#include <iostream>
#include <thread>
#include <chrono>
#include "depthoffieldrenderer.h"
#include <iomanip>


DOFRenderer::DOFRenderer(float _aperture, int _secondaryRayCount, float _focalLength) : aperture(_aperture),
                                                                                        numSamples(_secondaryRayCount), focalLength(_focalLength) {}

std::random_device DOFRenderer::rd;
std::mt19937 DOFRenderer::gen(DOFRenderer::rd());

Color DOFRenderer::sample(const Ray &ray, const Scene& scene, const Camera& camera) const {

    std::uniform_real_distribution<float> dis(-1.0, 1.0);

    // calculate the point of focus
    Vector3d focusPoint = ray.origin + ray.direction * focalLength;

    // Final color
    Color finalColor;

    // Calculate all secondary Rays
    for (int i = 0; i < numSamples; i++) {
        // create a random point on the aperture
        Vector3d rnd = Vector3d(dis(gen), dis(gen), 0);
        Vector3d apertureOffset = aperture * (rnd.x * camera.getRightDirection() + rnd.y * camera.getUpDirection());

        // create the new ray with the offset point
        Vector3d dofRayOrigin = ray.origin + apertureOffset;
        Vector3d dofRayDirection = normalized(focusPoint - dofRayOrigin);
        Ray dofRay(dofRayOrigin, dofRayDirection);

        // get Color of the new Ray
        finalColor += scene.traceRay(dofRay);
    }


    // trace the new ray and return the color
    return finalColor /= float(numSamples);;
}

void DOFRenderer::renderThread(const Scene *scene, Camera const *camera, Texture *image, const DOFRenderer *renderer, int width, int widthStep, int widthOffset, int height, int heightStep, int heightOffset, std::atomic<int> *k, int const stepSize) {
    float const aspectRatio = static_cast<float>(height) / width;
    for (int y = heightOffset; y < height; y += heightStep) {
        for (int x = widthOffset; x < width; x += widthStep) {
            Ray ray = camera->createRay((static_cast<float>(x) / width * 2 - 1), -(static_cast<float>(y) / height * 2 - 1) * aspectRatio);

            // Trace rays with DOF
            image->setPixelAt(x, y, clamped(renderer->sample(ray, *scene, *camera)));

            // Super hacky progress bar!
            if (++*k % stepSize == 0) {
                std::cout << "=" << std::flush;
            }
        }
    }
}


Texture DOFRenderer::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 << "(SimpleRenderer): 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, this, width, nThreads, t, height, 1, 0, &k, stepSize);
    }

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

    // 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;
}