// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/sync/model/syncable_service_based_bridge.h"

#include <string_view>
#include <utility>

#include "base/functional/bind.h"
#include "base/functional/callback_helpers.h"
#include "base/memory/weak_ptr.h"
#include "base/run_loop.h"
#include "base/strings/stringprintf.h"
#include "base/test/bind.h"
#include "base/test/metrics/histogram_tester.h"
#include "base/test/mock_callback.h"
#include "base/test/task_environment.h"
#include "components/sync/base/client_tag_hash.h"
#include "components/sync/engine/data_type_activation_response.h"
#include "components/sync/model/client_tag_based_data_type_processor.h"
#include "components/sync/model/conflict_resolution.h"
#include "components/sync/model/model_error.h"
#include "components/sync/model/sync_change.h"
#include "components/sync/model/syncable_service.h"
#include "components/sync/protocol/persisted_entity_data.pb.h"
#include "components/sync/test/data_type_store_test_util.h"
#include "components/sync/test/mock_data_type_local_change_processor.h"
#include "components/sync/test/mock_data_type_worker.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace syncer {
namespace {

using testing::_;
using testing::ElementsAre;
using testing::Eq;
using testing::IsEmpty;
using testing::NotNull;
using testing::Pair;
using testing::Return;

const DataType kDataType = PREFERENCES;
const std::string_view kSyncableServiceStartTimeHistogramName =
    "Sync.SyncableServiceStartTime.PREFERENCE";
const std::string_view kMaybeClearDataHistogramName =
    "Sync.SyncableService.MaybeClearDataIfMetadataEmptyOrInvalid.PREFERENCE";

sync_pb::EntitySpecifics GetTestSpecifics(const std::string& name = "name") {
  sync_pb::EntitySpecifics specifics;
  // Make specifics non empty, to avoid it being interpreted as a tombstone.
  specifics.mutable_preference()->set_name(name);
  return specifics;
}

MATCHER_P(SyncDataMatches, name, "") {
  return arg.IsValid() && arg.GetDataType() == kDataType &&
         arg.GetSpecifics().preference().name() == name;
}

MATCHER_P2(SyncChangeMatches, change_type, name, "") {
  return arg.change_type() == change_type &&
         arg.sync_data().GetDataType() == kDataType &&
         arg.sync_data().GetSpecifics().preference().name() == name;
}

MATCHER_P(HasName, name, "") {
  return arg && arg->specifics.preference().name() == name;
}

class MockSyncableService : public SyncableService {
 public:
  MOCK_METHOD(void, WaitUntilReadyToSync, (base::OnceClosure done), (override));
  MOCK_METHOD(void, WillStartInitialSync, (), (override));
  MOCK_METHOD(std::optional<syncer::ModelError>,
              MergeDataAndStartSyncing,
              (DataType type,
               const SyncDataList& initial_sync_data,
               std::unique_ptr<SyncChangeProcessor> sync_processor),
              (override));
  MOCK_METHOD(void, StopSyncing, (DataType type), (override));
  MOCK_METHOD(void, StayStoppedAndMaybeClearData, (DataType type), (override));
  MOCK_METHOD(std::optional<ModelError>,
              ProcessSyncChanges,
              (const base::Location& from_here,
               const SyncChangeList& change_list),
              (override));
  MOCK_METHOD(SyncDataList, GetAllSyncData, (DataType type), (const override));

  base::WeakPtr<SyncableService> AsWeakPtr() override {
    return weak_ptr_factory_.GetWeakPtr();
  }
  MOCK_METHOD(std::string,
              GetClientTag,
              (const EntityData& entity_data),
              (const override));
  MOCK_METHOD(bool, SupportsGetClientTag, (), (const override));

 private:
  base::WeakPtrFactory<MockSyncableService> weak_ptr_factory_{this};
};

class SyncableServiceBasedBridgeTest : public ::testing::Test {
 public:
  SyncableServiceBasedBridgeTest(const SyncableServiceBasedBridgeTest&) =
      delete;
  SyncableServiceBasedBridgeTest& operator=(
      const SyncableServiceBasedBridgeTest&) = delete;

 protected:
  SyncableServiceBasedBridgeTest()
      : store_(DataTypeStoreTestUtil::CreateInMemoryStoreForTest()) {
    ON_CALL(syncable_service_, WaitUntilReadyToSync)
        .WillByDefault([](base::OnceClosure done) { std::move(done).Run(); });
    ON_CALL(syncable_service_, MergeDataAndStartSyncing)
        .WillByDefault(
            [&](DataType type, const SyncDataList& initial_sync_data,
                std::unique_ptr<SyncChangeProcessor> sync_processor) {
              start_syncing_sync_processor_ = std::move(sync_processor);
              return std::nullopt;
            });
  }

