/*
 * 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.skywalking.oap.server.receiver.log.provider.handler.grpc;

import io.grpc.stub.StreamObserver;
import lombok.extern.slf4j.Slf4j;
import org.apache.skywalking.apm.network.common.v3.Commands;
import org.apache.skywalking.apm.network.logging.v3.LogData;
import org.apache.skywalking.apm.network.logging.v3.LogReportServiceGrpc;
import org.apache.skywalking.oap.server.library.util.StringUtil;
import org.apache.skywalking.oap.log.analyzer.module.LogAnalyzerModule;
import org.apache.skywalking.oap.log.analyzer.provider.log.ILogAnalyzerService;
import org.apache.skywalking.oap.server.library.module.ModuleManager;
import org.apache.skywalking.oap.server.library.server.grpc.GRPCHandler;
import org.apache.skywalking.oap.server.telemetry.TelemetryModule;
import org.apache.skywalking.oap.server.telemetry.api.CounterMetrics;
import org.apache.skywalking.oap.server.telemetry.api.HistogramMetrics;
import org.apache.skywalking.oap.server.telemetry.api.MetricsCreator;
import org.apache.skywalking.oap.server.telemetry.api.MetricsTag;

/**
 * Collect log data
 */
@Slf4j
public class LogReportServiceGrpcHandler extends LogReportServiceGrpc.LogReportServiceImplBase implements GRPCHandler {

    private final HistogramMetrics histogram;
    private final CounterMetrics errorCounter;
    private final ILogAnalyzerService logAnalyzerService;

    public LogReportServiceGrpcHandler(final ModuleManager moduleManager) {
        MetricsCreator metricsCreator = moduleManager.find(TelemetryModule.NAME)
                                                     .provider()
                                                     .getService(MetricsCreator.class);
        this.logAnalyzerService = moduleManager.find(LogAnalyzerModule.NAME)
                                               .provider()
                                               .getService(ILogAnalyzerService.class);

        histogram = metricsCreator.createHistogramMetric(
            "log_in_latency", "The process latency of log",
            new MetricsTag.Keys("protocol"), new MetricsTag.Values("grpc")
        );
        errorCounter = metricsCreator.createCounter("log_analysis_error_count", "The error number of log analysis",
                                                    new MetricsTag.Keys("protocol"), new MetricsTag.Values("grpc")
        );
    }

    @Override
    public StreamObserver<LogData> collect(final StreamObserver<Commands> responseObserver) {
        return new StreamObserver<LogData>() {

            private String serviceName;

            /**
             * If this is not the first element of the streaming,
             * use the previous not-null name as the service name.
             */
            private void setServiceName(LogData.Builder builder) {
                if (StringUtil.isEmpty(serviceName) && StringUtil.isNotEmpty(builder.getService())) {
                    serviceName = builder.getService();
                } else if (StringUtil.isNotEmpty(serviceName)) {
                    builder.setService(serviceName);
                }
            }

            @Override
            public void onNext(final LogData logData) {
                if (log.isDebugEnabled()) {
                    log.debug("received log in streaming");
                }
                HistogramMetrics.Timer timer = histogram.createTimer();
                try {
                    LogData.Builder builder = logData.toBuilder();
                    setServiceName(builder);
                    logAnalyzerService.doAnalysis(builder, null);
                } catch (Exception e) {
                    errorCounter.inc();
                    log.error(e.getMessage(), e);
                } finally {
                    timer.finish();
                }
            }

            @Override
            public void onError(final Throwable throwable) {
                log.error(throwable.getMessage(), throwable);
            }

            @Override
            public void onCompleted() {
                responseObserver.onNext(Commands.newBuilder().build());
                responseObserver.onCompleted();
            }
        };
    }
}
