/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.wicket.examples.compref;

import org.apache.wicket.behavior.Behavior;
import org.apache.wicket.examples.WicketExamplePage;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.link.Link;
import org.apache.wicket.model.PropertyModel;

/**
 * Page with examples on {@link org.apache.wicket.markup.html.link.Link}.
 * 
 * @author Eelco Hillenius
 */
public class LinkPage extends WicketExamplePage
{
	/**
	 * Constructor
	 */
	public LinkPage()
	{
		// power to the annonymous classes!

		// first create a simple value holder object
		final Count count1 = new Count();

		// add a link which, when clicked, increases our counter when a link is clicked, its onClick
		// method is called
		Link<Void> link1 = new Link<Void>("link1") {
			public void onClick() {
				count1.increment();
			}
		};
		add(link1);

		// add a counter label to the link so that we can display it in the body of the link
		link1.add(new Label("label1", count1::toString));

		final Count count2 = new Count();
		// Same idea as above, but now we record a state change. Note that the URL will change
		// because of this, and pressing the back button and clicking the link again would revert to
		// the older value. The same thing could have been achieved by using setModelObject,
		// which implicitly registers a state change (of type ComponentModelChange).
		Link<Void> linkWithStateChange = new Link<Void>("linkWithStateChange") {
			@Override
			public void onClick()
			{
				count2.increment();
				addStateChange();
			}
		};
		add(linkWithStateChange);
		linkWithStateChange.add(new Label("label", new PropertyModel<>(count2, "count")));

		// we can attach Link components to any HTML tag we want. If it is an anchor (<a href...),
		// the url to this component is put in the href attribute. For other components, a onclick
		// javascript event handler is created that triggers the round trip

		// it is of course possible to - instead of the above approach - hide as much of the
		// component as possible within a class.
		class CustomLink extends Link<Void>
		{
			final Count count2;

			/**
			 * Construct.
			 * 
			 * @param id
			 */
			public CustomLink(String id)
			{
				super(id);
				count2 = new Count();
				add(new ClickCountLabel("label2", count2));
			}

			@Override
			public void onClick()
			{
				count2.increment();
			}
		}
		add(new CustomLink("link2"));

		// and if we know we are going to attach it to a <input type="button> tag, we shouldn't use
		// a label, but an AttributeModifier instead.
		class ButtonLink extends Link<Void>
		{
			final Count count3;

			/**
			 * Construct.
			 * 
			 * @param id
			 */
			public ButtonLink(String id)
			{
				super(id);
				count3 = new Count();
				add(Behavior.onAttribute("value", oldValue -> "this button is clicked " + count3.getCount() + " times"));
			}

			@Override
			public void onClick()
			{
				count3.increment();
			}
		}
		add(new ButtonLink("link3"));
	}

	/**
	 * Simple custom label that displays the link click count.
	 */
	private static class ClickCountLabel extends Label
	{
		/**
		 * Construct.
		 * 
		 * @param id
		 *            component id
		 * @param clickCount
		 *            the count object
		 */
		public ClickCountLabel(String id, final Count clickCount)
		{
			// call super with a simple lambda model that displays the
			// current number of clicks
			super(id, clickCount::toString);
		}
	}

	/**
	 * Override base method to provide an explanation
	 */
	@Override
	protected void explain()
	{
		String html = "<a href=\"#\" wicket:id=\"link1\">this link is clicked <span wicket:id=\"label1\">n</span> times</a>";
		String code = "        final Count count1 = new Count(); // simple counter object\n"
			+ "        Link link1 = new Link(\"link1\") {\n"
			+ "            public void onClick() {\n"
			+ "                count1.increment();\n"
			+ "            }\n"
			+ "        };\n"
			+ "        link1.add(new Label(\"label1\", new Model<String>() {\n"
			+ "            public Object getObject() {\n"
			+ "                return count1.toString();\n"
			+ "            }\n"
			+ "        }));\n"
			+ "        add(link1);";
		add(new ExplainPanel(html, code));

	}
}