/*
    * Copyright 2012-2021 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.function.BiFunction;
  import java.util.regex.Matcher;
  
  import javax.annotation.PostConstruct;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  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.codelibs.fess.util.DocumentUtil;
  import org.lastaflute.di.core.exception.ComponentNotFoundException;
  import org.lastaflute.di.core.factory.SingletonLaContainerFactory;
  import org.lastaflute.web.util.LaRequestUtil;
  
  public class PathMappingHelper extends AbstractConfigHelper {
  
      private static final Logger logger = LogManager.getLogger(PathMappingHelper.class);
  
      protected static final String FUNCTION_ENCODEURL_MATCHER = "function:encodeUrl";
  
      protected static final String GROOVY_MATCHER = "groovy:";
  
      protected final Map<String, List<PathMapping>> pathMappingMap = new HashMap<>();
  
      protected volatile List<PathMapping> cachedPathMappingList = null;
  
      @PostConstruct
      public void init() {
          if (logger.isDebugEnabled()) {
              logger.debug("Initialize {}", this.getClass().getSimpleName());
          }
          load();
      }
  
      @Override
      public int load() {
          final List<String> ptList = getProcessTypeList();
  
          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());
              });
              return cachedPathMappingList.size();
          } catch (final ComponentNotFoundException e) {
              if (logger.isDebugEnabled()) {
                  logger.debug("Failed to load path mappings.", e);
              }
              cachedPathMappingList = new ArrayList<>();
          } catch (final Exception e) {
              logger.warn("Failed to load path mappings.", e);
          }
          return 0;
      }
  
      protected List<String> getProcessTypeList() {
          final List<String> ptList = new ArrayList<>();
          final String executeType = System.getProperty("lasta.env");
          if (Constants.EXECUTE_TYPE_CRAWLER.equalsIgnoreCase(executeType)) {
              ptList.add(Constants.PROCESS_TYPE_REPLACE);
          } else {
              ptList.add(Constants.PROCESS_TYPE_DISPLAYING);
              ptList.add(Constants.PROCESS_TYPE_BOTH);
          }
          return ptList;
      }
  
      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) { // for crawling
         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)) {
                 String replacement = pathMapping.getReplacement();
                 if (replacement == null) {
                     replacement = StringUtil.EMPTY;
                 }
                 result = result.replaceAll("(\"[^\"]*)" + pathMapping.getRegex() + "([^\"]*\")", "$1" + replacement + "$2");
             }
         }
         return result;
     }
 
     public String replaceUrl(final String url) { // for display or url converer
         if (cachedPathMappingList == null) {
             synchronized (this) {
                 if (cachedPathMappingList == null) {
                     init();
                 }
             }
         }
         return replaceUrl(cachedPathMappingList, url);
     }
 
     public BiFunction<String, Matcher, String> createPathMatcher(final Matcher matcher, final String replacement) { // for PathMapping
         if (FUNCTION_ENCODEURL_MATCHER.equals(replacement)) {
             return (u, m) -> DocumentUtil.encodeUrl(u);
         }
         if (!replacement.startsWith(GROOVY_MATCHER)) {
             return (u, m) -> m.replaceAll(replacement);
         }
         final String template = replacement.substring(GROOVY_MATCHER.length());
         return (u, m) -> {
             final Map<String, Object> paramMap = new HashMap<>();
             paramMap.put("url", u);
             paramMap.put("matcher", m);
             final Object value =
                     ComponentUtil.getScriptEngineFactory().getScriptEngine(Constants.DEFAULT_SCRIPT).evaluate(template, paramMap);
             if (value == null) {
                 return u;
             }
             return value.toString();
         };
     }
 
     protected String replaceUrl(final List<PathMapping> pathMappingList, final String url) {
         String newUrl = url;
         for (final PathMapping pathMapping : pathMappingList) {
             if (matchUserAgent(pathMapping)) {
                 newUrl = pathMapping.process(this, newUrl);
             }
         }
         return newUrl;
     }
 
     protected 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;
     }
 }