#ifndef __MAPNIK_VECTOR_TILE_LAYER_H__
#define __MAPNIK_VECTOR_TILE_LAYER_H__

// mapnik-vector-tile
#include "vector_tile_config.hpp"

// mapnik
#include <mapnik/box2d.hpp>
#include <mapnik/datasource.hpp>
#include <mapnik/feature.hpp>
#include <mapnik/layer.hpp>
#include <mapnik/map.hpp>
#include <mapnik/projection.hpp>
#include <mapnik/proj_transform.hpp>
#include <mapnik/scale_denominator.hpp>
#include <mapnik/value.hpp>
#include <mapnik/view_transform.hpp>

// protozero
#include <protozero/pbf_writer.hpp>

// std
#include <map>
#include <unordered_map>
#include <utility>

namespace mapnik
{

namespace vector_tile_impl
{

struct layer_builder_pbf
{
    typedef std::map<std::string, unsigned> keys_container;
    typedef std::unordered_map<mapnik::value, unsigned> values_container;

    keys_container keys;
    values_container values;
    std::string & layer_buffer;
    bool empty;
    bool painted;

    layer_builder_pbf(std::string const & name, std::uint32_t extent, std::string & _layer_buffer)
        : keys(),
          values(),
          layer_buffer(_layer_buffer),
          empty(true),
          painted(false)
    {
        protozero::pbf_writer layer_writer(layer_buffer);
        layer_writer.add_uint32(Layer_Encoding::VERSION, 2);
        layer_writer.add_string(Layer_Encoding::NAME, name);
        layer_writer.add_uint32(Layer_Encoding::EXTENT, extent);
    }

    void make_painted()
    {
        painted = true;
    }

    void make_not_empty()
    {
        empty = false;
    }

    MAPNIK_VECTOR_INLINE protozero::pbf_writer add_feature(mapnik::feature_impl const& mapnik_feature,
                                                           std::vector<std::uint32_t> & feature_tags);
};

class tile_layer
{
private:
    bool valid_;
    mapnik::datasource_ptr ds_;
    mapnik::projection target_proj_;
    mapnik::projection source_proj_;
    mapnik::proj_transform prj_trans_;
    std::string buffer_;
    std::string name_;
    std::uint32_t layer_extent_;
    mapnik::box2d<double> target_buffered_extent_;
    mapnik::box2d<double> source_buffered_extent_;
    mapnik::query query_;
    mapnik::view_transform view_trans_;
    bool empty_;
    bool painted_;

public:
    tile_layer(mapnik::Map const& map,
               mapnik::layer const& lay,
               mapnik::box2d<double> const& tile_extent_bbox,
               std::uint32_t tile_size,
               std::int32_t buffer_size,
               double scale_factor,
               double scale_denom,
               int offset_x,
               int offset_y)
        : valid_(true),
          ds_(lay.datasource()),
          target_proj_(map.srs(), true),
          source_proj_(lay.srs(), true),
          prj_trans_(target_proj_, source_proj_),
          buffer_(),
          name_(lay.name()),
          layer_extent_(calc_extent(tile_size)),
          target_buffered_extent_(calc_target_buffered_extent(tile_extent_bbox, buffer_size, lay, map)),
          source_buffered_extent_(calc_source_buffered_extent()),
          query_(calc_query(scale_factor, scale_denom, tile_extent_bbox, lay)),
          view_trans_(layer_extent_, layer_extent_, tile_extent_bbox, offset_x, offset_y),
          empty_(true),
          painted_(false)
    {
    }


    tile_layer(tile_layer && rhs)
        : valid_(std::move(rhs.valid_)),
          ds_(std::move(rhs.ds_)),
          target_proj_(std::move(rhs.target_proj_)),
          source_proj_(std::move(rhs.source_proj_)),
          prj_trans_(target_proj_, source_proj_),
          buffer_(std::move(rhs.buffer_)),
          name_(std::move(rhs.name_)),
          layer_extent_(std::move(rhs.layer_extent_)),
          target_buffered_extent_(std::move(rhs.target_buffered_extent_)),
          source_buffered_extent_(std::move(rhs.source_buffered_extent_)),
          query_(std::move(rhs.query_)),
          view_trans_(std::move(rhs.view_trans_)),
          empty_(std::move(rhs.empty_)),
          painted_(std::move(rhs.painted_)) {}

    tile_layer& operator=(tile_layer&&) = default;

    tile_layer(tile_layer const& rhs) = delete;
    tile_layer& operator=(const tile_layer&) = delete;

    std::uint32_t calc_extent(std::uint32_t layer_extent)
    {
        if (!ds_)
        {
            valid_ = false;
            return 4096;
        }
        auto ds_extent = ds_->params().template get<mapnik::value_integer>("vector_layer_extent");
        if (ds_extent)
        {
            layer_extent = *ds_extent;
        }
        if (layer_extent == 0)
        {
            valid_ = false;
            layer_extent = 4096;
        }
        return layer_extent;
    }

