/**
 * 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.
 *
 * Copyright 2012-2015 the original author or authors.
 */
package org.assertj.swing.driver;

import static org.assertj.core.util.Lists.newArrayList;
import static org.assertj.swing.timing.Pause.pause;
import static org.assertj.swing.util.TimeoutWatch.startWatchWithTimeoutOf;

import java.awt.Component;
import java.awt.Container;
import java.util.List;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.swing.JList;
import javax.swing.JPopupMenu;

import org.assertj.swing.annotation.RunsInEDT;
import org.assertj.swing.core.ComponentMatcher;
import org.assertj.swing.core.Robot;
import org.assertj.swing.core.TypeMatcher;
import org.assertj.swing.util.TimeoutWatch;

/**
 * Looks up the {@code JList} in the pop-up raised by a {@code JComboBox}, if the LAF actually uses one.
 *
 * @author Alex Ruiz
 */
final class JComboBoxDropDownListFinder {
  static final ComponentMatcher LIST_MATCHER = new TypeMatcher(JList.class);

  private final Robot robot;

  JComboBoxDropDownListFinder(Robot robot) {
    this.robot = robot;
  }

  /**
   * Finds the {@code JList} in the pop-up raised by a {@code JComboBox}, if the LAF actually uses one.
   *
   * @return the found {@code JList}, or {@code null} if a drop-down list cannot be found.
   */
  @RunsInEDT
  @Nullable
  JList<?> findDropDownList() {
    JPopupMenu popup = robot.findActivePopupMenu();
    if (popup == null) {
      TimeoutWatch watch = startWatchWithTimeoutOf(robot.settings().timeoutToFindPopup());
      popup = robot.findActivePopupMenu();
      while (popup == null) {
        if (watch.isTimeOut()) {
          return null;
        }
        pause();
        popup = robot.findActivePopupMenu();
      }
    }
    return findListIn(popup);
  }

  private @Nullable JList<?> findListIn(@Nonnull Container parent) {
    List<Component> found = newArrayList(robot.finder().findAll(parent, LIST_MATCHER));
    if (found.size() != 1) {
      return null;
    }
    return (JList<?>) found.get(0);
  }
}