/*
 * Copyright (c) 2011-2019 Contributors to the Eclipse Foundation
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 * which is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 */
package io.vertx.core.spi.tracing;

import io.vertx.core.Context;
import io.vertx.core.http.*;
import io.vertx.test.faketracer.Span;
import io.vertx.test.faketracer.FakeTracer;
import org.junit.Test;

import java.util.List;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import java.util.function.Function;
import java.util.stream.Collectors;

public abstract class HttpTracingTestBase extends HttpTestBase {

  private FakeTracer tracer;

  @Override
  protected VertxTracer getTracer() {
    return tracer = new FakeTracer();
  }

  @Test
  public void testHttpServerRequest() throws Exception {
    server.requestHandler(req -> {
      assertNotNull(tracer.activeSpan());
      req.response().end();
    });
    startServer();
    Context ctx = vertx.getOrCreateContext();
    ctx.runOnContext(v -> {
      Span rootSpan = tracer.newTrace();
      tracer.activate(rootSpan);
      client.getNow(8080, "localhost", "/1", onSuccess(resp -> {
        resp.endHandler(v2 -> {
          assertEquals(rootSpan, tracer.activeSpan());
          assertEquals(200, resp.statusCode());
        });
      }));
    });
    waitUntil(() -> tracer.getFinishedSpans().size() == 2);
    assertSingleTrace(tracer.getFinishedSpans());
  }

  @Test
  public void testHttpServerRequestWithClient() throws Exception {
    server.requestHandler(req -> {
      assertNotNull(tracer.activeSpan());
      switch (req.path()) {
        case "/1": {
          vertx.setTimer(10, id1 -> {
            client.getNow(8080, "localhost", "/2", resp1 -> {
              vertx.setTimer(10, id2 -> {
                client.getNow(8080, "localhost", "/2", resp2 -> {
                  req.response().end();
                });
              });
            });
          });
          break;
        }
        case "/2": {
          req.response().end();
          break;
        }
        default: {
          req.response().setStatusCode(500).end();
        }
      }
    });
    startServer();
    Context ctx = vertx.getOrCreateContext();
    ctx.runOnContext(v -> {
      Span rootSpan = tracer.newTrace();
      tracer.activate(rootSpan);
      client.getNow(8080, "localhost", "/1", onSuccess(resp -> {
        resp.endHandler(v2 -> {
          assertEquals(rootSpan, tracer.activeSpan());
          assertEquals(200, resp.statusCode());
        });
      }));
    });
    // client request to /1, server request /1, client request /2, server request /2
    waitUntil(() -> tracer.getFinishedSpans().size() == 6);
    assertSingleTrace(tracer.getFinishedSpans());
  }

  @Test
  public void testMultipleHttpServerRequest() throws Exception {
    server.requestHandler(req -> {
      assertNotNull(tracer.activeSpan());
      switch (req.path()) {
        case "/1": {
          vertx.setTimer(10, id -> {
            client.getNow(8080, "localhost", "/2", resp -> {
              req.response().end();
            });
          });
          break;
        }
        case "/2": {
          req.response().end();
          break;
        }
        default: {
          req.response().setStatusCode(500).end();
        }
      }
    });
    startServer();

    Context ctx = vertx.getOrCreateContext();
    ctx.runOnContext(v -> {
      Span rootSpan = tracer.newTrace();
      tracer.activate(rootSpan);
      client.getNow(8080, "localhost", "/1", onSuccess(resp -> {
        assertEquals(rootSpan, tracer.activeSpan());
        assertEquals(200, resp.statusCode());
      }));
    });


    waitUntil(() -> tracer.getFinishedSpans().size() == 4);
    List<Span> finishedSpans = tracer.getFinishedSpans();
    assertEquals(4, finishedSpans.size());
    assertSingleTrace(finishedSpans);

    Map<Integer, Span> spanMap = finishedSpans.stream()
      .collect(Collectors.toMap(o -> o.id, Function.identity()));

    List<Span> lastServerSpans = finishedSpans.stream()
      .filter(mockSpan ->  mockSpan.getTags().get("span_kind").equals("server"))
      .filter(mockSpan -> mockSpan.getTags().get("http.url").contains("localhost:8080/2"))
      .collect(Collectors.toList());
    assertEquals(1, lastServerSpans.size());

    String scheme = createBaseServerOptions().isSsl() ? "https" : "http";
    for (Span server2Span: lastServerSpans) {
      Span client2Span = spanMap.get(server2Span.parentId);
      assertEquals("GET", client2Span.operation);
      assertEquals(scheme + "://localhost:8080/2", client2Span.getTags().get("http.url"));
      assertEquals("200", client2Span.getTags().get("http.status_code"));
      assertEquals("client", client2Span.getTags().get("span_kind"));
      Span server1Span = spanMap.get(client2Span.parentId);
      assertEquals("GET", server1Span.operation);
      assertEquals(scheme + "://localhost:8080/1", server1Span.getTags().get("http.url"));
      assertEquals("200", client2Span.getTags().get("http.status_code"));
      assertEquals("server", server1Span.getTags().get("span_kind"));
      Span client1Span = spanMap.get(server1Span.parentId);
      assertEquals("GET", client1Span.operation);
      assertEquals(scheme + "://localhost:8080/1", client1Span.getTags().get("http.url"));
      assertEquals("200", client2Span.getTags().get("http.status_code"));
      assertEquals("client", client1Span.getTags().get("span_kind"));
    }
  }

  private void assertSingleTrace(List<Span> spans) {
    for (int i = 1; i < spans.size(); i++) {
      assertEquals(spans.get(i - 1).traceId, spans.get(i).traceId);
    }
  }
}
