/* 
 * 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 parquet.hadoop.metadata;

import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.List;

import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig.Feature;

/**
 * Meta Data block stored in the footer of the file
 * contains file level (Codec, Schema, ...) and block level (location, columns, record count, ...) meta data
 *
 * @author Julien Le Dem
 */
public class ParquetMetadata {

    private static ObjectMapper objectMapper = new ObjectMapper();
    private static ObjectMapper prettyObjectMapper = new ObjectMapper();

    static {
        prettyObjectMapper.configure(Feature.INDENT_OUTPUT, true);
    }

    /**
     * @param parquetMetaData
     * @return the json representation
     */
    public static String toJSON(ParquetMetadata parquetMetaData) {
        return toJSON(parquetMetaData, objectMapper);
    }

    /**
     * @param parquetMetaData
     * @return the pretty printed json representation
     */
    public static String toPrettyJSON(ParquetMetadata parquetMetaData) {
        return toJSON(parquetMetaData, prettyObjectMapper);
    }

    private static String toJSON(ParquetMetadata parquetMetaData, ObjectMapper mapper) {
        StringWriter stringWriter = new StringWriter();
        try {
            mapper.writeValue(stringWriter, parquetMetaData);
        } catch (JsonGenerationException e) {
            throw new RuntimeException(e);
        } catch (JsonMappingException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return stringWriter.toString();
    }

    /**
     * @param json the json representation
     * @return the parsed object
     */
    public static ParquetMetadata fromJSON(String json) {
        try {
            return objectMapper.readValue(new StringReader(json), ParquetMetadata.class);
        } catch (JsonParseException e) {
            throw new RuntimeException(e);
        } catch (JsonMappingException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private final FileMetaData fileMetaData;
    private final List<BlockMetaData> blocks;

    /**
     * @param fileMetaData     file level metadata
     * @param blocks           block level metadata
     * @param keyValueMetaData
     */
    public ParquetMetadata(FileMetaData fileMetaData, List<BlockMetaData> blocks) {
        this.fileMetaData = fileMetaData;
        this.blocks = blocks;
    }

    /**
     * @return block level metadata
     */
    public List<BlockMetaData> getBlocks() {
        return blocks;
    }

    /**
     * @return file level meta data
     */
    public FileMetaData getFileMetaData() {
        return fileMetaData;
    }


    @Override
    public String toString() {
        return "ParquetMetaData{" + fileMetaData + ", blocks: " + blocks + "}";
    }

}