/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://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.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

//
//  @author raver119@gmail.com
//

#include <op_boilerplate.h>
#include <types/float16.h>
#include <ops/declarable/helpers/batched_gemm.h>
#include <helpers/BlasHelper.h>
#include <execution/Threads.h>


namespace nd4j    {
namespace ops     {
namespace helpers {


template <typename T>
void bgemm_(const std::vector<NDArray*>& vA, const std::vector<NDArray*>& vB, std::vector<NDArray*>& vC, const NDArray* alphas, const NDArray* betas, int transA, int transB, int M, int N, int K, const int lda, const int ldb, const int ldc) {

    int batchSize = vA.size();

    if (BlasHelper::getInstance()->hasBatchedGEMM<T>()) {
        auto arr = vA.at(0);
        CBLAS_TRANSPOSE *tA, *tB;
        int *tM, *tN, *tK, *tldA, *tldB, *tldC, *tsize;
        // mkl requires mnk etc as arrays, cuda doesn't
        ALLOCATE(tA, arr->getContext()->getWorkspace(), batchSize, CBLAS_TRANSPOSE);
        ALLOCATE(tB, arr->getContext()->getWorkspace(), batchSize, CBLAS_TRANSPOSE);
        ALLOCATE(tM, arr->getContext()->getWorkspace(), batchSize, int);
        ALLOCATE(tN, arr->getContext()->getWorkspace(), batchSize, int);
        ALLOCATE(tK, arr->getContext()->getWorkspace(), batchSize, int);
        ALLOCATE(tldA, arr->getContext()->getWorkspace(), batchSize, int);
        ALLOCATE(tldB, arr->getContext()->getWorkspace(), batchSize, int);
        ALLOCATE(tldC, arr->getContext()->getWorkspace(), batchSize, int);
        ALLOCATE(tsize, arr->getContext()->getWorkspace(), batchSize, int);

        shape::fill(tA, (CBLAS_TRANSPOSE) transA, batchSize);
        shape::fill(tB, (CBLAS_TRANSPOSE) transB, batchSize);

        shape::fill(tM, M, batchSize);
        shape::fill(tN, N, batchSize);
        shape::fill(tK, K, batchSize);
        shape::fill(tldA, lda, batchSize);
        shape::fill(tldB, ldb, batchSize);
        shape::fill(tldC, ldc, batchSize);
        shape::fill(tsize, 1, batchSize);

        std::vector<T*> buffersA(batchSize);
        std::vector<T*> buffersB(batchSize);
        std::vector<T*> buffersC(batchSize);

        for (int e = 0; e < batchSize; e++) {
            buffersA[e] = reinterpret_cast<T *>(vA[e]->buffer());
            buffersB[e] = reinterpret_cast<T *>(vB[e]->buffer());
            buffersC[e] = reinterpret_cast<T *>(vC[e]->buffer());
        }

        if (std::is_same<T, double>::value) {
            BlasHelper::getInstance()->dgemmBatched()(CblasColMajor, tA, tB, tM, tN, tK, (double *) alphas->getBuffer(), (double **) buffersA.data(), tldA, (double **) buffersB.data(), tldB, (double *) betas->getBuffer(),(double **)  buffersC.data(), tldC, vA.size(), tsize);
        } else if (std::is_same<T, float >::value) {
            BlasHelper::getInstance()->sgemmBatched()(CblasColMajor, tA, tB, tM, tN, tK, (float *) alphas->getBuffer(), (float **) buffersA.data(), tldA, (float **) buffersB.data(), tldB, (float *) betas->getBuffer(), (float **) buffersC.data(), tldC, vA.size(), tsize);
        }

        // release temporary arrays
        RELEASE(tA, arr->getContext()->getWorkspace());
        RELEASE(tB, arr->getContext()->getWorkspace());
        RELEASE(tM, arr->getContext()->getWorkspace());
        RELEASE(tN, arr->getContext()->getWorkspace());
        RELEASE(tK, arr->getContext()->getWorkspace());
        RELEASE(tldA, arr->getContext()->getWorkspace());
        RELEASE(tldB, arr->getContext()->getWorkspace());
        RELEASE(tldC, arr->getContext()->getWorkspace());
        RELEASE(tsize, arr->getContext()->getWorkspace());
    } else {
        CBLAS_TRANSPOSE tA = (CBLAS_TRANSPOSE) transA;
        CBLAS_TRANSPOSE tB = (CBLAS_TRANSPOSE) transB;

        int vaSize = vA.size();

        auto func = PRAGMA_THREADS_FOR {
            for (auto p = start; p < stop; p++) {
                auto A = reinterpret_cast<T *>(vA.at(p)->buffer());
                auto B = reinterpret_cast<T *>(vB.at(p)->buffer());
                auto C = reinterpret_cast<T *>(vC.at(p)->buffer());
                auto alpha = alphas->e<T>(p);
                auto beta = betas->e<T>(p);
                for (int m = 0; m < M; ++m) {
                    for (int n = 0; n < N; ++n) {
                        T c_mnp = 0;

                        PRAGMA_OMP_SIMD
                        for (int k = 0; k < K; ++k)
                            c_mnp += A[tA == CblasNoTrans ? (m + k * lda) : (m * lda + k)] * B[tB == CblasNoTrans ? (k + n * ldb) : (k * ldb + n)];

                        C[m + n * ldc] = alpha * c_mnp + beta * C[m + n * ldc];
                    }
                }
            }
        };

        samediff::Threads::parallel_tad(func, 0, vaSize);
    }
}


void bgemm(const std::vector<NDArray*>& vA, const std::vector<NDArray*>& vB, std::vector<NDArray*>& vC, const NDArray* alphas, const NDArray* betas, int transA, int transB, int M, int N, int K, const int lda, const int ldb, const int ldc) {
    auto xType = vA.at(0)->dataType();
    BUILD_SINGLE_SELECTOR(xType, bgemm_, (vA, vB, vC, alphas, betas, transA, transB, M, N, K, lda, ldb, ldc), FLOAT_TYPES);
}

BUILD_SINGLE_TEMPLATE(template void bgemm_, (const std::vector<NDArray*>& vA, const std::vector<NDArray*>& vB, std::vector<NDArray*>& vC, const NDArray* alphas, const NDArray* betas, int transA, int transB, int M, int N, int K, const int lda, const int ldb, const int ldc), FLOAT_TYPES);

}
}
}