/*
 * 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.rocketmq.ons.open.trace.core.hook;

import java.lang.reflect.Field;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.rocketmq.remoting.CommandCustomHeader;
import org.apache.rocketmq.remoting.RPCHook;
import org.apache.rocketmq.remoting.protocol.RemotingCommand;

import static org.apache.rocketmq.ons.api.impl.authority.SessionCredentials.AccessKey;
import static org.apache.rocketmq.ons.api.impl.authority.SessionCredentials.ONSChannelKey;

public abstract class AbstractRPCHook implements RPCHook {
    protected ConcurrentHashMap<Class<? extends CommandCustomHeader>, Field[]> fieldCache =
            new ConcurrentHashMap<Class<? extends CommandCustomHeader>, Field[]>();


    protected SortedMap<String, String> parseRequestContent(RemotingCommand request, String ak, String onsChannel) {
        CommandCustomHeader header = request.readCustomHeader();
        // sort property
        SortedMap<String, String> map = new TreeMap<String, String>();
        map.put(AccessKey, ak);
        map.put(ONSChannelKey, onsChannel);
        try {
            // add header properties
            if (null != header) {
                Field[] fields = fieldCache.get(header.getClass());
                if (null == fields) {
                    fields = header.getClass().getDeclaredFields();
                    for (Field field : fields) {
                        field.setAccessible(true);
                    }
                    Field[] tmp = fieldCache.putIfAbsent(header.getClass(), fields);
                    if (null != tmp) {
                        fields = tmp;
                    }
                }

                for (Field field : fields) {
                    Object value = field.get(header);
                    if (null != value && !field.isSynthetic()) {
                        map.put(field.getName(), value.toString());
                    }
                }
            }
            return map;
        }
        catch (Exception e) {
            throw new RuntimeException("incompatible exception.", e);
        }
    }

}