/*
 * 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.kylin.stream.source.kafka;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Constructor;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.TreeMap;

import com.fasterxml.jackson.databind.DeserializationFeature;
import org.apache.commons.lang3.StringUtils;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kylin.cube.model.CubeDesc;
import org.apache.kylin.cube.model.CubeJoinedFlatTableDesc;
import org.apache.kylin.metadata.model.TblColRef;
import org.apache.kylin.stream.core.exception.StreamingException;
import org.apache.kylin.stream.core.model.StreamingMessage;
import org.apache.kylin.stream.core.source.IStreamingMessageParser;
import org.apache.kylin.stream.core.source.MessageParserInfo;
import org.apache.kylin.stream.core.util.TimeDerivedColumnType;
import org.apache.kylin.stream.source.kafka.KafkaPosition.KafkaPartitionPosition;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.MapType;
import com.fasterxml.jackson.databind.type.SimpleType;
import com.google.common.collect.Lists;

/**
 * each json message with a "timestamp" field
 */
public final class TimedJsonStreamParser implements IStreamingMessageParser<ConsumerRecord<byte[], byte[]>> {

    private static final Logger logger = LoggerFactory.getLogger(TimedJsonStreamParser.class);
    private final ObjectMapper mapper = new ObjectMapper();
    private final JavaType mapType = MapType.construct(HashMap.class, SimpleType.construct(String.class),
            SimpleType.construct(Object.class));
    private List<TblColRef> allColumns;
    private boolean formatTs = false;//not used
    private String tsColName = "timestamp";
    private String tsParser = null;
    private AbstractTimeParser streamTimeParser;

    /**
     * the path of {"user" : {"name": "kite", "sex":"female"}}
     * is user_name -> [user, name]
     */
    private Map<String, String[]> columnToSourceFieldMapping = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
    private Map<String, Object> root = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
    private Map<String, Object> tmp = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);

    public TimedJsonStreamParser(CubeDesc cubeDesc, MessageParserInfo parserInfo) {
        this(new CubeJoinedFlatTableDesc(cubeDesc).getAllColumns(), parserInfo);
    }

    public TimedJsonStreamParser(List<TblColRef> cols, MessageParserInfo parserInfo) {
        this.allColumns = cols;
        if (parserInfo != null) {
            this.formatTs = parserInfo.isFormatTs();
            this.tsColName = parserInfo.getTsColName();
            Map<String, String> mapping = parserInfo.getColumnToSourceFieldMapping();
            if (mapping != null && !mapping.isEmpty()) {
                for (String col : mapping.keySet()) {
                    if (mapping.get(col) != null && mapping.get(col).contains("."))
                        columnToSourceFieldMapping.put(col, mapping.get(col).split("\\."));
                }
                logger.info("Using parser field mapping by {}", parserInfo.getColumnToSourceFieldMapping());
            }
            this.tsParser = parserInfo.getTsParser();

            if (!StringUtils.isEmpty(tsParser)) {
                try {
                    Class clazz = Class.forName(tsParser);
                    Constructor constructor = clazz.getConstructor(MessageParserInfo.class);
                    streamTimeParser = (AbstractTimeParser) constructor.newInstance(parserInfo);
                } catch (Exception e) {
                    throw new IllegalStateException("Invalid StreamingConfig, tsParser " + tsParser + ", tsPattern " + parserInfo.getTsPattern() + ".", e);
                }
            } else {
                parserInfo.setTsParser("org.apache.kylin.stream.source.kafka.LongTimeParser");
                parserInfo.setTsPattern("MS");
                streamTimeParser = new LongTimeParser(parserInfo);
            }
        }
        mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        mapper.disable(DeserializationFeature.FAIL_ON_INVALID_SUBTYPE);
        mapper.enable(DeserializationFeature.USE_JAVA_ARRAY_FOR_JSON_ARRAY);
        logger.info("TimedJsonStreamParser with formatTs {} tsColName {}", formatTs, tsColName);
    }

    @Override
    public StreamingMessage parse(ConsumerRecord<byte[], byte[]> record) {
        try {
            Map<String, Object> message = mapper.readValue(parseToString(record.value()), mapType);
            root.clear();
            root.putAll(message);
            String tsStr = root.get(tsColName).toString();
            //Preconditions.checkArgument(!StringUtils.isEmpty(tsStr), "Timestamp field " + tsColName + //
            //" cannot be null, the message offset is " + messageAndOffset.getOffset() + " content is " + new String(messageAndOffset.getRawData()));
            long t;
            if (StringUtils.isEmpty(tsStr)) {
                t = 0;
            } else {
                t = streamTimeParser.parseTime(tsStr);
            }
            ArrayList<String> result = Lists.newArrayList();

            for (TblColRef column : allColumns) {
                String columnName = column.getName();
                TimeDerivedColumnType columnType = TimeDerivedColumnType.getTimeDerivedColumnType(columnName);
                if (columnType != null) {
                    result.add(String.valueOf(columnType.normalize(t)));
                } else {
                    Object value = root.get(columnName.toLowerCase(Locale.ROOT));
                    if (value == null) {
                        String[] pathToValue = columnToSourceFieldMapping.get(columnName);
                        if (pathToValue != null) {
                            result.add(processMultiLevelJson(pathToValue, root));
                        } else {
                            result.add(StringUtils.EMPTY);
                        }
                    } else {
                        result.add(value.toString());
                    }
                }
            }

            return new StreamingMessage(result, new KafkaPartitionPosition(record.partition(), record.offset()), t,
                    Collections.<String, Object>emptyMap());
        } catch (IOException e) {
            logger.error("error", e);
            throw new RuntimeException(e);
        }
    }

    private String parseToString(byte[] bytes) {
        String value;
        try {
            value = new String(bytes, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new StreamingException(e);
        }
        return value;
    }

    private String processMultiLevelJson(String[] path, Map map) {
        Object value = null;
        for (String key : path) {
            value = map.get(key);
            if (value instanceof Map) {
                tmp.clear();
                tmp.putAll((Map) value);
                map = tmp;
            } else {
                break;
            }
        }
        return objToString(value);
    }

    public static String objToString(Object value) {
        if (value == null)
            return StringUtils.EMPTY;
        if (value.getClass().isArray())
            return String.valueOf(Arrays.asList((Object[]) value));
        return String.valueOf(value);
    }
}
