/**
 * 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.core;

import static org.assertj.swing.timing.Pause.pause;

import java.awt.AWTEvent;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.Toolkit;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

import org.assertj.swing.input.InputState;
import org.assertj.swing.monitor.WindowMonitor;

/**
 * Posts {@code AWTEvent}s in an AWT {@code EventQueue}.
 * 
 * @author Yvonne Wang
 */
class AWTEventPoster {
  private final Toolkit toolkit;
  private final InputState inputState;
  private final WindowMonitor windowMonitor;
  private final Settings settings;

  AWTEventPoster(@Nonnull Toolkit toolkit, @Nonnull InputState inputState, @Nonnull WindowMonitor windowMonitor,
      @Nonnull Settings settings) {
    this.toolkit = toolkit;
    this.inputState = inputState;
    this.windowMonitor = windowMonitor;
    this.settings = settings;
  }

  // Post the given event to the corresponding event queue for the given component.
  void postEvent(@Nullable Component c, @Nonnull AWTEvent event) {
    // Force an update of the input state, so that we're in synch internally. Otherwise we might post more events before
    // this one gets processed and end up using stale values for those events.
    inputState.update(event);
    EventQueue eventQueue = eventQueueFor(c);
    if (eventQueue != null) {
      eventQueue.postEvent(event);
    }
    pause(settings.delayBetweenEvents());
  }

  /* Usually only needed when dealing with Applets. */
  private @Nullable EventQueue eventQueueFor(@Nullable Component c) {
    return c != null ? windowMonitor.eventQueueFor(c) : toolkit.getSystemEventQueue();
  }
}