/*
 * 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.ajax.markup.html.form;

import org.apache.wicket.Component;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.attributes.AjaxRequestAttributes;
import org.apache.wicket.ajax.form.AjaxFormSubmitBehavior;
import org.apache.wicket.markup.html.form.Button;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.model.IModel;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A button that submits the form via Ajax. <br>
 * Note that an HTML type attribute of "submit" is automatically changed to "button"- Use
 * {@link AjaxFallbackButton} if you want to support non-Ajax form submits too.
 * 
 * @since 1.3
 * 
 * @author Igor Vaynberg (ivaynberg)
 */
public abstract class AjaxButton extends Button
{
        private static final long serialVersionUID = 1L;

        private static final Logger logger = LoggerFactory.getLogger(AjaxButton.class);

        private final Form<?> form;

        /**
         * Construct.
         * 
         * @param id
         */
        public AjaxButton(String id)
        {
                this(id, null, null);
        }

        /**
         * 
         * Construct.
         * 
         * @param id
         * @param model
         *            model used to set <code>value</code> markup attribute
         */
        public AjaxButton(String id, IModel<String> model)
        {
                this(id, model, null);
        }

        /**
         * 
         * Construct.
         * 
         * @param id
         * @param form
         */
        public AjaxButton(String id, Form<?> form)
        {
                this(id, null, form);
        }


        /**
         * Construct.
         * 
         * @param id
         * @param model
         *            model used to set <code>value</code> markup attribute
         * @param form
         */
        public AjaxButton(String id, IModel<String> model, final Form<?> form)
        {
                super(id, model);
                this.form = form;
        }

        @Override
        protected void onInitialize()
        {
                super.onInitialize();

                add(newAjaxFormSubmitBehavior("click"));
        }

        protected AjaxFormSubmitBehavior newAjaxFormSubmitBehavior(String event)
        {
                return new AjaxFormSubmitBehavior(form, event)
                {
                        private static final long serialVersionUID = 1L;

                        @Override
                        protected void onSubmit(AjaxRequestTarget target)
                        {
                                AjaxButton.this.onSubmit(target);
                        }

                        @Override
                        protected void onAfterSubmit(AjaxRequestTarget target)
                        {
                                AjaxButton.this.onAfterSubmit(target);
                        }

                        @Override
                        protected void onError(AjaxRequestTarget target)
                        {
                                AjaxButton.this.onError(target);
                        }

                        @Override
                        protected void updateAjaxAttributes(AjaxRequestAttributes attributes)
                        {
                                super.updateAjaxAttributes(attributes);

                                // do not allow normal form submit to happen
                                attributes.setPreventDefault(true);

                                AjaxButton.this.updateAjaxAttributes(attributes);
                        }
                        
                        @Override
                        protected boolean shouldTriggerJavaScriptSubmitEvent()
                        {
                                return AjaxButton.this.shouldTriggerJavaScriptSubmitEvent();
                        }

                        @Override
                        public boolean getDefaultProcessing()
                        {
                                return AjaxButton.this.getDefaultFormProcessing();
                        }
                        
                        @Override
                        public boolean getStatelessHint(Component component)
                        {
                                return AjaxButton.this.getStatelessHint();
                        }
                };
        }

        /**
         * Controls whether or not a JS <code>submit</code> should be triggered on the submitting form.
         * False by default.
         * 
         * @return true if <code>submit</code> should be triggered, false otherwise
         */
        protected boolean shouldTriggerJavaScriptSubmitEvent()
        {
                return false;
        }

        protected void updateAjaxAttributes(AjaxRequestAttributes attributes)
        {
        }

        /**
         * Returns the form if it was set in constructor, otherwise returns the form nearest in parent
         * hierarchy.
         * 
         * @see org.apache.wicket.markup.html.form.FormComponent#getForm()
         */
        @Override
        public Form<?> getForm()
        {
                if (form != null)
                {
                        return form;
                }
                else
                {
                        return super.getForm();
                }
        }

        /**
         * This method is never called.
         * 
         * @see #onSubmit(AjaxRequestTarget)
         */
        @Override
        public final void onSubmit()
        {
                logger.warn("unexpected invocation of #onSubmit() on {}", this);
        }

        @Override
        public final void onAfterSubmit()
        {
                logger.warn("unexpected invocation of #onAfterSubmit() on {}", this);
        }

        /**
         * This method is never called.
         * 
         * @see #onError(AjaxRequestTarget)
         */
        @Override
        public final void onError()
        {
                logger.warn("unexpected invocation of #onError() on {}", this);
        }

        /**
         * Listener method invoked on form submit with no errors, before {@link Form#onSubmit()}.
         * 
         * @param target
         */
        protected void onSubmit(AjaxRequestTarget target)
        {
        }

        /**
         * Listener method invoked on form submit with no errors, after {@link Form#onSubmit()}.
         *
         * @param target
         */
        protected void onAfterSubmit(AjaxRequestTarget target)
        {
        }

        /**
         * Listener method invoked on form submit with errors
         *
         * @param target
         */
        protected void onError(AjaxRequestTarget target)
        {
        }

        @Override
        protected boolean getStatelessHint()
        {
                return false;
        }
}