/**
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 *
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 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
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 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
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 *    along with this program. If not, see
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 *    code of portions of this program with the OpenSSL library under certain
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#include "mongo/db/exec/sbe/expression_test_base.h"
#include "mongo/db/exec/sbe/vm/vm.h"

namespace mongo::sbe {
class SBEConcatTest : public EExpressionTestFixture {
protected:
    void runAndAssertExpression(const vm::CodeFragment* compiledExpr,
                                std::string_view expectedVal) {
        auto [tag, val] = runCompiledExpression(compiledExpr);
        value::ValueGuard guard(tag, val);

        ASSERT(value::isString(tag));
        ASSERT_EQUALS(value::getStringView(tag, val), expectedVal);
    }

    void runAndAssertNothing(const vm::CodeFragment* compiledExpr) {
        auto [tag, val] = runCompiledExpression(compiledExpr);
        value::ValueGuard guard(tag, val);

        ASSERT_EQUALS(value::TypeTags::Nothing, tag);
    }
};

TEST_F(SBEConcatTest, ComputesEmptyStringsConcat) {
    value::OwnedValueAccessor slotAccessor1;
    value::OwnedValueAccessor slotAccessor2;
    auto argSlot1 = bindAccessor(&slotAccessor1);
    auto argSlot2 = bindAccessor(&slotAccessor2);
    auto concatExpr = sbe::makeE<sbe::EFunction>(
        "concat", sbe::makeEs(makeE<EVariable>(argSlot1), makeE<EVariable>(argSlot2)));
    auto compiledExpr = compileExpression(*concatExpr);

    auto [tag1, val1] = value::makeNewString("");
    auto [tag2, val2] = value::makeNewString("");
    slotAccessor1.reset(tag1, val1);
    slotAccessor2.reset(tag2, val2);
    runAndAssertExpression(compiledExpr.get(), "");
}

TEST_F(SBEConcatTest, ComputesSingleStringConcat) {
    value::OwnedValueAccessor slotAccessor1;
    auto argSlot1 = bindAccessor(&slotAccessor1);
    auto concatExpr = sbe::makeE<sbe::EFunction>("concat", sbe::makeEs(makeE<EVariable>(argSlot1)));
    auto compiledExpr = compileExpression(*concatExpr);

    auto [tag1, val1] = value::makeNewString("Test");
    slotAccessor1.reset(tag1, val1);
    runAndAssertExpression(compiledExpr.get(), "Test");
}

TEST_F(SBEConcatTest, ComputesStringConcat) {
    value::OwnedValueAccessor slotAccessor1;
    value::OwnedValueAccessor slotAccessor2;
    auto argSlot1 = bindAccessor(&slotAccessor1);
    auto argSlot2 = bindAccessor(&slotAccessor2);
    auto concatExpr = sbe::makeE<sbe::EFunction>(
        "concat", sbe::makeEs(makeE<EVariable>(argSlot1), makeE<EVariable>(argSlot2)));
    auto compiledExpr = compileExpression(*concatExpr);

    auto [tag1, val1] = value::makeNewString("F");
    auto [tag2, val2] = value::makeNewString("1");
    ASSERT_EQUALS(value::TypeTags::StringSmall, tag1);
    slotAccessor1.reset(tag1, val1);
    slotAccessor2.reset(tag2, val2);
    runAndAssertExpression(compiledExpr.get(), "F1");

    auto [bigStringTag1, bigStringVal1] = value::makeNewString("Make sure that ");
    auto [bigStringTag2, bigStringVal2] = value::makeNewString("this is a long string.");
    ASSERT_EQUALS(value::TypeTags::StringBig, bigStringTag1);
    slotAccessor1.reset(bigStringTag1, bigStringVal1);
    slotAccessor2.reset(bigStringTag2, bigStringVal2);
    runAndAssertExpression(compiledExpr.get(), "Make sure that this is a long string.");

    auto bsonString1 = BSON("key"
                            << "bson ");
    auto bsonString2 = BSON("key"
                            << "string");
    auto bsonStringVal1 = value::bitcastFrom<const char*>(bsonString1["key"].value());
    auto bsonStringVal2 = value::bitcastFrom<const char*>(bsonString2["key"].value());
    slotAccessor1.reset(value::TypeTags::bsonString, bsonStringVal1);
    slotAccessor2.reset(value::TypeTags::bsonString, bsonStringVal2);
    runAndAssertExpression(compiledExpr.get(), "bson string");
}

