package fr.paris.lutece.plugins.knowledge.service;
   
   import dev.langchain4j.data.message.ChatMessage;
   import dev.langchain4j.store.memory.chat.ChatMemoryStore;
   import fr.paris.lutece.plugins.knowledge.business.Bot;
   import fr.paris.lutece.plugins.knowledge.business.BotSession;
   import fr.paris.lutece.plugins.knowledge.business.BotSessionHome;
   import fr.paris.lutece.plugins.knowledge.rs.RequestData;
   import fr.paris.lutece.portal.service.security.LuteceUser;
  import fr.paris.lutece.portal.service.security.SecurityService;
  import org.apache.commons.lang3.tuple.Pair;
  import org.apache.commons.lang3.tuple.ImmutablePair;
  
  
  
  import static dev.langchain4j.data.message.ChatMessageDeserializer.messagesFromJson;
  import static dev.langchain4j.data.message.ChatMessageSerializer.messagesToJson;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  public class ChatMemoryService
  {
      private static final String ATTRIBUTE_CHAT_MEMORY_MAP = "CHAT_MEMORY_MAP";
      
      /**
       * Retrieves a chat memory associated with the given project ID from the provided session. If no chat memory exists for the given project ID, a new one is
       * created.
       * 
       * @param session
       *            The current HTTP session.
       * @param projectId
       *            The ID of the project for which the chat memory is to be fetched.
       * @return The associated MessageWindowChatMemory object or a new one if none exists.
       */
      @SuppressWarnings( "unchecked" )
      public static Pair<PersistentChatMemoryStore, String> getChatMemory(HttpServletRequest request, RequestData data, Bot bot, String sessionId ) {
          LuteceUser luteceUser = SecurityService.getInstance().getRegisteredUser(request);
          HttpSession session = request.getSession();
           PersistentChatMemoryStore chatMemoryStore = null;
      
          Map<String, PersistentChatMemoryStore> chatMemoryStoreMap = (Map<String, PersistentChatMemoryStore>) session.getAttribute(ATTRIBUTE_CHAT_MEMORY_MAP);
      
          if (chatMemoryStoreMap == null) {
              chatMemoryStoreMap = new HashMap<>();
              session.setAttribute(ATTRIBUTE_CHAT_MEMORY_MAP, chatMemoryStoreMap);
          }
  
  
          if( data.getBotSessionId() != null ) {
              chatMemoryStore = chatMemoryStoreMap.get( data.getBotSessionId() );
          }
  
          String botSessionId;
  
          if (chatMemoryStore == null) {
              if (data.getBotSessionId() != null) {
                  BotSession botSession = BotSessionHome.findByAccessCode( luteceUser.getAccessCode(), data.getBotSessionId() ).get();
                  chatMemoryStore = new PersistentChatMemoryStore();
                  chatMemoryStore.updateMessages(botSession.getSessionId(), messagesFromJson(botSession.getContent()));
                  chatMemoryStoreMap.put( botSession.getSessionId() , chatMemoryStore);
                  botSessionId = botSession.getSessionId();
              } else {
                  BotSession botSession = createNewBotSession(bot, sessionId, luteceUser );
                  chatMemoryStore = new PersistentChatMemoryStore();
                  chatMemoryStoreMap.put(sessionId, chatMemoryStore);
                  botSessionId = botSession.getSessionId();
              }
          } else {
              botSessionId = data.getBotSessionId();
          }
      
          return new ImmutablePair<>(chatMemoryStore, botSessionId);
      }
  
      private static BotSession createNewBotSession(Bot bot, String sessionId, LuteceUser luteceUser ) {
          long timestamp = System.currentTimeMillis();
          BotSessiondge/business/BotSession.html#BotSession">BotSession botSession = new BotSession();
          botSession.setCreationDate(new java.sql.Date(timestamp));
          botSession.setBotId(bot.getId());
          botSession.setAccessCode( luteceUser.getAccessCode( ) );
          botSession.setSessionId( sessionId );
          return BotSessionHome.create(botSession);
      }
  
        static class PersistentChatMemoryStore implements ChatMemoryStore {
          @Override
          public List<ChatMessage> getMessages(Object memoryId) {
  
          BotSession botSession = BotSessionHome.findBySessionId( (String) memoryId ).get( );
          return messagesFromJson( botSession.getContent( ) );
          }
  
          @Override
          public void updateMessages(Object memoryId, List<ChatMessage> messages) {
  
             BotSession botSession = BotSessionHome.findBySessionId( (String) memoryId ).get( );
             botSession.setContent( messagesToJson( messages ) );
             BotSessionHome.update( botSession );
         }
 
         @Override
         public void deleteMessages(Object memoryId) {
             BotSessionHome.remove( (int) memoryId );
         }
     }
 
 }