  ~SyncableServiceBasedBridgeTest() override = default;

  void InitializeBridge(DataType data_type = kDataType) {
    real_processor_ = std::make_unique<syncer::ClientTagBasedDataTypeProcessor>(
        data_type, /*dump_stack=*/base::DoNothing());
    mock_processor_.DelegateCallsByDefaultTo(real_processor_.get());
    bridge_ = std::make_unique<SyncableServiceBasedBridge>(
        data_type,
        DataTypeStoreTestUtil::FactoryForForwardingStore(store_.get()),
        mock_processor_.CreateForwardingProcessor(), &syncable_service_);
  }

  void ShutdownBridge() {
    // `bridge_` must outlive `start_syncing_sync_processor_`, so reset it
    // first.
    start_syncing_sync_processor_.reset();
    bridge_.reset();
    // The mock is still delegating to `real_processor_`, so we reset it too.
    ASSERT_TRUE(testing::Mock::VerifyAndClear(&mock_processor_));
    real_processor_.reset();
  }

  syncer::DataTypeActivationRequest GetTestActivationRequest() {
    syncer::DataTypeActivationRequest request;
    request.error_handler = mock_error_handler_.Get();
    request.cache_guid = "TestCacheGuid";
    request.authenticated_gaia_id = GaiaId("SomeGaiaId");
    return request;
  }

  void StartSyncing() {
    base::RunLoop loop;
    real_processor_->OnSyncStarting(
        GetTestActivationRequest(),
        base::BindLambdaForTesting(
            [&](std::unique_ptr<syncer::DataTypeActivationResponse> response) {
              worker_ = MockDataTypeWorker::CreateWorkerAndConnectSync(
                  std::move(response));
              loop.Quit();
            }));
    loop.Run();

    ASSERT_NE(nullptr, worker_);
  }

  std::map<std::string, std::unique_ptr<EntityData>> GetAllData() {
    std::unique_ptr<DataBatch> batch = bridge_->GetAllDataForDebugging();
    EXPECT_NE(nullptr, batch);

    std::map<std::string, std::unique_ptr<EntityData>> storage_key_to_data;
    while (batch && batch->HasNext()) {
      storage_key_to_data.insert(batch->Next());
    }
    return storage_key_to_data;
  }

  const std::string kClientTag = "clienttag";
  const ClientTagHash kClientTagHash =
      ClientTagHash::FromUnhashed(kDataType, kClientTag);

  base::test::SingleThreadTaskEnvironment task_environment_;
  testing::NiceMock<MockSyncableService> syncable_service_;
  testing::NiceMock<MockDataTypeLocalChangeProcessor> mock_processor_;
  base::MockCallback<ModelErrorHandler> mock_error_handler_;
  const std::unique_ptr<DataTypeStore> store_;
  std::unique_ptr<syncer::ClientTagBasedDataTypeProcessor> real_processor_;
  std::unique_ptr<SyncableServiceBasedBridge> bridge_;
  std::unique_ptr<MockDataTypeWorker> worker_;
  // SyncChangeProcessor received via MergeDataAndStartSyncing(), or null if it
  // hasn't been called.
  std::unique_ptr<SyncChangeProcessor> start_syncing_sync_processor_;
};

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldStartSyncingWithEmptyInitialRemoteData) {
  // Bridge initialization alone, without sync itself starting, should not
  // issue calls to the syncable service.
  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing).Times(0);
  InitializeBridge();

  // Starting sync itself is also not sufficient, until initial remote data is
  // received.
  StartSyncing();

