/********************************************************************************
 * Copyright (c) 2023 CEA-List
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 ********************************************************************************/

#include <memory>
#include <vector>

#include "aidge/data/Tensor.hpp"
#include "aidge/operator/ReLU.hpp"
#include "aidge/utils/Types.h"
#include "aidge/backend/cpu/data/GetCPUPtr.h"
#include "aidge/utils/ErrorHandling.hpp"

#include "aidge/backend/cpu/operator/ReLUImpl.hpp"
#include "aidge/backend/cpu/operator/ReLUImpl_forward_kernels.hpp"
#include "aidge/backend/cpu/operator/ReLUImpl_backward_kernels.hpp"

Aidge::NbElts_t Aidge::ReLUImpl_cpu::getNbRequiredProtected(const Aidge::IOIndex_t /*inputIdx*/) const {
    // this implementation can be in-place
    return 0;
}

void Aidge::ReLUImpl_cpu::forward() {
    std::shared_ptr<Tensor> in0 = std::static_pointer_cast<Tensor>(mOp.getRawInput(0));
    AIDGE_ASSERT(in0, "missing input #0");

    // Find the correct kernel type
    auto kernelFunc = Registrar<ReLUImplForward_cpu>::create({
        in0->dataType(),
        std::static_pointer_cast<Tensor>(mOp.getRawOutput(0))->dataType()});

    // Call kernel
    kernelFunc(in0->size(),
        getCPUPtr(mOp.getRawInput(0)),
        getCPUPtr(mOp.getRawOutput(0)));
}

void Aidge::ReLUImpl_cpu::backward() {
    // reversing in and out Tensors
    std::shared_ptr<Tensor> in0 = std::static_pointer_cast<Tensor>(mOp.getRawOutput(0))->grad();
    std::shared_ptr<Tensor> out0 = std::static_pointer_cast<Tensor>(mOp.getRawInput(0))->grad();
    AIDGE_ASSERT(out0, "missing input #0");

    // Find the correct kernel type
    auto kernelFunc = Registrar<ReLUImplBackward_cpu>::create({
        in0->dataType(),
        out0->dataType()
    });

    // Call kernel
    kernelFunc(in0->size(), getCPUPtr(in0), getCPUPtr(out0));
}