/*
 * 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.captcha;

import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.markup.html.AjaxLink;
import org.apache.wicket.extensions.markup.html.captcha.CaptchaImageResource;
import org.apache.wicket.feedback.ContainerFeedbackMessageFilter;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.markup.html.form.RequiredTextField;
import org.apache.wicket.markup.html.image.Image;
import org.apache.wicket.markup.html.panel.FeedbackPanel;
import org.apache.wicket.markup.html.panel.GenericPanel;
import org.apache.wicket.model.PropertyModel;

public abstract class AbstractCaptchaForm<T> extends GenericPanel<T>
{
    private static final long serialVersionUID = 1L;

    /**
     * The generated random text;
     */
    protected String randomText;

    /**
     * The text provided by the user
     */
    private String captchaText;

    private final CaptchaImageResource captchaImageResource;

    /**
     * Constructor.
     *
     * @param id
     *          The component id
     */
    public AbstractCaptchaForm(String id)
    {
        super(id);

        Form<T> form = new Form<T>("form")
        {
            @Override
            public void onSubmit()
            {
                if (!randomText.equals(captchaText))
                {
                    error("Captcha text '" + captchaText + "' is wrong.\n" +
                            "Correct text was: " + randomText);
                }
                else
                {
                    info("Success!");
                }

                // force redrawing
                captchaImageResource.invalidate();
            }
        };
        add(form);

        final FeedbackPanel feedback = new FeedbackPanel("feedback",
                new ContainerFeedbackMessageFilter(AbstractCaptchaForm.this));
        form.add(feedback);

        captchaImageResource = createCaptchaImageResource();
        final Image captchaImage = new Image("image", captchaImageResource);
        captchaImage.setOutputMarkupId(true);
        form.add(captchaImage);

        AjaxLink<Void> changeCaptchaLink = new AjaxLink<Void>("changeLink") {
            @Override
            public void onClick(AjaxRequestTarget target)
            {
                captchaImageResource.invalidate();
                target.add(captchaImage);
            }
        };
        form.add(changeCaptchaLink);

        form.add(new RequiredTextField<String>("text",
                new PropertyModel<>(AbstractCaptchaForm.this, "captchaText"), String.class)
        {
            @Override
            protected final void onComponentTag(final ComponentTag tag)
            {
                super.onComponentTag(tag);
                // clear the field after each render
                tag.put("value", "");
            }
        });
    }

    protected abstract CaptchaImageResource createCaptchaImageResource();
}