  // Once the initial data is fetched from the server,
  // MergeDataAndStartSyncing() should be exercised.
  EXPECT_CALL(syncable_service_,
              MergeDataAndStartSyncing(kDataType, IsEmpty(), NotNull()));
  worker_->UpdateFromServer();
  EXPECT_THAT(GetAllData(), IsEmpty());
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldStartSyncingWithNonEmptyInitialRemoteData) {
  InitializeBridge();
  StartSyncing();

  // Once the initial data is fetched from the server,
  // MergeDataAndStartSyncing() should be exercised.
  EXPECT_CALL(syncable_service_,
              MergeDataAndStartSyncing(
                  kDataType, ElementsAre(SyncDataMatches("name1")), NotNull()));
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  EXPECT_THAT(GetAllData(), ElementsAre(Pair(kClientTagHash.value(), _)));
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldWaitUntilModelReadyToSync) {
  base::OnceClosure syncable_service_ready_cb;
  ON_CALL(syncable_service_, WaitUntilReadyToSync)
      .WillByDefault([&](base::OnceClosure done) {
        syncable_service_ready_cb = std::move(done);
      });

  EXPECT_CALL(mock_processor_, ModelReadyToSync).Times(0);
  EXPECT_CALL(syncable_service_, WaitUntilReadyToSync).Times(0);
  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing).Times(0);

  // Bridge initialization alone, without sync itself starting, should not
  // issue calls to the syncable service.
  InitializeBridge();

  EXPECT_CALL(syncable_service_, WaitUntilReadyToSync);
  // Required to initialize the store.
  base::RunLoop().RunUntilIdle();
  ASSERT_TRUE(syncable_service_ready_cb);

  // Sync itself starting should wait until the syncable service becomes ready,
  // before issuing any other call (e.g. MergeDataAndStartSyncing()).
  real_processor_->OnSyncStarting(GetTestActivationRequest(),
                                  base::DoNothing());

  // When the SyncableService gets ready, the bridge should propagate this
  // information to the processor.
  EXPECT_CALL(mock_processor_, ModelReadyToSync);
  std::move(syncable_service_ready_cb).Run();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldStopSyncableServiceIfPreviouslyStarted) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer();

  EXPECT_CALL(syncable_service_, StopSyncing(kDataType));
  real_processor_->OnSyncStopping(CLEAR_METADATA);

  EXPECT_CALL(syncable_service_, StopSyncing).Times(0);
  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldStopSyncableServiceDuringShutdownIfPreviouslyStarted) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer();

  EXPECT_CALL(syncable_service_, StopSyncing(kDataType));
  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldNotStopSyncableServiceIfNotPreviouslyStarted) {
  EXPECT_CALL(syncable_service_, StopSyncing).Times(0);
  InitializeBridge();
  StartSyncing();
  real_processor_->OnSyncStopping(KEEP_METADATA);
}

// Regression test for crbug.com/401453180.
TEST_F(SyncableServiceBasedBridgeTest,
       ShouldMaybeClearDataIfPendingClearMetadataOnStart) {
  // Simulate prior initial sync done.
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  ShutdownBridge();

  EXPECT_CALL(syncable_service_, StopSyncing).Times(0);
  EXPECT_CALL(syncable_service_, StayStoppedAndMaybeClearData).Times(0);
  InitializeBridge();

  base::RunLoop loop;
  ON_CALL(syncable_service_, WaitUntilReadyToSync)
      .WillByDefault([&](base::OnceClosure done) {
        // This should mark sync metadata as pending clear on start.
        real_processor_->ClearMetadataIfStopped();
        // Metadata has not been cleared yet.
        ASSERT_THAT(GetAllData(), Not(IsEmpty()));
        std::move(done).Run();
        loop.Quit();
      });

  base::HistogramTester histogram_tester;
  EXPECT_CALL(syncable_service_, StayStoppedAndMaybeClearData(kDataType));
  // The processor should clear the pre-existing metadata and lead to
  // StayStoppedAndMaybeClearData() being called.
  loop.Run();
  histogram_tester.ExpectUniqueSample(kMaybeClearDataHistogramName,
                                      /*sample=*/true,
                                      /*expected_bucket_count=*/1);
  ASSERT_THAT(GetAllData(), IsEmpty());

