/*
 * Copyright (c) 2019-2024, NVIDIA CORPORATION.  All rights reserved.
 *
 * 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.
 */

#pragma once

#include "tensorrt_llm/layers/baseLayer.h"
#include "tensorrt_llm/layers/decodingParams.h"
#include "tensorrt_llm/runtime/common.h"
#include "tensorrt_llm/runtime/decodingOutput.h"

#include <optional>
#include <utility>

namespace tc = tensorrt_llm::common;

namespace tensorrt_llm::layers
{

template <typename T>
class BeamSearchLayer : public BaseLayer
{
    using Base = BaseLayer;

public:
    BeamSearchLayer(DecoderDomain const& decoderDomain, std::shared_ptr<runtime::BufferManager> bufferManager);

    void setup(runtime::SizeType32 const batchSize, runtime::SizeType32 const beamWidth, BufferConstPtr batchSlots,
        std::shared_ptr<BaseSetupParams> const& setupParams) override;

    void forwardAsync(std::shared_ptr<BaseDecodingOutputs> const& outputs,
        std::shared_ptr<BaseDecodingInputs> const& inputs) override;

    [[nodiscard]] size_t getWorkspaceSize() const noexcept override;

private:
    void allocateBuffer(runtime::SizeType32 batchSize, runtime::SizeType32 beamWidth);

private:
    using Base::mDecoderDomain;

    BufferPtr mWorkspace;
    TensorPtr mDiversityRateDevice; //<! [batchSize] shaped, in device memory.
    TensorPtr mLengthPenaltyDevice; //<! [batchSize] shaped, in device memory.
    TensorPtr mEarlyStoppingDevice; //<! [batchSize] shaped, in device memory.
    TensorPtr mDiversityRateHost;   //<! [batchSize] shaped, in pinned host memory.
    TensorPtr mLengthPenaltyHost;   //<! [batchSize] shaped, in pinned host memory.
    TensorPtr mEarlyStoppingHost;   //<! [batchSize] shaped, in pinned host memory.
};

} // namespace tensorrt_llm::layers