/*
 * Copyright 2013-2019 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.cloud.sleuth.instrument.web;

import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicReference;

import brave.Span;
import brave.Tracer;
import brave.sampler.Sampler;
import org.awaitility.Awaitility;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.cloud.sleuth.SpanName;
import org.springframework.cloud.sleuth.instrument.DefaultTestAutoConfiguration;
import org.springframework.cloud.sleuth.util.ArrayListSpanReporter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.task.SimpleAsyncTaskExecutor;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.test.context.junit4.SpringRunner;

import static java.util.concurrent.TimeUnit.SECONDS;
import static org.assertj.core.api.BDDAssertions.then;

@RunWith(SpringRunner.class)
@SpringBootTest(
		classes = { TraceAsyncIntegrationTests.TraceAsyncITestConfiguration.class },
		properties = "spring.sleuth.http.legacy.enabled=true")
public class TraceAsyncIntegrationTests {

	@Autowired
	ClassPerformingAsyncLogic classPerformingAsyncLogic;

	@Autowired
	Tracer tracer;

	@Autowired
	ArrayListSpanReporter reporter;

	@Before
	public void cleanup() {
		this.reporter.clear();
		this.classPerformingAsyncLogic.clear();
	}

	@Test
	public void should_set_span_on_an_async_annotated_method() {
		whenAsyncProcessingTakesPlace();

		thenANewAsyncSpanGetsCreated();
	}

	@Test
	public void should_set_span_with_custom_method_on_an_async_annotated_method() {
		whenAsyncProcessingTakesPlaceWithCustomSpanName();

		thenAsyncSpanHasCustomName();
	}

	@Test
	public void should_continue_a_span_on_an_async_annotated_method() {
		Span span = givenASpanInCurrentThread();

		try (Tracer.SpanInScope ws = this.tracer.withSpanInScope(span)) {
			whenAsyncProcessingTakesPlace();
		}
		finally {
			span.finish();
		}

		thenTraceIdIsPassedFromTheCurrentThreadToTheAsyncOne(span);
	}

	@Test
	public void should_continue_a_span_with_custom_method_on_an_async_annotated_method() {
		Span span = givenASpanInCurrentThread();

		try (Tracer.SpanInScope ws = this.tracer.withSpanInScope(span)) {
			whenAsyncProcessingTakesPlaceWithCustomSpanName();
		}
		finally {
			span.finish();
		}

		thenTraceIdIsPassedFromTheCurrentThreadToTheAsyncOneAndSpanHasCustomName(span);
	}

	private Span givenASpanInCurrentThread() {
		return this.tracer.nextSpan().name("http:existing");
	}

	private void whenAsyncProcessingTakesPlace() {
		this.classPerformingAsyncLogic.invokeAsynchronousLogic();
	}

	private void whenAsyncProcessingTakesPlaceWithCustomSpanName() {
		this.classPerformingAsyncLogic.customNameInvokeAsynchronousLogic();
	}

	private void thenTraceIdIsPassedFromTheCurrentThreadToTheAsyncOne(final Span span) {
		Awaitility.await().atMost(5, SECONDS).untilAsserted(() -> {
			then(TraceAsyncIntegrationTests.this.classPerformingAsyncLogic.getSpan()
					.context().traceId()).isEqualTo(span.context().traceId());
			then(this.reporter.getSpans()).hasSize(2);
			// HTTP
			then(this.reporter.getSpans().get(0).name()).isEqualTo("http:existing");
			// ASYNC
			then(this.reporter.getSpans().get(1).tags())
					.containsEntry("class", "ClassPerformingAsyncLogic")
					.containsEntry("method", "invokeAsynchronousLogic");
		});
	}

	private void thenANewAsyncSpanGetsCreated() {
		Awaitility.await().atMost(5, SECONDS).untilAsserted(() -> {
			then(this.reporter.getSpans()).hasSize(1);
			zipkin2.Span storedSpan = this.reporter.getSpans().get(0);
			then(storedSpan.name()).isEqualTo("invoke-asynchronous-logic");
			then(storedSpan.tags()).containsEntry("class", "ClassPerformingAsyncLogic")
					.containsEntry("method", "invokeAsynchronousLogic");
		});
	}

	private void thenTraceIdIsPassedFromTheCurrentThreadToTheAsyncOneAndSpanHasCustomName(
			final Span span) {
		Awaitility.await().atMost(5, SECONDS).untilAsserted(() -> {
			then(TraceAsyncIntegrationTests.this.classPerformingAsyncLogic.getSpan()
					.context().traceId()).isEqualTo(span.context().traceId());
			then(this.reporter.getSpans()).hasSize(2);
			// HTTP
			then(this.reporter.getSpans().get(0).name()).isEqualTo("http:existing");
			// ASYNC
			then(this.reporter.getSpans().get(1).tags())
					.containsEntry("class", "ClassPerformingAsyncLogic")
					.containsEntry("method", "customNameInvokeAsynchronousLogic");
		});
	}

	private void thenAsyncSpanHasCustomName() {
		Awaitility.await().atMost(5, SECONDS).untilAsserted(() -> {
			then(this.reporter.getSpans()).hasSize(1);
			zipkin2.Span storedSpan = this.reporter.getSpans().get(0);
			then(storedSpan.name()).isEqualTo("foo");
			then(storedSpan.tags()).containsEntry("class", "ClassPerformingAsyncLogic")
					.containsEntry("method", "customNameInvokeAsynchronousLogic");
		});
	}

	@After
	public void cleanTrace() {
		this.reporter.clear();
	}

	@DefaultTestAutoConfiguration
	@EnableAsync
	@Configuration
	static class TraceAsyncITestConfiguration {

		@Bean
		ClassPerformingAsyncLogic asyncClass(Tracer tracer) {
			return new ClassPerformingAsyncLogic(tracer);
		}

		@Bean
		Sampler defaultSampler() {
			return Sampler.ALWAYS_SAMPLE;
		}

		@Bean
		ArrayListSpanReporter reporter() {
			return new ArrayListSpanReporter();
		}

		@Bean
		Executor fooExecutor() {
			return new SimpleAsyncTaskExecutor();
		}

		@Bean
		Executor barExecutor() {
			return new SimpleAsyncTaskExecutor();
		}

	}

	static class ClassPerformingAsyncLogic {

		private final Tracer tracer;

		AtomicReference<Span> span = new AtomicReference<>();

		ClassPerformingAsyncLogic(Tracer tracer) {
			this.tracer = tracer;
		}

		@Async("fooExecutor")
		public void invokeAsynchronousLogic() {
			this.span.set(this.tracer.currentSpan());
		}

		@Async
		@SpanName("foo")
		public void customNameInvokeAsynchronousLogic() {
			this.span.set(this.tracer.currentSpan());
		}

		public Span getSpan() {
			return this.span.get();
		}

		public void clear() {
			this.span.set(null);
		}

	}

}