  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldMaybeClearDataIfMetadataEmpty) {
  base::RunLoop loop;
  EXPECT_CALL(syncable_service_, StayStoppedAndMaybeClearData(kDataType))
      .WillOnce([&]() { loop.Quit(); });
  base::HistogramTester histogram_tester;
  // No metadata exists, thus any account data in the syncable service should be
  // cleared.
  InitializeBridge();
  loop.Run();
  histogram_tester.ExpectUniqueSample(kMaybeClearDataHistogramName,
                                      /*sample=*/true,
                                      /*expected_bucket_count=*/1);

  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldMaybeClearDataIfMetadataInconsistentOnNextStartup) {
  // Simulate pre-existing metadata in the store without initial sync done.
  {
    std::unique_ptr<DataTypeStore::WriteBatch> batch =
        store_->CreateWriteBatch();
    batch->WriteData(kClientTagHash.value(),
                     GetTestSpecifics().SerializeAsString());
    base::RunLoop loop;
    store_->CommitWriteBatch(
        std::move(batch),
        base::BindLambdaForTesting(
            [&](const std::optional<ModelError>& error) { loop.Quit(); }));
    loop.Run();
  }

  // Simulate a successful initial sync.
  InitializeBridge();
  StartSyncing();
  ASSERT_THAT(GetAllData(), IsEmpty());
  ShutdownBridge();

  base::RunLoop loop;
  // On the next startup, the metadata is currently empty, which should trigger
  // StayStoppedAndMaybeClearData().
  EXPECT_CALL(syncable_service_, StayStoppedAndMaybeClearData(kDataType))
      .WillOnce([&]() { loop.Quit(); });
  base::HistogramTester histogram_tester;
  // Metadata exists but initial sync is not done, thus leading to an
  // inconsistent state, which should trigger StayStoppedAndMaybeClearData().
  InitializeBridge();
  loop.Run();
  histogram_tester.ExpectUniqueSample(kMaybeClearDataHistogramName,
                                      /*sample=*/true,
                                      /*expected_bucket_count=*/1);

  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldNotMaybeClearDataIfMetadataNotEmpty) {
  // Simulate prior initial sync done.
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  ShutdownBridge();

  base::RunLoop loop;
  ON_CALL(syncable_service_, WaitUntilReadyToSync)
      .WillByDefault([&](base::OnceClosure done) {
        std::move(done).Run();
        loop.Quit();
      });
  EXPECT_CALL(syncable_service_, StayStoppedAndMaybeClearData(kDataType))
      .Times(0);
  base::HistogramTester histogram_tester;
  InitializeBridge();
  // Metadata exists and initial sync is done, thus leading to no need to clear
  // data.
  loop.Run();
  histogram_tester.ExpectUniqueSample(kMaybeClearDataHistogramName,
                                      /*sample=*/false,
                                      /*expected_bucket_count=*/1);

  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldNotStopSyncableServiceDuringShutdownIfNotPreviouslyStarted) {
  EXPECT_CALL(syncable_service_, StopSyncing).Times(0);
  InitializeBridge();
  StartSyncing();
  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldPropagateErrorDuringStart) {
  // Instrument MergeDataAndStartSyncing() to return an error.
  ON_CALL(syncable_service_, MergeDataAndStartSyncing)
      .WillByDefault(Return(
          ModelError(FROM_HERE, syncer::ModelError::Type::kGenericTestError)));

  EXPECT_CALL(mock_error_handler_, Run);

  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer();

  // Since the syncable service failed to start, it shouldn't be stopped.
  EXPECT_CALL(syncable_service_, StopSyncing).Times(0);
  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldKeepSyncingWhenSyncStoppedTemporarily) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));

  // Stopping Sync temporarily (KEEP_METADATA) should *not* result in the
  // SyncableService being stopped.
  EXPECT_CALL(syncable_service_, StopSyncing).Times(0);
  real_processor_->OnSyncStopping(KEEP_METADATA);
  EXPECT_THAT(GetAllData(), ElementsAre(Pair(kClientTagHash.value(), _)));

