/**
 *    Copyright (C) 2022-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#include "mongo/platform/basic.h"

#include "mongo/db/catalog/capped_visibility.h"
#include "mongo/db/catalog/catalog_test_fixture.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/collection_write_path.h"
#include "mongo/db/concurrency/lock_state.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/record_id_helpers.h"
#include "mongo/db/repl/replication_coordinator_mock.h"
#include "mongo/unittest/unittest.h"

namespace mongo {
namespace {

class CappedCollectionTest : public ServiceContextMongoDTest {
public:
    CappedCollectionTest() : ServiceContextMongoDTest(Options().engine("wiredTiger")) {}

protected:
    void setUp() override {
        // Set up mongod.
        ServiceContextMongoDTest::setUp();

        auto service = getServiceContext();
        _storage = std::make_unique<repl::StorageInterfaceImpl>();

        // Set up ReplicationCoordinator and ensure that we are primary.
        auto replCoord = std::make_unique<repl::ReplicationCoordinatorMock>(service);
        ASSERT_OK(replCoord->setFollowerMode(repl::MemberState::RS_PRIMARY));
        repl::ReplicationCoordinator::set(service, std::move(replCoord));

        // Set up oplog collection. If the WT storage engine is used, the oplog collection is
        // expected to exist when fetching the next opTime (LocalOplogInfo::getNextOpTimes) to use
        // for a write.
        {
            auto opCtx = newOperationContext();
            repl::createOplog(opCtx.get());
        }
    }


    void makeCapped(NamespaceString nss, long long cappedSize = 8192) {
        CollectionOptions options;
        options.capped = true;
        options.cappedSize = cappedSize;  // Maximum size of capped collection in bytes.
        bool createIdIndex = false;
        auto opCtx = newOperationContext();
        ASSERT_OK(storageInterface()->createCollection(opCtx.get(), nss, options, createIdIndex));
    }

    ServiceContext::UniqueOperationContext newOperationContext() {
        return Client::getCurrent()->makeOperationContext();
    }

    typedef std::pair<ServiceContext::UniqueClient, ServiceContext::UniqueOperationContext>
        ClientAndCtx;

    ClientAndCtx makeClientAndCtx(const std::string& clientName) {
        auto client = getServiceContext()->makeClient(clientName);
        auto opCtx = client->makeOperationContext();
        client->swapLockState(std::make_unique<LockerImpl>(getServiceContext()));
        return std::make_pair(std::move(client), std::move(opCtx));
    }

    repl::StorageInterface* storageInterface() {
        return _storage.get();
    }

    std::unique_ptr<repl::StorageInterface> _storage;
};

template <typename T>
void assertSwError(StatusWith<T> sw, ErrorCodes::Error code) {
    ASSERT_EQ(sw.getStatus().code(), code);
}

Status insertBSON(OperationContext* opCtx, const NamespaceString& nss, RecordId id) {
    AutoGetCollection ac(opCtx, nss, MODE_IX);
    const CollectionPtr& coll = ac.getCollection();
    BSONObj obj = BSON("a" << 1);
    WriteUnitOfWork wuow(opCtx);

    auto cappedObserver = coll->getCappedVisibilityObserver();
    cappedObserver->registerWriter(opCtx->recoveryUnit());

    coll->registerCappedInsert(opCtx, id);
    auto status =
        collection_internal::insertDocument(opCtx, coll, InsertStatement(obj, id), nullptr);
    if (!status.isOK()) {
        return status;
    }
    wuow.commit();
    return Status::OK();
}

Status _insertBSON(OperationContext* opCtx, const CollectionPtr& coll, RecordId id) {
    BSONObj obj = BSON("a" << 1);
    auto cappedObserver = coll->getCappedVisibilityObserver();
    cappedObserver->registerWriter(opCtx->recoveryUnit());
    coll->registerCappedInsert(opCtx, id);
    return collection_internal::insertDocument(opCtx, coll, InsertStatement(obj), nullptr);
}

TEST_F(CappedCollectionTest, SeekNear) {
    NamespaceString nss = NamespaceString::createNamespaceString_forTest("local.non.oplog");
    makeCapped(nss);

