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// Copyright 2024-2026 Alişah Özcan
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0
// Developer: Alişah Özcan

#include <heongpu/host/bfv/encoder.cuh>

namespace heongpu
{

    __host__ HEEncoder<Scheme::BFV>::HEEncoder(HEContext<Scheme::BFV>& context)
    {
        if (!context.context_generated_)
        {
            throw std::invalid_argument("HEContext is not generated!");
        }

        scheme_ = context.scheme_;

        n = context.n;
        n_power = context.n_power;

        slot_count_ = n;

        plain_modulus_ = context.plain_modulus2_;

        plain_ntt_tables_ = context.plain_ntt_tables_;
        plain_intt_tables_ = context.plain_intt_tables_;

        n_plain_inverse_ = context.n_plain_inverse_;

        // Encode - Decode Index
        std::vector<Data64> encode_index;

        int m = n << 1;
        int gen = 3;
        int pos = 1;
        int index = 0;
        int location = 0;
        for (int i = 0; i < int(n / 2); i++)
        {
            index = (pos - 1) >> 1;
            location = gpuntt::bitreverse(index, n_power);
            encode_index.push_back(location);
            pos *= gen;
            pos &= (m - 1);
        }
        for (int i = int(n / 2); i < n; i++)
        {
            index = (m - pos - 1) >> 1;
            location = gpuntt::bitreverse(index, n_power);
            encode_index.push_back(location);
            pos *= gen;
            pos &= (m - 1);
        }

        encoding_location_ =
            std::make_shared<DeviceVector<Data64>>(encode_index);
    }

    __host__ void
    HEEncoder<Scheme::BFV>::encode_bfv(Plaintext<Scheme::BFV>& plain,
                                       const std::vector<uint64_t>& message,
                                       const cudaStream_t stream)
    {
        DeviceVector<Data64> output_memory(n, stream);

        DeviceVector<Data64> message_gpu(slot_count_, stream);
        cudaMemcpyAsync(message_gpu.data(), message.data(),
                        message.size() * sizeof(Data64), cudaMemcpyHostToDevice,
                        stream);
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        encode_kernel_bfv<<<dim3((n >> 8), 1, 1), 256, 0, stream>>>(
            output_memory.data(), message_gpu.data(),
            encoding_location_->data(), plain_modulus_->data(), message.size());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        gpuntt::ntt_rns_configuration<Data64> cfg_intt = {
            .n_power = n_power,
            .ntt_type = gpuntt::INVERSE,
            .ntt_layout = gpuntt::PerPolynomial,
            .reduction_poly = gpuntt::ReductionPolynomial::X_N_plus,
            .zero_padding = false,
            .mod_inverse = n_plain_inverse_->data(),
            .stream = stream};

        gpuntt::GPU_INTT_Inplace(output_memory.data(),
                                 plain_intt_tables_->data(),
                                 plain_modulus_->data(), cfg_intt, 1, 1);

        plain.memory_set(std::move(output_memory));
    }

    __host__ void
    HEEncoder<Scheme::BFV>::encode_bfv(Plaintext<Scheme::BFV>& plain,
                                       const std::vector<int64_t>& message,
                                       const cudaStream_t stream)
    {
        DeviceVector<Data64> output_memory(n, stream);

        DeviceVector<Data64> message_gpu(slot_count_, stream);
        cudaMemcpyAsync(message_gpu.data(), message.data(),
                        message.size() * sizeof(Data64), cudaMemcpyHostToDevice,
                        stream);
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        encode_kernel_bfv<<<dim3((n >> 8), 1, 1), 256, 0, stream>>>(
            output_memory.data(), message_gpu.data(),
            encoding_location_->data(), plain_modulus_->data(), message.size());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        gpuntt::ntt_rns_configuration<Data64> cfg_intt = {
            .n_power = n_power,
            .ntt_type = gpuntt::INVERSE,
            .ntt_layout = gpuntt::PerPolynomial,
            .reduction_poly = gpuntt::ReductionPolynomial::X_N_plus,
            .zero_padding = false,
            .mod_inverse = n_plain_inverse_->data(),
            .stream = stream};

        gpuntt::GPU_INTT_Inplace(output_memory.data(),
                                 plain_intt_tables_->data(),
                                 plain_modulus_->data(), cfg_intt, 1, 1);

        plain.memory_set(std::move(output_memory));
    }

    __host__ void
    HEEncoder<Scheme::BFV>::encode_bfv(Plaintext<Scheme::BFV>& plain,
                                       const HostVector<uint64_t>& message,
                                       const cudaStream_t stream)
    {
        DeviceVector<Data64> output_memory(n, stream);

