/*
 * Copyright 2024 Google LLC
 *
 * 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
 *
 *       http://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 com.google.cloud.firestore.it;

import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_BATCH_COMMIT;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_BULK_WRITER_COMMIT;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_COL_REF_LIST_DOCUMENTS;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_DOC_REF_CREATE;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_DOC_REF_DELETE;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_DOC_REF_GET;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_DOC_REF_LIST_COLLECTIONS;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_DOC_REF_SET;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_DOC_REF_UPDATE;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_PARTITION_QUERY;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_QUERY_GET;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_TRANSACTION_BEGIN;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_TRANSACTION_COMMIT;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_TRANSACTION_GET_AGGREGATION_QUERY;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_TRANSACTION_GET_DOCUMENTS;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_TRANSACTION_GET_QUERY;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_TRANSACTION_ROLLBACK;
import static com.google.cloud.firestore.telemetry.TelemetryConstants.METHOD_NAME_TRANSACTION_RUN;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
import static org.junit.Assume.assumeTrue;

import com.google.api.gax.rpc.NotFoundException;
import com.google.cloud.firestore.BulkWriter;
import com.google.cloud.firestore.BulkWriterOptions;
import com.google.cloud.firestore.CollectionGroup;
import com.google.cloud.firestore.DocumentReference;
import com.google.cloud.firestore.FieldMask;
import com.google.cloud.firestore.FieldPath;
import com.google.cloud.firestore.Firestore;
import com.google.cloud.firestore.FirestoreOpenTelemetryOptions;
import com.google.cloud.firestore.FirestoreOptions;
import com.google.cloud.firestore.Precondition;
import com.google.cloud.firestore.Query;
import com.google.cloud.firestore.SetOptions;
import com.google.cloud.firestore.WriteBatch;
import com.google.cloud.firestore.it.ITTracingTest.Pojo;
import com.google.cloud.opentelemetry.trace.TraceConfiguration;
import com.google.cloud.opentelemetry.trace.TraceExporter;
import com.google.cloud.trace.v1.TraceServiceClient;
import com.google.common.base.Preconditions;
import com.google.devtools.cloudtrace.v1.Trace;
import com.google.devtools.cloudtrace.v1.TraceSpan;
import io.opentelemetry.api.GlobalOpenTelemetry;
import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.SpanContext;
import io.opentelemetry.api.trace.TraceFlags;
import io.opentelemetry.api.trace.TraceState;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.context.Context;
import io.opentelemetry.context.Scope;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.common.CompletableResultCode;
import io.opentelemetry.sdk.resources.Resource;
import io.opentelemetry.sdk.trace.SdkTracerProvider;
import io.opentelemetry.sdk.trace.export.BatchSpanProcessor;
import io.opentelemetry.sdk.trace.export.SpanExporter;
import io.opentelemetry.sdk.trace.samplers.Sampler;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.TreeMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

// This End-to-End test verifies Client-side Tracing Functionality instrumented using the
// OpenTelemetry API.
// The test depends on the following external APIs/Services:
// 1. Java OpenTelemetry SDK
// 2. Cloud Trace Exporter
// 3. TraceServiceClient from Cloud Trace API v1.
//
// Permissions required to run this test (https://cloud.google.com/trace/docs/iam#trace-roles):
// 1. gcloud auth application-default login must be run with the test user.
// 2. To write traces, test user must have one of roles/cloudtrace.[admin|agent|user] roles.
// 3. To read traces, test user must have one of roles/cloudtrace.[admin|user] roles.
//
// Each test-case has the following workflow:
// 1. OpenTelemetry SDK is initialized with Cloud Trace Exporter and 100% Trace Sampling
// 2. On initialization, Firestore client is provided the OpenTelemetry SDK object from (1)
// 3. A custom TraceID is generated and injected using a custom SpanContext
// 4. Firestore operations are run inside a root TraceSpan created using the custom SpanContext from
// (3).
// 5. Traces are read-back using TraceServiceClient and verified against expected Call Stacks.
// TODO In the future it would be great to have a single test-driver for this test and
// ITTracingTest.
public abstract class ITE2ETracingTest extends ITBaseTest {
  protected abstract boolean isUsingGlobalOpenTelemetrySDK();