    {
        auto opCtx = newOperationContext();
        ASSERT_OK(insertBSON(opCtx.get(), nss, RecordId(1)));
        ASSERT_OK(insertBSON(opCtx.get(), nss, RecordId(2)));
        ASSERT_OK(insertBSON(opCtx.get(), nss, RecordId(3)));
        ASSERT_OK(insertBSON(opCtx.get(), nss, RecordId(4)));
    }

    {
        // Delete the first and third so that we have some gaps to use for inexact seeks.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        collection_internal::deleteDocument(
            opCtx.get(), coll, kUninitializedStmtId, RecordId(1), nullptr);
        collection_internal::deleteDocument(
            opCtx.get(), coll, kUninitializedStmtId, RecordId(3), nullptr);
        wuow.commit();
    }

    // Forward cursor seeks
    {
        // Seek to a non-existent record and expect to land on the first record because no previous
        // record exists.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        auto cur = coll->getCursor(opCtx.get());
        auto rec = cur->seekNear(RecordId(1));
        ASSERT(rec);
        ASSERT_EQ(rec->id, RecordId(2));
    }

    {
        // Seek to a non-existent record and expect to land on the logically previous record.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        auto cur = coll->getCursor(opCtx.get());
        auto rec = cur->seekNear(RecordId(3));
        ASSERT(rec);
        ASSERT_EQ(rec->id, RecordId(2));
    }

    {
        // Seek exactly.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        auto cur = coll->getCursor(opCtx.get());
        auto rec = cur->seekNear(RecordId(4));
        ASSERT(rec);
        ASSERT_EQ(rec->id, RecordId(4));
    }

    {
        // Seek to a non-existent record and expect to land on the logically-previous record, which
        // is the last record.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        auto cur = coll->getCursor(opCtx.get());
        auto rec = cur->seekNear(RecordId(5));
        ASSERT(rec);
        ASSERT_EQ(rec->id, RecordId(4));
    }

    // Reverse cursor seeks
    {
        // Seek to a non-existent record and expect to land on the logically-previous record, which
        // is the first record.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        auto cur = coll->getCursor(opCtx.get(), false /* forward */);
        auto rec = cur->seekNear(RecordId(1));
        ASSERT(rec);
        ASSERT_EQ(rec->id, RecordId(2));
    }

    {
        // Seek exactly.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        auto cur = coll->getCursor(opCtx.get(), false /* forward */);
        auto rec = cur->seekNear(RecordId(2));
        ASSERT(rec);
        ASSERT_EQ(rec->id, RecordId(2));
    }

    {
        // Seek to a non-existent record and expect to land on the logically previous record.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        auto cur = coll->getCursor(opCtx.get(), false /* forward */);
        auto rec = cur->seekNear(RecordId(3));
        ASSERT(rec);
        ASSERT_EQ(rec->id, RecordId(4));
    }

    {
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        auto cur = coll->getCursor(opCtx.get(), false /* forward */);
        auto rec = cur->seekNear(RecordId(5));
        ASSERT(rec);
        ASSERT_EQ(rec->id, RecordId(4));
    }


    {
        // Delete the remaining records.
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        WriteUnitOfWork wuow(opCtx.get());
        collection_internal::deleteDocument(
            opCtx.get(), coll, kUninitializedStmtId, RecordId(2), nullptr);
        collection_internal::deleteDocument(
            opCtx.get(), coll, kUninitializedStmtId, RecordId(4), nullptr);
        wuow.commit();
    }

    {
        auto opCtx(newOperationContext());
        AutoGetCollection ac(opCtx.get(), nss, MODE_IX);
        const CollectionPtr& coll = ac.getCollection();
        auto cur = coll->getCursor(opCtx.get());
        auto rec = cur->seekNear(RecordId(2));
        ASSERT_FALSE(rec);
        rec = cur->seekNear(RecordId(4));
        ASSERT_FALSE(rec);
    }
}

TEST_F(CappedCollectionTest, InsertOutOfOrder) {
    NamespaceString nss = NamespaceString::createNamespaceString_forTest("local.non.oplog");
    makeCapped(nss);
    {
        // RecordId's are inserted out-of-order.
        auto opCtx = newOperationContext();
        ASSERT_OK(insertBSON(opCtx.get(), nss, RecordId(1)));
        ASSERT_OK(insertBSON(opCtx.get(), nss, RecordId(3)));
        ASSERT_OK(insertBSON(opCtx.get(), nss, RecordId(2)));
    }

