/*
 * Copyright (c) 2023, 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 <cstdint>
#include <optional>
#include <string>

namespace common
{

class QuantMode
{
    // [WARNING] KEEP BELOW DEFINITION IN SYNC WITH tensorrt_llm/quantization/mode.py
public:
    using BaseType = std::uint32_t;

    explicit constexpr QuantMode(BaseType value) noexcept
        : mValue{value}
    {
    }

    QuantMode() noexcept = default;

    constexpr QuantMode(QuantMode const&) noexcept = default;

    constexpr QuantMode& operator=(QuantMode const& other) noexcept = default;

    static constexpr QuantMode none() noexcept
    {
        return QuantMode(BaseType(0));
    }

    static constexpr QuantMode int4Weights() noexcept
    {
        return QuantMode(BaseType(1u) << 0);
    }

    static constexpr QuantMode int8Weights() noexcept
    {
        return QuantMode(BaseType(1u) << 1);
    }

    static constexpr QuantMode activations() noexcept
    {
        return QuantMode(BaseType(1u) << 2);
    }

    static constexpr QuantMode perChannelScaling() noexcept
    {
        return QuantMode(BaseType(1u) << 3);
    }

    static constexpr QuantMode perTokenScaling() noexcept
    {
        return QuantMode(BaseType(1u) << 4);
    }

    static constexpr QuantMode perGroupScaling() noexcept
    {
        return QuantMode(BaseType(1u) << 5);
    }

    static constexpr QuantMode int8KvCache() noexcept
    {
        return QuantMode(BaseType(1u) << 6);
    }

    static constexpr QuantMode fp8KvCache() noexcept
    {
        return QuantMode(BaseType(1u) << 7);
    }

    static constexpr QuantMode fp8Qdq() noexcept
    {
        return QuantMode(BaseType(1u) << 8);
    }

    static constexpr QuantMode fp8RowWise() noexcept
    {
        return QuantMode(BaseType(1u) << 3 | BaseType(1u) << 4 | BaseType(1u) << 9);
    }

    constexpr BaseType value() const noexcept
    {
        return mValue;
    }

    constexpr bool isSet(QuantMode const& mode) const noexcept
    {
        return (mValue & mode.value()) == mode.value();
    }

    constexpr bool hasInt4Weights() const noexcept
    {
        return isSet(int4Weights());
    }

    constexpr bool hasInt8Weights() const noexcept
    {
        return isSet(int8Weights());
    }

    constexpr bool hasActivations() const noexcept
    {
        return isSet(activations());
    }

    constexpr bool hasPerChannelScaling() const noexcept
    {
        return isSet(perChannelScaling());
    }

    constexpr bool hasPerTokenScaling() const noexcept
    {
        return isSet(perTokenScaling());
    }

    constexpr bool hasPerGroupScaling() const noexcept
    {
        return isSet(perGroupScaling());
    }

    constexpr bool hasStaticActivationScaling() const noexcept
    {
        return !hasPerTokenScaling();
    }

    constexpr bool hasInt8KvCache() const noexcept
    {
        return isSet(int8KvCache());
    }

    constexpr bool hasFp8KvCache() const noexcept
    {
        return isSet(fp8KvCache());
    }

    constexpr bool hasFp8Qdq() const noexcept
    {
        return isSet(fp8Qdq());
    }

    constexpr bool hasFp8RowWise() const noexcept
    {
        return isSet(fp8RowWise());
    }

    constexpr bool hasKvCacheQuant() const noexcept
    {
        return hasInt8KvCache() || hasFp8KvCache();
    }

    static constexpr QuantMode fromDescription(bool quantizeWeights = false, bool quantizeActivations = false,
        bool perToken = false, bool perChannel = false, bool perGroup = false, bool useInt4Weights = false,
        bool useInt8KvCache = false, bool useFp8KvCache = false, bool useFp8Qdq = false, bool useFp8RowWise = false)
    {
        QuantMode quantMode{};
        if (quantizeWeights)
        {
            if (useInt4Weights)
                quantMode += int4Weights();
            else
                quantMode += int8Weights();
        }

