/*
 * SPDX-FileCopyrightText: Copyright (c) 2024-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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 "cuda_hint.cuh"
#include "mha_stdheaders.cuh"
#include "utils.cuh"
#ifndef __CUDACC__
#include <cuda_runtime.h>
#endif
#include <cuda_fp16.h>
#include <cuda_fp8.h>

namespace gmma
{

enum class SwizzleMode : uint64_t
{
    kNONE = 0,
    k128 = 1,
    k64 = 2,
    k32 = 3
};

struct MatDesc
{
    uint64_t addr : 16;
    uint64_t dimKOffset : 16;
    uint64_t dimMNOffset : 16;
    uint64_t pad0 : 1;
    uint64_t baseOffset : 3;
    uint64_t pad1 : 10;
    SwizzleMode swizzle : 2;

    enum class Raw : uint64_t
    {
    };

    [[nodiscard]] __device__ inline MatDesc withAddr(void const* data) const
    {
        MatDesc ret = *this;
        ret.addr = encode(__cvta_generic_to_shared(data));
        return ret;
    }

    static __device__ inline uint32_t encode(uint32_t val)
    {
        return (val & 0x3FFFFU) >> 4;
    }

    __device__ inline bool operator==(MatDesc const& other) const
    {
        return raw() == other.raw();
    }

    __device__ inline Raw const& raw() const
    {
        static_assert(sizeof(MatDesc) == 8);
        return reinterpret_cast<Raw const&>(*this);
    }

    static __device__ inline MatDesc fromRaw(Raw const& raw)
    {
        return reinterpret_cast<MatDesc const&>(raw);
    }
};

static_assert(sizeof(MatDesc) == 8);

[[nodiscard]] __device__ inline MatDesc::Raw addAddr(MatDesc::Raw base, void const* data)
{
    assert((uint32_t(__cvta_generic_to_shared(data)) & ~0x3FFFFU) == 0);
    MatDesc::Raw ret = base;
    auto& u32x2 = reinterpret_cast<uint32_t(&)[2]>(ret);
    u32x2[0] += static_cast<uint32_t>(__cvta_generic_to_shared(data)) >> 4;
    return ret;
}

__device__ inline MatDesc makeMatDesc(void const* data, uint32_t dimKByteOffset, uint32_t dimMNByteOffset,
    void const* patternStartAddr, SwizzleMode swizzleMode)
{
    uint32_t const patternAddr = __cvta_generic_to_shared(patternStartAddr);
    uint32_t const baseAlign = [&]() -> uint32_t
    {
        switch (swizzleMode)
        {
        case SwizzleMode::kNONE: return 1;
        case SwizzleMode::k128: return 1024;
        case SwizzleMode::k64: return 512;
        case SwizzleMode::k32: return 256;
        }
        asm volatile("trap;\n");
        return 0;
    }();
    uint32_t const baseOffset = ((patternAddr % baseAlign == 0) ? 0U : ((patternAddr >> 0x7) & 0x7));
    return MatDesc{
        /*addr=*/MatDesc::encode(__cvta_generic_to_shared(data)),
        /*dimKOffset=*/MatDesc::encode(dimKByteOffset),
        /*dimMNOffset=*/MatDesc::encode(dimMNByteOffset),
        /*pad0=*/0,
        /*baseOffset=*/baseOffset,
        /*pad1=*/0,
        /*swizzle=*/swizzleMode,
    };
}

__device__ inline MatDesc makeMatDesc(
    void const* data, uint32_t dimKByteOffset, uint32_t dimMNByteOffset, SwizzleMode swizzleMode)
{
    return makeMatDesc(data, dimKByteOffset, dimMNByteOffset, data, swizzleMode);
}

inline constexpr uint32_t instM = 64;

template <typename MathElem>
inline constexpr uint32_t instK = 32 / sizeof(MathElem);

inline constexpr uint32_t instNBase = 8;

// for both a and b, outer-dim is gemm-K and inner-dim is gemm-M or gemm-N
// acc is used as both input and output.
template <typename InputElem, uint32_t n, bool transA = false, bool transB = false>
__device__ void mma_async_shmA(
    float (&acc)[exactDiv(n, instNBase)][2][2], MatDesc::Raw descA, MatDesc::Raw descB, bool accHasVal);
template <typename InputElem, uint32_t n, bool transA = false, bool transB = false>
__device__ void mma_async_regA(
    float (&acc)[exactDiv(n, instNBase)][2][2], uint32_t const (&a)[2][2][1], MatDesc::Raw descB, bool accHasVal);

__device__ inline void fence()
{
    asm volatile("wgmma.fence.sync.aligned;\n");
}

__device__ inline void commit_group()
{
    asm volatile("wgmma.commit_group.sync.aligned;\n");
}

template <uint32_t targetNbInFlightGroups>
__device__ inline void wait_group()
{
    asm volatile("wgmma.wait_group.sync.aligned %0\n; " ::"n"(targetNbInFlightGroups));
}

template <bool swizzle, typename T, uint32_t rows, uint32_t cols, bool alignedForSwizzle>
constexpr SwizzleMode getSwizzleMode(Array2D<T, rows, cols, alignedForSwizzle> const&)
{
    constexpr auto rowBytes = Array2D<T, rows, cols, alignedForSwizzle>::rowBytes;
    if constexpr (!swizzle)
    {
        return SwizzleMode::kNONE;
    }
    if constexpr (rowBytes % 128 == 0)
    {
        return SwizzleMode::k128;
    }
    else if constexpr (rowBytes == 64)
    {
        return SwizzleMode::k64;
    }
    else
    {
        static_assert(rowBytes == 32);
        return SwizzleMode::k32;
    }
}
} // namespace gmma

#include "gmma_impl.cuh"