  // Helper class to track call-stacks in a trace
  protected static class TraceContainer {

    // Maps Span ID to TraceSpan
    private final Map<Long, TraceSpan> idSpanMap;

    // Maps Parent Span ID to a list of Child SpanIDs, useful for top-down traversal
    private final Map<Long, List<Long>> parentChildIdMap;

    // Tracks the Root Span ID
    private long rootId;

    public TraceContainer(String rootSpanName, Trace trace) {
      idSpanMap = new TreeMap<>();
      parentChildIdMap = new TreeMap<>();
      for (TraceSpan span : trace.getSpansList()) {
        long spanId = span.getSpanId();
        idSpanMap.put(spanId, span);
        if (rootSpanName.equals(span.getName())) {
          rootId = span.getSpanId();
        }

        // Add self as a child of the parent span
        if (!parentChildIdMap.containsKey(span.getParentSpanId())) {
          parentChildIdMap.put(span.getParentSpanId(), new ArrayList<>());
        }
        parentChildIdMap.get(span.getParentSpanId()).add(spanId);
      }
    }

    String spanName(long spanId) {
      return idSpanMap.get(spanId).getName();
    }

    List<Long> childSpans(long spanId) {
      return parentChildIdMap.get(spanId);
    }

    // This method only works for matching call stacks with traces which have children of distinct
    // type at all levels. This is good enough as the intention is to validate if the e2e path is
    // WAI - the intention is not to validate Cloud Trace's correctness w.r.t. durability of all
    // kinds of traces.
    boolean containsCallStack(String... callStack) throws RuntimeException {
      List<String> expectedCallStack = Arrays.asList(callStack);
      if (expectedCallStack.isEmpty()) {
        throw new RuntimeException("Input callStack is empty");
      }
      return dfsContainsCallStack(rootId, expectedCallStack);
    }

    // Depth-first check for call stack in the trace
    private boolean dfsContainsCallStack(long spanId, List<String> expectedCallStack) {
      logger.info(
          "span="
              + spanName(spanId)
              + ", expectedCallStack[0]="
              + (expectedCallStack.isEmpty() ? "null" : expectedCallStack.get(0)));
      if (expectedCallStack.isEmpty()) {
        return false;
      }
      if (spanName(spanId).equals(expectedCallStack.get(0))) {
        // Recursion termination
        if (childSpans(spanId) == null) {
          logger.info("No more children for " + spanName(spanId));
          return true;
        } else {
          // Examine the child spans
          for (Long childSpan : childSpans(spanId)) {
            int callStackListSize = expectedCallStack.size();
            logger.info(
                "childSpan="
                    + spanName(childSpan)
                    + ", expectedCallStackSize="
                    + callStackListSize);
            if (dfsContainsCallStack(
                childSpan,
                expectedCallStack.subList(
                    /* fromIndexInclusive= */ 1, /*toIndexExclusive*/ callStackListSize))) {
              return true;
            }
          }
        }
      } else {
        logger.info(spanName(spanId) + " didn't match " + expectedCallStack.get(0));
      }
      return false;
    }
  }

  private static final Logger logger = Logger.getLogger(ITE2ETracingTest.class.getName());

  private static final String SERVICE = "google.firestore.v1.Firestore/";

  private static final String BATCH_GET_DOCUMENTS_RPC_NAME = "BatchGetDocuments";

  private static final String BATCH_WRITE_RPC_NAME = "BatchWrite";

  private static final String BEGIN_TRANSACTION_RPC_NAME = "BeginTransaction";

  private static final String COMMIT_RPC_NAME = "Commit";

  private static final String LIST_COLLECTIONS_RPC_NAME = "ListCollectionIds";

  private static final String LIST_DOCUMENTS_RPC_NAME = "ListDocuments";

  private static final String ROLLBACK_RPC_NAME = "Rollback";

  private static final String RUN_AGGREGATION_QUERY_RPC_NAME = "RunAggregationQuery";

  private static final String RUN_QUERY_RPC_NAME = "RunQuery";

  private static final int NUM_TRACE_ID_BYTES = 32;

  private static final int NUM_SPAN_ID_BYTES = 16;

  private static final int GET_TRACE_RETRY_COUNT = 60;

  private static final int GET_TRACE_RETRY_BACKOFF_MILLIS = 1000;

  private static final int TRACE_FORCE_FLUSH_MILLIS = 3000;

  private static final int TRACE_PROVIDER_SHUTDOWN_MILLIS = 1000;

