/*
 * 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.stateless;

import java.util.Arrays;
import java.util.Optional;

import org.apache.wicket.Component;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.form.AjaxFormComponentUpdatingBehavior;
import org.apache.wicket.ajax.markup.html.AjaxFallbackLink;
import org.apache.wicket.ajax.markup.html.form.AjaxSubmitLink;
import org.apache.wicket.examples.WicketExamplePage;
import org.apache.wicket.extensions.ajax.markup.html.IndicatingAjaxButton;
import org.apache.wicket.extensions.ajax.markup.html.IndicatingAjaxFallbackLink;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.form.DropDownChoice;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.markup.html.form.StatelessForm;
import org.apache.wicket.markup.html.form.TextField;
import org.apache.wicket.markup.html.link.BookmarkablePageLink;
import org.apache.wicket.markup.html.link.Link;
import org.apache.wicket.markup.html.panel.FeedbackPanel;
import org.apache.wicket.model.AbstractReadOnlyModel;
import org.apache.wicket.model.Model;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.util.string.StringValue;


public class AjaxStatelessExample extends WicketExamplePage
{
    private static final String COUNTER_PARAM = "counter";

    /**
     * Constructor that is invoked when page is invoked without a session.
     *
     * @param parameters
     *            Page parameters
     */
    public AjaxStatelessExample(final PageParameters parameters)
    {
        super(parameters);
        setStatelessHint(true);
        
        add(new Label("message", new SessionModel()));
        add(new BookmarkablePageLink<>("indexLink", Index.class));
        
        final Label incrementLabel = new Label("incrementLabel", () -> {
            String counter = getParameter(parameters, COUNTER_PARAM);
            return counter != null ? Integer.parseInt(counter) : 0;
        });
        final Link<?> incrementLink = new AjaxFallbackLink<Void>("incrementLink")
        {
            @Override
            public void onClick(final Optional<AjaxRequestTarget> target)
            {
                Integer counter = (Integer)incrementLabel.getDefaultModelObject();
                updateParams(getPageParameters(), counter);

                target.ifPresent(ajaxTarget -> ajaxTarget.add(incrementLabel, this));
            }
            
            @Override
            protected boolean getStatelessHint()
            {
                return true;
            }
        };

        add(incrementLink);
        add(incrementLabel.setOutputMarkupId(true));

        final TextField<String> nameField = new TextField<>("name", new Model<>(""));
        final TextField<String> surnameField = new TextField<>("surname", new Model<>(""));

        final Form<String> form = new StatelessForm<String>("inputForm")
        {
            @Override
            protected void onSubmit()
            {
            }
        };
        final DropDownChoice<String> select = new DropDownChoice<>("select",
            new Model<>("2"), Arrays.asList("1", "2", "3"));
        final Label selectedValue = new Label("selectedValue", "");
        add(selectedValue.setOutputMarkupId(true));

        select.add(new AjaxFormComponentUpdatingBehavior("change")
        {
            @Override
            protected void onUpdate(final AjaxRequestTarget target)
            {
                final String value = select.getModelObject();
                selectedValue.setDefaultModelObject("Selected value: " + value);
                target.add(selectedValue);
            }
            
            @Override
            public boolean getStatelessHint(Component component)
            {
                return true;
            }
        });

        form.add(nameField.setRequired(true));
        form.add(surnameField.setRequired(true));

        final Component feedback = new FeedbackPanel("feedback");
        final Label submittedValues = new Label("submittedValues", "");

        form.add(feedback.setOutputMarkupId(true));
        form.add(submittedValues.setOutputMarkupId(true));

        form.add(new AjaxSubmitLink("submit")
        {
            @Override
            protected void onError(AjaxRequestTarget target)
            {
                super.onError(target);
                target.add(feedback);
            }

            @Override
            protected void onSubmit(AjaxRequestTarget target)
            {
                super.onSubmit(target);
                String values = "Your name is: " + nameField.getModelObject() + " " + surnameField.getModelObject();
                submittedValues.setDefaultModelObject(values);
                target.add(feedback, submittedValues);
            }
            
            @Override
            protected boolean getStatelessHint()
            {
                return true;
            }
        });

        add(form);

        add(select);


        add(new IndicatingAjaxFallbackLink<Void>("indicatingLink")
        {
            @Override
            public void onClick(final Optional<AjaxRequestTarget> target)
            {
                try
                {
                    Thread.sleep(5000); // 1000 milliseconds is one second.
                }
                catch (InterruptedException ex)
                {
                    Thread.currentThread().interrupt();
                }
            }
            
            @Override
            protected boolean getStatelessHint()
            {
                return true;
            }

        });

        StatelessForm indicatingForm = new StatelessForm("indicatingForm");

        add(indicatingForm);
        add(new IndicatingAjaxButton("indicatingButton", indicatingForm)
        {
            @Override
            protected void onSubmit(AjaxRequestTarget target)
            {
                try
                {
                    Thread.sleep(5000); // 1000 milliseconds is one second.
                }
                catch (InterruptedException ex)
                {
                    Thread.currentThread().interrupt();
                }
            }
            
            @Override
            protected boolean getStatelessHint()
            {
                return true;
            }
        });

    }

    private String getParameter(final PageParameters parameters, final String key)
    {
        final StringValue value = parameters.get(key);

        if (value.isNull() || value.isEmpty())
        {
            return null;
        }

        return value.toString();
    }

    protected final void updateParams(final PageParameters pageParameters, final int counter)
    {
        pageParameters.set(COUNTER_PARAM, Integer.toString(counter + 1));
    }
}