/*
 * Copyright 2017 Google
 *
 * 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.
 */

#import <FirebaseFirestore/FirebaseFirestore.h>

#import <XCTest/XCTest.h>

#include <memory>
#include <vector>

#import "FirebaseCore/Sources/Public/FirebaseCore/FIRTimestamp.h"

#import "Firestore/Source/API/FIRDocumentReference+Internal.h"
#import "Firestore/Source/API/FSTUserDataReader.h"

#import "Firestore/Example/Tests/Util/FSTIntegrationTestCase.h"

#include "Firestore/core/src/core/database_info.h"
#include "Firestore/core/src/credentials/empty_credentials_provider.h"
#include "Firestore/core/src/local/local_documents_view.h"
#include "Firestore/core/src/local/local_store.h"
#include "Firestore/core/src/local/memory_persistence.h"
#include "Firestore/core/src/local/query_engine.h"
#include "Firestore/core/src/local/target_data.h"
#include "Firestore/core/src/model/database_id.h"
#include "Firestore/core/src/model/document_key.h"
#include "Firestore/core/src/model/mutation_batch_result.h"
#include "Firestore/core/src/model/precondition.h"
#include "Firestore/core/src/model/set_mutation.h"
#include "Firestore/core/src/remote/connectivity_monitor.h"
#include "Firestore/core/src/remote/datastore.h"
#include "Firestore/core/src/remote/firebase_metadata_provider.h"
#include "Firestore/core/src/remote/firebase_metadata_provider_noop.h"
#include "Firestore/core/src/remote/remote_event.h"
#include "Firestore/core/src/remote/remote_store.h"
#include "Firestore/core/src/util/async_queue.h"
#include "Firestore/core/src/util/hard_assert.h"
#include "Firestore/core/src/util/status.h"
#include "Firestore/core/src/util/string_apple.h"
#include "Firestore/core/test/unit/remote/create_noop_connectivity_monitor.h"
#include "Firestore/core/test/unit/testutil/async_testing.h"
#include "Firestore/core/test/unit/testutil/testutil.h"
#include "absl/memory/memory.h"

using firebase::Timestamp;
using firebase::firestore::google_firestore_v1_Value;
using firebase::firestore::core::DatabaseInfo;
using firebase::firestore::credentials::EmptyAppCheckCredentialsProvider;
using firebase::firestore::credentials::EmptyAuthCredentialsProvider;
using firebase::firestore::credentials::User;
using firebase::firestore::local::LocalStore;
using firebase::firestore::local::MemoryPersistence;
using firebase::firestore::local::Persistence;
using firebase::firestore::local::QueryEngine;
using firebase::firestore::model::BatchId;
using firebase::firestore::model::DatabaseId;
using firebase::firestore::model::DocumentKeySet;
using firebase::firestore::model::MutationBatch;
using firebase::firestore::model::MutationBatchResult;
using firebase::firestore::model::OnlineState;
using firebase::firestore::model::TargetId;
using firebase::firestore::remote::ConnectivityMonitor;
using firebase::firestore::remote::CreateFirebaseMetadataProviderNoOp;
using firebase::firestore::remote::CreateNoOpConnectivityMonitor;
using firebase::firestore::remote::Datastore;
using firebase::firestore::remote::FirebaseMetadataProvider;
using firebase::firestore::remote::GrpcConnection;
using firebase::firestore::remote::RemoteEvent;
using firebase::firestore::remote::RemoteStore;
using firebase::firestore::remote::RemoteStoreCallback;
using firebase::firestore::testutil::AsyncQueueForTesting;
using firebase::firestore::testutil::Map;
using firebase::firestore::testutil::SetMutation;
using firebase::firestore::util::AsyncQueue;
using firebase::firestore::util::MakeString;
using firebase::firestore::util::Status;

NS_ASSUME_NONNULL_BEGIN

#pragma mark - FSTRemoteStoreEventCapture

@interface FSTRemoteStoreEventCapture : NSObject

- (instancetype)init __attribute__((unavailable("Use initWithTestCase:")));

