/*
 * Copyright 2002-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.web.reactive.function.server;

import java.util.List;
import java.util.Map;
import java.util.Objects;

import org.jspecify.annotations.Nullable;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.http.server.reactive.HttpHandler;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.reactive.DispatcherHandler;
import org.springframework.web.reactive.HandlerMapping;
import org.springframework.web.reactive.config.EnableWebFlux;
import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
import org.springframework.web.testfixture.http.server.reactive.bootstrap.AbstractHttpHandlerIntegrationTests;
import org.springframework.web.testfixture.http.server.reactive.bootstrap.HttpServer;
import org.springframework.web.util.pattern.PathPattern;

import static org.assertj.core.api.Assertions.assertThat;
import static org.springframework.web.reactive.function.BodyInserters.fromPublisher;
import static org.springframework.web.reactive.function.server.RequestPredicates.accept;
import static org.springframework.web.reactive.function.server.RouterFunctions.nest;
import static org.springframework.web.reactive.function.server.RouterFunctions.route;

/**
 * Tests the use of {@link HandlerFunction} and {@link RouterFunction} in a
 * {@link DispatcherHandler}, combined with {@link Controller}s.
 *
 * @author Arjen Poutsma
 */
class DispatcherHandlerIntegrationTests extends AbstractHttpHandlerIntegrationTests {


	@Override
	protected HttpHandler createHttpHandler() {
		ApplicationContext wac = new AnnotationConfigApplicationContext(TestConfiguration.class);
		DispatcherHandler webHandler = new DispatcherHandler(wac);

		return WebHttpHandlerBuilder.webHandler(webHandler).build();
	}


	@ParameterizedHttpServerTest
	void mono(HttpServer httpServer) throws Exception {
		startServer(httpServer);

		ResponseEntity<Person> result = getRestClient().get().uri("http://localhost:" + this.port + "/mono")
				.retrieve().toEntity(Person.class);

		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
		assertThat(result.getBody().getName()).isEqualTo("John");
	}

	@ParameterizedHttpServerTest
	void flux(HttpServer httpServer) throws Exception {
		startServer(httpServer);

		ResponseEntity<List<Person>> result = getRestClient().get().uri("http://localhost:" + this.port + "/flux")
				.retrieve().toEntity(new ParameterizedTypeReference<>() {});

		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
		List<Person> body = result.getBody();
		assertThat(body).hasSize(2);
		assertThat(body.get(0).getName()).isEqualTo("John");
		assertThat(body.get(1).getName()).isEqualTo("Jane");
	}

	@ParameterizedHttpServerTest
	void controller(HttpServer httpServer) throws Exception {
		startServer(httpServer);

		ResponseEntity<Person> result = getRestClient().get().uri("http://localhost:" + this.port + "/controller")
				.retrieve().toEntity(Person.class);

		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
		assertThat(result.getBody().getName()).isEqualTo("John");
	}

	@ParameterizedHttpServerTest
	void attributes(HttpServer httpServer) throws Exception {
		startServer(httpServer);

		ResponseEntity<String> result = getRestClient().get().uri("http://localhost:" + this.port + "/attributes/bar")
				.retrieve().toEntity(String.class);

		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
	}

	@ParameterizedHttpServerTest
	void nested(HttpServer httpServer) throws Exception {
		startServer(httpServer);

		ResponseEntity<String> result = getRestClient().get().uri("http://localhost:" + this.port + "/foo/bar")
				.retrieve().toEntity(String.class);

		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
	}

	@EnableWebFlux
	@Configuration
	static class TestConfiguration {

		@Bean
		public PersonHandler personHandler() {
			return new PersonHandler();
		}

		@Bean
		public PersonController personController() {
			return new PersonController();
		}

		@Bean
		public AttributesHandler attributesHandler() {
			return new AttributesHandler();
		}

		@Bean
		public RouterFunction<EntityResponse<Person>> monoRouterFunction(PersonHandler personHandler) {
			return route(RequestPredicates.GET("/mono"), personHandler::mono);
		}

		@Bean
		public RouterFunction<ServerResponse> fluxRouterFunction(PersonHandler personHandler) {
			return route(RequestPredicates.GET("/flux"), personHandler::flux);
		}

		@Bean
		public RouterFunction<ServerResponse> attributesRouterFunction(AttributesHandler attributesHandler) {
			return nest(RequestPredicates.GET("/attributes"),
					route(RequestPredicates.GET("/{foo}"), attributesHandler::attributes));
		}

		@Bean
		public RouterFunction<ServerResponse> nested() {
			return route()
					.path("/foo", () -> route()
							.nest(accept(MediaType.APPLICATION_JSON), builder -> builder
									.GET("/bar", request -> ServerResponse.ok().build()))
							.build())
					.build();
		}

	}


	private static class PersonHandler {

		public Mono<EntityResponse<Person>> mono(ServerRequest request) {
			Person person = new Person("John");
			return EntityResponse.fromObject(person).build();
		}

		public Mono<ServerResponse> flux(ServerRequest request) {
			Person person1 = new Person("John");
			Person person2 = new Person("Jane");
			return ServerResponse.ok().body(
					fromPublisher(Flux.just(person1, person2), Person.class));
		}
	}


	private static class AttributesHandler {

		@SuppressWarnings("unchecked")
		public Mono<ServerResponse> attributes(ServerRequest request) {
			assertThat(request.attributes().containsKey(RouterFunctions.REQUEST_ATTRIBUTE)).isTrue();
			assertThat(request.attributes().containsKey(HandlerMapping.BEST_MATCHING_HANDLER_ATTRIBUTE)).isTrue();

			Map<String, String> pathVariables =
					(Map<String, String>) request.attributes().get(RouterFunctions.URI_TEMPLATE_VARIABLES_ATTRIBUTE);
			assertThat(pathVariables).isNotNull();
			assertThat(pathVariables).hasSize(1);
			assertThat(pathVariables.get("foo")).isEqualTo("bar");

			pathVariables =
					(Map<String, String>) request.attributes().get(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);
			assertThat(pathVariables).isNotNull();
			assertThat(pathVariables).hasSize(1);
			assertThat(pathVariables.get("foo")).isEqualTo("bar");


			PathPattern pattern =
					(PathPattern) request.attributes().get(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE);
			assertThat(pattern).isNotNull();
			assertThat(pattern.getPatternString()).isEqualTo("/attributes/{foo}");

			pattern = (PathPattern) request.attributes()
					.get(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
			assertThat(pattern).isNotNull();
			assertThat(pattern.getPatternString()).isEqualTo("/attributes/{foo}");

			return ServerResponse.ok().build();
		}
	}


	@Controller
	public static class PersonController {

		@RequestMapping("/controller")
		@ResponseBody
		public Mono<Person> controller() {
			return Mono.just(new Person("John"));
		}
	}


	private static class Person {

		private String name;

		@SuppressWarnings("unused")
		public Person() {
		}

		public Person(String name) {
			this.name = name;
		}

		public String getName() {
			return this.name;
		}

		@SuppressWarnings("unused")
		public void setName(String name) {
			this.name = name;
		}

		@Override
		public boolean equals(@Nullable Object o) {
			if (this == o) {
				return true;
			}
			if (o == null || getClass() != o.getClass()) {
				return false;
			}
			Person person = (Person) o;
			return Objects.equals(this.name, person.name);
		}

		@Override
		public int hashCode() {
			return this.name != null ? this.name.hashCode() : 0;
		}

		@Override
		public String toString() {
			return "Person{" + "name='" + this.name + '\'' + '}';
		}
	}

}
