#include <QApplication>
#include <QGraphicsView>
#include <QGraphicsScene>
#include <fstream>
#include <iostream>
#include <algorithm>
#include <vector>
#include <chrono>
#include <cmath>
#include <unordered_map>
#include "Point.h"

// constants
static const int SCENE_WIDTH = 512;
static const int SCENE_HEIGHT = 512;

void render_points(QGraphicsScene* scene, const vector<Point>& points) {
    for(const auto& point : points) {
        point.draw(scene);
    }
}

void render_line(QGraphicsScene* scene, const Point& p1, const Point& p2) {
    p1.lineTo(scene, p2);
}

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);

    // open file
    string filename = "grid6x6.txt";

    ifstream input;
    input.open(filename);

    // the vector of points
    vector<Point> points;

    // read points from file
    int N;
    int x;
    int y;

    input >> N;

    for (int i = 0; i < N; ++i) {
        input >> x >> y;
        points.push_back(Point(x, y));
    }
    input.close();

    // setup graphical window
    QGraphicsView *view = new QGraphicsView();
    QGraphicsScene *scene = new QGraphicsScene(0, 0, SCENE_WIDTH, SCENE_HEIGHT);
    view->setScene(scene);
    // draw points to screen all at once
    render_points(scene, points);
    view->scale(1, -1); //screen y-axis is inverted
    view->resize(view->sizeHint());
    view->setWindowTitle("Fast Pattern Recognition");

    sort(points.begin(), points.end());
    auto begin = chrono::high_resolution_clock::now();

    vector<pair<double, Point>> angles;
    int draws = 0;
    for (int p1 = 0; p1 < N-1; p1++) {
        angles.clear();
        for (int p2 = p1 + 1; p2 < N; p2++) {
            double angle = points.at(p1).slopeTo(points.at(p2));
            angles.push_back({ angle, points.at(p2) });
        }
        sort(angles.begin(), angles.end());

        int num_in_row = 0;
        for (int i = 1; i < angles.size(); i++) {
            double prev_angle = angles[i - 1].first;
            if (angles[i].first == prev_angle) {
                num_in_row++;
                if (num_in_row >= 2) {
                    render_line(scene, points.at(p1), angles[i].second);
                    draws++;
                }
            } else {
                num_in_row = 0;
            }
        }
    }
    cout << draws << endl;

    auto end = chrono::high_resolution_clock::now();
    cout << "Computing line segments took "
         << std::chrono::duration_cast<chrono::milliseconds>(end - begin).count()
         << " milliseconds." << endl;

    view->show();
    return a.exec(); // start Qt event loop
}