/*
 * Copyright 2012-present 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.webflux.actuate.endpoint.web;

import java.util.Collection;
import java.util.Collections;
import java.util.Map;

import org.jspecify.annotations.Nullable;

import org.springframework.aot.hint.BindingReflectionHintsRegistrar;
import org.springframework.aot.hint.RuntimeHints;
import org.springframework.aot.hint.RuntimeHintsRegistrar;
import org.springframework.aot.hint.annotation.Reflective;
import org.springframework.aot.hint.annotation.ReflectiveRuntimeHintsRegistrar;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.boot.actuate.endpoint.OperationResponseBody;
import org.springframework.boot.actuate.endpoint.web.EndpointLinksResolver;
import org.springframework.boot.actuate.endpoint.web.EndpointMapping;
import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
import org.springframework.boot.actuate.endpoint.web.ExposableWebEndpoint;
import org.springframework.boot.actuate.endpoint.web.Link;
import org.springframework.boot.webflux.actuate.endpoint.web.WebFluxEndpointHandlerMapping.WebFluxEndpointHandlerMappingRuntimeHints;
import org.springframework.context.annotation.ImportRuntimeHints;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.reactive.HandlerMapping;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.util.UriComponentsBuilder;

/**
 * A custom {@link HandlerMapping} that makes web endpoints available over HTTP using
 * Spring WebFlux.
 *
 * @author Andy Wilkinson
 * @author Phillip Webb
 * @author Brian Clozel
 * @since 4.0.0
 */
@ImportRuntimeHints(WebFluxEndpointHandlerMappingRuntimeHints.class)
public class WebFluxEndpointHandlerMapping extends AbstractWebFluxEndpointHandlerMapping implements InitializingBean {

	private final EndpointLinksResolver linksResolver;

	/**
	 * Creates a new {@code WebFluxEndpointHandlerMapping} instance that provides mappings
	 * for the given endpoints.
	 * @param endpointMapping the base mapping for all endpoints
	 * @param endpoints the web endpoints
	 * @param endpointMediaTypes media types consumed and produced by the endpoints
	 * @param corsConfiguration the CORS configuration for the endpoints or {@code null}
	 * @param linksResolver resolver for determining links to available endpoints
	 * @param shouldRegisterLinksMapping whether the links endpoint should be registered
	 */
	public WebFluxEndpointHandlerMapping(EndpointMapping endpointMapping, Collection<ExposableWebEndpoint> endpoints,
			EndpointMediaTypes endpointMediaTypes, @Nullable CorsConfiguration corsConfiguration,
			EndpointLinksResolver linksResolver, boolean shouldRegisterLinksMapping) {
		super(endpointMapping, endpoints, endpointMediaTypes, corsConfiguration, shouldRegisterLinksMapping);
		this.linksResolver = linksResolver;
		setOrder(-100);
	}

	@Override
	protected LinksHandler getLinksHandler() {
		return new WebFluxLinksHandler();
	}

	/**
	 * Handler for root endpoint providing links.
	 */
	class WebFluxLinksHandler implements LinksHandler {

		@Override
		@ResponseBody
		@Reflective
		public Map<String, Map<String, Link>> links(ServerWebExchange exchange) {
			String requestUri = UriComponentsBuilder.fromUri(exchange.getRequest().getURI())
				.replaceQuery(null)
				.toUriString();
			Map<String, Link> links = WebFluxEndpointHandlerMapping.this.linksResolver.resolveLinks(requestUri);
			return OperationResponseBody.of(Collections.singletonMap("_links", links));
		}

		@Override
		public String toString() {
			return "Actuator root web endpoint";
		}

	}

	static class WebFluxEndpointHandlerMappingRuntimeHints implements RuntimeHintsRegistrar {

		private final ReflectiveRuntimeHintsRegistrar reflectiveRegistrar = new ReflectiveRuntimeHintsRegistrar();

		private final BindingReflectionHintsRegistrar bindingRegistrar = new BindingReflectionHintsRegistrar();

		@Override
		public void registerHints(RuntimeHints hints, @Nullable ClassLoader classLoader) {
			this.reflectiveRegistrar.registerRuntimeHints(hints, WebFluxLinksHandler.class);
			this.bindingRegistrar.registerReflectionHints(hints.reflection(), Link.class);
		}

	}

}