        if (quantizeActivations)
        {
            quantMode += activations();
        }

        if (perChannel)
        {
            quantMode += QuantMode::perChannelScaling();
        }
        if (perToken)
        {
            quantMode += QuantMode::perTokenScaling();
        }
        if (perGroup)
        {
            quantMode += QuantMode::perGroupScaling();
        }

        if (useInt8KvCache)
        {
            quantMode += int8KvCache();
        }

        if (useFp8KvCache)
        {
            quantMode += fp8KvCache();
        }

        if (useFp8Qdq)
        {
            quantMode += fp8Qdq();
        }

        if (useFp8RowWise)
        {
            quantMode += fp8RowWise();
        }

        return quantMode;
    }

    static constexpr QuantMode useSmoothQuant(bool perToken = false, bool perChannel = false)
    {
        return fromDescription(true, true, perToken, perChannel);
    }

    static constexpr QuantMode useWeightOnly(bool useInt4Weights = false, bool perGroup = false)
    {
        return fromDescription(true, false, false, false, perGroup, useInt4Weights);
    }

    static const QuantMode fromQuantAlgo(
        std::optional<std::string> quantAlgo = std::nullopt, std::optional<std::string> kvCacheQuantAlgo = std::nullopt)
    {
        QuantMode quantMode{};
        if (quantAlgo == "W8A16")
        {
            quantMode = useWeightOnly(false, false);
        }
        else if (quantAlgo == "W4A16")
        {
            quantMode = useWeightOnly(true, false);
        }
        else if (quantAlgo == "W4A16_AWQ")
        {
            quantMode = useWeightOnly(true, true);
        }
        else if (quantAlgo == "W4A8_AWQ")
        {
            quantMode = useWeightOnly(true, true);
        }
        else if (quantAlgo == "W4A16_GPTQ")
        {
            quantMode = useWeightOnly(true, true);
        }
        else if (quantAlgo == "W8A8_SQ_PER_CHANNEL")
        {
            quantMode = useSmoothQuant(false, true);
        }
        else if (quantAlgo == "W8A8_SQ_PER_TENSOR_PLUGIN")
        {
            quantMode = useSmoothQuant(false, false);
        }
        else if (quantAlgo == "W8A8_SQ_PER_CHANNEL_PER_TOKEN_PLUGIN")
        {
            quantMode = useSmoothQuant(true, true);
        }
        else if (quantAlgo == "W8A8_SQ_PER_CHANNEL_PER_TENSOR_PLUGIN")
        {
            quantMode = useSmoothQuant(false, true);
        }
        else if (quantAlgo == "W8A8_SQ_PER_TENSOR_PER_TOKEN_PLUGIN")
        {
            quantMode = useSmoothQuant(true, false);
        }
        else if (quantAlgo == "FP8")
        {
            quantMode = fromDescription(false, false, false, false, false, false, false, false, true);
        }
        else if (quantAlgo == "FP8_ROWWISE")
        {
            quantMode = fromDescription(false, false, true, true, false, false, false, false, false, true);
        }

        if (kvCacheQuantAlgo == "INT8")
        {
            quantMode += int8KvCache();
        }
        else if (kvCacheQuantAlgo == "FP8")
        {
            quantMode += fp8KvCache();
        }

        return quantMode;
    }

    constexpr QuantMode operator+(QuantMode const& other) const noexcept
    {
        return QuantMode(mValue | other.mValue);
    }

    constexpr QuantMode& operator+=(QuantMode const& other) noexcept
    {
        return *this = *this + other;
    }

    constexpr QuantMode operator-(QuantMode const& other) const noexcept
    {
        return QuantMode(mValue & ~other.mValue);
    }

    constexpr QuantMode& operator-=(QuantMode const& other) noexcept
    {
        return *this = *this - other;
    }

    constexpr bool operator==(QuantMode const& other) const noexcept
    {
        return mValue == other.mValue;
    }

    constexpr bool operator!=(QuantMode const& other) const noexcept
    {
        return !(*this == other);
    }

private:
    BaseType mValue{0};
};

} // namespace common