/**
 *    Copyright (C) 2020-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)
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 *    file(s), but you are not obligated to do so. If you do not wish to do so,
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 *    it in the license file.
 */

#include "mongo/platform/basic.h"

#include "mongo/db/catalog/catalog_test_fixture.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/index_catalog_entry_impl.h"
#include "mongo/db/catalog_raii.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/s/shard_key_index_util.h"

namespace mongo {
namespace {

constexpr int kIndexVersion = 2;

class ShardKeyIndexUtilTest : public CatalogTestFixture {
public:
    ShardKeyIndexUtilTest() : CatalogTestFixture() {}

    void createIndex(const BSONObj& spec) {
        // Build the specified index on the collection.
        WriteUnitOfWork wuow(opCtx());
        auto* indexCatalog = _coll->getWritableCollection(opCtx())->getIndexCatalog();
        uassertStatusOK(indexCatalog->createIndexOnEmptyCollection(
            opCtx(), _coll->getWritableCollection(opCtx()), spec));
        wuow.commit();
    }

    const NamespaceString& nss() const {
        return _nss;
    }

    const CollectionPtr& coll() const {
        return (*_coll).getCollection();
    }

    OperationContext* opCtx() {
        return operationContext();
    }

protected:
    void setUp() override {
        CatalogTestFixture::setUp();
        _coll.emplace(opCtx(), _nss, MODE_X);
        ASSERT_OK(storageInterface()->createCollection(opCtx(), _nss, {}));
    }

    void tearDown() override {
        _coll.reset();
        CatalogTestFixture::tearDown();
    }

private:
    const NamespaceString _nss = NamespaceString::createNamespaceString_forTest("test.user");
    boost::optional<AutoGetCollection> _coll;
};

TEST_F(ShardKeyIndexUtilTest, SimpleKeyPattern) {
    createIndex(BSON("key" << BSON("y" << 1) << "name"
                           << "y"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));

    const auto index =
        findShardKeyPrefixedIndex(opCtx(), coll(), BSON("x" << 1), true /* requireSingleKey */);

    ASSERT_TRUE(index);
    ASSERT_EQ("x", index->descriptor()->indexName());
}

TEST_F(ShardKeyIndexUtilTest, HashedKeyPattern) {
    createIndex(BSON("key" << BSON("y" << 1) << "name"
                           << "y"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x"
                                   << "hashed")
                           << "name"
                           << "xhashed"
                           << "v" << kIndexVersion));

    const auto index = findShardKeyPrefixedIndex(opCtx(),
                                                 coll(),
                                                 BSON("x"
                                                      << "hashed"),
                                                 true /* requireSingleKey */);

    ASSERT_TRUE(index);
    ASSERT_EQ("xhashed", index->descriptor()->indexName());
}

TEST_F(ShardKeyIndexUtilTest, PrefixKeyPattern) {
    createIndex(BSON("key" << BSON("y" << 1) << "name"
                           << "y"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1 << "y" << 1 << "z" << 1) << "name"
                           << "xyz"
                           << "v" << kIndexVersion));

    const auto index = findShardKeyPrefixedIndex(
        opCtx(), coll(), BSON("x" << 1 << "y" << 1), true /* requireSingleKey */);

    ASSERT_TRUE(index);
    ASSERT_EQ("xyz", index->descriptor()->indexName());
}

TEST_F(ShardKeyIndexUtilTest, ExcludesIncompatibleIndexes) {
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "sparse"
                           << "sparse" << true << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "partial"
                           << "partialFilterExpression" << BSON("x" << BSON("$exists" << true))
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "collation"
                           << "collation"
                           << BSON("locale"
                                   << "fr")
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));


    const auto index =
        findShardKeyPrefixedIndex(opCtx(), coll(), BSON("x" << 1), true /* requireSingleKey */);

    ASSERT_TRUE(index);
    ASSERT_EQ("x", index->descriptor()->indexName());
}

TEST_F(ShardKeyIndexUtilTest, ExcludesMultiKeyIfRequiresSingleKey) {
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));

    DBDirectClient client(opCtx());
    client.insert(nss(), BSON("x" << BSON_ARRAY(1 << 2)));

    const auto index =
        findShardKeyPrefixedIndex(opCtx(), coll(), BSON("x" << 1), true /* requireSingleKey */);

    ASSERT_FALSE(index);
}

TEST_F(ShardKeyIndexUtilTest, IncludesMultiKeyIfSingleKeyNotRequired) {
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));

    DBDirectClient client(opCtx());
    client.insert(nss(), BSON("x" << BSON_ARRAY(1 << 2)));

    const auto index =
        findShardKeyPrefixedIndex(opCtx(), coll(), BSON("x" << 1), false /* requireSingleKey */);

    ASSERT_TRUE(index);
    ASSERT_EQ("x", index->descriptor()->indexName());
}

TEST_F(ShardKeyIndexUtilTest, LastShardIndexWithSingleCandidate) {
    createIndex(BSON("key" << BSON("y" << 1) << "name"
                           << "y"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1 << "y" << 1) << "name"
                           << "xy"
                           << "v" << kIndexVersion << "hidden" << true));

    ASSERT_TRUE(isLastNonHiddenShardKeyIndex(opCtx(), coll(), "x", BSON("x" << 1)));
}

TEST_F(ShardKeyIndexUtilTest, LastShardIndexWithMultipleCandidates) {
    createIndex(BSON("key" << BSON("y" << 1) << "name"
                           << "y"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1 << "y" << 1) << "name"
                           << "xy"
                           << "v" << kIndexVersion));

    ASSERT_FALSE(isLastNonHiddenShardKeyIndex(opCtx(), coll(), "x", BSON("x" << 1)));
}

TEST_F(ShardKeyIndexUtilTest, LastShardIndexWithIncompatibleIndex) {
    createIndex(BSON("key" << BSON("y" << 1) << "name"
                           << "y"
                           << "v" << kIndexVersion));
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));

    ASSERT_FALSE(isLastNonHiddenShardKeyIndex(opCtx(), coll(), "y", BSON("x" << 1)));
}

TEST_F(ShardKeyIndexUtilTest, LastShardIndexWithNonExistingIndex) {
    createIndex(BSON("key" << BSON("x" << 1) << "name"
                           << "x"
                           << "v" << kIndexVersion));

    ASSERT_FALSE(isLastNonHiddenShardKeyIndex(opCtx(), coll(), "y", BSON("x" << 1)));
}

}  // namespace
}  // namespace mongo