/*
 * 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.actuate.endpoint.web.annotation;

import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Supplier;
import java.util.stream.Collectors;

import javax.servlet.GenericServlet;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.junit.Test;

import org.springframework.boot.actuate.endpoint.EndpointId;
import org.springframework.boot.actuate.endpoint.ExposableEndpoint;
import org.springframework.boot.actuate.endpoint.annotation.DiscoveredEndpoint;
import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
import org.springframework.boot.actuate.endpoint.web.EndpointServlet;
import org.springframework.boot.actuate.endpoint.web.ExposableServletEndpoint;
import org.springframework.boot.autoconfigure.AutoConfigurations;
import org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration;
import org.springframework.boot.test.context.assertj.AssertableApplicationContext;
import org.springframework.boot.test.context.runner.ApplicationContextRunner;
import org.springframework.boot.test.context.runner.ContextConsumer;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.validation.annotation.Validated;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatExceptionOfType;

/**
 * Tests for {@link ServletEndpointDiscoverer}.
 *
 * @author Phillip Webb
 * @author Stephane Nicoll
 */
public class ServletEndpointDiscovererTests {

	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner();

	@Test
	public void getEndpointsWhenNoEndpointBeansShouldReturnEmptyCollection() {
		this.contextRunner.withUserConfiguration(EmptyConfiguration.class)
				.run(assertDiscoverer(
						(discoverer) -> assertThat(discoverer.getEndpoints()).isEmpty()));
	}

	@Test
	public void getEndpointsShouldIncludeServletEndpoints() {
		this.contextRunner.withUserConfiguration(TestServletEndpoint.class)
				.run(assertDiscoverer((discoverer) -> {
					Collection<ExposableServletEndpoint> endpoints = discoverer
							.getEndpoints();
					assertThat(endpoints).hasSize(1);
					ExposableServletEndpoint endpoint = endpoints.iterator().next();
					assertThat(endpoint.getEndpointId())
							.isEqualTo(EndpointId.of("testservlet"));
					assertThat(endpoint.getEndpointServlet()).isNotNull();
					assertThat(endpoint).isInstanceOf(DiscoveredEndpoint.class);
				}));
	}

	@Test
	public void getEndpointsShouldDiscoverProxyServletEndpoints() {
		this.contextRunner.withUserConfiguration(TestProxyServletEndpoint.class)
				.withConfiguration(
						AutoConfigurations.of(ValidationAutoConfiguration.class))
				.run(assertDiscoverer((discoverer) -> {
					Collection<ExposableServletEndpoint> endpoints = discoverer
							.getEndpoints();
					assertThat(endpoints).hasSize(1);
					ExposableServletEndpoint endpoint = endpoints.iterator().next();
					assertThat(endpoint.getEndpointId())
							.isEqualTo(EndpointId.of("testservlet"));
					assertThat(endpoint.getEndpointServlet()).isNotNull();
					assertThat(endpoint).isInstanceOf(DiscoveredEndpoint.class);
				}));
	}

	@Test
	public void getEndpointsShouldNotDiscoverRegularEndpoints() {
		this.contextRunner.withUserConfiguration(WithRegularEndpointConfiguration.class)
				.run(assertDiscoverer((discoverer) -> {
					Collection<ExposableServletEndpoint> endpoints = discoverer
							.getEndpoints();
					List<EndpointId> ids = endpoints.stream()
							.map(ExposableEndpoint::getEndpointId)
							.collect(Collectors.toList());
					assertThat(ids).containsOnly(EndpointId.of("testservlet"));
				}));
	}

	@Test
	public void getEndpointWhenEndpointHasOperationsShouldThrowException() {
		this.contextRunner.withUserConfiguration(TestServletEndpointWithOperation.class)
				.run(assertDiscoverer((discoverer) -> assertThatExceptionOfType(
						IllegalStateException.class).isThrownBy(discoverer::getEndpoints)
								.withMessageContaining(
										"ServletEndpoints must not declare operations")));
	}

	@Test
	public void getEndpointWhenEndpointNotASupplierShouldThrowException() {
		this.contextRunner.withUserConfiguration(TestServletEndpointNotASupplier.class)
				.run(assertDiscoverer((discoverer) -> assertThatExceptionOfType(
						IllegalStateException.class).isThrownBy(discoverer::getEndpoints)
								.withMessageContaining("must be a supplier")));
	}

	@Test
	public void getEndpointWhenEndpointSuppliesWrongTypeShouldThrowException() {
		this.contextRunner
				.withUserConfiguration(TestServletEndpointSupplierOfWrongType.class)
				.run(assertDiscoverer((discoverer) -> assertThatExceptionOfType(
						IllegalStateException.class).isThrownBy(discoverer::getEndpoints)
								.withMessageContaining(
										"must supply an EndpointServlet")));
	}

	@Test
	public void getEndpointWhenEndpointSuppliesNullShouldThrowException() {
		this.contextRunner.withUserConfiguration(TestServletEndpointSupplierOfNull.class)
				.run(assertDiscoverer((discoverer) -> assertThatExceptionOfType(
						IllegalStateException.class).isThrownBy(discoverer::getEndpoints)
								.withMessageContaining("must not supply null")));
	}

	private ContextConsumer<AssertableApplicationContext> assertDiscoverer(
			Consumer<ServletEndpointDiscoverer> consumer) {
		return (context) -> {
			ServletEndpointDiscoverer discoverer = new ServletEndpointDiscoverer(context,
					null, Collections.emptyList());
			consumer.accept(discoverer);
		};
	}

	@Configuration(proxyBeanMethods = false)
	static class EmptyConfiguration {

	}

	@Configuration(proxyBeanMethods = false)
	@Import({ TestEndpoint.class, TestServletEndpoint.class })
	static class WithRegularEndpointConfiguration {

	}

	@ServletEndpoint(id = "testservlet")
	static class TestServletEndpoint implements Supplier<EndpointServlet> {

		@Override
		public EndpointServlet get() {
			return new EndpointServlet(TestServlet.class);
		}

	}

	@ServletEndpoint(id = "testservlet")
	@Validated
	static class TestProxyServletEndpoint implements Supplier<EndpointServlet> {

		@Override
		public EndpointServlet get() {
			return new EndpointServlet(TestServlet.class);
		}

	}

	@Endpoint(id = "test")
	static class TestEndpoint {

	}

	@ServletEndpoint(id = "testservlet")
	static class TestServletEndpointWithOperation implements Supplier<EndpointServlet> {

		@Override
		public EndpointServlet get() {
			return new EndpointServlet(TestServlet.class);
		}

		@ReadOperation
		public String read() {
			return "error";
		}

	}

	private static class TestServlet extends GenericServlet {

		@Override
		public void service(ServletRequest req, ServletResponse res)
				throws ServletException, IOException {
		}

	}

	@ServletEndpoint(id = "testservlet")
	static class TestServletEndpointNotASupplier {

	}

	@ServletEndpoint(id = "testservlet")
	static class TestServletEndpointSupplierOfWrongType implements Supplier<String> {

		@Override
		public String get() {
			return "error";
		}

	}

	@ServletEndpoint(id = "testservlet")
	static class TestServletEndpointSupplierOfNull implements Supplier<EndpointServlet> {

		@Override
		public EndpointServlet get() {
			return null;
		}

	}

}
