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

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

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

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

    BraggPrediction prediction(experiment,latt, high_res_A, ewald_sphere_angle_cutoff);
    auto refl = prediction.GetReflections(ewald_sphere_angle_cutoff);

    QuickIntegrateResult ret;
    IntegrationStats stats(6.0, high_res_A, 10); // Wilson statistics is only linear in certain resolution range

    for (const auto &r_iter: refl) {
        Reflection r = r_iter;

        if (IntegrateInternal(r, ptr, image.GetWidth(), image.GetHeight(), special_value, saturation)) {
            ret.reflections.push_back(r);
            stats.AddReflection(r);
        }
    }
    ret.b_factor = stats.BFactor();
    return ret;
}

QuickIntegrateResult QuickIntegrate::Integrate(const CompressedImage& image,
                                                  const CrystalLattice &latt,
                                                  float high_res_A) {
    if (image.GetCompressedSize() == 0)
        return {};

    switch (image.GetMode()) {
        case CompressedImageMode::Int8:
            return IntegrateInternal<int8_t>(image, latt, INT8_MIN, INT8_MAX, high_res_A);
        case CompressedImageMode::Int16:
            return IntegrateInternal<int16_t>(image, latt, INT16_MIN, INT16_MAX, high_res_A);
        case CompressedImageMode::Int32:
            return IntegrateInternal<int32_t>(image, latt, INT32_MIN, INT32_MAX, high_res_A);
        case CompressedImageMode::Uint8:
            return IntegrateInternal<uint8_t>(image, latt, UINT8_MAX, UINT8_MAX, high_res_A);
        case CompressedImageMode::Uint16:
            return IntegrateInternal<uint16_t>(image, latt, UINT16_MAX, UINT16_MAX, high_res_A);
        case CompressedImageMode::Uint32:
            return IntegrateInternal<uint16_t>(image, latt, UINT32_MAX, UINT32_MAX, high_res_A);
        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,
                                       int64_t special_value, int64_t saturation) {
    r.I = 0;
    r.bkg = 0;

    int64_t x0 = std::floor(r.center_x_pxl - r_3 - 1.0);
    int64_t x1 = std::ceil(r.center_x_pxl + r_3 + 1.0);
    int64_t y0 = std::floor(r.center_y_pxl - r_3 - 1.0);
    int64_t y1 = std::ceil(r.center_y_pxl + 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 - r.center_x_pxl) * (x - r.center_x_pxl) + (y - r.center_y_pxl) * (y - r.center_y_pxl);
            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;
        // minimum sigma is 1!
        if (I_sum >= 1)
            r.sigma = std::sqrt(static_cast<float>(I_sum));
        else
            r.sigma = 1;
        return true;
    }
    return false;
}