  // Since the SyncableService wasn't stopped, it shouldn't get restarted either
  // when Sync starts up again.
  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing).Times(0);
  StartSyncing();

  // Finally, shutting down the bridge (during browser shutdown) should also
  // stop the SyncableService.
  EXPECT_CALL(syncable_service_, StopSyncing(kDataType));
  ShutdownBridge();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldStartSyncingWithPreviousDirectoryDataAfterRestart) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));

  // Mimic restart, which shouldn't start syncing until OnSyncStarting() is
  // received (exercised in StartSyncing()).
  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing).Times(0);
  ShutdownBridge();
  InitializeBridge();

  EXPECT_CALL(syncable_service_,
              MergeDataAndStartSyncing(
                  kDataType, ElementsAre(SyncDataMatches("name1")), NotNull()));
  StartSyncing();
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldSupportDisableReenableSequence) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics());
  real_processor_->OnSyncStopping(CLEAR_METADATA);
  EXPECT_THAT(GetAllData(), IsEmpty());

  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing).Times(0);
  StartSyncing();
  EXPECT_CALL(syncable_service_,
              MergeDataAndStartSyncing(kDataType, IsEmpty(), NotNull()));
  worker_->UpdateFromServer();
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldPropagateLocalEntitiesDuringMerge) {
  ON_CALL(syncable_service_, MergeDataAndStartSyncing)
      .WillByDefault([&](DataType type, const SyncDataList& initial_sync_data,
                         std::unique_ptr<SyncChangeProcessor> sync_processor) {
        SyncChangeList change_list;
        change_list.emplace_back(
            FROM_HERE, SyncChange::ACTION_ADD,
            SyncData::CreateLocalData(kClientTag, "title", GetTestSpecifics()));
        const std::optional<ModelError> error =
            sync_processor->ProcessSyncChanges(FROM_HERE, change_list);
        EXPECT_FALSE(error.has_value());
        return std::nullopt;
      });

  InitializeBridge();
  StartSyncing();

  EXPECT_CALL(mock_processor_,
              Put(kClientTagHash.value(), NotNull(), NotNull()));
  worker_->UpdateFromServer();
  EXPECT_THAT(GetAllData(), ElementsAre(Pair(kClientTagHash.value(), _)));
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldPropagateLocalCreation) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer();
  ASSERT_THAT(start_syncing_sync_processor_, NotNull());
  ASSERT_THAT(GetAllData(), IsEmpty());

  EXPECT_CALL(mock_processor_,
              Put(kClientTagHash.value(), NotNull(), NotNull()));

  SyncChangeList change_list;
  change_list.emplace_back(
      FROM_HERE, SyncChange::ACTION_ADD,
      SyncData::CreateLocalData(kClientTag, "title", GetTestSpecifics()));
  const std::optional<ModelError> error =
      start_syncing_sync_processor_->ProcessSyncChanges(FROM_HERE, change_list);
  EXPECT_FALSE(error.has_value());
  EXPECT_THAT(GetAllData(), ElementsAre(Pair(kClientTagHash.value(), _)));
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldPropagateLocalUpdate) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  ASSERT_THAT(start_syncing_sync_processor_, NotNull());
  ASSERT_THAT(GetAllData(),
              ElementsAre(Pair(kClientTagHash.value(), HasName("name1"))));

  EXPECT_CALL(mock_processor_,
              Put(kClientTagHash.value(), NotNull(), NotNull()));

  SyncChangeList change_list;
  change_list.emplace_back(FROM_HERE, SyncChange::ACTION_UPDATE,
                           SyncData::CreateLocalData(
                               kClientTag, "title", GetTestSpecifics("name2")));
  const std::optional<ModelError> error =
      start_syncing_sync_processor_->ProcessSyncChanges(FROM_HERE, change_list);
  EXPECT_FALSE(error.has_value());
  EXPECT_THAT(GetAllData(),
              ElementsAre(Pair(kClientTagHash.value(), HasName("name2"))));
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldPropagateLocalDeletion) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  ASSERT_THAT(start_syncing_sync_processor_, NotNull());
  ASSERT_THAT(GetAllData(),
              ElementsAre(Pair(kClientTagHash.value(), HasName("name1"))));

