/*
    * 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.syncope.client.enduser;
  
  import com.fasterxml.jackson.core.type.TypeReference;
  import com.fasterxml.jackson.databind.json.JsonMapper;
  import java.io.IOException;
  import java.io.Serializable;
  import java.io.StringWriter;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Base64;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.stream.Collectors;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.lang3.math.NumberUtils;
  import org.apache.wicket.util.cookies.CookieDefaults;
  import org.apache.wicket.util.cookies.CookieUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public final class PreferenceManager implements Serializable {
  
      private static final long serialVersionUID = 3581434664555284193L;
  
      private static final Logger LOG = LoggerFactory.getLogger(PreferenceManager.class);
  
      private static final String COOKIE_NAME = "syncope2EnduserPrefs";
  
      private static final int ONE_YEAR_TIME = 60 * 60 * 24 * 365;
  
      private static final JsonMapper MAPPER = JsonMapper.builder().findAndAddModules().build();
  
      private static final TypeReference<Map<String, String>> MAP_TYPE_REF = new TypeReference<>() {
      };
  
      private static final List<Integer> PAGINATOR_CHOICES = Arrays.asList(new Integer[] { 10, 25, 50 });
  
      private static final CookieUtils COOKIE_UTILS;
  
      static {
          CookieDefaults cookieDefaults = new CookieDefaults();
          cookieDefaults.setMaxAge(ONE_YEAR_TIME);
          COOKIE_UTILS = new CookieUtils(cookieDefaults);
      }
  
      public List<Integer> getPaginatorChoices() {
          return PAGINATOR_CHOICES;
      }
  
      private Map<String, String> getPrefs(final String value) {
          Map<String, String> prefs;
          try {
              if (StringUtils.isNotBlank(value)) {
                  prefs = MAPPER.readValue(value, MAP_TYPE_REF);
              } else {
                  throw new Exception("Invalid cookie value '" + value + "'");
              }
          } catch (Exception e) {
              LOG.debug("No preferences found", e);
              prefs = new HashMap<>();
          }
  
          return prefs;
      }
  
      private String setPrefs(final Map<String, String> prefs) throws IOException {
          StringWriter writer = new StringWriter();
          MAPPER.writeValue(writer, prefs);
  
          return writer.toString();
      }
  
      public String get(final String key) {
          String result = null;
  
          String prefString = COOKIE_UTILS.load(COOKIE_NAME);
          if (prefString != null) {
              Map<String, String> prefs = getPrefs(new String(Base64.getDecoder().decode(prefString.getBytes())));
              result = prefs.get(key);
          }
 
         return result;
     }
 
     public Integer getPaginatorRows(final String key) {
         Integer result = getPaginatorChoices().get(0);
 
         String value = get(key);
         if (value != null) {
             result = NumberUtils.toInt(value, 10);
         }
 
         return result;
     }
 
     public List<String> getList(final String key) {
         List<String> result = new ArrayList<>();
 
         String compound = get(key);
 
         if (StringUtils.isNotBlank(compound)) {
             String[] items = compound.split(";");
             result.addAll(Arrays.asList(items));
         }
 
         return result;
     }
 
     public void set(final Map<String, List<String>> prefs) {
         Map<String, String> current = new HashMap<>();
 
         String prefString = COOKIE_UTILS.load(COOKIE_NAME);
         if (prefString != null) {
             current.putAll(getPrefs(new String(Base64.getDecoder().decode(prefString.getBytes()))));
         }
 
         // after retrieved previous setting in order to overwrite the key ...
         prefs.forEach((key, values) -> current.put(key, values.stream().collect(Collectors.joining(";"))));
 
         try {
             COOKIE_UTILS.save(COOKIE_NAME, Base64.getEncoder().encodeToString(setPrefs(current).getBytes()));
         } catch (IOException e) {
             LOG.error("Could not save {} info: {}", getClass().getSimpleName(), current, e);
         }
     }
 
     public void set(final String key, final String value) {
         String prefString = COOKIE_UTILS.load(COOKIE_NAME);
 
         final Map<String, String> current = new HashMap<>();
         if (prefString != null) {
             current.putAll(getPrefs(new String(Base64.getDecoder().decode(prefString.getBytes()))));
         }
 
         // after retrieved previous setting in order to overwrite the key ...
         current.put(key, value);
 
         try {
             COOKIE_UTILS.save(COOKIE_NAME, Base64.getEncoder().encodeToString(setPrefs(current).getBytes()));
         } catch (IOException e) {
             LOG.error("Could not save {} info: {}", getClass().getSimpleName(), current, e);
         }
     }
 
     public void setList(final String key, final List<String> values) {
         set(key, values.stream().collect(Collectors.joining(";")));
     }
 
     public void setList(final Map<String, List<String>> prefs) {
         set(prefs);
     }
 
     private PreferenceManager() {
         // private constructor for static utility class
     }
 }