        DeviceVector<Data64> message_gpu(slot_count_, stream);
        cudaMemcpyAsync(message_gpu.data(), message.data(),
                        message.size() * sizeof(Data64), cudaMemcpyHostToDevice,
                        stream);
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        encode_kernel_bfv<<<dim3((n >> 8), 1, 1), 256, 0, stream>>>(
            output_memory.data(), message_gpu.data(),
            encoding_location_->data(), plain_modulus_->data(), message.size());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        gpuntt::ntt_rns_configuration<Data64> cfg_intt = {
            .n_power = n_power,
            .ntt_type = gpuntt::INVERSE,
            .ntt_layout = gpuntt::PerPolynomial,
            .reduction_poly = gpuntt::ReductionPolynomial::X_N_plus,
            .zero_padding = false,
            .mod_inverse = n_plain_inverse_->data(),
            .stream = stream};

        gpuntt::GPU_INTT_Inplace(output_memory.data(),
                                 plain_intt_tables_->data(),
                                 plain_modulus_->data(), cfg_intt, 1, 1);

        plain.memory_set(std::move(output_memory));
    }

    __host__ void
    HEEncoder<Scheme::BFV>::encode_bfv(Plaintext<Scheme::BFV>& plain,
                                       const HostVector<int64_t>& message,
                                       const cudaStream_t stream)
    {
        DeviceVector<Data64> output_memory(n, stream);

        DeviceVector<Data64> message_gpu(slot_count_, stream);
        cudaMemcpyAsync(message_gpu.data(), message.data(),
                        message.size() * sizeof(Data64), cudaMemcpyHostToDevice,
                        stream);
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        encode_kernel_bfv<<<dim3((n >> 8), 1, 1), 256, 0, stream>>>(
            output_memory.data(), message_gpu.data(),
            encoding_location_->data(), plain_modulus_->data(), message.size());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        gpuntt::ntt_rns_configuration<Data64> cfg_intt = {
            .n_power = n_power,
            .ntt_type = gpuntt::INVERSE,
            .ntt_layout = gpuntt::PerPolynomial,
            .reduction_poly = gpuntt::ReductionPolynomial::X_N_plus,
            .zero_padding = false,
            .mod_inverse = n_plain_inverse_->data(),
            .stream = stream};

        gpuntt::GPU_INTT_Inplace(output_memory.data(),
                                 plain_intt_tables_->data(),
                                 plain_modulus_->data(), cfg_intt, 1, 1);

        plain.memory_set(std::move(output_memory));
    }

    __host__ void
    HEEncoder<Scheme::BFV>::decode_bfv(std::vector<uint64_t>& message,
                                       Plaintext<Scheme::BFV>& plain,
                                       const cudaStream_t stream)
    {
        DeviceVector<Data64> temp_memory(slot_count_ + n, stream);
        Data64* message_gpu = temp_memory.data();
        Data64* temp_plain = message_gpu + slot_count_;

        gpuntt::ntt_rns_configuration<Data64> cfg_ntt = {
            .n_power = n_power,
            .ntt_type = gpuntt::FORWARD,
            .ntt_layout = gpuntt::PerPolynomial,
            .reduction_poly = gpuntt::ReductionPolynomial::X_N_plus,
            .zero_padding = false,
            .stream = stream};

        gpuntt::GPU_NTT(plain.data(), temp_plain, plain_ntt_tables_->data(),
                        plain_modulus_->data(), cfg_ntt, 1, 1);
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        decode_kernel_bfv<<<dim3((n >> 8), 1, 1), 256, 0, stream>>>(
            message_gpu, temp_plain, encoding_location_->data());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        message.resize(slot_count_);

        cudaMemcpyAsync(message.data(), message_gpu,
                        slot_count_ * sizeof(uint64_t), cudaMemcpyDeviceToHost,
                        stream);
        HEONGPU_CUDA_CHECK(cudaGetLastError());
    }