  // Random int generator for trace ID and span ID
  private static Random random;

  private static SpanExporter traceExporter;

  // Required for reading back traces from Cloud Trace for validation
  private static TraceServiceClient traceClient_v1;

  // Custom SpanContext for each test, required for TraceID injection
  private static SpanContext customSpanContext;

  // Trace read back from Cloud Trace using traceClient_v1 for verification
  private static Trace retrievedTrace;

  private static String rootSpanName;
  private static Tracer tracer;

  // Required to set custom-root span
  private static OpenTelemetrySdk openTelemetrySdk;

  private static boolean isNightlyTesting;
  private static String projectId;

  private static Firestore firestore;

  @BeforeClass
  public static void setup() throws IOException {
    String jobType = System.getenv("GITHUB_ENV_VAR_KOKORO_JOB_TYPE");
    isNightlyTesting = jobType != null && jobType.equalsIgnoreCase("nightly");

    projectId = FirestoreOptions.getDefaultProjectId();
    logger.info("projectId:" + projectId);

    // TODO(jimit) Make it re-usable w/ InMemorySpanExporter
    traceExporter =
        TraceExporter.createWithConfiguration(
            TraceConfiguration.builder().setProjectId(projectId).build());

    traceClient_v1 = TraceServiceClient.create();

    random = new Random();
  }

  @Before
  public void before() throws Exception {
    // Set up OTel SDK
    Resource resource = Resource.getDefault();

    if (isUsingGlobalOpenTelemetrySDK()) {
      GlobalOpenTelemetry.resetForTest();
      openTelemetrySdk =
          OpenTelemetrySdk.builder()
              .setTracerProvider(
                  SdkTracerProvider.builder()
                      .setResource(resource)
                      .addSpanProcessor(BatchSpanProcessor.builder(traceExporter).build())
                      .setSampler(Sampler.alwaysOn())
                      .build())
              .buildAndRegisterGlobal();
    } else {
      openTelemetrySdk =
          OpenTelemetrySdk.builder()
              .setTracerProvider(
                  SdkTracerProvider.builder()
                      .setResource(resource)
                      .addSpanProcessor(BatchSpanProcessor.builder(traceExporter).build())
                      .setSampler(Sampler.alwaysOn())
                      .build())
              .build();
    }

    // Initialize the Firestore DB w/ the OTel SDK. Ideally we'd do this is the @BeforeAll method
    // but because gRPC traces need to be deterministically force-flushed, firestore.shutdown()
    // must be called in @After for each test.
    FirestoreOptions.Builder optionsBuilder = FirestoreOptions.newBuilder();
    if (!isUsingGlobalOpenTelemetrySDK()) {
      optionsBuilder =
          optionsBuilder.setOpenTelemetryOptions(
              FirestoreOpenTelemetryOptions.newBuilder()
                  .setOpenTelemetry(openTelemetrySdk)
                  .build());
    }

    String namedDb = System.getProperty("FIRESTORE_NAMED_DATABASE");
    if (namedDb != null) {
      logger.log(Level.INFO, "Integration test using named database " + namedDb);
      optionsBuilder = optionsBuilder.setDatabaseId(namedDb);
    } else {
      logger.log(Level.INFO, "Integration test using default database.");
    }
    firestore = optionsBuilder.build().getService();
    Preconditions.checkNotNull(
        firestore,
        "Error instantiating Firestore. Check that the service account credentials "
            + "were properly set.");

    // Set up the tracer for custom TraceID injection
    rootSpanName =
        String.format("%s%d", this.getClass().getSimpleName(), System.currentTimeMillis());
    if (isUsingGlobalOpenTelemetrySDK()) {
      tracer = GlobalOpenTelemetry.getTracer(rootSpanName);
    } else {
      tracer =
          firestore
              .getOptions()
              .getOpenTelemetryOptions()
              .getOpenTelemetry()
              .getTracer(rootSpanName);
    }

