using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace test1Program
{
    public partial class Form1 : Form
    {
        const float calHeightInPixels = 600.0f;
        const float calWidthInPixels = 348.0f;

        const float worldWidth = 100;
        const float worldHeight = 172;

        const float topLeftPlusX = 6;
        const float topLeftPlusY = 64;

        const float ButtonWidth = 18;
        const float ButtonHeight = 12;
        const float ButtonWidthPlusGap = ButtonWidth + 3.5f;
        const float ButtonHeightPlusGap = ButtonHeight + 5f;

        Point anchorPoint_ = new Point(0, 0);

        const int nColumns = 3;

        float buttonWidthPercent =
            ButtonWidth / ButtonWidthPlusGap;

        float buttonHeightPercent =
            ButtonHeight / ButtonHeightPlusGap;

        Timer sevenTimer_ = new Timer();
        bool sevenIsMoving_ = false;
        PointF topLeftOfSeven_ = 
            new PointF(6,64+2*ButtonHeightPlusGap);
        PointF velocityOfSeven_ = new PointF(0, 0);

        public Form1()
        {
            InitializeComponent();
            Width = (int) calWidthInPixels;
            Height = (int) calHeightInPixels;

            Paint += Form1_Paint;
            MouseClick += Form1_MouseClick;
            MouseMove += Form1_MouseMove;
            KeyDown += Form1_KeyDown;

            sevenTimer_.Tick += SevenTimer__Tick;
        }

        private void SevenTimer__Tick(object sender, EventArgs e)
        {
            topLeftOfSeven_.X += velocityOfSeven_.X;
            topLeftOfSeven_.Y += velocityOfSeven_.Y;

            // Check for hitting a wall.
            if (topLeftOfSeven_.X < 0 ||
                topLeftOfSeven_.X + ButtonWidth > worldWidth)
                velocityOfSeven_.X *= -1;

            if (topLeftOfSeven_.Y < 0 ||
                topLeftOfSeven_.Y + ButtonHeight > worldHeight)
                velocityOfSeven_.Y *= -1;

            Invalidate(true);
        }

        private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            sevenTimer_.Interval = 1000 / 30;
            sevenTimer_.Start();
            velocityOfSeven_.X = 1;
            velocityOfSeven_.Y = 1;
            sevenIsMoving_ = true;
        }

        private void Form1_MouseMove(object sender,
            MouseEventArgs e)
        {
            Graphics graphics = CreateGraphics();
            graphics.ScaleTransform(
               ClientRectangle.Width / worldWidth,
               ClientRectangle.Height / worldHeight);

            PointF[] transformPts = new PointF[2];
            transformPts[0] = new PointF(anchorPoint_.X,
                anchorPoint_.Y);
            transformPts[1] = new PointF(e.X, e.Y);

            graphics.TransformPoints(CoordinateSpace.World,
                CoordinateSpace.Device, transformPts);

            Text = String.Format("({0}, {1}) : ({2}, {3})",
                e.X - anchorPoint_.X, e.Y - anchorPoint_.Y,
                transformPts[1].X - transformPts[0].X,
                transformPts[1].Y - transformPts[0].Y);
        }

        private void Form1_MouseClick(object sender, MouseEventArgs e)
        {
            anchorPoint_.X = e.X;
            anchorPoint_.Y = e.Y;
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            // Compute pixels/worldUnit
            e.Graphics.ScaleTransform(
                ClientRectangle.Width / worldWidth,
                ClientRectangle.Height / worldHeight);

            e.Graphics.TranslateTransform(topLeftPlusX,
                topLeftPlusY);

            e.Graphics.ScaleTransform(ButtonWidthPlusGap,
                ButtonHeightPlusGap);

            for(int row=0;row<6;++row)
            {
                for(int column=0;column<nColumns;++column)
                {
                    e.Graphics.FillRectangle(Brushes.Red,
                        new RectangleF(column, row,
                        buttonWidthPercent, buttonHeightPercent));
                }
            }

            e.Graphics.ResetTransform();
            // Use drawing units
            e.Graphics.ScaleTransform(
    ClientRectangle.Width / worldWidth,
    ClientRectangle.Height / worldHeight);

            float xForDivide = worldWidth - ButtonWidth - 6;
            e.Graphics.TranslateTransform(
                xForDivide, topLeftPlusY);

            e.Graphics.ScaleTransform(ButtonWidthPlusGap,
                ButtonHeightPlusGap);

            for (int i = 0; i < 4; i++)
            {
                e.Graphics.FillRectangle(Brushes.Blue,
                    new RectangleF(0, i, buttonWidthPercent,
                    buttonHeightPercent)); 
            }

            e.Graphics.FillRectangle(Brushes.Blue,
                new RectangleF(0, 4, buttonWidthPercent,
                (ButtonHeight + ButtonHeightPlusGap)/
                ButtonHeightPlusGap));

            e.Graphics.ResetTransform();

            if (sevenIsMoving_)
            {
                // User drawing coordinates
                e.Graphics.ScaleTransform(
                     ClientRectangle.Width / worldWidth,
                     ClientRectangle.Height / worldHeight);

                e.Graphics.FillRectangle(Brushes.Indigo,
                    new RectangleF(topLeftOfSeven_.X,
                    topLeftOfSeven_.Y, 18, 12));
            }
        }
    }
}