#include <yt/cpp/mapreduce/io/yamr_table_reader.h>

#include <library/cpp/testing/gtest/gtest.h>

using namespace NYT;

template <>
void Out<std::tuple<TString, TString, TString>>(IOutputStream& out, const std::tuple<TString, TString, TString>& value) {
    out << "{" << std::get<0>(value) << ", " << std::get<1>(value) << ", " << std::get<2>(value) << "}";
}


////////////////////////////////////////////////////////////////////////////////

class TRowCollection
{
public:
    void AddRow(TStringBuf key, TStringBuf subkey, TStringBuf value)
    {
        TStringStream row;
        auto appendLenval = [&] (TStringBuf value) {
            ui32 size = value.size();
            row.Write(&size, sizeof(size));
            row.Write(value);
        };
        appendLenval(key);
        appendLenval(subkey);
        appendLenval(value);
        RowList_.push_back(row.Str());
    }

    TString GetStreamDataStartFromRow(ui64 rowIndex) const
    {
        Y_ABORT_UNLESS(rowIndex < RowList_.size());
        TStringStream ss;
        ss.Write("\xFC\xFF\xFF\xFF");
        ss.Write(&rowIndex, sizeof(rowIndex));
        for (size_t i = rowIndex; i != RowList_.size(); ++i) {
            ss.Write(RowList_[i]);
        }
        return ss.Str();
    }

    size_t ComputeTotalStreamSize() const {
        return GetStreamDataStartFromRow(0).size();
    }

private:
    TVector<TString> RowList_;
};

class TTestRawTableReader
    : public TRawTableReader
{
public:
    TTestRawTableReader(const TRowCollection& rowCollection)
        : RowCollection_(rowCollection)
        , DataToRead_(RowCollection_.GetStreamDataStartFromRow(0))
        , Input_(MakeHolder<TStringStream>(DataToRead_))
    { }

    TTestRawTableReader(const TRowCollection& rowCollection, size_t breakPoint)
        : RowCollection_(rowCollection)
        , DataToRead_(RowCollection_.GetStreamDataStartFromRow(0).substr(0, breakPoint))
        , Input_(MakeHolder<TStringStream>(DataToRead_))
        , Broken_(true)
    { }

    size_t DoRead(void* buf, size_t size) override
    {
        Y_ABORT_UNLESS(Input_);
        size_t res = Input_->Read(buf, size);
        if (!res && Broken_) {
            ythrow yexception() << "Stream is broken";
        }
        return res;
    }

    bool Retry(
        const TMaybe<ui32>& /*rangeIndex*/,
        const TMaybe<ui64>& rowIndex,
        const std::exception_ptr& /*error*/) override
    {
        if (--Retries < 0) {
            return false;
        }
        ui64 actualRowIndex = rowIndex ? *rowIndex : 0;
        DataToRead_ = RowCollection_.GetStreamDataStartFromRow(actualRowIndex);
        Input_ = MakeHolder<TStringInput>(DataToRead_);
        Broken_ = false;
        return true;
    }

    void ResetRetries() override
    { }

    bool HasRangeIndices() const override
    {
        return false;
    }

private:
    TRowCollection RowCollection_;
    TString DataToRead_;
    THolder<IInputStream> Input_;
    bool Broken_ = false;
    i32 Retries = 1;
};

TEST(TYamrTableReaderTest, TestReadRetry)
{
    const TVector<std::tuple<TString, TString, TString>> expectedResult = {
        {"foo1", "bar1", "baz1"},
        {"foo2", "bar2", "baz2"},
        {"foo3", "bar3", "baz3"},
    };

    TRowCollection rowCollection;
    for (const auto& row : expectedResult) {
        rowCollection.AddRow(std::get<0>(row), std::get<1>(row), std::get<2>(row));
    }

    ssize_t streamSize = rowCollection.ComputeTotalStreamSize();

    for (ssize_t breakPoint = -1; breakPoint < streamSize; ++breakPoint) {
        ::TIntrusivePtr<TRawTableReader> rawReader;
        if (breakPoint == -1) {
            rawReader = ::MakeIntrusive<TTestRawTableReader>(rowCollection);
        } else {
            rawReader = ::MakeIntrusive<TTestRawTableReader>(rowCollection, static_cast<size_t>(breakPoint));
        }

        TYaMRTableReader tableReader(rawReader);
        TVector<std::tuple<TString, TString, TString>> actualResult;
        for (; tableReader.IsValid(); tableReader.Next()) {
            EXPECT_TRUE(!tableReader.IsRawReaderExhausted());
            auto row = tableReader.GetRow();
            actualResult.emplace_back(row.Key, row.SubKey, row.Value);
        }
        EXPECT_TRUE(tableReader.IsRawReaderExhausted());
        EXPECT_EQ(actualResult, expectedResult);
    }
}

TEST(TYamrTableReaderTest, TestSkipRetry)
{
    const TVector<std::tuple<TString, TString, TString>> expectedResult = {
        {"foo1", "bar1", "baz1"},
        {"foo2", "bar2", "baz2"},
        {"foo3", "bar3", "baz3"},
    };

    TRowCollection rowCollection;
    for (const auto& row : expectedResult) {
        rowCollection.AddRow(std::get<0>(row), std::get<1>(row), std::get<2>(row));
    }

    ssize_t streamSize = rowCollection.ComputeTotalStreamSize();

    for (ssize_t breakPoint = -1; breakPoint < streamSize; ++breakPoint) {
        try {
            ::TIntrusivePtr<TRawTableReader> rawReader;
            if (breakPoint == -1) {
                rawReader = ::MakeIntrusive<TTestRawTableReader>(rowCollection);
            } else {
                rawReader = ::MakeIntrusive<TTestRawTableReader>(rowCollection, static_cast<size_t>(breakPoint));
            }

            TYaMRTableReader tableReader(rawReader);
            ui32 rowCount = 0;
            for (; tableReader.IsValid(); tableReader.Next()) {
                EXPECT_TRUE(!tableReader.IsRawReaderExhausted());
                ++rowCount;
            }
            EXPECT_TRUE(tableReader.IsRawReaderExhausted());
            EXPECT_EQ(rowCount, 3u);
        } catch (const std::exception& ex) {
            Cerr << breakPoint << Endl;
            Cerr << ex.what() << Endl;
            throw;
        }
    }
}

////////////////////////////////////////////////////////////////////////////////