TEST_F(SBEConcatTest, ComputesManyStringsConcat) {
    value::OwnedValueAccessor slotAccessor1;
    value::OwnedValueAccessor slotAccessor2;
    value::OwnedValueAccessor slotAccessor3;
    value::OwnedValueAccessor slotAccessor4;
    auto argSlot1 = bindAccessor(&slotAccessor1);
    auto argSlot2 = bindAccessor(&slotAccessor2);
    auto argSlot3 = bindAccessor(&slotAccessor3);
    auto argSlot4 = bindAccessor(&slotAccessor4);
    auto concatExpr = sbe::makeE<sbe::EFunction>("concat",
                                                 sbe::makeEs(makeE<EVariable>(argSlot1),
                                                             makeE<EVariable>(argSlot2),
                                                             makeE<EVariable>(argSlot3),
                                                             makeE<EVariable>(argSlot4)));
    auto compiledExpr = compileExpression(*concatExpr);

    auto bsonString = BSON("key"
                           << "Test ");
    auto bsonStringVal = value::bitcastFrom<const char*>(bsonString["key"].value());
    auto [tag2, val2] = value::makeNewString("for ");
    auto [tag3, val3] = value::makeNewString("many strings ");
    auto [tag4, val4] = value::makeNewString("concat");
    slotAccessor1.reset(value::TypeTags::bsonString, bsonStringVal);
    slotAccessor2.reset(tag2, val2);
    slotAccessor3.reset(tag3, val3);
    slotAccessor4.reset(tag4, val4);
    runAndAssertExpression(compiledExpr.get(), "Test for many strings concat");
}

TEST_F(SBEConcatTest, ComputesManyMoreStringsConcat) {
    const size_t smallArityLimit = std::numeric_limits<vm::SmallArityType>::max();

    for (auto arity : {smallArityLimit / 2,
                       smallArityLimit,
                       smallArityLimit - 1,
                       smallArityLimit + 1,
                       smallArityLimit * 10}) {
        std::vector<std::unique_ptr<EExpression>> args;
        args.reserve(arity);
        for (size_t idx = 0; idx < arity; ++idx) {
            args.push_back(makeE<EConstant>("x"));
        }

        auto concatExpr = makeE<EFunction>("concat", std::move(args));
        auto compiledExpr = compileExpression(*concatExpr);
        runAndAssertExpression(compiledExpr.get(), std::string(arity, 'x'));
    }
}

TEST_F(SBEConcatTest, ReturnsNothingForNonStringsConcat) {
    value::OwnedValueAccessor slotAccessor1;
    value::OwnedValueAccessor slotAccessor2;
    auto argSlot1 = bindAccessor(&slotAccessor1);
    auto argSlot2 = bindAccessor(&slotAccessor2);
    auto concatExpr = sbe::makeE<sbe::EFunction>(
        "concat", sbe::makeEs(makeE<EVariable>(argSlot1), makeE<EVariable>(argSlot2)));
    auto compiledExpr = compileExpression(*concatExpr);

    auto [tag1, val1] = value::makeNewString("abc");
    slotAccessor1.reset(tag1, val1);
    slotAccessor2.reset(value::TypeTags::NumberInt64, value::bitcastFrom<int64_t>(100));
    runAndAssertNothing(compiledExpr.get());
}

}  // namespace mongo::sbe