    // Get up a new SpanContext (ergo TraceId) for each test
    customSpanContext = getNewSpanContext();
    assertNotNull(customSpanContext);
    assertNull(retrievedTrace);

    // We only perform end-to-end tracing tests on a nightly basis.
    assumeTrue(isNightlyTesting);
  }

  @After
  public void after() throws Exception {
    firestore.shutdown();
    rootSpanName = null;
    tracer = null;
    retrievedTrace = null;
    customSpanContext = null;
  }

  @AfterClass
  public static void teardown() throws Exception {
    traceClient_v1.close();
    CompletableResultCode completableResultCode =
        openTelemetrySdk.getSdkTracerProvider().shutdown();
    completableResultCode.join(TRACE_PROVIDER_SHUTDOWN_MILLIS, TimeUnit.MILLISECONDS);
  }

  // Generates a random hex string of length `numBytes`
  private String generateRandomHexString(int numBytes) {
    StringBuffer newTraceId = new StringBuffer();
    while (newTraceId.length() < numBytes) {
      newTraceId.append(Integer.toHexString(random.nextInt()));
    }
    return newTraceId.substring(0, numBytes);
  }

  protected String generateNewTraceId() {
    return generateRandomHexString(NUM_TRACE_ID_BYTES);
  }

  // Generates a random 16-byte hex string
  protected String generateNewSpanId() {
    return generateRandomHexString(NUM_SPAN_ID_BYTES);
  }

  // Generates a new SpanContext w/ random traceId,spanId
  protected SpanContext getNewSpanContext() {
    String traceId = generateNewTraceId();
    String spanId = generateNewSpanId();
    logger.info("traceId=" + traceId + ", spanId=" + spanId);

    return SpanContext.create(traceId, spanId, TraceFlags.getSampled(), TraceState.getDefault());
  }

  protected Span getNewRootSpanWithContext() {
    // Execute the DB operation in the context of the custom root span.
    return tracer
        .spanBuilder(rootSpanName)
        .setParent(Context.root().with(Span.wrap(customSpanContext)))
        .startSpan();
  }

  protected String grpcSpanName(String rpcName) {
    return "Sent." + SERVICE + rpcName;
  }

  protected void waitForTracesToComplete() throws Exception {
    logger.info("Flushing traces...");
    CompletableResultCode completableResultCode =
        openTelemetrySdk.getSdkTracerProvider().forceFlush();
    completableResultCode.join(TRACE_FORCE_FLUSH_MILLIS, TimeUnit.MILLISECONDS);
  }

  // Validates `retrievedTrace`. Cloud Trace indexes traces w/ eventual consistency, even when
  // indexing traceId, therefore the test must retry a few times before the complete trace is
  // available.
  // For Transaction traces, there may be more spans than in the trace than specified in
  // `callStack`. So `numExpectedSpans` is the expected total number of spans (and not just the
  // spans in `callStack`)
  protected void fetchAndValidateTrace(
      String traceId, int numExpectedSpans, List<List<String>> callStackList)
      throws InterruptedException {
    // Large enough count to accommodate eventually consistent Cloud Trace backend
    int numRetries = GET_TRACE_RETRY_COUNT;
    // Account for rootSpanName
    numExpectedSpans++;

    // Fetch traces
    do {
      try {
        retrievedTrace = traceClient_v1.getTrace(projectId, traceId);
        assertEquals(traceId, retrievedTrace.getTraceId());

        logger.info(
            "expectedSpanCount="
                + numExpectedSpans
                + ", retrievedSpanCount="
                + retrievedTrace.getSpansCount());
      } catch (NotFoundException notFound) {
        logger.info("Trace not found, retrying in " + GET_TRACE_RETRY_BACKOFF_MILLIS + " ms");
      } catch (IndexOutOfBoundsException outOfBoundsException) {
        logger.info("Call stack not found in trace. Retrying.");
      }
      if (retrievedTrace == null || numExpectedSpans != retrievedTrace.getSpansCount()) {
        Thread.sleep(GET_TRACE_RETRY_BACKOFF_MILLIS);
      }
    } while (numRetries-- > 0
        && (retrievedTrace == null || numExpectedSpans != retrievedTrace.getSpansCount()));

    if (retrievedTrace == null || numExpectedSpans != retrievedTrace.getSpansCount()) {
      throw new RuntimeException(
          "Expected number of spans: "
              + numExpectedSpans
              + ", Actual number of spans: "
              + (retrievedTrace != null
                  ? retrievedTrace.getSpansList().toString()
                  : "Trace NOT_FOUND"));
    }

