/******************************************************************************
 *
 * Project:  FlatGeobuf
 * Purpose:  Packed RTree management
 * Author:   Björn Harrtell <bjorn at wololo dot org>
 *
 ******************************************************************************
 * Copyright (c) 2018-2020, Björn Harrtell <bjorn at wololo dot org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

// NOTE: The upstream of this file is in https://github.com/bjornharrtell/flatgeobuf/tree/master/src/cpp

#ifndef FLATGEOBUF_PACKEDRTREE_H_
#define FLATGEOBUF_PACKEDRTREE_H_

#include <cmath>
#include <numeric>

#include "flatbuffers/flatbuffers.h"

namespace mapserver {
namespace FlatGeobuf {

struct NodeItem {
    double minX;
    double minY;
    double maxX;
    double maxY;
    uint64_t offset;
    double width() const { return maxX - minX; }
    double height() const { return maxY - minY; }
    static NodeItem sum(NodeItem a, const NodeItem &b) {
        a.expand(b);
        return a;
    }
    static NodeItem create(uint64_t offset = 0);
    const NodeItem &expand(const NodeItem &r);
    bool intersects(const NodeItem &r) const;
    std::vector<double> toVector();
};

struct Item {
    NodeItem nodeItem;
};

struct SearchResultItem {
    uint64_t offset;
    uint64_t index;
};

std::ostream& operator << (std::ostream& os, NodeItem const& value);

uint32_t hilbert(uint32_t x, uint32_t y);
uint32_t hilbert(const NodeItem &n, uint32_t hilbertMax, const double minX, const double minY, const double width, const double height);
void hilbertSort(std::vector<std::shared_ptr<Item>> &items);
void hilbertSort(std::vector<NodeItem> &items);
NodeItem calcExtent(const std::vector<std::shared_ptr<Item>> &items);
NodeItem calcExtent(const std::vector<NodeItem> &rects);

/**
 * Packed R-Tree
 * Based on https://github.com/mourner/flatbush
 */
class PackedRTree {
    NodeItem _extent;
    NodeItem *_nodeItems = nullptr;
    uint64_t _numItems;
    uint64_t _numNodes;
    uint16_t _nodeSize;
    std::vector<std::pair<uint64_t, uint64_t>> _levelBounds;
    void init(const uint16_t nodeSize);
    void generateNodes();
    void fromData(const void *data);
public:
    ~PackedRTree() {
        if (_nodeItems != nullptr)
            delete[] _nodeItems;
    }
    PackedRTree(const std::vector<std::shared_ptr<Item>> &items, const NodeItem &extent, const uint16_t nodeSize = 16);
    PackedRTree(const std::vector<NodeItem> &nodes, const NodeItem &extent, const uint16_t nodeSize = 16);
    PackedRTree(const void *data, const uint64_t numItems, const uint16_t nodeSize = 16);
    std::vector<SearchResultItem> search(double minX, double minY, double maxX, double maxY) const;
    static std::vector<SearchResultItem> streamSearch(
        const uint64_t numItems, const uint16_t nodeSize, const NodeItem &item,
        const std::function<void(uint8_t *, size_t, size_t)> &readNode);
    static std::vector<std::pair<uint64_t, uint64_t>> generateLevelBounds(const uint64_t numItems, const uint16_t nodeSize);
    uint64_t size() const;
    static uint64_t size(const uint64_t numItems, const uint16_t nodeSize = 16);
    NodeItem getExtent() const;
    void streamWrite(const std::function<void(uint8_t *, size_t)> &writeData);
};

} }

#endif
