/*
 * 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.action;

import static androidx.test.espresso.matcher.ViewMatchers.isAssignableFrom;
import static androidx.test.espresso.matcher.ViewMatchers.isDescendantOfA;
import static androidx.test.espresso.matcher.ViewMatchers.isDisplayingAtLeast;
import static androidx.test.espresso.matcher.ViewMatchers.withEffectiveVisibility;
import static org.hamcrest.Matchers.allOf;
import static org.hamcrest.Matchers.anyOf;

import android.graphics.Rect;
import android.util.Log;
import android.view.View;
import android.widget.HorizontalScrollView;
import android.widget.ListView;
import android.widget.ScrollView;
import androidx.test.espresso.PerformException;
import androidx.test.espresso.UiController;
import androidx.test.espresso.ViewAction;
import androidx.test.espresso.matcher.ViewMatchers.Visibility;
import androidx.test.espresso.util.HumanReadables;
import org.hamcrest.BaseMatcher;
import org.hamcrest.Description;
import org.hamcrest.Matcher;

/** Enables scrolling to the given view. View must be a descendant of a ScrollView or ListView. */
public final class ScrollToAction implements ViewAction {
  private static final String TAG = ScrollToAction.class.getSimpleName();

  private final int isDisplayingAtLeastThreshold;

  public ScrollToAction() {
    this(90);
  }

  public ScrollToAction(int isDisplayingAtLeastThreshold) {
    this.isDisplayingAtLeastThreshold = isDisplayingAtLeastThreshold;
  }

  @Override
  public Matcher<View> getConstraints() {
    return allOf(
        withEffectiveVisibility(Visibility.VISIBLE),
        isDescendantOfA(
            anyOf(
                isAssignableFrom(ScrollView.class),
                isAssignableFrom(HorizontalScrollView.class),
                isAssignableFrom(ListView.class),
                isAssignableFromClassName("androidx.core.widget.NestedScrollView"),
                isAssignableFromClassName("android.support.v7.widget.RecyclerView"),
                isAssignableFromClassName("androidx.recyclerview.widget.RecyclerView"))));
  }

  private static Matcher<View> isAssignableFromClassName(String className) {
    try {
      Class<? extends View> clazz = (Class<? extends View>) Class.forName(className);
      return isAssignableFrom(clazz);
    } catch (ClassNotFoundException e) {
      // ignore the exception and return an empty matcher: androidx is not on classpath.
      return new BaseMatcher<View>() {
        @Override
        public void describeTo(Description description) {
        }
        @Override
        public boolean matches(Object o) {
          return false;
        }
      };
    }
  }

  @Override
  public void perform(UiController uiController, View view) {
    if (isDisplayingAtLeast(isDisplayingAtLeastThreshold).matches(view)) {
      Log.i(TAG, "View is already displayed. Returning.");
      return;
    }
    Rect rect = new Rect();
    view.getDrawingRect(rect);
    if (!view.requestRectangleOnScreen(rect, true /* immediate */)) {
      Log.w(TAG, "Scrolling to view was requested, but none of the parents scrolled.");
    }
    uiController.loopMainThreadUntilIdle();
    if (!isDisplayingAtLeast(isDisplayingAtLeastThreshold).matches(view)) {
      throw new PerformException.Builder()
          .withActionDescription(this.getDescription())
          .withViewDescription(HumanReadables.describe(view))
          .withCause(
              new RuntimeException(
                  "Scrolling to view was attempted, but the view is not displayed"))
          .build();
    }
  }

  @Override
  public String getDescription() {
    return "scroll to";
  }
}