    TraceContainer traceContainer = new TraceContainer(rootSpanName, retrievedTrace);

    for (List<String> callStack : callStackList) {
      // Update all call stacks to be rooted at rootSpanName
      ArrayList<String> expectedCallStack = new ArrayList<>(callStack);

      // numExpectedSpans should account for rootSpanName (not passed in callStackList)
      expectedCallStack.add(0, rootSpanName);

      // *May be* the full trace was returned
      logger.info("Checking if TraceContainer contains the callStack");
      String[] expectedCallList = new String[expectedCallStack.size()];
      if (!traceContainer.containsCallStack(expectedCallStack.toArray(expectedCallList))) {
        throw new RuntimeException(
            "Expected spans: "
                + expectedCallList.toString()
                + ", Actual spans: "
                + (retrievedTrace != null
                    ? retrievedTrace.getSpansList().toString()
                    : "Trace NOT_FOUND"));
      }
      logger.severe("CallStack not found in TraceContainer.");
    }
  }

  // Validates `retrievedTrace`. Cloud Trace indexes traces w/ eventual consistency, even when
  // indexing traceId, therefore the test must retry a few times before the complete trace is
  // available.
  // For Non-Transaction traces, there is a 1:1 ratio of spans in `spanNames` and in the trace.
  protected void fetchAndValidateTrace(String traceId, String... spanNames)
      throws InterruptedException {
    fetchAndValidateTrace(traceId, spanNames.length, Arrays.asList(Arrays.asList(spanNames)));
  }

  @Test
  public void traceContainerTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").whereEqualTo("foo", "my_non_existent_value").get().get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    Trace traceResp = null;
    int expectedSpanCount = 3;

    int numRetries = GET_TRACE_RETRY_COUNT;
    do {
      try {
        traceResp = traceClient_v1.getTrace(projectId, customSpanContext.getTraceId());
        if (traceResp.getSpansCount() == expectedSpanCount) {
          logger.info("Success: Got " + expectedSpanCount + " spans.");
          break;
        }
      } catch (NotFoundException notFoundException) {
        Thread.sleep(GET_TRACE_RETRY_BACKOFF_MILLIS);
        logger.info("Trace not found, retrying in " + GET_TRACE_RETRY_BACKOFF_MILLIS + " ms");
      }
      logger.info(
          "Trace Found. The trace did not contain "
              + expectedSpanCount
              + " spans. Going to retry.");
      numRetries--;
    } while (numRetries > 0);

    // Make sure we got as many spans as we expected.
    assertNotNull(traceResp);
    assertEquals(expectedSpanCount, traceResp.getSpansCount());

    TraceContainer traceCont = new TraceContainer(rootSpanName, traceResp);

    // Contains exact path
    assertTrue(
        traceCont.containsCallStack(
            rootSpanName, METHOD_NAME_QUERY_GET, grpcSpanName(RUN_QUERY_RPC_NAME)));

    // Top-level mismatch
    assertFalse(traceCont.containsCallStack(METHOD_NAME_QUERY_GET, RUN_QUERY_RPC_NAME));

    // Mid-level match
    assertFalse(traceCont.containsCallStack(rootSpanName, METHOD_NAME_QUERY_GET));

    // Leaf-level mismatch/missing
    assertFalse(
        traceCont.containsCallStack(
            rootSpanName, METHOD_NAME_QUERY_GET, RUN_AGGREGATION_QUERY_RPC_NAME));
  }

  @Test
  // Trace an Aggregation.Get request
  public void aggregateQueryGetTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      // Execute the Firestore SDK op
      firestore.collection("col").count().get().get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        "AggregationQuery.Get",
        grpcSpanName(RUN_AGGREGATION_QUERY_RPC_NAME));
  }