    {
        auto opCtx = newOperationContext();
        AutoGetCollectionForRead acfr(opCtx.get(), nss);
        const CollectionPtr& coll = acfr.getCollection();
        auto cursor = coll->getCursor(opCtx.get());
        ASSERT_EQ(cursor->next()->id, RecordId(1));
        ASSERT_EQ(cursor->next()->id, RecordId(2));
        ASSERT_EQ(cursor->next()->id, RecordId(3));
        ASSERT(!cursor->next());
    }
}

TEST_F(CappedCollectionTest, OplogOrder) {
    NamespaceString nss = NamespaceString::createNamespaceString_forTest("local.non.oplog");
    makeCapped(nss);

    auto id1 = RecordId(1);

    {  // first insert a document
        ServiceContext::UniqueOperationContext opCtx(newOperationContext());
        ASSERT_OK(insertBSON(opCtx.get(), nss, id1));
    }

    {
        ServiceContext::UniqueOperationContext opCtx(newOperationContext());
        AutoGetCollectionForRead ac(opCtx.get(), nss);
        const CollectionPtr& coll = ac.getCollection();
        auto cursor = coll->getCursor(opCtx.get());
        auto record = cursor->seekExact(id1);
        ASSERT(record);
        ASSERT_EQ(id1, record->id);
        ASSERT(!cursor->next());
    }

    {
        ServiceContext::UniqueOperationContext opCtx(newOperationContext());
        AutoGetCollectionForRead ac(opCtx.get(), nss);
        const CollectionPtr& coll = ac.getCollection();
        auto cursor = coll->getCursor(opCtx.get());
        auto record = cursor->seekNear(RecordId(id1.getLong() + 1));
        ASSERT(record);
        ASSERT_EQ(id1, record->id);
        ASSERT(!cursor->next());
    }

    {
        // now we insert 2 docs, but commit the 2nd one first.
        // we make sure we can't find the 2nd until the first is committed.
        auto [earlyClient, earlyCtx] = makeClientAndCtx("earlyReader");
        AutoGetCollectionForRead ac(earlyCtx.get(), nss);
        const CollectionPtr& coll = ac.getCollection();

        auto earlyCursor = coll->getCursor(earlyCtx.get());
        ASSERT_EQ(earlyCursor->seekExact(id1)->id, id1);
        coll.yield();
        earlyCursor->save();
        earlyCtx->recoveryUnit()->abandonSnapshot();

        auto [c1, t1] = makeClientAndCtx("t1");
        AutoGetCollection ac1(t1.get(), nss, MODE_IX);
        WriteUnitOfWork w1(t1.get());
        auto id2 = RecordId(20);
        ASSERT_OK(_insertBSON(t1.get(), ac1.getCollection(), id2));
        // do not commit yet

        auto id3 = RecordId(30);
        {  // create 2nd doc
            auto t2 = newOperationContext();
            AutoGetCollection ac2(t2.get(), nss, MODE_IX);
            {
                WriteUnitOfWork w2(t2.get());
                ASSERT_OK(_insertBSON(t2.get(), ac2.getCollection(), id3));
                w2.commit();
            }
        }

        {  // Other operations should not be able to see 2nd doc until w1 commits.
            coll.restore();
            earlyCursor->restore();
            ASSERT(!earlyCursor->next());
        }

        {
            auto [c2, t2] = makeClientAndCtx("t2");
            AutoGetCollectionForRead ac2(t2.get(), nss);
            auto cursor = ac2.getCollection()->getCursor(t2.get());
            auto record = cursor->seekExact(id1);
            ASSERT(record);
            ASSERT_EQ(id1, record->id);
            ASSERT(!cursor->next());
        }

        {
            auto [c2, t2] = makeClientAndCtx("t2");
            AutoGetCollectionForRead ac2(t2.get(), nss);
            auto cursor = coll->getCursor(t2.get());
            auto record = cursor->seekNear(id2);
            ASSERT(record);
            ASSERT_EQ(id1, record->id);
            ASSERT(!cursor->next());
        }

