/*
 * Copyright 2012-2019 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
 *
 *      https://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.client;

import java.util.Collection;
import java.util.List;
import java.util.function.BiFunction;
import java.util.stream.Collectors;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
import org.springframework.boot.autoconfigure.condition.NoneNestedConditions;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration;
import org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration.NotReactiveWebApplicationCondition;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.boot.web.client.RestTemplateCustomizer;
import org.springframework.boot.web.client.RestTemplateRequestCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for {@link RestTemplate}.
 *
 * @author Stephane Nicoll
 * @author Phillip Webb
 * @since 1.4.0
 */
@Configuration(proxyBeanMethods = false)
@AutoConfigureAfter(HttpMessageConvertersAutoConfiguration.class)
@ConditionalOnClass(RestTemplate.class)
@Conditional(NotReactiveWebApplicationCondition.class)
public class RestTemplateAutoConfiguration {

	@Bean
	@ConditionalOnMissingBean
	public RestTemplateBuilder restTemplateBuilder(ObjectProvider<HttpMessageConverters> messageConverters,
			ObjectProvider<RestTemplateCustomizer> restTemplateCustomizers,
			ObjectProvider<RestTemplateRequestCustomizer<?>> restTemplateRequestCustomizers) {
		RestTemplateBuilder builder = new RestTemplateBuilder();
		HttpMessageConverters converters = messageConverters.getIfUnique();
		if (converters != null) {
			builder = builder.messageConverters(converters.getConverters());
		}
		builder = addCustomizers(builder, restTemplateCustomizers, RestTemplateBuilder::customizers);
		builder = addCustomizers(builder, restTemplateRequestCustomizers, RestTemplateBuilder::requestCustomizers);
		return builder;
	}

	private <T> RestTemplateBuilder addCustomizers(RestTemplateBuilder builder, ObjectProvider<T> objectProvider,
			BiFunction<RestTemplateBuilder, Collection<T>, RestTemplateBuilder> method) {
		List<T> customizers = objectProvider.orderedStream().collect(Collectors.toList());
		if (!customizers.isEmpty()) {
			return method.apply(builder, customizers);
		}
		return builder;
	}

	static class NotReactiveWebApplicationCondition extends NoneNestedConditions {

		NotReactiveWebApplicationCondition() {
			super(ConfigurationPhase.PARSE_CONFIGURATION);
		}

		@ConditionalOnWebApplication(type = Type.REACTIVE)
		private static class ReactiveWebApplication {

		}

	}

}
