/*******************************************************************************
 * 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 "../ShapeDescriptor.h"
#include <shape.h>
#include <ShapeBuilders.h>

namespace nd4j {

//////////////////////////////////////////////////////////////////////////
// equal to operator
    bool ShapeDescriptor::operator==(const ShapeDescriptor &other) const {

        if (_empty != other._empty)
            return false;
        if (_rank != other._rank)
            return false;
        if (_order != other._order)
            return false;
        if (_dataType != other._dataType)
            return false;
        if (_ews != other._ews)
            return false;

        if (_shape != other._shape)
            return false;

        if (_strides != other._strides)
            return false;

        return true;
    }

//////////////////////////////////////////////////////////////////////////
// less than operator
    bool ShapeDescriptor::operator<(const ShapeDescriptor &other) const {
        return std::tie(_empty, _rank, _dataType, _ews, _order, _shape, _strides) <
               std::tie(other._empty, other._rank, other._dataType, other._ews, other._order, other._shape,
                        other._strides);
    }

    Nd4jLong *ShapeDescriptor::toShapeInfo() const {
        if (_empty) {
            if (_rank == 0)
                return ShapeBuilders::emptyShapeInfo(_dataType);
            else {
                return ShapeBuilders::emptyShapeInfo(_dataType, _order, _shape);
            }
        }


        switch (_rank) {
            case 0: {
                auto shapeInfo = ShapeBuilders::createScalarShapeInfo(_dataType);
                shapeInfo[2] = _ews;
                return shapeInfo;
            }
            case 1: {
                auto shapeInfo = ShapeBuilders::createVectorShapeInfo(_dataType, _shape[0]);
                shapeInfo[2 + _rank * 2] = _ews;
                shapeInfo[2] = _strides[0];
                shapeInfo[2 + _rank * 2 + 1] = _order;
                return shapeInfo;
            }
            default: {
                auto shapeInfo = ShapeBuilders::createShapeInfo(_dataType, _order, _shape);

                for (int e = 0; e < _rank; e++)
                    shapeInfo[e + 1 + _rank] = _strides[e];

                shapeInfo[2 + _rank * 2] = _ews;

                return shapeInfo;
            }
        }
    }

    ShapeDescriptor::ShapeDescriptor(const DataType type, const char order, const Nd4jLong *shape, const int rank)
            : _dataType(type), _order(order), _rank(rank), _ews(1) {
        _shape.resize(rank);
        _strides.resize(rank);

        for (int e = 0; e < rank; e++)
            _shape[e] = shape[e];

        if (order == 'c')
            shape::calcStrides(_shape.data(), _shape.size(), _strides.data());
        else
            shape::calcStridesFortran(_shape.data(), _shape.size(), _strides.data());


        for (auto v:_shape) {
            if (v == 0) {
                _empty = true;
                break;
            }
        }
    }

    ShapeDescriptor::ShapeDescriptor(const DataType type, const char order, const Nd4jLong *shape,
                                     const Nd4jLong *strides, const int rank, Nd4jLong ews, const bool empty) {
        _shape.resize(rank);
        _strides.resize(rank);

        _dataType = type;
        _order = order;
        _rank = rank;
        _empty = empty;
        _ews = ews;

        for (int e = 0; e < rank; e++)
            _shape[e] = shape[e];

        for (int e = 0; e < rank; e++)
            _strides[e] = strides[e];


        for (auto v:_shape) {
            if (v == 0) {
                _empty = true;
                break;
            }
        }
    }

//////////////////////////////////////////////////////////////////////////
    ShapeDescriptor::ShapeDescriptor(const DataType type, const char order, const std::vector<Nd4jLong> &shape)
            : _dataType(type), _order(order), _shape(shape) {
        _rank = shape.size();
        _ews = 1;

        if (_rank > 0) {
            _strides.resize(_rank);

            for (auto v:_shape) {
                if (v == 0) {
                    _empty = true;
                    break;
                }
            }

            // no point calculating strides for empty arrays
            if (!_empty) {
                if (order == 'c')
                    shape::calcStrides(_shape.data(), shape.size(), _strides.data());
                else
                    shape::calcStridesFortran(_shape.data(), shape.size(), _strides.data());
            } else {
                // all strides set to 0
                memset(_strides.data(), 0, sizeof(Nd4jLong) * shape.size());
            }
        }
    }

//////////////////////////////////////////////////////////////////////////
    ShapeDescriptor::ShapeDescriptor(const DataType type, const char order,
                                     const std::initializer_list<Nd4jLong> &shape) : _dataType(type), _order(order),
                                                                                     _shape(shape) {
        _rank = shape.size();
        _ews = 1;

        _strides.resize(shape.size());
        if (order == 'c')
            shape::calcStrides(_shape.data(), shape.size(), _strides.data());
        else
            shape::calcStridesFortran(_shape.data(), shape.size(), _strides.data());

        for (auto v:_shape) {
            if (v == 0) {
                _empty = true;
                break;
            }
        }
    }

//////////////////////////////////////////////////////////////////////////
    ShapeDescriptor::ShapeDescriptor(const DataType type, const char order, const std::vector<Nd4jLong> &shape,
                                     const std::vector<Nd4jLong> &strides, const Nd4jLong ews) : ShapeDescriptor(type,
                                                                                                                 order,
                                                                                                                 shape,
                                                                                                                 strides) {
        _ews = ews;
    }

    ShapeDescriptor::ShapeDescriptor(const DataType type, const Nd4jLong length) : _dataType(type), _ews(1),
                                                                                   _order('c'), _rank(1),
                                                                                   _empty(false) {
        _shape = {length};
        _strides = {1};
    }