    mapnik::box2d<double> calc_target_buffered_extent(mapnik::box2d<double> const& tile_extent_bbox,
                                               std::int32_t buffer_size,
                                               mapnik::layer const& lay,
                                               mapnik::Map const& map) const
    {
        mapnik::box2d<double> ext(tile_extent_bbox);
        double scale = ext.width() / layer_extent_;
        double buffer_padding = 2.0 * scale;
        boost::optional<int> layer_buffer_size = lay.buffer_size();
        if (layer_buffer_size) // if layer overrides buffer size, use this value to compute buffered extent
        {
            if (!ds_ || ds_->type() == datasource::Vector)
            {
                buffer_padding *= (*layer_buffer_size) * (static_cast<double>(layer_extent_) / VT_LEGACY_IMAGE_SIZE);
            }
            else
            {
                buffer_padding *= (*layer_buffer_size) * (static_cast<double>(layer_extent_));
            }
        }
        else
        {
            buffer_padding *= buffer_size;
        }
        double buffered_width = ext.width() + buffer_padding;
        double buffered_height = ext.height() + buffer_padding;
        if (buffered_width < 0.0)
        {
            buffered_width = 0.0;
        }
        if (buffered_height < 0.0)
        {
            buffered_height = 0.0;
        }
        ext.width(buffered_width);
        ext.height(buffered_height);
        
        boost::optional<box2d<double> > const& maximum_extent = map.maximum_extent();
        if (maximum_extent)
        {
            ext.clip(*maximum_extent);
        }
        return ext;
    }
    
    mapnik::box2d<double> calc_source_buffered_extent()
    {
        mapnik::box2d<double> new_extent(target_buffered_extent_);
        if (!prj_trans_.forward(new_extent, PROJ_ENVELOPE_POINTS))
        {
            // this modifies the layer_ext by clipping to the buffered_ext
            valid_ = false;
        }
        return new_extent;
    }

    mapnik::query calc_query(double scale_factor,
                             double scale_denom,
                             mapnik::box2d<double> const& tile_extent_bbox,
                             mapnik::layer const& lay)
    {
        // Adjust the scale denominator if required
        if (scale_denom <= 0.0)
        {
            double scale = tile_extent_bbox.width() / VT_LEGACY_IMAGE_SIZE;
            scale_denom = mapnik::scale_denominator(scale, target_proj_.is_geographic());
        }
        scale_denom *= scale_factor;
        if (!lay.visible(scale_denom))
        {
            valid_ = false;
        }

        mapnik::box2d<double> query_extent(lay.envelope()); // source projection

        // first, try intersection of map extent forward projected into layer srs
        if (source_buffered_extent_.intersects(query_extent))
        {
            // this modifies the query_extent by clipping to the buffered_ext
            query_extent.clip(source_buffered_extent_);
        }
        // if no intersection and projections are also equal, early return
        else if (prj_trans_.equal())
        {
            valid_ = false;
        }
        // next try intersection of layer extent back projected into map srs
        else if (prj_trans_.backward(query_extent, PROJ_ENVELOPE_POINTS) && target_buffered_extent_.intersects(query_extent))
        {
            query_extent.clip(target_buffered_extent_);
            // forward project layer extent back into native projection
            if (!prj_trans_.forward(query_extent, PROJ_ENVELOPE_POINTS))
            {
                throw std::runtime_error("vector_tile_processor: layer extent did not repoject back to map projection");
            }
        }
        else
        {
            // if no intersection then nothing to do for layer
            valid_ = false;    
        }
        double qw = tile_extent_bbox.width() > 0 ? tile_extent_bbox.width() : 1;
        double qh = tile_extent_bbox.height() > 0 ? tile_extent_bbox.height() : 1;
        if (!ds_ || ds_->type() == datasource::Vector)
        {
            qw = VT_LEGACY_IMAGE_SIZE / qw;
            qh = VT_LEGACY_IMAGE_SIZE / qh;
        }
        else
        {
            qw = static_cast<double>(layer_extent_) / qw;
            qh = static_cast<double>(layer_extent_) / qh;
        }
        mapnik::query::resolution_type res(qw, qh);
        mapnik::query q(query_extent, res, scale_denom, tile_extent_bbox);
        if (ds_)
        {
            mapnik::layer_descriptor lay_desc = ds_->get_descriptor();
            for (mapnik::attribute_descriptor const& desc : lay_desc.get_descriptors())
            {
                q.add_property_name(desc.get_name());
            }
        }
        return q;
    }

    mapnik::datasource_ptr get_ds() const
    {
        return ds_;
    }

    mapnik::featureset_ptr get_features() const
    {
        return ds_->features(query_);
    }

    mapnik::view_transform const& get_view_transform() const
    {
        return view_trans_;
    }

    mapnik::proj_transform const& get_proj_transform() const
    {
        return prj_trans_;
    }

    mapnik::box2d<double> const& get_source_buffered_extent() const
    {
        return source_buffered_extent_;
    }

    mapnik::box2d<double> const& get_target_buffered_extent() const
    {
        return target_buffered_extent_;
    }

    bool is_valid() const
    {
        return valid_;
    }

    std::uint32_t layer_extent() const
    {
        return layer_extent_;
    }

    std::string const& name() const
    {
        return name_;
    }
    
    void name(std::string const& val)
    {
        name_ = val;
    }

    bool is_empty() const
    {
        return empty_;
    }
     
    bool is_painted() const
    {
        return painted_;
    }
    
    void make_painted()
    {
        painted_ = true;
    }

    std::string const& get_data() const
    {
        return buffer_;
    }

    std::string & get_data()
    {
        return buffer_;
    }

    void build(layer_builder_pbf const& builder)
    {
        empty_ = builder.empty;
        painted_ = builder.painted;
    }
};

} // end ns vector_tile_impl

} // end ns mapnik

#if !defined(MAPNIK_VECTOR_TILE_LIBRARY)
#include "vector_tile_layer.ipp"
#endif

#endif // __MAPNIK_VECTOR_TILE_LAYER_H__
