GroupByTest

import com.codelegs.ao.clean_architecture.presentation.vault.entity.VaultFile;
import com.codelegs.ao.utils.mimetype.MimeType;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.runners.MockitoJUnitRunner;

import java.util.Comparator;
import java.util.List;

import io.reactivex.Observable;
import io.reactivex.ObservableSource;
import io.reactivex.annotations.NonNull;
import io.reactivex.functions.Consumer;
import io.reactivex.functions.Function;
import io.reactivex.observables.GroupedObservable;

@RunWith(MockitoJUnitRunner.class)
public class GroupByTest {
    @Test
    public void groupBy() {
        VaultFile f1 = new VaultFile("1", "F", new MimeType("C", 1, 1));
        f1.setName("C");
        VaultFile f2 = new VaultFile("1", "D", new MimeType("B", 1, 1));
        f2.setName("B");
        VaultFile f3 = new VaultFile("1", "F", new MimeType("Z", 1, 1));
        f3.setName("Z");
        VaultFile f4 = new VaultFile("1", "D", new MimeType("A", 1, 1));
        f4.setName("A");
        VaultFile f5 = new VaultFile("1", "F", new MimeType("T", 1, 1));
        f5.setName("T");
        VaultFile f6 = new VaultFile("1", "D", new MimeType("U", 1, 1));
        f6.setName("U");
        VaultFile f8 = new VaultFile("1", "D", new MimeType("P", 1, 1));
        f8.setName("P");
        VaultFile f9 = new VaultFile("1", "D", new MimeType("Q", 1, 1));
        f9.setName("Q");
        VaultFile f10 = new VaultFile("1", "F", new MimeType("F", 1, 1));
        f10.setName("F");
        VaultFile f11 = new VaultFile("1", "D", new MimeType("M", 1, 1));
        f11.setName("M");

        //TestObserver<VaultFile> observer = new TestObserver<>();

        Observable.fromArray(f1, f2, f3, f4, f5, f6, f8, f9, f10, f11)
                .groupBy(new Function<VaultFile, Boolean>() {
                    @Override
                    public Boolean apply(@NonNull VaultFile file) throws Exception {
                        return file.isFile();
                    }
                })
                .flatMap(new Function<GroupedObservable<Boolean, VaultFile>, ObservableSource<List<VaultFile>>>() {
                    @Override
                    public ObservableSource<List<VaultFile>> apply(@NonNull GroupedObservable<Boolean, VaultFile> booleanVaultFileGroupedObservable) throws Exception {
                        return booleanVaultFileGroupedObservable.toSortedList(new FileNameComparator()).toObservable();
                    }
                })
                .subscribe(new Consumer<List<VaultFile>>() {
                    @Override
                    public void accept(@NonNull List<VaultFile> files) throws Exception {
                        for (VaultFile file : files) {
                            System.out.println(file.getName() + " - " + file.getType());
                        }
                    }
                });
    }

    private static class FileNameComparator implements Comparator<VaultFile> {
        FileNameComparator() {
        }

        @Override
        public int compare(VaultFile o1, VaultFile o2) {
            return o1.getName().compareTo(o2.getName());
        }
    }
}