        {
            auto [c2, t2] = makeClientAndCtx("t2");
            AutoGetCollectionForRead ac2(t2.get(), nss);
            auto cursor = coll->getCursor(t2.get());
            auto record = cursor->seekNear(id3);
            ASSERT(record);
            ASSERT_EQ(id1, record->id);
            ASSERT(!cursor->next());
        }

        w1.commit();
    }

    {  // now all 3 docs should be visible
        auto opCtx = newOperationContext();
        AutoGetCollectionForRead ac(opCtx.get(), nss);
        const CollectionPtr& coll = ac.getCollection();
        auto cursor = coll->getCursor(opCtx.get());
        auto record = cursor->seekExact(id1);
        ASSERT_EQ(id1, record->id);
        ASSERT(cursor->next());
        ASSERT(cursor->next());
        ASSERT(!cursor->next());
    }

    // Rollback the last two writes entries, then insert entries with older RecordIds to ensure that
    // the visibility rules aren't violated.
    {
        auto opCtx = newOperationContext();
        AutoGetCollectionForRead ac(opCtx.get(), nss);
        const CollectionPtr& coll = ac.getCollection();
        coll->getRecordStore()->cappedTruncateAfter(
            opCtx.get(), id1, /*inclusive*/ false, [](auto _1, auto _2, auto _3) {});
    }

    {
        // Now we insert 2 docs with timestamps earlier than before, but commit the 2nd one first.
        // We make sure we can't find the 2nd until the first is committed.
        auto [earlyClient, earlyCtx] = makeClientAndCtx("earlyReader");
        AutoGetCollectionForRead ac(earlyCtx.get(), nss);
        const CollectionPtr& coll = ac.getCollection();
        auto earlyCursor = coll->getCursor(earlyCtx.get());
        ASSERT_EQ(earlyCursor->seekExact(id1)->id, id1);
        coll.yield();
        earlyCursor->save();
        earlyCtx->recoveryUnit()->abandonSnapshot();

        auto [c1, t1] = makeClientAndCtx("t1");
        AutoGetCollection ac1(t1.get(), nss, MODE_IX);
        WriteUnitOfWork w1(t1.get());
        auto id2 = RecordId(2);
        ASSERT_OK(_insertBSON(t1.get(), ac1.getCollection(), id2));

        // do not commit yet

        auto id3 = RecordId(3);
        {  // create 2nd doc
            auto t2 = newOperationContext();
            AutoGetCollection ac2(t2.get(), nss, MODE_IX);
            {
                WriteUnitOfWork w2(t2.get());
                ASSERT_OK(_insertBSON(t2.get(), ac2.getCollection(), id3));
                w2.commit();
            }
        }

        // Other operations should not be able to see 2nd doc until w1 commits.
        coll.restore();
        ASSERT(earlyCursor->restore());
        ASSERT(!earlyCursor->next());
        {
            auto [c2, t2] = makeClientAndCtx("t2");
            AutoGetCollectionForRead ac2(t2.get(), nss);
            auto cursor = coll->getCursor(t2.get());
            auto record = cursor->seekExact(id1);
            ASSERT(record);
            ASSERT_EQ(id1, record->id);
            ASSERT(!cursor->next());
        }

        {
            auto [c2, t2] = makeClientAndCtx("t2");
            AutoGetCollectionForRead ac2(t2.get(), nss);
            auto cursor = coll->getCursor(t2.get());
            auto record = cursor->seekNear(id2);
            ASSERT(record);
            ASSERT_EQ(id1, record->id);
            ASSERT(!cursor->next());
        }

        {
            auto [c2, t2] = makeClientAndCtx("t2");
            AutoGetCollectionForRead ac2(t2.get(), nss);
            auto cursor = coll->getCursor(t2.get());
            auto record = cursor->seekNear(id3);
            ASSERT(record);
            ASSERT_EQ(id1, record->id);
            ASSERT(!cursor->next());
        }

        w1.commit();
    }

    {  // now all 3 docs should be visible
        ServiceContext::UniqueOperationContext opCtx(newOperationContext());
        AutoGetCollectionForRead ac(opCtx.get(), nss);
        const CollectionPtr& coll = ac.getCollection();
        auto cursor = coll->getCursor(opCtx.get());
        auto record = cursor->seekExact(id1);
        ASSERT_EQ(id1, record->id);
        ASSERT(cursor->next());
        ASSERT(cursor->next());
        ASSERT(!cursor->next());
    }
}
}  // namespace
}  // namespace mongo