using System;

using System.Drawing;

using System.Drawing.Imaging;

using System.Windows.Forms;

using System.Collections.Generic;

namespace Assistance {

    public class MainWindow : Form {

        static public void Main() { Application.Run(new MainWindow()); }

		Bitmap bitmap = new Bitmap(1, 1);

		Canvas canvas = new Canvas();

		bool dragging = false;

		ActivePoint activePoint;

		Point offset;

		Point cursor;

		public MainWindow() {

			Paint += onPaint;

			MouseMove += onMouseMove;

			MouseDown += onMouseDown;

			MouseUp += onMouseUp;

			KeyDown += onKeyDown;

            WindowState = FormWindowState.Maximized;

        }

		protected override void OnPaintBackground(PaintEventArgs e) { }

        public void onPaint(Object sender, PaintEventArgs e) {

			if (bitmap.Size != ClientSize)

				bitmap = new Bitmap(ClientSize.Width, ClientSize.Height);

			Graphics g = Graphics.FromImage(bitmap);

			g.Clear(Color.White);

            draw(g);

			g.Flush();

			e.Graphics.DrawImageUnscaled(bitmap, new Rectangle(0, 0, ClientSize.Width, ClientSize.Height));

        }

		public Point windowToCanvas(Point p) {

			return new Point(p.x - ClientSize.Width/2.0, p.y - ClientSize.Height/2.0);

		}

		public Point canvasToWindow(Point p) {

			return new Point(p.x + ClientSize.Width/2.0, p.y + ClientSize.Height/2.0);

		}

		private void beginDrag() {

			dragging = true;

			offset = activePoint.position - cursor;

			activePoint.bringToFront();

		}

		private void endDrag() {

			dragging = false;

			offset = new Point();

		}

		public void onKeyDown(Object sender, KeyEventArgs e) {

			switch(e.KeyCode) {

			case Keys.D1:

				new VanishingPoint(canvas, cursor);

				break;

			case Keys.D2:

				new Grid(canvas, cursor);

				break;

			case Keys.Delete:

				if (activePoint != null)

					activePoint.assistant.remove();

				endDrag();

				break;

			}

			endDrag();

			Invalidate();

		}

		public void onMouseDown(Object sender, MouseEventArgs e) {

			cursor = windowToCanvas(new Point(e.Location.X, e.Location.Y));

			if (e.Button == MouseButtons.Left) {

				activePoint = canvas.findPoint(cursor);

				if (activePoint != null)

					beginDrag();

			}

			Invalidate();

		}

		public void onMouseUp(Object sender, MouseEventArgs e) {

			cursor = windowToCanvas(new Point(e.X, e.Y));

			if (e.Button == MouseButtons.Left)

				endDrag();

			if (!dragging)

				activePoint = canvas.findPoint(cursor);

			Invalidate();

		}

		public void onMouseMove(Object sender, MouseEventArgs e) {

			cursor = windowToCanvas(new Point(e.Location.X, e.Location.Y));

			if (dragging) {

				activePoint.assistant.onMovePoint(activePoint, cursor + offset);

			} else {

				activePoint = canvas.findPoint(cursor);

			}

			Invalidate();

        }

        public void draw(Graphics g) {

			g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

			g.TranslateTransform(0.5f*ClientSize.Width, 0.5f*ClientSize.Height);

			canvas.draw(g, activePoint, cursor + offset);

        }

    }

}