using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;

namespace Turtle
{
    public class Canvas : IDisposable
    {
        protected int angle;
        protected Pen turtlePen = (Pen)Pens.Black.Clone();

        public Bitmap Bitmap { get; protected set; }
        public Image Image { get; protected set; }

        public Point Position { get; set; }

        public int Angle
        {
            get { return angle; }
            set
            {
                angle = value;
                angle %= 360;

                if (angle < 0)
                {
                    angle += 360;
                }
            }
        }

        public int PenSize { get; set; }

        public int StepCount { get; set; }

        public int MaxStepCount { get; set; }

        public Canvas()
        {
            // initialize bitmap
            Bitmap = new Bitmap(700, 700);
            Image = Image.FromHbitmap(Bitmap.GetHbitmap());

            using (Graphics graphics = Graphics.FromImage(Image))
            {
                graphics.FillRectangle(Brushes.White, new Rectangle(0, 0, 700, 700));
            }

            // initialize state
            Position = new Point(350, 350);
            Angle = 0;
            PenSize = 0;
        }

        public void Dispose()
        {
            Bitmap.Dispose();
            Image.Dispose();
        }

        public void Execute(string name, List<int> args)
        {
            switch (name)
            {
                case "left": Angle -= args[0]; break;
                case "right": Angle += args[0]; break;
                case "pen":
                    PenSize = args[0];

                    break;

                case "forward":

                    #region forward

                    if (MaxStepCount != 0 && MaxStepCount < StepCount + 1)
                    {
                        break;
                    }

                    if (PenSize > 0)
                    {
                        StepCount++;
                    }

                    using (Graphics graphics = Graphics.FromImage(Image))
                    {
                        Point current = Position;
                        Point next = current;

                        double angle = Convert.ToDouble(Angle);
                        double radAngle = angle * Math.PI / 180;

                        next.X += Convert.ToInt32(Math.Sin(radAngle) * args[0]);
                        next.Y -= Convert.ToInt32(Math.Cos(radAngle) * args[0]);
                        
                        if (PenSize > 0)
                        {
                            turtlePen.Width = PenSize;
                            graphics.DrawLine(turtlePen, current, next);
                        }

                        Position = next;
                    }

                    #endregion

                    break;

                case "color":

                    #region color

                    int red = Math.Min(255, Math.Max(0, args[0]));
                    int green = Math.Min(255, Math.Max(0, args[1]));
                    int blue = Math.Min(255, Math.Max(0, args[2]));

                    turtlePen = new Pen(Color.FromArgb(red, green, blue));

                    #endregion

                    break;
            }
        }
    }
}