/*
 * 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.form;

import org.apache.wicket.Component;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.attributes.AjaxRequestAttributes;
import org.apache.wicket.ajax.attributes.ThrottlingSettings;
import org.apache.wicket.behavior.Behavior;
import org.apache.wicket.feedback.IFeedback;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.markup.html.form.FormComponent;
import org.apache.wicket.util.io.IClusterable;
import java.time.Duration;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;

/**
 * Ajax event behavior that submits the form and updates all form feedback panels on the page.
 * Useful for providing instant feedback.
 *
 * Can be bound either to a {@link Form form} or to a component inside a form.
 * 
 * @since 1.2
 * 
 * @author Igor Vaynberg (ivaynberg)
 * @see #onSubmit(org.apache.wicket.ajax.AjaxRequestTarget)
 * @see #onAfterSubmit(org.apache.wicket.ajax.AjaxRequestTarget)
 * @see #onError(org.apache.wicket.ajax.AjaxRequestTarget)
 */
public class AjaxFormValidatingBehavior extends Behavior
{
        private static final long serialVersionUID = 1L;

        private final String event;
        private final Duration throttleDelay;

        /**
         * The form that will be submitted via ajax
         */
        private Form<?> form;

        /**
         * A flag indicating whether this behavior has been rendered at least once
         */
        private boolean hasBeenRendered = false;

        /**
         * Construct.
         * 
         * @param event
         *            javascript event this behavior will be invoked on, like onclick
         */
        public AjaxFormValidatingBehavior(String event)
        {
                this(event, null);
        }

        /**
         * Construct.
         *
         * @param event
         *            javascript event this behavior will be invoked on, like onclick
         * @param throttleDelay
         *            the duration for which the Ajax call should be throttled
         */
        public AjaxFormValidatingBehavior(String event, Duration throttleDelay)
        {
                this.event = event;
                this.throttleDelay = throttleDelay;
        }

        @Override
        public void bind(Component component)
        {
                super.bind(component);

                if (component instanceof Form<?>)
                {
                        form = (Form<?>) component;
                }
                else
                {
                        form = Form.findForm(component);
                        if (form == null)
                        {
                                throw new WicketRuntimeException(AjaxFormValidatingBehavior.class.getSimpleName() +
                                                " should be bound to a Form component or a component that is inside a form!");
                        }
                }
        }

        @Override
        public void onConfigure(Component component)
        {
                super.onConfigure(component);

                if (hasBeenRendered == false)
                {
                        hasBeenRendered = true;

                        form.visitChildren(FormComponent.class, new FormValidateVisitor());
                }
        }

        protected void onSubmit(final AjaxRequestTarget target)
        {
                addFeedbackPanels(target);
        }

        protected void onAfterSubmit(final AjaxRequestTarget target)
        {
        }

        protected void onError(AjaxRequestTarget target)
        {
                addFeedbackPanels(target);
        }

        /**
         * Adds all feedback panels on the page to the ajax request target so they are updated
         * 
         * @param target
         */
        protected final void addFeedbackPanels(final AjaxRequestTarget target)
        {
                form.getPage().visitChildren(IFeedback.class, new IVisitor<Component, Void>()
                {
                        @Override
                        public void component(final Component component, final IVisit<Void> visit)
                        {
                                component.configure(); // feedback component might change its visibility
                                if (component.isVisibleInHierarchy())
                                {
                                        target.add(component);
                                }
                                else
                                {
                                        visit.dontGoDeeper();
                                }
                        }
                });
        }

        protected void updateAjaxAttributes(final AjaxRequestAttributes attributes)
        {
        }

        private class FormValidateVisitor implements IVisitor<FormComponent, Void>, IClusterable
        {
                private static final long serialVersionUID = 1L;

                @Override
                public void component(final FormComponent component, final IVisit<Void> visit)
                {
                        final AjaxFormSubmitBehavior behavior = new AjaxFormSubmitBehavior(form, event)
                        {
                                @Override
                                protected void updateAjaxAttributes(final AjaxRequestAttributes attributes)
                                {
                                        super.updateAjaxAttributes(attributes);

                                        if (throttleDelay != null)
                                        {
                                                String id = "throttle-" + component.getMarkupId();
                                                ThrottlingSettings throttlingSettings = new ThrottlingSettings(id,
                                                        throttleDelay);
                                                attributes.setThrottlingSettings(throttlingSettings);
                                        }

                                        AjaxFormValidatingBehavior.this.updateAjaxAttributes(attributes);
                                }

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

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

                                @Override
                                protected void onError(AjaxRequestTarget target)
                                {
                                        super.onError(target);
                                        AjaxFormValidatingBehavior.this.onError(target);
                                }
                        };
                        component.add(behavior);
                        visit.dontGoDeeper();
                }
        }
}