content: /*
   * Copyright (C) 2014 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package androidx.test.espresso.base;
  
  import static androidx.test.espresso.util.TreeIterables.breadthFirstViewTraversal;
  import static androidx.test.internal.util.Checks.checkMainThread;
  import static androidx.test.internal.util.Checks.checkNotNull;
  
  import android.view.View;
  import android.widget.AdapterView;
  import androidx.test.espresso.AmbiguousViewMatcherException;
  import androidx.test.espresso.NoMatchingViewException;
  import androidx.test.espresso.ViewFinder;
  import androidx.test.espresso.matcher.ViewMatchers;
  import androidx.test.espresso.util.IterablesKt;
  import androidx.test.espresso.util.Iterators;
  import androidx.test.espresso.util.StringJoinerKt;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Locale;
  import javax.inject.Inject;
  import javax.inject.Provider;
  import org.hamcrest.Matcher;
  
  /** Implementation of {@link ViewFinder}. */
  // TODO: in the future we may want to collect stats here about the size of the view
  // hierarchy, average matcher execution time, warn when matchers take too long to execute, etc.
  public final class ViewFinderImpl implements ViewFinder {
  
    private final Matcher<View> viewMatcher;
    private final Provider<View> rootViewProvider;
  
    @Inject
    ViewFinderImpl(Matcher<View> viewMatcher, Provider<View> rootViewProvider) {
      this.viewMatcher = viewMatcher;
      this.rootViewProvider = rootViewProvider;
    }
  
    @Override
    public View getView() throws AmbiguousViewMatcherException, NoMatchingViewException {
      checkMainThread();
      checkNotNull(viewMatcher);
  
      View root = rootViewProvider.get();
      Iterator<View> matchedViewIterator =
          IterablesKt.filter(breadthFirstViewTraversal(root), viewMatcher).iterator();
      View matchedView = null;
  
      while (matchedViewIterator.hasNext()) {
        if (matchedView != null) {
          // Ambiguous!
          throw new AmbiguousViewMatcherException.Builder()
              .withViewMatcher(viewMatcher)
              .withRootView(root)
              .withView1(matchedView)
              .withView2(matchedViewIterator.next())
              .withOtherAmbiguousViews(Iterators.toArray(matchedViewIterator, View.class))
              .build();
        } else {
          matchedView = matchedViewIterator.next();
        }
      }
      if (null == matchedView) {
        List<View> adapterViews =
            IterablesKt.filterToList(
                breadthFirstViewTraversal(root), ViewMatchers.isAssignableFrom(AdapterView.class));
  
        if (adapterViews.isEmpty()) {
          throw new NoMatchingViewException.Builder()
              .withViewMatcher(viewMatcher)
              .withRootView(root)
              .build();
        }
  
        String warning =
            String.format(
                Locale.ROOT,
                "\n"
                    + "If the target view is not part of the view hierarchy, you may need to use"
                    + " Espresso.onData to load it from one of the following AdapterViews:%s",
                StringJoinerKt.joinToString(adapterViews, "\n- "));
        throw new NoMatchingViewException.Builder()
            .withViewMatcher(viewMatcher)
            .withRootView(root)
            .withAdapterViews(adapterViews)
            .withAdapterViewWarning(warning)
            .build();
      } else {
        return matchedView;
      }
    }
  }
  