    __host__ void
    HEEncoder<Scheme::BFV>::decode_bfv(std::vector<int64_t>& message,
                                       Plaintext<Scheme::BFV>& plain,
                                       const cudaStream_t stream)
    {
        DeviceVector<Data64> temp_memory(slot_count_ + n, stream);
        Data64* message_gpu = temp_memory.data();
        Data64* temp_plain = message_gpu + slot_count_;

        gpuntt::ntt_rns_configuration<Data64> cfg_ntt = {
            .n_power = n_power,
            .ntt_type = gpuntt::FORWARD,
            .ntt_layout = gpuntt::PerPolynomial,
            .reduction_poly = gpuntt::ReductionPolynomial::X_N_plus,
            .zero_padding = false,
            .stream = stream};

        gpuntt::GPU_NTT(plain.data(), temp_plain, plain_ntt_tables_->data(),
                        plain_modulus_->data(), cfg_ntt, 1, 1);

        decode_kernel_bfv<<<dim3((n >> 8), 1, 1), 256, 0, stream>>>(
            message_gpu, temp_plain, encoding_location_->data());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        unsigned_signed_convert<<<dim3((slot_count_ >> 8), 1, 1), 256, 0,
                                  stream>>>(message_gpu, message_gpu,
                                            plain_modulus_->data());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        message.resize(slot_count_);

        cudaMemcpyAsync(message.data(), message_gpu,
                        slot_count_ * sizeof(int64_t), cudaMemcpyDeviceToHost,
                        stream);
        HEONGPU_CUDA_CHECK(cudaGetLastError());
    }

    __host__ void
    HEEncoder<Scheme::BFV>::decode_bfv(HostVector<uint64_t>& message,
                                       Plaintext<Scheme::BFV>& plain,
                                       const cudaStream_t stream)
    {
        DeviceVector<Data64> temp_memory(slot_count_ + n, stream);
        Data64* message_gpu = temp_memory.data();
        Data64* temp_plain = message_gpu + slot_count_;

        gpuntt::ntt_rns_configuration<Data64> cfg_ntt = {
            .n_power = n_power,
            .ntt_type = gpuntt::FORWARD,
            .ntt_layout = gpuntt::PerPolynomial,
            .reduction_poly = gpuntt::ReductionPolynomial::X_N_plus,
            .zero_padding = false,
            .stream = stream};

        gpuntt::GPU_NTT(plain.data(), temp_plain, plain_ntt_tables_->data(),
                        plain_modulus_->data(), cfg_ntt, 1, 1);

        decode_kernel_bfv<<<dim3((n >> 8), 1, 1), 256, 0, stream>>>(
            message_gpu, temp_plain, encoding_location_->data());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        message.resize(slot_count_);

        cudaMemcpyAsync(message.data(), message_gpu,
                        slot_count_ * sizeof(uint64_t), cudaMemcpyDeviceToHost,
                        stream);
        HEONGPU_CUDA_CHECK(cudaGetLastError());
    }

    __host__ void
    HEEncoder<Scheme::BFV>::decode_bfv(HostVector<int64_t>& message,
                                       Plaintext<Scheme::BFV>& plain,
                                       const cudaStream_t stream)
    {
        DeviceVector<Data64> temp_memory(slot_count_ + n, stream);
        Data64* message_gpu = temp_memory.data();
        Data64* temp_plain = message_gpu + slot_count_;

        gpuntt::ntt_rns_configuration<Data64> cfg_ntt = {
            .n_power = n_power,
            .ntt_type = gpuntt::FORWARD,
            .ntt_layout = gpuntt::PerPolynomial,
            .reduction_poly = gpuntt::ReductionPolynomial::X_N_plus,
            .zero_padding = false,
            .stream = stream};

        gpuntt::GPU_NTT(plain.data(), temp_plain, plain_ntt_tables_->data(),
                        plain_modulus_->data(), cfg_ntt, 1, 1);

        decode_kernel_bfv<<<dim3((n >> 8), 1, 1), 256, 0, stream>>>(
            message_gpu, temp_plain, encoding_location_->data());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        unsigned_signed_convert<<<dim3((slot_count_ >> 8), 1, 1), 256, 0,
                                  stream>>>(message_gpu, message_gpu,
                                            plain_modulus_->data());
        HEONGPU_CUDA_CHECK(cudaGetLastError());

        message.resize(slot_count_);

        cudaMemcpyAsync(message.data(), message_gpu,
                        slot_count_ * sizeof(int64_t), cudaMemcpyDeviceToHost,
                        stream);
        HEONGPU_CUDA_CHECK(cudaGetLastError());
    }

} // namespace heongpu