  EXPECT_CALL(mock_processor_, Delete(kClientTagHash.value(), _, NotNull()));

  SyncChangeList change_list;
  change_list.emplace_back(FROM_HERE, SyncChange::ACTION_DELETE,
                           SyncData::CreateLocalDelete(kClientTag, kDataType));

  const std::optional<ModelError> error =
      start_syncing_sync_processor_->ProcessSyncChanges(FROM_HERE, change_list);
  EXPECT_FALSE(error.has_value());
  EXPECT_THAT(GetAllData(), IsEmpty());
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldIgnoreLocalCreationIfPreviousError) {
  EXPECT_CALL(mock_processor_, Put).Times(0);

  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer();
  ASSERT_THAT(start_syncing_sync_processor_, NotNull());
  ASSERT_THAT(GetAllData(), IsEmpty());

  // We fake an error, reported by the bridge.
  EXPECT_CALL(mock_error_handler_, Run);
  real_processor_->ReportError(
      ModelError(FROM_HERE, syncer::ModelError::Type::kGenericTestError));
  ASSERT_TRUE(real_processor_->GetError());

  // Further local changes should be ignored.
  SyncChangeList change_list;
  change_list.emplace_back(
      FROM_HERE, SyncChange::ACTION_ADD,
      SyncData::CreateLocalData(kClientTag, "title", GetTestSpecifics()));
  const std::optional<ModelError> error =
      start_syncing_sync_processor_->ProcessSyncChanges(FROM_HERE, change_list);
  EXPECT_TRUE(error.has_value());
  EXPECT_THAT(GetAllData(), IsEmpty());
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldPropagateRemoteCreation) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer();
  ASSERT_THAT(start_syncing_sync_processor_, NotNull());
  ASSERT_THAT(GetAllData(), IsEmpty());

  EXPECT_CALL(syncable_service_,
              ProcessSyncChanges(_, ElementsAre(SyncChangeMatches(
                                        SyncChange::ACTION_ADD, "name1"))));
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  EXPECT_THAT(GetAllData(),
              ElementsAre(Pair(kClientTagHash.value(), HasName("name1"))));
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldPropagateRemoteUpdates) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  ASSERT_THAT(start_syncing_sync_processor_, NotNull());
  ASSERT_THAT(GetAllData(),
              ElementsAre(Pair(kClientTagHash.value(), HasName("name1"))));

  EXPECT_CALL(syncable_service_,
              ProcessSyncChanges(_, ElementsAre(SyncChangeMatches(
                                        SyncChange::ACTION_UPDATE, "name2"))));
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name2"));
  EXPECT_THAT(GetAllData(),
              ElementsAre(Pair(kClientTagHash.value(), HasName("name2"))));

  // A second update for the same entity.
  EXPECT_CALL(syncable_service_,
              ProcessSyncChanges(_, ElementsAre(SyncChangeMatches(
                                        SyncChange::ACTION_UPDATE, "name3"))));
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name3"));
  EXPECT_THAT(GetAllData(),
              ElementsAre(Pair(kClientTagHash.value(), HasName("name3"))));
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldPropagateRemoteDeletion) {
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  ASSERT_THAT(start_syncing_sync_processor_, NotNull());
  ASSERT_THAT(GetAllData(),
              ElementsAre(Pair(kClientTagHash.value(), HasName("name1"))));

  EXPECT_CALL(syncable_service_,
              ProcessSyncChanges(_, ElementsAre(SyncChangeMatches(
                                        SyncChange::ACTION_DELETE, "name1"))));
  worker_->TombstoneFromServer(kClientTagHash);
  EXPECT_THAT(GetAllData(), IsEmpty());
}