  @Test
  public void bulkWriterCommitTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      // Execute the Firestore SDK op
      ScheduledExecutorService bulkWriterExecutor = Executors.newSingleThreadScheduledExecutor();
      BulkWriter bulkWriter =
          firestore.bulkWriter(BulkWriterOptions.builder().setExecutor(bulkWriterExecutor).build());
      bulkWriter.set(
          firestore.collection("col").document("foo"),
          Collections.singletonMap("bulk-foo", "bulk-bar"));
      bulkWriter.close();
      bulkWriterExecutor.awaitTermination(100, TimeUnit.MILLISECONDS);
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_BULK_WRITER_COMMIT,
        grpcSpanName(BATCH_WRITE_RPC_NAME));
  }

  @Test
  public void partitionQueryTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      CollectionGroup collectionGroup = firestore.collectionGroup("col");
      collectionGroup.getPartitions(3).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_PARTITION_QUERY,
        grpcSpanName(METHOD_NAME_PARTITION_QUERY));
  }

  @Test
  public void collectionListDocumentsTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").listDocuments();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_COL_REF_LIST_DOCUMENTS,
        grpcSpanName(LIST_DOCUMENTS_RPC_NAME));
  }

  @Test
  public void docRefCreateTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document().create(Collections.singletonMap("foo", "bar")).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_CREATE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefCreate2TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document().create(new Pojo(1)).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_CREATE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefSetTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("foo").set(Collections.singletonMap("foo", "bar")).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_SET,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefSet2TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore
          .collection("col")
          .document("foo")
          .set(Collections.singletonMap("foo", "bar"), SetOptions.merge())
          .get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_SET,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefSet3TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("foo").set(new Pojo(1)).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_SET,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefSet4TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("foo").set(new Pojo(1), SetOptions.merge()).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_SET,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefUpdateTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore
          .collection("col")
          .document("foo")
          .update(Collections.singletonMap("foo", "bar"))
          .get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_UPDATE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefUpdate2TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore
          .collection("col")
          .document("foo")
          .update(Collections.singletonMap("foo", "bar"), Precondition.NONE)
          .get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_UPDATE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefUpdate3TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("foo").update("key", "value", "key2", "value2").get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_UPDATE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefUpdate4TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore
          .collection("col")
          .document("foo")
          .update(FieldPath.of("key"), "value", FieldPath.of("key2"), "value2")
          .get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_UPDATE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefUpdate5TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore
          .collection("col")
          .document("foo")
          .update(Precondition.NONE, "key", "value", "key2", "value2")
          .get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_UPDATE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefUpdate6TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore
          .collection("col")
          .document("foo")
          .update(Precondition.NONE, FieldPath.of("key"), "value", FieldPath.of("key2"), "value2")
          .get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_UPDATE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefDeleteTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("doc0").delete().get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_DELETE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefDelete2TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("doc0").delete(Precondition.NONE).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_DELETE,
        METHOD_NAME_BATCH_COMMIT,
        grpcSpanName(COMMIT_RPC_NAME));
  }

  @Test
  public void docRefGetTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("doc0").get().get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_GET,
        grpcSpanName(BATCH_GET_DOCUMENTS_RPC_NAME));
  }

  @Test
  public void docRefGet2TraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("doc0").get(FieldMask.of("foo")).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_GET,
        grpcSpanName(BATCH_GET_DOCUMENTS_RPC_NAME));
  }

  @Test
  public void docListCollectionsTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").document("doc0").listCollections();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    // Read and validate traces
    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        METHOD_NAME_DOC_REF_LIST_COLLECTIONS,
        grpcSpanName(LIST_COLLECTIONS_RPC_NAME));
  }

  @Test
  public void getAllTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      DocumentReference docRef0 = firestore.collection("col").document();
      DocumentReference docRef1 = firestore.collection("col").document();
      DocumentReference[] docs = {docRef0, docRef1};
      firestore.getAll(docs).get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    fetchAndValidateTrace(
        customSpanContext.getTraceId(), grpcSpanName(BATCH_GET_DOCUMENTS_RPC_NAME));
  }

