/*
    * Copyright 2012-2017 CodeLibs Project and the Others.
    *
    * 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.
   */
  package org.codelibs.fess.helper;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.regex.Matcher;
  
  import javax.annotation.PostConstruct;
  
  import org.codelibs.core.lang.StringUtil;
  import org.codelibs.fess.Constants;
  import org.codelibs.fess.es.config.exbhv.PathMappingBhv;
  import org.codelibs.fess.es.config.exentity.PathMapping;
  import org.codelibs.fess.util.ComponentUtil;
  import org.lastaflute.di.core.factory.SingletonLaContainerFactory;
  import org.lastaflute.web.util.LaRequestUtil;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class PathMappingHelper {
  
      private static final Logger logger = LoggerFactory.getLogger(PathMappingHelper.class);
  
      private final Map<String, List<PathMapping>> pathMappingMap = new HashMap<>();
  
      volatile List<PathMapping> cachedPathMappingList = null;
  
      @PostConstruct
      public void init() {
          final List<String> ptList = new ArrayList<>();
          ptList.add(Constants.PROCESS_TYPE_DISPLAYING);
          ptList.add(Constants.PROCESS_TYPE_BOTH);
  
          try {
              final PathMappingBhv pathMappingBhv = ComponentUtil.getComponent(PathMappingBhv.class);
              cachedPathMappingList = pathMappingBhv.selectList(cb -> {
                  cb.query().addOrderBy_SortOrder_Asc();
                  cb.query().setProcessType_InScope(ptList);
                  cb.fetchFirst(ComponentUtil.getFessConfig().getPagePathMappingMaxFetchSizeAsInteger());
              });
          } catch (final Exception e) {
              logger.warn("Failed to load path mappings.", e);
          }
      }
  
      public void setPathMappingList(final String sessionId, final List<PathMapping> pathMappingList) {
          if (sessionId != null) {
              if (pathMappingList != null) {
                  pathMappingMap.put(sessionId, pathMappingList);
              } else {
                  removePathMappingList(sessionId);
              }
          }
      }
  
      public void removePathMappingList(final String sessionId) {
          pathMappingMap.remove(sessionId);
      }
  
      public List<PathMapping> getPathMappingList(final String sessionId) {
          if (sessionId == null) {
              return null;
          }
          return pathMappingMap.get(sessionId);
      }
  
      public String replaceUrl(final String sessionId, final String url) {
          final List<PathMapping> pathMappingList = getPathMappingList(sessionId);
          if (pathMappingList == null) {
              return url;
          }
          return replaceUrl(pathMappingList, url);
      }
  
      public String replaceUrls(final String text) {
          if (cachedPathMappingList == null) {
              synchronized (this) {
                  if (cachedPathMappingList == null) {
                      init();
                  }
              }
          }
          String result = text;
         for (final PathMapping pathMapping : cachedPathMappingList) {
             if (matchUserAgent(pathMapping)) {
                 result =
                         result.replaceAll("(\"[^\"]*)" + pathMapping.getRegex() + "([^\"]*\")", "$1" + pathMapping.getReplacement() + "$2");
             }
         }
         return result;
     }
 
     public String replaceUrl(final String url) {
         if (cachedPathMappingList == null) {
             synchronized (this) {
                 if (cachedPathMappingList == null) {
                     init();
                 }
             }
         }
         return replaceUrl(cachedPathMappingList, url);
     }
 
     private String replaceUrl(final List<PathMapping> pathMappingList, final String url) {
         String newUrl = url;
         for (final PathMapping pathMapping : pathMappingList) {
             if (matchUserAgent(pathMapping)) {
                 final Matcher matcher = pathMapping.getMatcher(newUrl);
                 if (matcher.find()) {
                     newUrl = matcher.replaceAll(pathMapping.getReplacement());
                 }
             }
         }
         return newUrl;
     }
 
     private boolean matchUserAgent(final PathMapping pathMapping) {
         if (!pathMapping.hasUAMathcer()) {
             return true;
         }
 
         if (SingletonLaContainerFactory.getExternalContext().getRequest() != null) {
             return LaRequestUtil.getOptionalRequest().map(request -> {
                 final String userAgent = request.getHeader("user-agent");
                 if (StringUtil.isBlank(userAgent)) {
                     return false;
                 }
 
                 return pathMapping.getUAMatcher(userAgent).find();
             }).orElse(false);
         }
         return false;
     }
 }