TEST(SyncableServiceBasedBridgeLocalChangeProcessorTest,
     ShouldDropIfCommitted) {
  const std::string kClientTagHash = "clienttaghash1";

  base::test::SingleThreadTaskEnvironment task_environment;
  std::unique_ptr<DataTypeStore> store =
      DataTypeStoreTestUtil::CreateInMemoryStoreForTest();
  SyncableServiceBasedBridge::InMemoryStore in_memory_store;
  testing::NiceMock<MockDataTypeLocalChangeProcessor> mock_processor;

  in_memory_store[kClientTagHash] = sync_pb::PersistedEntityData();

  std::unique_ptr<SyncChangeProcessor> sync_change_processor =
      SyncableServiceBasedBridge::CreateLocalChangeProcessorForTesting(
          HISTORY_DELETE_DIRECTIVES, store.get(), &in_memory_store,
          &mock_processor);

  EXPECT_CALL(mock_processor, IsEntityUnsynced(kClientTagHash))
      .WillOnce(Return(false));
  EXPECT_CALL(mock_processor, UntrackEntityForStorageKey(kClientTagHash));

  sync_pb::EntitySpecifics specifics;
  specifics.mutable_history_delete_directive();

  SyncChangeList change_list;
  change_list.push_back(
      SyncChange(FROM_HERE, SyncChange::ACTION_DELETE,
                 SyncData::CreateRemoteData(
                     specifics, ClientTagHash::FromHashed(kClientTagHash))));

  sync_change_processor->ProcessSyncChanges(FROM_HERE, change_list);

  EXPECT_EQ(0U, in_memory_store.count(kClientTagHash));
}

TEST(SyncableServiceBasedBridgeLocalChangeProcessorTest,
     ShouldNotDropIfUnsynced) {
  const std::string kClientTagHash = "clienttaghash1";

  base::test::SingleThreadTaskEnvironment task_environment;
  std::unique_ptr<DataTypeStore> store =
      DataTypeStoreTestUtil::CreateInMemoryStoreForTest();
  SyncableServiceBasedBridge::InMemoryStore in_memory_store;
  testing::NiceMock<MockDataTypeLocalChangeProcessor> mock_processor;

  in_memory_store[kClientTagHash] = sync_pb::PersistedEntityData();

  std::unique_ptr<SyncChangeProcessor> sync_change_processor =
      SyncableServiceBasedBridge::CreateLocalChangeProcessorForTesting(
          HISTORY_DELETE_DIRECTIVES, store.get(), &in_memory_store,
          &mock_processor);

  EXPECT_CALL(mock_processor, IsEntityUnsynced(kClientTagHash))
      .WillOnce(Return(true));
  EXPECT_CALL(mock_processor, UntrackEntityForStorageKey).Times(0);

  sync_pb::EntitySpecifics specifics;
  specifics.mutable_history_delete_directive();

  SyncChangeList change_list;
  change_list.push_back(
      SyncChange(FROM_HERE, SyncChange::ACTION_DELETE,
                 SyncData::CreateRemoteData(
                     specifics, ClientTagHash::FromHashed(kClientTagHash))));

  sync_change_processor->ProcessSyncChanges(FROM_HERE, change_list);

  EXPECT_EQ(1U, in_memory_store.count(kClientTagHash));
}

TEST_F(SyncableServiceBasedBridgeTest, ConflictShouldUseRemote) {
  InitializeBridge();

  EntityData remote_data;
  remote_data.client_tag_hash = kClientTagHash;
  remote_data.specifics = GetTestSpecifics();
  ASSERT_FALSE(remote_data.is_deleted());

  EXPECT_THAT(bridge_->ResolveConflict("storagekey1", remote_data),
              Eq(ConflictResolution::kUseRemote));
}

TEST_F(SyncableServiceBasedBridgeTest,
       ConflictWithRemoteDeletionShouldUseLocal) {
  InitializeBridge();

  EntityData remote_data;
  remote_data.client_tag_hash = kClientTagHash;
  ASSERT_TRUE(remote_data.is_deleted());

  EXPECT_THAT(bridge_->ResolveConflict("storagekey1", remote_data),
              Eq(ConflictResolution::kUseLocal));
}

// This ensures that for extensions, the conflict is resolved in favor of the
// server, to prevent extensions from being reinstalled after uninstall.
TEST_F(SyncableServiceBasedBridgeTest,
       ConflictWithRemoteExtensionUninstallShouldUseRemote) {
  InitializeBridge(EXTENSIONS);

  EntityData remote_data;
  remote_data.client_tag_hash = kClientTagHash;
  ASSERT_TRUE(remote_data.is_deleted());

