/********************************************************************************
 * 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
 *
 ********************************************************************************/

#ifndef AIDGE_CORE_OPERATOR_CONVDEPTHWISE_H_
#define AIDGE_CORE_OPERATOR_CONVDEPTHWISE_H_

#include <array>
#include <cmath>    // std::floor
#include <cstddef>  // std::size_t
#include <string>
#include <utility>  // std::pair
#include <vector>

#include "aidge/data/Tensor.hpp"
#include "aidge/graph/Node.hpp"
#include "aidge/operator/OperatorTensor.hpp"
#include "aidge/operator/Producer.hpp"
#include "aidge/utils/ArrayHelpers.hpp"
#include "aidge/utils/StaticAttributes.hpp"
#include "aidge/utils/Registrar.hpp"
#include "aidge/utils/Types.h"

namespace Aidge {
enum class ConvDepthWiseAttr { StrideDims, DilationDims, KernelDims, NoBias };

template <DimIdx_t DIM>
class ConvDepthWise_Op : public OperatorTensor,
                public Registrable<ConvDepthWise_Op<DIM>, std::string, std::shared_ptr<OperatorImpl>(const ConvDepthWise_Op<DIM> &)>,
                public StaticAttributes<ConvDepthWiseAttr,
                                       std::array<DimSize_t, DIM>,
                                       std::array<DimSize_t, DIM>,
                                       std::array<DimSize_t, DIM>,
                                       bool> {
public:
    static const std::string Type;

    ConvDepthWise_Op() = delete;

    using Attributes_ = StaticAttributes<ConvDepthWiseAttr,
                                             std::array<DimSize_t, DIM>,
                                             std::array<DimSize_t, DIM>,
                                             std::array<DimSize_t, DIM>,
                                             bool>;
    template <ConvDepthWiseAttr e>
    using attr = typename Attributes_::template attr<e>;

    constexpr ConvDepthWise_Op(const std::array<DimSize_t, DIM> &kernel_dims,
                               const std::array<DimSize_t, DIM> &stride_dims = create_array<DimSize_t,DIM>(1),
                               const std::array<DimSize_t, DIM> &dilation_dims = create_array<DimSize_t,DIM>(1),
                               bool no_bias=false)
        : OperatorTensor(Type, 1, 2, 1),
          Attributes_(attr<ConvDepthWiseAttr::StrideDims>(stride_dims),
                      attr<ConvDepthWiseAttr::DilationDims>(dilation_dims),
                      attr<ConvDepthWiseAttr::KernelDims>(kernel_dims),
                      attr<ConvDepthWiseAttr::NoBias>(no_bias)) {}

    /**
     * @brief Copy-constructor. Copy the operator attributes and its output tensor(s), but not its input tensors (the new operator has no input associated).
     * @param op Operator to copy.
     */
    ConvDepthWise_Op(const ConvDepthWise_Op<DIM>& op);

    /**
     * @brief Clone the operator using its copy-constructor.
     * @see Operator::ConvDepthWise_Op
     */
    std::shared_ptr<Operator> clone() const override {
        return std::make_shared<ConvDepthWise_Op<DIM>>(*this);
    }


    bool forwardDims(bool /*allowDataDependency*/ = false) override final;

    std::vector<std::pair<std::vector<DimSize_t>, std::vector<DimSize_t>>>
    computeReceptiveField(const std::vector<DimSize_t>& firstEltDims,
                          const std::vector<DimSize_t>& outputDims,
                          const IOIndex_t outputIdx = 0) const override;

    void setBackend(const std::string &name, DeviceIdx_t device = 0) override;

    DimSize_t nbChannels() const {
        if (!getInput(1)) {
            AIDGE_THROW_OR_ABORT(std::runtime_error, "Convolution operator has no weight Tensor associated so no specific number of channel imposed.");
        }
        return getInput(1)->template dims<DIM+2>()[0];
    }

    static const std::vector<std::string> getInputsName(){
        return {"data_input", "weight", "bias"};
    }
    static const std::vector<std::string> getOutputsName(){
        return {"data_output"};
    }
};

template <std::array<DimSize_t, 1>::size_type DIM>
inline std::shared_ptr<Node> ConvDepthWise(const DimSize_t nbChannels,
                                           const std::array<DimSize_t, DIM> &kernelDims,
                                           const std::string& name = "",
                                           const std::array<DimSize_t, DIM> &strideDims = create_array<DimSize_t,DIM>(1),
                                           const std::array<DimSize_t, DIM> &dilationDims = create_array<DimSize_t,DIM>(1),
                                           bool noBias=false) {
    // FIXME: properly handle default w&b initialization in every cases
    static_assert(DIM<=MaxDim,"Too many kernel dimensions required by ConvDepthWise, not supported");
    auto convDW = std::make_shared<Node>(std::make_shared<ConvDepthWise_Op<static_cast<DimIdx_t>(DIM)>>(kernelDims, strideDims, dilationDims, noBias), name);
    addProducer(convDW, 1, append(nbChannels, append(DimSize_t(1), kernelDims)), "w");
    addProducer(convDW, 2, {(noBias ? 0 : nbChannels)}, "b");
    return convDW;
}

// helper with C-style array instead of std::array for kernel_dims to allow automatic template DIM deduction
template <DimSize_t DIM>
inline std::shared_ptr<Node> ConvDepthWise(
    const DimSize_t nbChannels,
    DimSize_t const (&kernelDims)[DIM],
    const std::string& name = "",
    const std::array<DimSize_t, DIM> &strideDims = create_array<DimSize_t,DIM>(1),
    const std::array<DimSize_t, DIM> &dilationDims = create_array<DimSize_t,DIM>(1),
    bool noBias=false) {
    static_assert(DIM<=MaxDim,"Too many kernel dimensions required by ConvDepthWise, not supported");
    return ConvDepthWise(nbChannels, to_array(kernelDims), name, strideDims, dilationDims, noBias);
}
}  // namespace Aidge

extern template class Aidge::ConvDepthWise_Op<2>;

namespace {
template <>
const char *const EnumStrings<Aidge::ConvDepthWiseAttr>::data[] = {"StrideDims", "DilationDims",
                                                          "KernelDims", "NoBias"};
}

#endif /* AIDGE_CORE_OPERATOR_CONVDEPTHWISE_H_ */