  @Test
  public void queryGetTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore.collection("col").whereEqualTo("foo", "my_non_existent_value").get().get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    fetchAndValidateTrace(
        customSpanContext.getTraceId(), METHOD_NAME_QUERY_GET, grpcSpanName(RUN_QUERY_RPC_NAME));
  }

  @Test
  public void transactionTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore
          .runTransaction(
              transaction -> {
                Query q = firestore.collection("col").whereGreaterThan("bla", "");
                DocumentReference d = firestore.collection("col").document("foo");
                // Document Query.
                transaction.get(q).get();

                // Aggregation Query.
                transaction.get(q.count());

                // Get multiple documents.
                transaction.getAll(d, d).get();

                // Commit 2 documents.
                transaction.set(
                    firestore.collection("foo").document("bar"),
                    Collections.singletonMap("foo", "bar"));
                transaction.set(
                    firestore.collection("foo").document("bar2"),
                    Collections.singletonMap("foo2", "bar2"));
                return 0;
              })
          .get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        /* numExpectedSpans= */ 11,
        Arrays.asList(
            Arrays.asList(
                METHOD_NAME_TRANSACTION_RUN,
                METHOD_NAME_TRANSACTION_BEGIN,
                grpcSpanName(BEGIN_TRANSACTION_RPC_NAME)),
            Arrays.asList(
                METHOD_NAME_TRANSACTION_RUN,
                METHOD_NAME_TRANSACTION_BEGIN,
                grpcSpanName(BEGIN_TRANSACTION_RPC_NAME)),
            Arrays.asList(
                METHOD_NAME_TRANSACTION_RUN,
                METHOD_NAME_TRANSACTION_GET_QUERY,
                grpcSpanName(RUN_QUERY_RPC_NAME)),
            Arrays.asList(
                METHOD_NAME_TRANSACTION_RUN,
                METHOD_NAME_TRANSACTION_GET_AGGREGATION_QUERY,
                grpcSpanName(RUN_AGGREGATION_QUERY_RPC_NAME)),
            Arrays.asList(
                METHOD_NAME_TRANSACTION_RUN,
                METHOD_NAME_TRANSACTION_GET_DOCUMENTS,
                grpcSpanName(BATCH_GET_DOCUMENTS_RPC_NAME)),
            Arrays.asList(
                METHOD_NAME_TRANSACTION_RUN,
                METHOD_NAME_TRANSACTION_COMMIT,
                grpcSpanName(COMMIT_RPC_NAME))));
  }

  @Test
  public void transactionRollbackTraceTest() throws Exception {
    String myErrorMessage = "My error message.";
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      firestore
          .runTransaction(
              transaction -> {
                if (true) {
                  throw (new Exception(myErrorMessage));
                }
                return 0;
              })
          .get();
    } catch (Exception e) {
      // Catch and move on.
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    fetchAndValidateTrace(
        customSpanContext.getTraceId(),
        /* numExpectedSpans= */ 5,
        Arrays.asList(
            Arrays.asList(
                METHOD_NAME_TRANSACTION_RUN,
                METHOD_NAME_TRANSACTION_BEGIN,
                grpcSpanName(BEGIN_TRANSACTION_RPC_NAME)),
            Arrays.asList(
                METHOD_NAME_TRANSACTION_RUN,
                METHOD_NAME_TRANSACTION_ROLLBACK,
                grpcSpanName(ROLLBACK_RPC_NAME))));
  }

  @Test
  public void writeBatchTraceTest() throws Exception {
    // Make sure the test has a new SpanContext (and TraceId for injection)
    assertNotNull(customSpanContext);

    // Inject new trace ID
    Span rootSpan = getNewRootSpanWithContext();
    try (Scope ignored = rootSpan.makeCurrent()) {
      WriteBatch batch = firestore.batch();
      DocumentReference docRef = firestore.collection("foo").document();
      batch.create(docRef, Collections.singletonMap("foo", "bar"));
      batch.update(docRef, Collections.singletonMap("foo", "bar"));
      batch.delete(docRef);
      batch.commit().get();
    } finally {
      rootSpan.end();
    }
    waitForTracesToComplete();

    fetchAndValidateTrace(
        customSpanContext.getTraceId(), METHOD_NAME_BATCH_COMMIT, grpcSpanName(COMMIT_RPC_NAME));
  }
}
