/*
 * 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.core.request.mapper;

import java.util.List;

import org.apache.wicket.Application;
import org.apache.wicket.request.Request;
import org.apache.wicket.request.Url;
import org.apache.wicket.request.component.IRequestablePage;
import org.apache.wicket.request.mapper.info.PageComponentInfo;
import org.apache.wicket.request.mapper.parameter.IPageParametersEncoder;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.request.mapper.parameter.PageParametersEncoder;
import org.apache.wicket.util.string.Strings;

/**
 * Decodes and encodes the following URLs:
 * 
 * <pre>
 *  Page Class - Render (BookmarkablePageRequestHandler)
 *  /wicket/bookmarkable/org.apache.wicket.MyPage
 *  (will redirect to hybrid alternative if page is not stateless)
 * 
 *  Page Instance - Render Hybrid (RenderPageRequestHandler for pages that were created using bookmarkable URLs)
 *  /wicket/bookmarkable/org.apache.wicket.MyPage?2
 * 
 *  Page Instance - Bookmarkable Listener (BookmarkableListenerRequestHandler)
 *  /wicket/bookmarkable/org.apache.wicket.MyPage?2-click-foo-bar-baz
 *  /wicket/bookmarkable/org.apache.wicket.MyPage?2-click.1-foo-bar-baz (1 is behavior index)
 *  (these will redirect to hybrid if page is not stateless)
 * </pre>
 * 
 * @author Matej Knopp
 */
public class BookmarkableMapper extends AbstractBookmarkableMapper
{
        /**
         * Construct.
         */
        public BookmarkableMapper()
        {
                this(new PageParametersEncoder());
        }

        /**
         * Construct.
         *
         * @param pageParametersEncoder
         */
        public BookmarkableMapper(IPageParametersEncoder pageParametersEncoder)
        {
                super("notUsed", pageParametersEncoder);
        }

        @Override
        protected Url buildUrl(UrlInfo info)
        {
                Url url = new Url();
                url.getSegments().add(getContext().getNamespace());
                url.getSegments().add(getContext().getBookmarkableIdentifier());
                url.getSegments().add(info.getPageClass().getName());

                encodePageComponentInfo(url, info.getPageComponentInfo());

                return encodePageParameters(url, info.getPageParameters(), pageParametersEncoder);
        }

        @Override
        protected UrlInfo parseRequest(Request request)
        {
                if (Application.exists())
                {
                        if (Application.get().getSecuritySettings().getEnforceMounts())
                        {
                                return null;
                        }
                }

                if (matches(request))
                {
                        Url url = request.getUrl();

                        // try to extract page and component information from URL
                        PageComponentInfo info = getPageComponentInfo(url);

                        List<String> segments = url.getSegments();

                        // load the page class
                        String className;
                        if (segments.size() >= 3)
                        {
                                className = segments.get(2);
                        }
                        else
                        {
                                className = segments.get(1);
                        }

                        if (Strings.isEmpty(className))
                        {
                                return null;
                        }

                        Class<? extends IRequestablePage> pageClass = getPageClass(className);

                        if (pageClass != null && IRequestablePage.class.isAssignableFrom(pageClass))
                        {
                                // extract the PageParameters from URL if there are any
                                PageParameters pageParameters = extractPageParameters(request, 3,
                                        pageParametersEncoder);
                                if (pageParameters != null)
                                {
                                        pageParameters.setLocale(resolveLocale());
                                }

                                return new UrlInfo(info, pageClass, pageParameters);
                        }
                }
                return null;
        }

        @Override
        protected boolean pageMustHaveBeenCreatedBookmarkable()
        {
                return true;
        }

        @Override
        public int getCompatibilityScore(Request request)
        {
                int score = 0;
                if (matches(request))
                {
                        score = Integer.MAX_VALUE;
                }
                return score;
        }

        private boolean matches(final Request request)
        {
                boolean matches = false;
                Url url = request.getUrl();
                Url baseUrl = request.getClientUrl();
                String namespace = getContext().getNamespace();
                String bookmarkableIdentifier = getContext().getBookmarkableIdentifier();
                String pageIdentifier = getContext().getPageIdentifier();

                List<String> segments = url.getSegments();
                int segmentsSize = segments.size();

                if (segmentsSize >= 3 && urlStartsWithAndHasPageClass(url, namespace, bookmarkableIdentifier))
                {
                        matches = true;
                }
                // baseUrl = 'wicket/bookmarkable/com.example.SomePage[?...]', requestUrl = 'bookmarkable/com.example.SomePage'
                else if (baseUrl.getSegments().size() == 3 && urlStartsWith(baseUrl, namespace, bookmarkableIdentifier)
                                && segmentsSize >= 2 && urlStartsWithAndHasPageClass(url, bookmarkableIdentifier))
                {
                        matches = true;
                }
                // baseUrl = 'bookmarkable/com.example.SomePage', requestUrl = 'bookmarkable/com.example.SomePage'
                else if (baseUrl.getSegments().size() == 2 && urlStartsWith(baseUrl, bookmarkableIdentifier)
                                && segmentsSize == 2 && urlStartsWithAndHasPageClass(url, bookmarkableIdentifier))
                {
                        matches = true;
                }
                // baseUrl = 'wicket/page[?...]', requestUrl = 'bookmarkable/com.example.SomePage'
                else if (baseUrl.getSegments().size() == 2 && urlStartsWith(baseUrl, namespace, pageIdentifier)
                                && segmentsSize >= 2 && urlStartsWithAndHasPageClass(url, bookmarkableIdentifier))
                {
                        matches = true;
                }

                return matches;
        }

        /**
         * Checks whether the url starts with the given segments and additionally
         * checks whether the following segment is non-empty
         *
         * @param url
         *          The url to be checked
         * @param segments
         *          The expected leading segments
         * @return {@code true} if the url starts with the given segments and there is non-empty segment after them
         */
        protected boolean urlStartsWithAndHasPageClass(Url url, String... segments)
        {
                boolean result = urlStartsWith(url, segments);

                if (result)
                {
                        List<String> urlSegments = url.getSegments();
                        if (urlSegments.size() == segments.length)
                        {
                                result = false;
                        }
                        else
                        {
                                String pageClassSegment = urlSegments.get(segments.length);
                                if (Strings.isEmpty(pageClassSegment))
                                {
                                        result = false;
                                }
                        }
                }

                return result;
        }
}