- (instancetype)initWithTestCase:(XCTestCase *_Nullable)testCase NS_DESIGNATED_INITIALIZER;

- (void)expectWriteEventWithDescription:(NSString *)description;
- (void)expectListenEventWithDescription:(NSString *)description;

@property(nonatomic, weak, nullable) XCTestCase *testCase;
@property(nonatomic, strong) NSMutableArray<XCTestExpectation *> *writeEventExpectations;
@property(nonatomic, strong) NSMutableArray<XCTestExpectation *> *listenEventExpectations;
@end

@implementation FSTRemoteStoreEventCapture {
  std::vector<RemoteEvent> _listenEvents;
  std::vector<MutationBatchResult> _writeEvents;
}

- (instancetype)initWithTestCase:(XCTestCase *_Nullable)testCase {
  if (self = [super init]) {
    _testCase = testCase;
    _writeEventExpectations = [NSMutableArray array];
    _listenEventExpectations = [NSMutableArray array];
  }
  return self;
}

- (void)expectWriteEventWithDescription:(NSString *)description {
  [self.writeEventExpectations
      addObject:[self.testCase
                    expectationWithDescription:[NSString
                                                   stringWithFormat:@"write event %lu: %@",
                                                                    (unsigned long)
                                                                        self.writeEventExpectations
                                                                            .count,
                                                                    description]]];
}

- (void)expectListenEventWithDescription:(NSString *)description {
  [self.listenEventExpectations
      addObject:[self.testCase
                    expectationWithDescription:[NSString
                                                   stringWithFormat:@"listen event %lu: %@",
                                                                    (unsigned long)
                                                                        self.listenEventExpectations
                                                                            .count,
                                                                    description]]];
}

- (void)applySuccessfulWriteWithResult:(MutationBatchResult)batchResult {
  _writeEvents.push_back(std::move(batchResult));
  XCTestExpectation *expectation = [self.writeEventExpectations objectAtIndex:0];
  [self.writeEventExpectations removeObjectAtIndex:0];
  [expectation fulfill];
}

- (void)rejectFailedWriteWithBatchID:(__unused BatchId)batchID error:(__unused NSError *)error {
  HARD_FAIL("Not implemented");
}

- (DocumentKeySet)remoteKeysForTarget:(__unused TargetId)targetId {
  return DocumentKeySet{};
}

- (void)applyRemoteEvent:(const RemoteEvent &)remoteEvent {
  _listenEvents.push_back(remoteEvent);
  XCTestExpectation *expectation = [self.listenEventExpectations objectAtIndex:0];
  [self.listenEventExpectations removeObjectAtIndex:0];
  [expectation fulfill];
}

- (void)rejectListenWithTargetID:(__unused const TargetId)targetID error:(__unused NSError *)error {
  HARD_FAIL("Not implemented");
}

@end

class RemoteStoreEventCapture : public RemoteStoreCallback {
 public:
  explicit RemoteStoreEventCapture(XCTestCase *test_case)
      : underlying_capture_([[FSTRemoteStoreEventCapture alloc] initWithTestCase:test_case]) {
  }

  void ExpectWriteEvent(NSString *description) {
    [underlying_capture_ expectWriteEventWithDescription:description];
  }

  void ExpectListenEvent(NSString *description) {
    [underlying_capture_ expectListenEventWithDescription:description];
  }

  void ApplyRemoteEvent(const RemoteEvent &remote_event) override {
    [underlying_capture_ applyRemoteEvent:remote_event];
  }

  void HandleRejectedListen(TargetId target_id, Status error) override {
    [underlying_capture_ rejectListenWithTargetID:target_id error:error.ToNSError()];
  }

  void HandleSuccessfulWrite(MutationBatchResult batch_result) override {
    [underlying_capture_ applySuccessfulWriteWithResult:std::move(batch_result)];
  }

  void HandleRejectedWrite(BatchId batch_id, Status error) override {
    [underlying_capture_ rejectFailedWriteWithBatchID:batch_id error:error.ToNSError()];
  }

  void HandleOnlineStateChange(OnlineState) override {
    HARD_FAIL("Not implemented");
  }

  model::DocumentKeySet GetRemoteKeys(TargetId target_id) const override {
    return [underlying_capture_ remoteKeysForTarget:target_id];
  }

 private:
  FSTRemoteStoreEventCapture *underlying_capture_;
};

