/*
 * 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.apm.plugin.spring.webflux.v5;

import java.lang.reflect.Method;
import java.util.List;
import org.apache.skywalking.apm.agent.core.context.CarrierItem;
import org.apache.skywalking.apm.agent.core.context.ContextCarrier;
import org.apache.skywalking.apm.agent.core.context.ContextManager;
import org.apache.skywalking.apm.agent.core.context.tag.Tags;
import org.apache.skywalking.apm.agent.core.context.tag.Tags.HTTP;
import org.apache.skywalking.apm.agent.core.context.trace.AbstractSpan;
import org.apache.skywalking.apm.agent.core.context.trace.SpanLayer;
import org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.EnhancedInstance;
import org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.InstanceMethodsAroundInterceptor;
import org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.MethodInterceptResult;
import org.apache.skywalking.apm.network.trace.component.ComponentsDefine;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.web.reactive.HandlerMapping;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.ServerWebExchangeDecorator;
import org.springframework.web.server.adapter.DefaultServerWebExchange;
import org.springframework.web.util.pattern.PathPattern;
import reactor.core.publisher.Mono;

public class DispatcherHandlerHandleMethodInterceptor implements InstanceMethodsAroundInterceptor {

    @Override
    public void beforeMethod(EnhancedInstance objInst, Method method, Object[] allArguments, Class<?>[] argumentsTypes,
                             MethodInterceptResult result) throws Throwable {
        EnhancedInstance instance = getInstance(allArguments[0]);

        ServerWebExchange exchange = (ServerWebExchange) allArguments[0];

        ContextCarrier carrier = new ContextCarrier();
        CarrierItem next = carrier.items();
        HttpHeaders headers = exchange.getRequest().getHeaders();
        while (next.hasNext()) {
            next = next.next();
            List<String> header = headers.get(next.getHeadKey());
            if (header != null && header.size() > 0) {
                next.setHeadValue(header.get(0));
            }
        }

        AbstractSpan span = ContextManager.createEntrySpan(exchange.getRequest().getURI().getPath(), carrier);
        span.setComponent(ComponentsDefine.SPRING_WEBFLUX);
        SpanLayer.asHttp(span);
        Tags.URL.set(span, exchange.getRequest().getURI().toString());
        HTTP.METHOD.set(span, exchange.getRequest().getMethodValue());
        instance.setSkyWalkingDynamicField(ContextManager.capture());
        span.prepareForAsync();
        ContextManager.stopSpan(span);

        objInst.setSkyWalkingDynamicField(span);
    }

    @Override
    public Object afterMethod(EnhancedInstance objInst, Method method, Object[] allArguments, Class<?>[] argumentsTypes,
                              Object ret) throws Throwable {
        ServerWebExchange exchange = (ServerWebExchange) allArguments[0];
        AbstractSpan span = (AbstractSpan) objInst.getSkyWalkingDynamicField();

        return ((Mono) ret).doFinally(s -> {
            try {
                Object pathPattern = exchange.getAttribute(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
                if (pathPattern != null) {
                    span.setOperationName(((PathPattern) pathPattern).getPatternString());
                }
                HttpStatus httpStatus = exchange.getResponse().getStatusCode();
                // fix webflux-2.0.0-2.1.0 version have bug. httpStatus is null. not support
                if (httpStatus != null) {
                    Tags.STATUS_CODE.set(span, Integer.toString(httpStatus.value()));
                    if (httpStatus.isError()) {
                        span.errorOccurred();
                    }
                }
            } finally {
                span.asyncFinish();
            }
        });

    }

    @Override
    public void handleMethodException(EnhancedInstance objInst, Method method, Object[] allArguments,
                                      Class<?>[] argumentsTypes, Throwable t) {
    }

    public static EnhancedInstance getInstance(Object o) {
        EnhancedInstance instance = null;
        if (o instanceof DefaultServerWebExchange) {
            instance = (EnhancedInstance) o;
        } else if (o instanceof ServerWebExchangeDecorator) {
            ServerWebExchange delegate = ((ServerWebExchangeDecorator) o).getDelegate();
            return getInstance(delegate);
        }
        return instance;
    }

}

@@ -3564,42 +3564,55 @@
     
-objInst.setSkyWalkingDynamicField(
+exchange.getAttributes().put(%22SKYWALING_SPAN%22, 
 span
@@ -3903,89 +3903,148 @@
     
-AbstractSpan span = (AbstractSpan) objInst.getSkyWalkingDynamicField(
+return ((Mono) ret).doFinally(s -%3E %7B%0A            AbstractSpan span = (AbstractSpan) exchange.getAttributes().get(%22SKYWALING_SPAN%22
 );%0A
-%0A
         
 retu
@@ -4043,45 +4043,36 @@
     
-return ((Mono) ret).doFinally(s -%3E %7B%0A
+    if (span != null) %7B%0A    
     
@@ -4097,24 +4097,28 @@
             
+   
+ 
 Object pathP
@@ -4209,24 +4209,28 @@
             
+    
 if (pathPatt
@@ -4256,32 +4256,36 @@
                 
+  
+  
 span.setOperatio
@@ -4347,32 +4347,36 @@
                 
+    
 %7D%0A              
@@ -4373,24 +4373,28 @@
             
+ 
+   
 HttpStatus h
@@ -4441,24 +4441,28 @@
 atusCode();%0A
+    
             
@@ -4550,32 +4550,36 @@
                 
+    
 if (httpStatus !
@@ -4580,32 +4580,36 @@
 atus != null) %7B%0A
+    
                 
@@ -4690,32 +4690,36 @@
                 
+    
 if (httpStatus.i
@@ -4726,24 +4726,28 @@
 sError()) %7B%0A
+    
             
@@ -4792,34 +4792,40 @@
                 
-%7D%0A
+    %7D%0A  
                 
@@ -4816,34 +4816,40 @@
                 
-%7D%0A
+  %7D%0A    
             %7D fi
@@ -4868,24 +4868,28 @@
             
+    
 span.asyncFi
@@ -4892,24 +4892,42 @@
 ncFinish();%0A
+                %7D%0A
             
@@ -4940,17 +4940,16 @@
     %7D);%0A
-%0A
     %7D%0A%0A 

Fix webflux sharing span across multiple threads (#5177)