/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2025 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/

// mapnik
#include <mapnik/warp.hpp>
#include <mapnik/config.hpp>
#include <mapnik/image.hpp>
#include <mapnik/image_scaling_traits.hpp>
#include <mapnik/image_util.hpp>
#include <mapnik/geometry/box2d.hpp>
#include <mapnik/view_transform.hpp>
#include <mapnik/raster.hpp>
#include <mapnik/proj_transform.hpp>
#include <mapnik/safe_cast.hpp>

#include <mapnik/warning.hpp>
MAPNIK_DISABLE_WARNING_PUSH
#include <mapnik/warning_ignore_agg.hpp>
#include "agg_image_filters.h"
#include "agg_trans_bilinear.h"
#include "agg_span_interpolator_linear.h"
#include "agg_span_image_filter_rgba.h"
#include "agg_rendering_buffer.h"
#include "agg_pixfmt_rgba.h"
#include "agg_rasterizer_scanline_aa.h"
#include "agg_basics.h"
#include "agg_scanline_bin.h"
#include "agg_renderer_scanline.h"
#include "agg_span_allocator.h"
#include "agg_image_accessors.h"
#include "agg_renderer_scanline.h"
MAPNIK_DISABLE_WARNING_POP

namespace mapnik {

template<typename T>
struct pixel_format
{
    using type = typename detail::agg_scaling_traits<T>::pixfmt_pre;
};

template<>
struct pixel_format<image_rgba8>
{
    struct src_blender
    {
        using color_type = agg::rgba8;
        using order_type = agg::order_rgba;
        using value_type = typename color_type::value_type;

        static inline void
          blend_pix(unsigned /*op*/, value_type* p, unsigned cr, unsigned cg, unsigned cb, unsigned ca, unsigned cover)
        {
            agg::comp_op_rgba_src<color_type, order_type>::blend_pix(p, cr, cg, cb, ca, cover);
        }
    };

    // Use comp_op_src to fix seams between faces of the mesh
    using type = agg::pixfmt_custom_blend_rgba<src_blender, agg::rendering_buffer>;
};

template<typename T>
MAPNIK_DECL void warp_image(T& target,
                            T const& source,
                            proj_transform const& prj_trans,
                            box2d<double> const& target_ext,
                            box2d<double> const& source_ext,
                            double offset_x,
                            double offset_y,
                            unsigned mesh_size,
                            scaling_method_e scaling_method,
                            double filter_factor,
                            std::optional<double> const& nodata_value)
{
    using image_type = T;
    using pixel_type = typename image_type::pixel_type;
    using pixfmt_pre = typename detail::agg_scaling_traits<image_type>::pixfmt_pre;
    using color_type = typename detail::agg_scaling_traits<image_type>::color_type;
    using output_pixfmt_type = typename pixel_format<T>::type;
    using renderer_base = agg::renderer_base<output_pixfmt_type>;
    using interpolator_type = typename detail::agg_scaling_traits<image_type>::interpolator_type;

    constexpr std::size_t pixel_size = sizeof(pixel_type);

    view_transform ts(source.width(), source.height(), source_ext);
    view_transform tt(target.width(), target.height(), target_ext, offset_x, offset_y);

    std::size_t mesh_nx = std::ceil(source.width() / double(mesh_size) + 1);
    std::size_t mesh_ny = std::ceil(source.height() / double(mesh_size) + 1);

    image_gray64f xs(mesh_nx, mesh_ny, false);
    image_gray64f ys(mesh_nx, mesh_ny, false);

    // Precalculate reprojected mesh
    for (std::size_t j = 0; j < mesh_ny; ++j)
    {
        for (std::size_t i = 0; i < mesh_nx; ++i)
        {
            xs(i, j) = std::min(i * mesh_size, source.width());
            ys(i, j) = std::min(j * mesh_size, source.height());
            ts.backward(&xs(i, j), &ys(i, j));
        }
    }
    prj_trans.backward(xs.data(), ys.data(), nullptr, mesh_nx * mesh_ny);

    agg::rasterizer_scanline_aa<> rasterizer;
    agg::scanline_bin scanline;
    agg::rendering_buffer buf(target.bytes(), target.width(), target.height(), target.width() * pixel_size);
    output_pixfmt_type pixf(buf);
    renderer_base rb(pixf);
    rasterizer.clip_box(0, 0, target.width(), target.height());
    agg::rendering_buffer buf_tile(const_cast<unsigned char*>(source.bytes()),
                                   source.width(),
                                   source.height(),
                                   source.width() * pixel_size);

    pixfmt_pre pixf_tile(buf_tile);

    using img_accessor_type = agg::image_accessor_clone<pixfmt_pre>;
    img_accessor_type ia(pixf_tile);

    agg::span_allocator<color_type> sa;
    // Project mesh cells into target interpolating raster inside each one
    for (std::size_t j = 0; j < mesh_ny - 1; ++j)
    {
        for (std::size_t i = 0; i < mesh_nx - 1; ++i)
        {
            double polygon[8] = {xs(i, j),
                                 ys(i, j),
                                 xs(i + 1, j),
                                 ys(i + 1, j),
                                 xs(i + 1, j + 1),
                                 ys(i + 1, j + 1),
                                 xs(i, j + 1),
                                 ys(i, j + 1)};
            tt.forward(polygon + 0, polygon + 1);
            tt.forward(polygon + 2, polygon + 3);
            tt.forward(polygon + 4, polygon + 5);
            tt.forward(polygon + 6, polygon + 7);