  EXPECT_THAT(bridge_->ResolveConflict("storagekey1", remote_data),
              Eq(ConflictResolution::kUseRemote));
}

// Same as above but for APPS.
TEST_F(SyncableServiceBasedBridgeTest,
       ConflictWithRemoteAppUninstallShouldUseRemote) {
  InitializeBridge(APPS);

  EntityData remote_data;
  remote_data.client_tag_hash = kClientTagHash;
  ASSERT_TRUE(remote_data.is_deleted());

  EXPECT_THAT(bridge_->ResolveConflict("storagekey1", remote_data),
              Eq(ConflictResolution::kUseRemote));
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldMeasureSyncableServiceStartTime) {
  // The following writes data into store for the next run.
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  // Mimic restart.
  ShutdownBridge();

  base::RunLoop loop;
  ON_CALL(syncable_service_, WaitUntilReadyToSync)
      .WillByDefault([&](base::OnceClosure done) {
        std::move(done).Run();
        loop.Quit();
      });

  base::HistogramTester histogram_tester;
  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing);
  // Initial data is loaded from the store.
  InitializeBridge();
  loop.Run();
  histogram_tester.ExpectTotalCount(kSyncableServiceStartTimeHistogramName, 1);
}

// This also covers the case where the user opts in for sync later.
TEST_F(SyncableServiceBasedBridgeTest,
       ShouldNotMeasureSyncableServiceStartTimeIfNoInitialData) {
  base::HistogramTester histogram_tester;
  // No initial data.
  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing).Times(0);
  InitializeBridge();
  StartSyncing();
  histogram_tester.ExpectTotalCount(kSyncableServiceStartTimeHistogramName, 0);

  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing);
  // Initial merge happens on response from server.
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  histogram_tester.ExpectTotalCount(kSyncableServiceStartTimeHistogramName, 0);
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldNotMeasureSyncableServiceStartTimeOnSyncRestart) {
  // The following writes data into store for the next run.
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  // Mimic restart, which shouldn't start syncing until OnSyncStarting() is
  // received (exercised in StartSyncing()).
  ShutdownBridge();

  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing);
  // Initial data is loaded from the store.
  InitializeBridge();
  StartSyncing();

  base::HistogramTester histogram_tester;
  // Mimic sync restart.
  real_processor_->OnSyncStopping(CLEAR_METADATA);
  StartSyncing();

  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing);
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  // This case shouldn't be logged into the metric.
  histogram_tester.ExpectTotalCount(kSyncableServiceStartTimeHistogramName, 0);
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldNotMeasureSyncableServiceStartTimeOnError) {
  base::HistogramTester histogram_tester;
  InitializeBridge();
  StartSyncing();
  histogram_tester.ExpectTotalCount(kSyncableServiceStartTimeHistogramName, 0);

  // Instrument MergeDataAndStartSyncing() to return an error.
  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing)
      .WillOnce(Return(
          ModelError(FROM_HERE, syncer::ModelError::Type::kGenericTestError)));
  EXPECT_CALL(mock_error_handler_, Run);

  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
  histogram_tester.ExpectTotalCount(kSyncableServiceStartTimeHistogramName, 0);
}

TEST_F(SyncableServiceBasedBridgeTest, ShouldCallWillStartInitialSync) {
  ::testing::InSequence in_sequence;
  EXPECT_CALL(syncable_service_, WillStartInitialSync);
  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing);

  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));
}

TEST_F(SyncableServiceBasedBridgeTest,
       ShouldNotCallWillStartInitialSyncUponBrowserRestart) {
  // The following writes data into store for the next run.
  InitializeBridge();
  StartSyncing();
  worker_->UpdateFromServer(kClientTagHash, GetTestSpecifics("name1"));

  // Mimic restart.
  ShutdownBridge();

  EXPECT_CALL(syncable_service_, MergeDataAndStartSyncing);
  EXPECT_CALL(syncable_service_, WillStartInitialSync).Times(0);
  // Initial data is loaded from the store.
  InitializeBridge();
  StartSyncing();
}

}  // namespace
}  // namespace syncer