/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2014 wcm.io
    * %%
    * Licensed 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.
   * #L%
   */
  package io.wcm.handler.url.impl.modes;
  
  import java.util.Set;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.sling.api.adapter.Adaptable;
  import org.apache.sling.api.resource.Resource;
  import org.apache.sling.api.resource.ResourceResolver;
  import org.jetbrains.annotations.NotNull;
  import org.jetbrains.annotations.Nullable;
  
  import com.day.cq.wcm.api.Page;
  
  import io.wcm.handler.url.UrlModes;
  import io.wcm.handler.url.integrator.IntegratorHandler;
  import io.wcm.handler.url.spi.UrlHandlerConfig;
  import io.wcm.sling.commons.adapter.AdaptTo;
  import io.wcm.wcm.commons.util.Path;
  
  /**
   * Default mode: Does generate a full externalized URL only if both siteUrl and siteUrlSecure parameter
   * are set in context-specific configuration. If not set, only URLs without hostname are generated.
   * If the target is an internal content page, siteUrl or siteUrlSecure is chosen automatically depending on the secure
   * state of the page.
   */
  public final class DefaultUrlMode extends AbstractUrlMode {
  
    @Override
    public @NotNull String getId() {
      return "DEFAULT";
    }
  
    @Override
    public String getLinkUrlPrefix(@NotNull Adaptable adaptable, @NotNull Set<String> runModes,
        @Nullable Page currentPage, @Nullable Page targetPage) {
      // default to full url for content URLs
      return UrlModes.FULL_URL.getLinkUrlPrefix(adaptable, runModes, currentPage, targetPage);
    }
  
    @Override
    public String getResourceUrlPrefix(@NotNull Adaptable adaptable, @NotNull Set<String> runModes,
        @Nullable Page currentPage, @Nullable Resource targetResource) {
      // in integrator template mode or if resource is from another site default to full URL mode, otherwise to no-hostname mode
      IntegratorHandler integratorHandler = AdaptTo.notNull(adaptable, IntegratorHandler.class);
      if (integratorHandler.isIntegratorTemplateMode()
          || linksToOtherDomain(adaptable, currentPage, targetResource)) {
        return UrlModes.FULL_URL.getResourceUrlPrefix(adaptable, runModes, currentPage, targetResource);
      }
      return UrlModes.NO_HOSTNAME.getResourceUrlPrefix(adaptable, runModes, currentPage, targetResource);
    }
  
    /**
     * Checks if the target resource is located outsite the current site, and if for this other
     * resource context a valid url configuration with a specific hostname exists.
     * @param adaptable Adaptable
     * @param currentPage Current page (may be null)
     * @param targetResource Target resource (may be null)
     * @return true if the target resources is located in another site/context with separate url configuration
     */
    private boolean linksToOtherDomain(Adaptable adaptable, Page currentPage, Resource targetResource) {
      if (currentPage == null || targetResource == null) {
        return false;
      }
  
      UrlHandlerConfig urlHandlerConfig = AdaptTo.notNull(adaptable, UrlHandlerConfig.class);
      Resource currentResource = AdaptTo.notNull(currentPage, Resource.class);
      ResourceResolver resourceResolver = currentResource.getResourceResolver();
      String currentSiteRoot = getRootPath(currentPage.getPath(), urlHandlerConfig.getSiteRootLevel(currentResource), resourceResolver);
      String pathSiteRoot = getRootPath(targetResource.getPath(), urlHandlerConfig.getSiteRootLevel(targetResource), resourceResolver);
      boolean notInCurrentSite = !StringUtils.equals(currentSiteRoot, pathSiteRoot);
  
      if (notInCurrentSite) {
        UrlConfig targetUrlConfig = new UrlConfig(targetResource);
        return targetUrlConfig.isValid();
      }
      else {
        return false;
      }
    }
  
   /**
    * Gets site root level path of a site.
    * @param path Path of page within the site
    * @param rootLevel Level of root page
    * @param resourceResolver Resource resolver
    * @return Site root path for the site. The path is not checked for validness.
    */
   private String getRootPath(String path, int rootLevel, ResourceResolver resourceResolver) {
     String rootPath = Path.getAbsoluteParent(path, rootLevel, resourceResolver);
 
     // strip off everything after first "." - root path may be passed with selectors/extension which is not relevant
     if (StringUtils.contains(rootPath, ".")) {
       rootPath = StringUtils.substringBefore(rootPath, ".");
     }
 
     return rootPath;
   }
 
 }