using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp10
{
    public partial class Form1 : Form
    {
        public static List<Point> pool;
        public static Point first;
        public static Point second;

        public Form1()
        {
            InitializeComponent();

            pool = new List<Point>();
        }

        private void Canvas_MouseDown(object sender, MouseEventArgs e)
        {
            listBox1.Items.Add("Point: (" + e.X + ", " + e.Y + ")");
            first = new Point(e.X, e.Y);
            pool.Add(e.Location);

            /*
            using (Pen slacker = new Pen(Color.BurlyWood))
            {
                g.DrawLine(slacker, 0, 0, Canvas.Width, Canvas.Height);
            }
            */
        }

        private void Canvas_MouseUp(object sender, MouseEventArgs e)
        {
            second = e.Location;
            pool.Add(e.Location);
            listBox1.Items.Add("Line: ");
            listBox1.Items.Add("(" + first.X + ", " + first.Y + ") to (" + e.X + ", " + e.Y + ")");

            Canvas.Refresh();
        }

        private void Canvas_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;

            using (Pen myPen = new Pen(Color.BurlyWood))
            {
                using (Brush myBrush = new SolidBrush(Color.BurlyWood))
                {
                    for (int i = 0; i < pool.Count; i += 2)
                    {
                        g.FillCircle(myBrush, pool[i].X, pool[i].Y, 20);
                        g.DrawLine(myPen, pool[i], pool[i + 1]);
                    }
                }
            }
        }
    }

    public static class GraphicsExtensions
    {
        public static void DrawCircle(this Graphics g, Pen pen,
                                      float centerX, float centerY, float radius)
        {
            g.DrawEllipse(pen, centerX - radius, centerY - radius,
                          radius + radius, radius + radius);
        }

        public static void FillCircle(this Graphics g, Brush brush,
                                      float centerX, float centerY, float radius)
        {
            g.FillEllipse(brush, centerX - radius, centerY - radius,
                          radius + radius, radius + radius);
        }
    }
}