/*
 * 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.extensions.ajax.markup.html.modal;

import org.apache.wicket.Component;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.ajax.AjaxEventBehavior;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.attributes.AjaxCallListener;
import org.apache.wicket.ajax.attributes.AjaxRequestAttributes;
import org.apache.wicket.ajax.attributes.AjaxRequestAttributes.EventPropagation;
import org.apache.wicket.extensions.ajax.markup.html.modal.theme.DefaultTheme;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.markup.html.panel.Panel;

/**
 * Presents a modal dialog to the user. See {@link #open(Component, AjaxRequestTarget)} and
 * {@link #close(AjaxRequestTarget)} methods.
 * <p>
 * Note: This component does not provide any styling by itself, so you have can add a
 * {@link DefaultTheme} to this component if aren't styling these CSS classes by yourself:
 * <dl>
 * <dt>modal-dialog-overlay</dt>
 * <dd>the wrapper around the actual dialog, usually used to overlay the rest of the document</dd>
 * <dt>modal-dialog</dt>
 * <dd>the actual dialog</dd>
 * <dt>modal-dialog-content</dt>
 * <dd>any additional styling for the content of this dialog</dd>
 * </dl>
 *
 * @author Igor Vaynberg (ivaynberg)
 * @author svenmeier
 */
public class ModalDialog extends Panel
{

        private static final long serialVersionUID = 1L;

        private static final String OVERLAY_ID = "overlay";

        private static final String DIALOG_ID = "dialog";

        /**
         * The id for the content of this dialoh.
         *
         * @see #setContent(Component)
         * @see #open(Component, AjaxRequestTarget)
         */
        public static final String CONTENT_ID = "content";

        private final WebMarkupContainer overlay;

        private final WebMarkupContainer dialog;

        private boolean removeContentOnClose;

        public ModalDialog(String id)
        {
                super(id);

                setOutputMarkupId(true);

                overlay = newOverlay(OVERLAY_ID);
                overlay.setVisible(false);
                add(overlay);

                dialog = newDialog(DIALOG_ID);
                overlay.add(dialog);
        }

        /**
         * Factory method for the overlay markup around the dialog.
         *
         * @param overlayId
         *      id
         * @return overlay
         */
        protected WebMarkupContainer newOverlay(String overlayId)
        {
                return new WebMarkupContainer(overlayId);
        }

        /**
         * Factory method for the dialog markup around the content.
         *
         * @param dialogId
         *      id
         * @return overlay
         */
        protected WebMarkupContainer newDialog(String dialogId)
        {
                return new WebMarkupContainer(dialogId);
        }

        /**
         * Set a content.
         *
         * @param content
         * @see #open(AjaxRequestTarget)
         */
        public void setContent(Component content)
        {
                if (!CONTENT_ID.equals(content.getId()))
                {
                        throw new IllegalArgumentException(
                                "Content must have wicket id set to ModalDialog.CONTENT_ID");
                }

                dialog.addOrReplace(content);

                removeContentOnClose = false;
        }

        /**
         * Open the dialog with a content.
         * <p>
         * The content will be removed on close of the dialog.
         *
         * @param content
         *      the content
         * @param target
         *      an optional Ajax target
         * @return this
         * @see #setContent(Component)
         * @see #close(AjaxRequestTarget)
         */
        public ModalDialog open(Component content, AjaxRequestTarget target)
        {
                setContent(content);
                removeContentOnClose = true;

                overlay.setVisible(true);

                if (target != null)
                {
                        target.add(this);
                }

                return this;
        }

        /**
         * Open the dialog.
         *
         * @param target
         *      an optional Ajax target
         * @return this
         * @see #setContent(Component)
         */
        public ModalDialog open(AjaxRequestTarget target)
        {
                if (overlay.size() == 0)
                {
                        throw new WicketRuntimeException(
                                String.format("ModalDialog with id '%s' has no content set!", getId()));
                }

                overlay.setVisible(true);

                if (target != null)
                {
                        target.add(this);
                }

                return this;
        }

        /**
         * Is this dialog open.
         *
         * @return <code>true</code> if open
         */
        public boolean isOpen()
        {
                return overlay.isVisible();
        }

        /**
         * Close this dialog.
         * <p>
         * If opened via {@link #open(Component, AjaxRequestTarget)}, the content is removed from the
         * component tree
         *
         * @param target
         *      an optional Ajax target
         * @return this
         * @see #open(Component, AjaxRequestTarget)
         */
        public ModalDialog close(AjaxRequestTarget target)
        {
                overlay.setVisible(false);
                if (removeContentOnClose)
                {
                        dialog.removeAll();
                }

                if (target != null)
                {
                        target.add(this);
                }

                return this;
        }

        /**
         * Close this dialog on press of escape key.
         *
         * @return this
         */
        public ModalDialog closeOnEscape()
        {
                overlay.add(new CloseBehavior("keydown")
                {
                        protected CharSequence getPrecondition()
                        {
                                return "return Wicket.Event.keyCode(attrs.event) == 27";
                        }
                });
                return this;
        }

        /**
         * Close this dialog on click outside.
         *
         * @return this
         */
        public ModalDialog closeOnClick()
        {
                overlay.add(new CloseBehavior("click")
                {
                        protected CharSequence getPrecondition()
                        {
                                return String.format("return attrs.event.target.id === '%s';",
                                        overlay.getMarkupId());
                        }
                });
                return this;
        }

        /**
         * Convenience method to trap focus inside the overlay.
         *
         * @return this
         * @see TrapFocusBehavior
         */
        public ModalDialog trapFocus()
        {
                overlay.add(new TrapFocusBehavior());

                return this;
        }

        /**
         * can be overridden to change the {@link AjaxRequestAttributes} of the default
         * {@link CloseBehavior} executed on close. For example to change the Ajax Channel.
         *
         * @param attributes
         *      the {@link AjaxRequestAttributes} of the default {@link CloseBehavior}
         */
        protected void postProcessCloseBehaviorAjaxAttributes(AjaxRequestAttributes attributes)
        {
                // no op
        }

        private abstract class CloseBehavior extends AjaxEventBehavior
        {
                private CloseBehavior(String event)
                {
                        super(event);
                }

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

                        // has to stop immediately to prevent an enclosing dialog to close too
                        attributes.setEventPropagation(EventPropagation.STOP_IMMEDIATE);

                        attributes.getAjaxCallListeners().add(new AjaxCallListener()
                        {
                                @Override
                                public CharSequence getPrecondition(Component component)
                                {
                                        return CloseBehavior.this.getPrecondition();
                                }
                        });

                        postProcessCloseBehaviorAjaxAttributes(attributes);
                }

                protected CharSequence getPrecondition()
                {
                        return "";
                }

                @Override
                protected void onEvent(AjaxRequestTarget target)
                {
                        close(target);
                }
        }
}