#pragma mark - FSTDatastoreTests

@interface FSTDatastoreTests : XCTestCase

@end

@implementation FSTDatastoreTests {
  std::shared_ptr<AsyncQueue> _testWorkerQueue;
  std::unique_ptr<LocalStore> _localStore;
  std::unique_ptr<Persistence> _persistence;

  DatabaseInfo _databaseInfo;
  QueryEngine _queryEngine;

  std::unique_ptr<ConnectivityMonitor> _connectivityMonitor;
  std::unique_ptr<FirebaseMetadataProvider> _firebaseMetadataProvider;
  std::shared_ptr<Datastore> _datastore;
  std::unique_ptr<RemoteStore> _remoteStore;
}

- (void)setUp {
  [super setUp];

  NSString *projectID = [FSTIntegrationTestCase projectID];
  FIRFirestoreSettings *settings = [FSTIntegrationTestCase settings];
  if (!settings.sslEnabled) {
    GrpcConnection::UseInsecureChannel(MakeString(settings.host));
  }

  DatabaseId database_id(MakeString(projectID));

  _databaseInfo =
      DatabaseInfo(database_id, "test-key", MakeString(settings.host), settings.sslEnabled);

  _testWorkerQueue = AsyncQueueForTesting();
  _connectivityMonitor = CreateNoOpConnectivityMonitor();
  _firebaseMetadataProvider = CreateFirebaseMetadataProviderNoOp();
  _datastore = std::make_shared<Datastore>(
      _databaseInfo, _testWorkerQueue, std::make_shared<EmptyAuthCredentialsProvider>(),
      std::make_shared<EmptyAppCheckCredentialsProvider>(), _connectivityMonitor.get(),
      _firebaseMetadataProvider.get());

  _persistence = MemoryPersistence::WithEagerGarbageCollector();
  _localStore =
      absl::make_unique<LocalStore>(_persistence.get(), &_queryEngine, User::Unauthenticated());

  _remoteStore = absl::make_unique<RemoteStore>(_localStore.get(), _datastore, _testWorkerQueue,
                                                _connectivityMonitor.get(), [](OnlineState) {});

  _testWorkerQueue->Enqueue([=] { _remoteStore->Start(); });
}

- (void)tearDown {
  XCTestExpectation *completion = [self expectationWithDescription:@"shutdown"];
  _testWorkerQueue->Enqueue([=] {
    _remoteStore->Shutdown();
    [completion fulfill];
  });
  [self awaitExpectations];

  [super tearDown];
}

- (void)testCommit {
  XCTestExpectation *expectation = [self expectationWithDescription:@"commitWithCompletion"];

  _datastore->CommitMutations({}, [self, expectation](const Status &status) {
    (void)self;  // Avoid unused lambda capture error in Xcode 12.
    XCTAssertTrue(status.ok(), @"Failed to commit");
    [expectation fulfill];
  });

  [self awaitExpectations];
}

- (void)testStreamingWrite {
  RemoteStoreEventCapture capture(self);
  capture.ExpectWriteEvent(@"write mutations");

  _remoteStore->set_sync_engine(&capture);

  auto mutation = SetMutation("rooms/eros", Map("name", "Eros"));
  MutationBatch batch = MutationBatch(23, Timestamp::Now(), {}, {mutation});
  _testWorkerQueue->Enqueue([=] {
    _remoteStore->AddToWritePipeline(batch);
    // The added batch won't be written immediately because write stream wasn't yet open --
    // trigger its opening.
    _remoteStore->FillWritePipeline();
  });

  [self awaitExpectations];
}

- (void)awaitExpectations {
  [self waitForExpectationsWithTimeout:4.0
                               handler:^(NSError *_Nullable expectationError) {
                                 if (expectationError) {
                                   XCTFail(@"Error waiting for timeout: %@", expectationError);
                                 }
                               }];
}

@end

NS_ASSUME_NONNULL_END