/*
 *  ******************************************************************************
 *  *
 *  *
 *  * This program and the accompanying materials are made available under the
 *  * terms of the Apache License, Version 2.0 which is available at
 *  * https://www.apache.org/licenses/LICENSE-2.0.
 *  *
 *  *  See the NOTICE file distributed with this work for additional
 *  *  information regarding copyright ownership.
 *  * 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.
 *  *
 *  * SPDX-License-Identifier: Apache-2.0
 *  *****************************************************************************
 */

package org.datavec.api.transform.analysis.json;

import com.tdunning.math.stats.TDigest;
import org.apache.commons.codec.binary.Base64;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonNode;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;

public class TDigestDeserializer extends JsonDeserializer<TDigest> {
    @Override
    public TDigest deserialize(JsonParser jp, DeserializationContext d) throws IOException, JsonProcessingException {
        JsonNode node = (JsonNode)jp.getCodec().readTree(jp);
        String field = node.get("digest").asText();
        Base64 b = new Base64();
        byte[] bytes = b.decode(field);
        try(ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(bytes))){
            return (TDigest) ois.readObject();
        } catch (Exception e){
            throw new RuntimeException("Error deserializing TDigest object from JSON", e);
        }
    }
}