            rasterizer.reset();
            rasterizer.move_to_d(std::floor(polygon[0]), std::floor(polygon[1]));
            rasterizer.line_to_d(std::floor(polygon[2]), std::floor(polygon[3]));
            rasterizer.line_to_d(std::floor(polygon[4]), std::floor(polygon[5]));
            rasterizer.line_to_d(std::floor(polygon[6]), std::floor(polygon[7]));

            std::size_t const x0 = i * mesh_size;
            std::size_t const y0 = j * mesh_size;
            std::size_t const x1 = std::min((i + 1) * mesh_size, source.width());
            std::size_t const y1 = std::min((j + 1) * mesh_size, source.height());
            agg::trans_affine const tr(polygon, x0, y0, x1, y1);
            if (tr.is_valid())
            {
                interpolator_type interpolator(tr);
                if (scaling_method == SCALING_NEAR)
                {
                    using span_gen_type = typename detail::agg_scaling_traits<image_type>::span_image_filter;
                    span_gen_type sg(ia, interpolator);
                    agg::render_scanlines_bin(rasterizer, scanline, rb, sa, sg);
                }
                else
                {
                    using span_gen_type = typename detail::agg_scaling_traits<image_type>::span_image_resample_affine;
                    agg::image_filter_lut filter;
                    detail::set_scaling_method(filter, scaling_method, filter_factor);
                    std::optional<typename span_gen_type::value_type> nodata;
                    if (nodata_value)
                    {
                        nodata = safe_cast<typename span_gen_type::value_type>(*nodata_value);
                    }
                    span_gen_type sg(ia, interpolator, filter, nodata);
                    agg::render_scanlines_bin(rasterizer, scanline, rb, sa, sg);
                }
            }
        }
    }
}

namespace detail {

struct warp_image_visitor
{
    warp_image_visitor(raster& target_raster,
                       proj_transform const& prj_trans,
                       box2d<double> const& source_ext,
                       double offset_x,
                       double offset_y,
                       unsigned mesh_size,
                       scaling_method_e scaling_method,
                       double filter_factor,
                       std::optional<double> const& nodata_value)
        : target_raster_(target_raster),
          prj_trans_(prj_trans),
          source_ext_(source_ext),
          offset_x_(offset_x),
          offset_y_(offset_y),
          mesh_size_(mesh_size),
          scaling_method_(scaling_method),
          filter_factor_(filter_factor),
          nodata_value_(nodata_value)
    {}

    void operator()(image_null const&) const {}

    template<typename T>
    void operator()(T const& source) const
    {
        using image_type = T;
        // source and target image data types must match
        if (target_raster_.data_.template is<image_type>())
        {
            image_type& target = util::get<image_type>(target_raster_.data_);
            warp_image(target,
                       source,
                       prj_trans_,
                       target_raster_.ext_,
                       source_ext_,
                       offset_x_,
                       offset_y_,
                       mesh_size_,
                       scaling_method_,
                       filter_factor_,
                       nodata_value_);
        }
    }

    raster& target_raster_;
    proj_transform const& prj_trans_;
    box2d<double> const& source_ext_;
    double offset_x_;
    double offset_y_;
    unsigned mesh_size_;
    scaling_method_e scaling_method_;
    double filter_factor_;
    std::optional<double> const& nodata_value_;
};

} // namespace detail

void reproject_and_scale_raster(raster& target,
                                raster const& source,
                                proj_transform const& prj_trans,
                                double offset_x,
                                double offset_y,
                                unsigned mesh_size,
                                scaling_method_e scaling_method,
                                std::optional<double> const& nodata_value)
{
    detail::warp_image_visitor warper(target,
                                      prj_trans,
                                      source.ext_,
                                      offset_x,
                                      offset_y,
                                      mesh_size,
                                      scaling_method,
                                      source.get_filter_factor(),
                                      nodata_value);
    util::apply_visitor(warper, source.data_);
}

void reproject_and_scale_raster(raster& target,
                                raster const& source,
                                proj_transform const& prj_trans,
                                double offset_x,
                                double offset_y,
                                unsigned mesh_size,
                                scaling_method_e scaling_method)
{
    reproject_and_scale_raster(target, source, prj_trans, offset_x, offset_y, mesh_size, scaling_method, std::nullopt);
}

template MAPNIK_DECL void warp_image(image_rgba8&,
                                     image_rgba8 const&,
                                     proj_transform const&,
                                     box2d<double> const&,
                                     box2d<double> const&,
                                     double,
                                     double,
                                     unsigned,
                                     scaling_method_e,
                                     double,
                                     std::optional<double> const&);

template MAPNIK_DECL void warp_image(image_gray8&,
                                     image_gray8 const&,
                                     proj_transform const&,
                                     box2d<double> const&,
                                     box2d<double> const&,
                                     double,
                                     double,
                                     unsigned,
                                     scaling_method_e,
                                     double,
                                     std::optional<double> const&);

template MAPNIK_DECL void warp_image(image_gray16&,
                                     image_gray16 const&,
                                     proj_transform const&,
                                     box2d<double> const&,
                                     box2d<double> const&,
                                     double,
                                     double,
                                     unsigned,
                                     scaling_method_e,
                                     double,
                                     std::optional<double> const&);

template MAPNIK_DECL void warp_image(image_gray32f&,
                                     image_gray32f const&,
                                     proj_transform const&,
                                     box2d<double> const&,
                                     box2d<double> const&,
                                     double,
                                     double,
                                     unsigned,
                                     scaling_method_e,
                                     double,
                                     std::optional<double> const&);

} // namespace mapnik
