/*
    * 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.core.persistence.jpa.attrvalue.validation;
  
  import com.fasterxml.jackson.databind.json.JsonMapper;
  import java.io.IOException;
  import javax.ws.rs.core.MediaType;
  import org.apache.syncope.core.persistence.api.attrvalue.validation.InvalidPlainAttrValueException;
  import org.apache.syncope.core.persistence.api.entity.PlainAttrValue;
  import org.apache.syncope.core.persistence.api.entity.PlainSchema;
  import org.apache.tika.Tika;
  
  public class BinaryValidator extends AbstractValidator {
  
      private static final long serialVersionUID = 1344152444666540361L;
  
      private static final JsonMapper MAPPER = JsonMapper.builder().findAndAddModules().build();
  
      private static final Tika TIKA = new Tika();
  
      static {
          TIKA.setMaxStringLength(-1);
      }
  
      @Override
      protected void doValidate(final PlainSchema schema, final PlainAttrValue attrValue) {
          // check Binary schemas MIME Type mismatches
          if (attrValue.getBinaryValue() != null) {
              byte[] binaryValue = attrValue.getBinaryValue();
              String mimeType = TIKA.detect(binaryValue);
  
              boolean valid = true;
              if (!mimeType.equals(attrValue.getAttr().getSchema().getMimeType())) {
                  if (MediaType.TEXT_PLAIN.equals(mimeType)
                          && MediaType.APPLICATION_JSON.equals(attrValue.getAttr().getSchema().getMimeType())) {
  
                      String decoded = new String(binaryValue).trim();
                      valid = (decoded.startsWith("{") && decoded.endsWith("}"))
                              || (decoded.startsWith("[") && decoded.endsWith("]"))
                              && isValidJSON(decoded);
                  } else {
                      valid = false;
                  }
              }
              if (!valid) {
                  throw new InvalidPlainAttrValueException(
                          "Found MIME type: '" + mimeType + "', expecting: '"
                          + attrValue.getAttr().getSchema().getMimeType() + '\'');
              }
          }
      }
  
      private static boolean isValidJSON(final String value) {
          try {
              MAPPER.readTree(value);
              return true;
          } catch (IOException e) {
              LOG.debug("Invalid JSON string: {}", value, e);
              return false;
          }
      }
  }