/*
    * Copyright (C) 2025 B3Partners B.V.
    *
    * SPDX-License-Identifier: MIT
    */
   
   package org.tailormap.api.configuration;
   
   import com.fasterxml.jackson.annotation.JsonTypeInfo;
  import com.fasterxml.jackson.core.StreamReadFeature;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.SerializationFeature;
  import com.fasterxml.jackson.databind.jsontype.BasicPolymorphicTypeValidator;
  import java.io.IOException;
  import java.lang.invoke.MethodHandles;
  import java.nio.charset.StandardCharsets;
  import org.jspecify.annotations.NonNull;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.BeanClassLoaderAware;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  import org.springframework.core.convert.ConversionService;
  import org.springframework.core.convert.support.GenericConversionService;
  import org.springframework.security.jackson2.SecurityJackson2Modules;
  import org.springframework.session.config.SessionRepositoryCustomizer;
  import org.springframework.session.jdbc.JdbcIndexedSessionRepository;
  
  @Configuration(proxyBeanMethods = false)
  public class JdbcSessionConfiguration implements BeanClassLoaderAware {
    private static final Logger logger =
        LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
    private static final String CREATE_SESSION_ATTRIBUTE_QUERY = """
  INSERT INTO %TABLE_NAME%_ATTRIBUTES (SESSION_PRIMARY_ID, ATTRIBUTE_NAME, ATTRIBUTE_BYTES)
  VALUES (?, ?, convert_from(?, 'UTF8')::jsonb)
  """;
  
    private static final String UPDATE_SESSION_ATTRIBUTE_QUERY = """
  UPDATE %TABLE_NAME%_ATTRIBUTES
  SET ATTRIBUTE_BYTES = encode(?, 'escape')::jsonb
  WHERE SESSION_PRIMARY_ID = ?
  AND ATTRIBUTE_NAME = ?
  """;
  
    private ClassLoader classLoader;
  
    @Bean
    SessionRepositoryCustomizer<JdbcIndexedSessionRepository> customizer() {
      return (sessionRepository) -> {
        sessionRepository.setCreateSessionAttributeQuery(CREATE_SESSION_ATTRIBUTE_QUERY);
        sessionRepository.setUpdateSessionAttributeQuery(UPDATE_SESSION_ATTRIBUTE_QUERY);
      };
    }
  
    @Bean("springSessionConversionService")
    public ConversionService springSessionConversionService(ObjectMapper objectMapper) {
  
      BasicPolymorphicTypeValidator ptv = BasicPolymorphicTypeValidator.builder()
          .allowIfSubType("org.tailormap.api.security.")
          .allowIfSubType("org.springframework.security.")
          .allowIfSubType("java.util.")
          .allowIfSubType(java.lang.Number.class)
          .allowIfSubType("java.time.")
          .allowIfBaseType(Object.class)
          .build();
  
      ObjectMapper copy = objectMapper
          .copy()
          .configure(
              StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION.mappedFeature(),
              (logger.isDebugEnabled() || logger.isTraceEnabled()))
          .configure(SerializationFeature.INDENT_OUTPUT, (logger.isDebugEnabled() || logger.isTraceEnabled()));
  
      // register mixins early so Jackson picks up the @JsonCreator constructor for TailormapUserDetails
      // implementations
      copy.addMixIn(
          org.tailormap.api.security.TailormapUserDetailsImpl.class,
          org.tailormap.api.security.TailormapUserDetailsImplMixin.class);
  
      copy.addMixIn(
          org.tailormap.api.security.TailormapOidcUser.class,
          org.tailormap.api.security.TailormapOidcUserMixin.class);
  
      copy.registerModules(SecurityJackson2Modules.getModules(this.classLoader))
          .activateDefaultTyping(ptv, ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
  
      final GenericConversionService converter = new GenericConversionService();
      // Object -> byte[] (serialize to JSON bytes)
      converter.addConverter(Object.class, byte[].class, source -> {
        try {
          logger.debug("Serializing Spring Session: {}", source);
          return copy.writerFor(Object.class).writeValueAsBytes(source);
        } catch (IOException e) {
          logger.error("Error serializing Spring Session object: {}", source, e);
          throw new RuntimeException("Unable to serialize Spring Session.", e);
        }
      });
      // byte[] -> Object (deserialize from JSON bytes)
     converter.addConverter(byte[].class, Object.class, source -> {
       try {
         logger.debug(
             "Deserializing Spring Session from bytes, length: {} ({})",
             source.length,
             new String(source, StandardCharsets.UTF_8));
         return copy.readValue(source, Object.class);
       } catch (IOException e) {
         String preview;
         try {
           String content = new String(source, StandardCharsets.UTF_8);
           int maxLength = 256;
           preview = content.length() > maxLength ? content.substring(0, maxLength) + "..." : content;
         } catch (Exception ex) {
           preview = "<unavailable>";
         }
         logger.error(
             "Error deserializing Spring Session from bytes, length: {}, preview: {}",
             source.length,
             preview,
             e);
         throw new RuntimeException("Unable to deserialize Spring Session.", e);
       }
     });
 
     return converter;
   }
 
   @Override
   public void setBeanClassLoader(@NonNull ClassLoader classLoader) {
     this.classLoader = classLoader;
   }
 }