/*
 * 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.hadoop.hdds.server;

import com.google.protobuf.ServiceException;
import io.opentelemetry.api.trace.Span;
import io.opentelemetry.context.Scope;
import java.util.function.Function;
import org.apache.hadoop.hdds.tracing.TracingUtil;
import org.apache.hadoop.hdds.utils.ProtocolMessageMetrics;
import org.apache.ratis.util.UncheckedAutoCloseable;
import org.apache.ratis.util.function.CheckedFunction;
import org.slf4j.Logger;

/**
 * Dispatch message after tracing and message logging for insight.
 * <p>
 * This is a generic utility to dispatch message in ServerSide translators.
 * <p>
 * It logs the message type/content on DEBUG/TRACING log for insight and create
 * a new span based on the tracing information.
 */
public class OzoneProtocolMessageDispatcher<REQUEST, RESPONSE, TYPE extends Enum<TYPE>> {

  private final String serviceName;

  private final ProtocolMessageMetrics<TYPE>
      protocolMessageMetrics;

  private final Logger logger;
  private final Function<REQUEST, String> requestPreprocessor;
  private final Function<RESPONSE, String> responsePreprocessor;

  public OzoneProtocolMessageDispatcher(String serviceName,
      ProtocolMessageMetrics<TYPE> protocolMessageMetrics,
      Logger logger) {
    this(serviceName, protocolMessageMetrics, logger,
        OzoneProtocolMessageDispatcher::escapeNewLines,
        OzoneProtocolMessageDispatcher::escapeNewLines);
  }

  public OzoneProtocolMessageDispatcher(String serviceName,
      ProtocolMessageMetrics<TYPE> protocolMessageMetrics,
      Logger logger,
      Function<REQUEST, String> requestPreprocessor,
      Function<RESPONSE, String> responsePreprocessor) {
    this.serviceName = serviceName;
    this.protocolMessageMetrics = protocolMessageMetrics;
    this.logger = logger;
    this.requestPreprocessor = requestPreprocessor;
    this.responsePreprocessor = responsePreprocessor;
  }

  public RESPONSE processRequest(
      REQUEST request,
      CheckedFunction<REQUEST, RESPONSE, ServiceException> methodCall,
      TYPE type,
      String traceId) throws ServiceException {
    Span span = TracingUtil.importAndCreateSpan(type.toString(), traceId);
    try (Scope currentScope = span.makeCurrent()) {
      if (logger.isTraceEnabled()) {
        logger.trace(
            "[service={}] [type={}] request is received: <json>{}</json>",
            serviceName,
            type,
            requestPreprocessor.apply(request));
      } else if (logger.isDebugEnabled()) {
        logger.debug("{} {} request is received",
            serviceName, type);
      }

      RESPONSE response;
      try (UncheckedAutoCloseable ignored =
               protocolMessageMetrics.measure(type)) {
        response = methodCall.apply(request);
      }

      if (logger.isTraceEnabled()) {
        logger.trace(
            "[service={}] [type={}] request is processed. Response: "
                + "<json>{}</json>",
            serviceName,
            type,
            responsePreprocessor.apply(response));
      }
      return response;

    } finally {
      span.end();
    }
  }

  private static String escapeNewLines(Object input) {
    return input.toString().replaceAll("\n", "\\\\n");
  }
}
