//
// Created by arvids on 13.12.22.
//

#include "superrenderer.h"
#include "common/ray.h"
#include <iostream>
#include <chrono>
#include <vector>
#include <iomanip>
#include "camera/camera.h"
#include "scene/scene.h"

void SuperRenderer::renderThread(const Scene *scene, Camera const *camera, Texture *image, int width, int widthStep,
                                 int widthOffset, int height, int heightStep, int heightOffset, std::atomic<int> *k,
                                 int const stepSize, int superSamplingFactor) {
    float const aspectRatio = static_cast<float>(height) / width;
    for (int y = heightOffset; y < height; y += heightStep) {
        for (int x = widthOffset; x < width; x += widthStep) {
            Color fragmentColor = {};
            fragmentColor = calcSuperColor(scene, camera, width, height, superSamplingFactor, aspectRatio, y, x,
                                           fragmentColor);
            fragmentColor /= static_cast<float>(superSamplingFactor * superSamplingFactor);
            image->setPixelAt(x, y, clamped(fragmentColor));
            // Super hacky progress bar!
            if (++*k % stepSize == 0) {
                std::cout << "=" << std::flush;
            }
        }
    }
}

Color &
SuperRenderer::calcSuperColor(const Scene *scene, const Camera *camera, int width, int height, int superSamplingFactor,
                              const float aspectRatio, int y, int x, Color &fragmentColor) {
    for (int x1 = 0; x1 < superSamplingFactor; x1++) {
        for (int y1 = 0; y1 < superSamplingFactor; y1++) {
            float offsetX = (-0.5f + static_cast<float>(x1) / static_cast<float>(superSamplingFactor - 1));
            float offsetY = (-0.5f + static_cast<float>(y1) / static_cast<float>(superSamplingFactor - 1));

            Ray ray = camera->createRay(((static_cast<float>(x) + offsetX) / static_cast<float>(width) * 2.0f - 1),
                                        -((static_cast<float>(y) + offsetY) / static_cast<float>(height) * 2.0f - 1) * aspectRatio);
            fragmentColor += scene->traceRay(ray);
        }
    }
    return fragmentColor;
}

Texture SuperRenderer::renderImage(Scene const &scene, Camera const &camera, int width, int height) {
    Texture image(width, height);

    // Setup timer
    std::chrono::steady_clock::time_point start, stop;

    // Reset Ray counting
    Ray::resetRayCount();

    // Super-hacky progress bar!
    std::cout << "(SuperRenderer): Begin rendering..." << std::endl;
    std::cout << "| 0%";
    int const barSize = 50;
    int const stepSize = (width * height) / barSize;
    for (int i = 0; i < barSize - 3 - 5; ++i)
        std::cout << " ";
    std::cout << "100% |" << std::endl << "|";
    std::atomic<int> k(0);

    /* Start timer */ start = std::chrono::steady_clock::now();

    // Spawn a thread for every logical processor -1, calling the renderThread function
    int const nThreads = std::thread::hardware_concurrency();
    std::vector<std::thread> threads;
    for (int t = 0; t < nThreads - 1; ++t) {
        threads.emplace_back(renderThread, &scene, &camera, &image, width, nThreads, t, height, 1, 0, &k, stepSize,
                             this->superSamplingFactor);
    }

    // Call the renderThread function yourself
    renderThread(&scene, &camera, &image, width, nThreads, nThreads - 1, height, 1, 0, &k, stepSize,
                 this->superSamplingFactor);

    // Rejoin the threads
    for (int t = 0; t < nThreads - 1; ++t) {
        threads[t].join();
    }

    // Stop timer
    stop = std::chrono::steady_clock::now();

    std::cout << "| Done!" << std::endl;

    // Calculate the Time taken in seconds
    double seconds = std::chrono::duration_cast<std::chrono::duration<double>>(stop - start).count();

    std::cout << "Time: " << seconds << "s" << std::endl;

    // Get the number of seconds per ray
    int rays = Ray::getRayCount();

    std::cout << "Paths: " << rays << std::endl;
    std::cout << "Paths per second: " << std::fixed << std::setprecision(0) << rays / seconds << std::endl;


    return image;
}


void SuperRenderer::setSuperSamplingFactor(int superSamplingFactor) {
    SuperRenderer::superSamplingFactor = superSamplingFactor;
}