/******************************************************************************
 * Copyright (c) 2016-2017, Bradley J Chambers (brad.chambers@gmail.com)
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following
 * conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided
 *       with the distribution.
 *     * Neither the name of Hobu, Inc. or Flaxen Geo Consulting nor the
 *       names of its contributors may be used to endorse or promote
 *       products derived from this software without specific prior
 *       written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 ****************************************************************************/

#include "SampleFilter.hpp"

#include <pdal/KDIndex.hpp>
#include <pdal/util/ProgramArgs.hpp>
#include <pdal/util/Utils.hpp>

#include <string>
#include <vector>

namespace pdal
{

static StaticPluginInfo const s_info
{
    "filters.sample",
    "Subsampling filter",
    "http://pdal.io/stages/filters.sample.html"
};

CREATE_STATIC_STAGE(SampleFilter, s_info)

std::string SampleFilter::getName() const
{
    return s_info.name;
}


void SampleFilter::addArgs(ProgramArgs& args)
{
    args.add("radius", "Radius", m_radius, 1.0);
}


void SampleFilter::addDimensions(PointLayoutPtr layout)
{
    layout->registerDim(Dimension::Id::Classification);
}


PointViewSet SampleFilter::run(PointViewPtr inView)
{
    point_count_t np = inView->size();

    // Return empty PointViewSet if the input PointView has no points.
    // Otherwise, make a new output PointView.
    PointViewSet viewSet;
    if (!np)
        return viewSet;
    PointViewPtr outView = inView->makeNew();

    // Build the 3D KD-tree.
    KD3Index index(*inView);
    index.build();

    // All points are marked as kept (1) by default. As they are masked by
    // neighbors within the user-specified radius, their value is changed to 0.
    std::vector<int> keep(np, 1);

    // We are able to subsample in a single pass over the shuffled indices.
    for (PointId i = 0; i < np; ++i)
    {
        // If a point is masked, it is forever masked, and cannot be part of the
        // sampled cloud. Otherwise, the current index is appended to the output
        // PointView.
        if (keep[i] == 0)
            continue;
        outView->appendPoint(*inView, i);

        // We now proceed to mask all neighbors within m_radius of the kept
        // point.
        auto ids = index.radius(i, m_radius);
        for (auto const& id : ids)
            keep[id] = 0;
    }

    // Simply calculate the percentage of retained points.
    double frac = (double)outView->size() / (double)inView->size();
    log()->get(LogLevel::Debug2)
        << "Retaining " << outView->size() << " of " << inView->size()
        << " points (" << 100 * frac << "%)\n";

    viewSet.insert(outView);
    return viewSet;
}

} // namespace pdal
