBottomSheetExpanded()) {
+            // Back should first hide the bottom sheet if it is expanded
+            nearbyParentFragmentView.hideBottomSheet()
+        } else if (nearbyParentFragmentView.isDetailsBottomSheetVisible()) {
+            nearbyParentFragmentView.hideBottomDetailsSheet()
+        }
+    }
+
+    /**
+     * Initiates a search for places within the area. Depending on whether the search
+     * is close to the current location, the map and list are updated
+     * accordingly.
+     */
+    fun searchInTheArea() {
+        if (searchCloseToCurrentLocation()) {
+            updateMapAndList(LocationChangeType.LOCATION_SIGNIFICANTLY_CHANGED)
+        } else {
+            updateMapAndList(LocationChangeType.SEARCH_CUSTOM_AREA)
+        }
+    }
+
+    /**
+     * Returns true if search this area button is used around our current location, so that we can
+     * continue following our current location again
+     *
+     * @return Returns true if search this area button is used around our current location
+     */
+    fun searchCloseToCurrentLocation(): Boolean {
+        if (null == nearbyParentFragmentView.getLastMapFocus()) {
+            return true
+        }
+        //TODO
+        val myLocation = Location("")
+        val destLocation = Location("")
+        destLocation.latitude = nearbyParentFragmentView.getMapFocus().latitude
+        destLocation.longitude = nearbyParentFragmentView.getMapFocus().longitude
+        myLocation.latitude = nearbyParentFragmentView.getLastMapFocus().latitude
+        myLocation.longitude = nearbyParentFragmentView.getLastMapFocus().longitude
+        val distance = myLocation.distanceTo(destLocation)
+
+        return (distance <= 2000.0 * 3 / 4)
+    }
+
+    fun onMapReady() {
+        initializeMapOperations()
+    }
+
+    companion object {
+        private val DUMMY = Proxy.newProxyInstance(
+            NearbyParentFragmentContract.View::class.java.getClassLoader(),
+            arrayOf<Class<*>>(NearbyParentFragmentContract.View::class.java),
+            InvocationHandler { proxy: Any?, method: Method?, args: Array<Any?>? ->
+                if (method!!.name == "onMyEvent") {
+                    return@InvocationHandler null
+                } else if (String::class.java == method.returnType) {
+                    return@InvocationHandler ""
+                } else if (Int::class.java == method.returnType) {
+                    return@InvocationHandler 0
+                } else if (Int::class.javaPrimitiveType == method.returnType) {
+                    return@InvocationHandler 0
+                } else if (Boolean::class.java == method.returnType) {
+                    return@InvocationHandler java.lang.Boolean.FALSE
+                } else if (Boolean::class.javaPrimitiveType == method.returnType) {
+                    return@InvocationHandler false
+                } else {
+                    return@InvocationHandler null
+                }
+            }
+        ) as NearbyParentFragmentContract.View
+    }
+}

app/src/test/kotlin/fr/free/nrw/commons/nearby/NearbyParentFragmentPresenterTest.kt

@@ -31,6 +31,12 @@ class NearbyParentFragmentPresenterTest {
     @Mock
     internal lateinit var bookmarkLocationsDao: BookmarkLocationsDao
 
+    @Mock
+    internal lateinit var placesRepository: PlacesRepository
+
+    @Mock
+    internal lateinit var nearbyController: NearbyController
+
     @Mock
     internal lateinit var latestLocation: LatLng
 
@@ -52,7 +58,8 @@ class NearbyParentFragmentPresenterTest {
     @Throws(Exception::class)
     fun setUp() {
         MockitoAnnotations.openMocks(this)
-        nearbyPresenter = NearbyParentFragmentPresenter(bookmarkLocationsDao)
+        nearbyPresenter =
+            NearbyParentFragmentPresenter(bookmarkLocationsDao, placesRepository, nearbyController)
         nearbyPresenter.attachView(nearbyParentFragmentView)
     }
 
@@ -322,7 +329,7 @@ class NearbyParentFragmentPresenterTest {
 
     @Test
     fun testSetActionListeners() {
-        nearbyPresenter.setActionListeners(any())
+        nearbyPresenter.setActionListeners(null)
         verify(nearbyParentFragmentView).setFABPlusAction(any())
         verify(nearbyParentFragmentView).setFABRecenterAction(any())
     }
@@ -454,11 +461,11 @@ class NearbyParentFragmentPresenterTest {
         nearbyPlacesInfo.boundaryCoordinates = arrayOf()
         nearbyPlacesInfo.currentLatLng = latestLocation
         nearbyPlacesInfo.searchLatLng = latestLocation
-        nearbyPlacesInfo.placeList = null
+        nearbyPlacesInfo.placeList = emptyList<Place>()
 
         whenever(bookmarkLocationsDao.allBookmarksLocations).thenReturn(Collections.emptyList())
-        nearbyPresenter.updateMapMarkers(nearbyPlacesInfo.placeList, latestLocation, true)
+        nearbyPresenter.updateMapMarkers(nearbyPlacesInfo.placeList, latestLocation, null)
-        Mockito.verify(nearbyParentFragmentView).updateMapMarkers(any())
+        Mockito.verify(nearbyParentFragmentView).setFilterState()
         Mockito.verify(nearbyParentFragmentView).setProgressBarVisibility(false)
         Mockito.verify(nearbyParentFragmentView).updateListFragment(nearbyPlacesInfo.placeList)
     }