// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#include "QuickIntegrate.h"
#include <iostream>

QuickIntegrate::QuickIntegrate(const DiffractionExperiment &in_experiment)
        : experiment(in_experiment) {}

template<class T>
std::vector<Reflection> QuickIntegrate::IntegrateInternal(const CompressedImage &image, const CrystalLattice &latt,
                                                          int64_t special_value, int64_t saturation) {
    auto start = std::chrono::high_resolution_clock::now();
    std::vector<uint8_t> buffer;
    auto ptr = reinterpret_cast<const T*>(image.GetUncompressedPtr(buffer));

    std::vector<Reflection> ret;

    Coord Astar = latt.Astar();
    Coord Bstar = latt.Bstar();
    Coord Cstar = latt.Cstar();

    DiffractionGeometry geom = experiment.GetDiffractionGeometry();
    for (int h = -max_value; h < max_value; h++) {
        for (int k = -max_value; k < max_value; k++) {
            for (int l = -max_value; l < max_value; l++) {
                Coord recip = Astar * h + Bstar * k + Cstar * l;
                float d = 1.0f / recip.Length();
                float dist_ewald_sphere = geom.DistFromEwaldSphere(recip);
                if (d > d_min && dist_ewald_sphere < ewald_sphere_dist_cutoff) {
                    auto [x,y] = geom.RecipToDector(recip);
                    if ((x >= 0) && (x < image.GetWidth()) && (y >= 0) && (y < image.GetHeight())) {
                        Reflection r{.h = h, .k = k, .l = l, .center_x = x, .center_y = y, .d = d};
                        bool observed = IntegrateInternal(r, ptr, image.GetWidth(), image.GetHeight(),
                                          x, y, special_value, saturation);
                        if (observed)
                            ret.push_back(r);
                    }
                }
            }
        }
    }
    return ret;
}

std::vector<Reflection> QuickIntegrate::Integrate(const CompressedImage& image, const CrystalLattice &latt) {
    if (image.GetCompressedSize() == 0)
        return {};

    switch (image.GetMode()) {
        case CompressedImageMode::Int8:
            return IntegrateInternal<int8_t>(image, latt, INT8_MIN, INT8_MAX);
        case CompressedImageMode::Int16:
            return IntegrateInternal<int16_t>(image, latt, INT16_MIN, INT16_MAX);
        case CompressedImageMode::Int32:
            return IntegrateInternal<int32_t>(image, latt, INT32_MIN, INT32_MAX);
        case CompressedImageMode::Uint8:
            return IntegrateInternal<uint8_t>(image, latt, UINT8_MAX, UINT8_MAX);
        case CompressedImageMode::Uint16:
            return IntegrateInternal<uint16_t>(image, latt, UINT16_MAX, UINT16_MAX);
        case CompressedImageMode::Uint32:
            return IntegrateInternal<uint16_t>(image, latt, UINT32_MAX, UINT32_MAX);
        default:
            throw JFJochException(JFJochExceptionCategory::InputParameterInvalid,
                                  "Image mode not supported");
    }

}

template<class T>
bool QuickIntegrate::IntegrateInternal(Reflection &r, const T *image, size_t xpixel, size_t ypixel,
                                       float center_x, float center_y,
                                       int64_t special_value, int64_t saturation) {
    r.I = 0;
    r.bkg = 0;

    int64_t x0 = std::floor(center_x - r_3 - 1.0);
    int64_t x1 = std::ceil(center_x + r_3 + 1.0);
    int64_t y0 = std::floor(center_y - r_3 - 1.0);
    int64_t y1 = std::ceil(center_y + r_3 + 1.0);
    if (x0 < 0)
        x0 = 0;
    if (y0 < 0)
        y0 = 0;
    if (x1 >= xpixel)
        x1 = xpixel - 1;
    if (y1 >= ypixel)
        y1 = ypixel - 1;

    int64_t I_sum = 0;
    int64_t I_npixel = 0;
    int64_t bkg_sum = 0;
    int64_t bkg_npixel = 0;

    for (int64_t y = y0; y <= y1; y++) {
        for (int64_t x = x0; x <= x1; x++) {
            float dist_sq = (x - center_x) * (x - center_x) + (y - center_y) * (y - center_y);
            if (image[y * xpixel + x] == special_value || image[y * xpixel + x] == saturation) {
                continue;
            } else if (dist_sq < r_1_sq) {
                I_sum += image[y * xpixel + x];
                I_npixel++;
            } else if (dist_sq >= r_2_sq && dist_sq < r_3_sq) {
                bkg_sum += image[y * xpixel + x];
                bkg_npixel++;
            }
        }
    }

    if ((I_npixel > 2) && (bkg_npixel > 5)) {
        r.bkg = static_cast<float>(bkg_sum) / static_cast<float>(bkg_npixel);
        r.I = static_cast<float>(I_sum) - static_cast<float>(I_npixel) * r.bkg;
        if (I_sum > 0)
            r.sigma = std::sqrt(static_cast<float>(I_sum));
        else
            r.sigma = 0;
        return true;
    }
    return false;
}