/*
 * Copyright 2012-2017 the original author or authors.
 *
 * Licensed 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.springframework.boot.autoconfigure.web.reactive;

import java.util.List;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.AutoConfigureOrder;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.http.server.reactive.HttpHandler;
import org.springframework.web.reactive.DispatcherHandler;
import org.springframework.web.reactive.function.server.HandlerStrategies;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.RouterFunctions;
import org.springframework.web.reactive.result.view.ViewResolver;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebHandler;
import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
import org.springframework.web.server.session.WebSessionManager;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for {@link HttpHandler}.
 *
 * @author Brian Clozel
 * @author Stephane Nicoll
 * @since 2.0.0
 */
@Configuration
@ConditionalOnClass({ DispatcherHandler.class, HttpHandler.class })
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.REACTIVE)
@ConditionalOnMissingBean(HttpHandler.class)
@AutoConfigureAfter({ WebFluxAutoConfiguration.class })
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
public class HttpHandlerAutoConfiguration {

	@Configuration
	@ConditionalOnMissingBean(RouterFunction.class)
	public static class AnnotationConfig {

		private ApplicationContext applicationContext;

		public AnnotationConfig(ApplicationContext applicationContext) {
			this.applicationContext = applicationContext;
		}

		@Bean
		public HttpHandler httpHandler() {
			return WebHttpHandlerBuilder.applicationContext(this.applicationContext)
					.build();
		}

	}

	@Configuration
	@ConditionalOnBean(RouterFunction.class)
	public static class FunctionalConfig {

		private final List<WebFilter> webFilters;

		private final WebSessionManager webSessionManager;

		private HandlerStrategies.Builder handlerStrategiesBuilder;

		private final List<ViewResolver> viewResolvers;

		public FunctionalConfig(ObjectProvider<List<WebFilter>> webFilters,
				ObjectProvider<WebSessionManager> webSessionManager,
				ObjectProvider<HandlerStrategies.Builder> handlerStrategiesBuilder,
				ObjectProvider<List<ViewResolver>> viewResolvers) {
			this.webFilters = webFilters.getIfAvailable();
			if (this.webFilters != null) {
				AnnotationAwareOrderComparator.sort(this.webFilters);
			}
			this.webSessionManager = webSessionManager.getIfAvailable();
			this.handlerStrategiesBuilder = handlerStrategiesBuilder.getIfAvailable();
			this.viewResolvers = viewResolvers.getIfAvailable();
		}

		@Bean
		public HttpHandler httpHandler(List<RouterFunction<?>> routerFunctions) {
			routerFunctions.sort(new AnnotationAwareOrderComparator());
			RouterFunction<?> routerFunction = routerFunctions.stream()
					.reduce(RouterFunction::andOther).get();
			if (this.handlerStrategiesBuilder == null) {
				this.handlerStrategiesBuilder = HandlerStrategies.builder();
			}
			if (this.viewResolvers != null) {
				this.viewResolvers.forEach(this.handlerStrategiesBuilder::viewResolver);
			}
			WebHandler webHandler = RouterFunctions.toHttpHandler(routerFunction,
					this.handlerStrategiesBuilder.build());
			WebHttpHandlerBuilder builder = WebHttpHandlerBuilder.webHandler(webHandler)
					.sessionManager(this.webSessionManager);
			builder.filters(this.webFilters);
			return builder.build();
		}

	}

}

@@ -2056,16 +2056,28 @@
 .server.
+adapter.Http
 WebHandl
@@ -2074,24 +2074,31 @@
 tpWebHandler
+Adapter
 ;%0Aimport org
@@ -4453,16 +4453,126 @@
 );%0A%09%09%09%7D%0A
+%09%09%09if (this.webFilters != null) %7B%0A%09%09%09%09this.webFilters.forEach(this.handlerStrategiesBuilder::webFilter);%0A%09%09%09%7D%0A
 %09%09%09if (t
@@ -4689,19 +4689,20 @@
 %0A%09%09%09
-Web
+Http
 Handler 
 webH
@@ -4697,19 +4697,20 @@
 Handler 
-web
+http
 Handler 
@@ -4809,76 +4809,79 @@
 %0A%09%09%09
-WebHttpHandlerBuilder builder = Web
+if (this.webSessionManager != null) %7B%0A%09%09%09%09((
 Http
+Web
 Handler
-Builder.webHandler(web
+Adapter) http
 Hand
@@ -4890,19 +4890,23 @@
 r)%0A%09%09%09%09%09
+%09
 .se
+tSe
 ssionMan
@@ -4942,67 +4942,31 @@
 %0A%09%09%09
-builder.filters(this.webFilters);%0A%09%09%09return builder.build()
+%7D%0A%09%09%09return httpHandler
 ;%0A%09%09

Align with breaking API changes in latest Spring Framework snapshots