    ShapeDescriptor::ShapeDescriptor(const Nd4jLong *shapeInfo, bool inheritDtype) {
        _order = shape::order(shapeInfo);
        _ews = shape::elementWiseStride(shapeInfo);
        _rank = shape::rank(shapeInfo);

        if (inheritDtype)
            _dataType = ArrayOptions::dataType(shapeInfo);

        _empty = shape::isEmpty(shapeInfo);

        for (int e = 0; e < _rank; e++) {
            _shape.emplace_back(shapeInfo[e + 1]);
            if (shapeInfo[e + 1] == 0)
                _empty = true;
        }

        for (int e = 0; e < _rank; e++)
            _strides.emplace_back(shapeInfo[e + 1 + _rank]);
    }

    ShapeDescriptor::ShapeDescriptor(const Nd4jLong *shapeInfo, const nd4j::DataType dtypeOverride)
            : ShapeDescriptor::ShapeDescriptor(shapeInfo, false) {
        _dataType = dtypeOverride;
    }

    ShapeDescriptor::ShapeDescriptor(const Nd4jLong *shapeInfo, const Nd4jLong *dtypeOverride)
            : ShapeDescriptor::ShapeDescriptor(shapeInfo, ArrayOptions::dataType(dtypeOverride)) {
        //
    }

    ShapeDescriptor::ShapeDescriptor(const Nd4jLong *shapeInfo, const Nd4jLong *dtypeOverride,
                                     const Nd4jLong *orderOverride) : ShapeDescriptor::ShapeDescriptor(shapeInfo,
                                                                                                       ArrayOptions::dataType(
                                                                                                               dtypeOverride)) {
        _order = shape::order(orderOverride);
    }

    int ShapeDescriptor::rank() const {
        return _rank;
    }

    Nd4jLong ShapeDescriptor::ews() const {
        return _ews;
    }

    Nd4jLong ShapeDescriptor::arrLength() const {

        Nd4jLong len = 1;
        for (const auto &dim : const_cast<ShapeDescriptor *>(this)->shape())
            len *= dim;
        return len;
    }

    char ShapeDescriptor::order() const {
        return _order;
    }

    DataType ShapeDescriptor::dataType() const {
        return _dataType;
    }

    bool ShapeDescriptor::isEmpty() const {
        return _empty;
    }

    std::vector<Nd4jLong> &ShapeDescriptor::shape() {
        return _shape;
    }

    std::vector<Nd4jLong> &ShapeDescriptor::strides() {
        return _strides;
    }

    ShapeDescriptor::ShapeDescriptor(const ShapeDescriptor &other) {
        _rank = other._rank;
        _ews = other._ews;
        _empty = other._empty;
        _dataType = other._dataType;
        _order = other._order;
        _shape = other._shape;
        _strides = other._strides;
    }

//////////////////////////////////////////////////////////////////////////
    ShapeDescriptor::ShapeDescriptor(const DataType type, const char order, const std::vector<Nd4jLong> &shape,
                                     const std::vector<Nd4jLong> &strides) : _dataType(type), _order(order),
                                                                             _shape(shape) {

        if (strides.empty() && !shape.empty()) {
            _strides.resize(shape.size());
            if (order == 'c')
                shape::calcStrides(_shape.data(), shape.size(), _strides.data());
            else
                shape::calcStridesFortran(_shape.data(), shape.size(), _strides.data());
        } else {
            _strides = strides;
        }


        for (auto v:_shape) {
            if (v == 0) {
                _empty = true;
                break;
            }
        }
    }

    ShapeDescriptor ShapeDescriptor::emptyDescriptor(const DataType type) {
        ShapeDescriptor descriptor;
        descriptor._dataType = type;
        descriptor._empty = true;
        descriptor._rank = 0;
        descriptor._order = 'c';
        descriptor._ews = 1;

        return descriptor;
    }

    ShapeDescriptor ShapeDescriptor::scalarDescriptor(const DataType type) {
        ShapeDescriptor descriptor;
        descriptor._dataType = type;
        descriptor._empty = false;
        descriptor._rank = 0;
        descriptor._order = 'c';
        descriptor._ews = 1;

        return descriptor;
    }

    ShapeDescriptor ShapeDescriptor::vectorDescriptor(const Nd4jLong length, const DataType type) {
        ShapeDescriptor descriptor;
        descriptor._dataType = type;
        descriptor._shape.emplace_back(length);

        if (length > 0)
            descriptor._strides.emplace_back(1);
        else {
            descriptor._strides.emplace_back(0);
            descriptor._empty = true;
        }

        descriptor._order = 'c';
        descriptor._ews = 1;
        descriptor._rank = 1;

        return descriptor;
    }
}

namespace std {
    size_t hash<nd4j::ShapeDescriptor>::operator()(const nd4j::ShapeDescriptor &k) const {
        auto res = std::hash<Nd4jLong>()(k.arrLength());
        res ^= std::hash<char>()(k.order()) + 0x9e3779b9 + (res << 6) + (res >> 2);
        res ^= k.dataType() + 0x9e3779b9 + (res << 6) + (res >> 2);
        res ^= std::hash<int>()(k.rank()) + 0x9e3779b9 + (res << 6) + (res >> 2);
        res ^= std::hash<Nd4jLong>()(k.ews()) + 0x9e3779b9 + (res << 6) + (res >> 2);
        auto shapes = const_cast<nd4j::ShapeDescriptor&>(k).shape();
        auto strides = const_cast<nd4j::ShapeDescriptor&>(k).strides();
        for (auto s: shapes) {
            res ^= std::hash<Nd4jLong>()(s) + 0x9e3779b9 + (res << 6) + (res >> 2);
        }

        for (auto s: strides) {
            res ^= std::hash<Nd4jLong>()(s) + 0x9e3779b9 + (res << 6) + (res >> 2);
        }

        return res;
    }
}