/*
    * 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.gbif.ws.security;
  
  import org.gbif.ws.CommonRuntimeException;
  
  import java.io.IOException;
  import java.util.Base64;
  
  import org.apache.commons.codec.digest.DigestUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.stereotype.Service;
  
  import com.fasterxml.jackson.databind.ObjectMapper;
  
  @Service
  public class Md5EncodeServiceImpl implements Md5EncodeService {
  
    private static final Logger LOG = LoggerFactory.getLogger(Md5EncodeServiceImpl.class);
  
    private ObjectMapper mapper;
  
    // See JacksonJsonObjectMapperProvider#getObjectMapper
    public Md5EncodeServiceImpl(ObjectMapper mapper) {
      this.mapper = mapper;
    }
  
    /**
     * Generates the Base64 encoded 128 bit MD5 digest of the entire content string suitable for the
     * Content-MD5 header value.
     * See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.15
     */
    @Override
    public String encode(Object entity) {
      try {
        byte[] content = mapper.writeValueAsBytes(entity);
  
        // TODO: 2019-07-31 char encoding should be ASCII
        return Base64.getEncoder().encodeToString(DigestUtils.md5(content));
      } catch (IOException e) {
        LOG.error("Failed to serialize http entity [{}]", entity);
        throw new CommonRuntimeException(e);
      }
    }
  }