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

namespace WindowsFormsApplication74
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        Snake snake=new Snake();
        int direct = 0;
        bool key = false;
        private void timer1_Tick(object sender, EventArgs e)
        {
            switch(direct)
            {
                case 1: snake.snake_moveup(); break;
                case 2: snake.snake_movedown(); break;
                case 3: snake.snake_moveleft(); break;
                case 4: snake.snake_moveright(); break;
            }
            Refresh();
        }

        private void pictureBox1_Paint(object sender, PaintEventArgs e)
        {
            if(key)
            {
                Graphics g = e.Graphics;
                snake.snake_draw(g);
            }
        }

        private void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Up) { direct = 1; }
            if (e.KeyCode == Keys.Down) { direct = 2; }
            if (e.KeyCode == Keys.Left) { direct = 3; }
            if (e.KeyCode == Keys.Right) { direct = 4; }
        }

        private void 开始ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            key = true;
            timer1.Enabled = true;
            direct = 3;
            Refresh();
        }

    }
    class Block 
    {
        public Point block_point;
        Size size = new Size(5,5);
        public void block_draw(Graphics g)
        {
            Rectangle rec = new Rectangle(block_point,size);
            SolidBrush sb=new SolidBrush(Color.Red);
            g.FillRectangle(sb,rec);
        }
    }
    class Snake 
    {
        public ArrayList snake_block = new ArrayList(4);//用于存储方块的数组
        public Snake() //构造函数
        {
            int x = 400, y = 100;
            for (int i = 0; i < 4;i++ )
            {
                Block block = new Block();
                block.block_point = new Point(x,y);
                snake_block.Add(block);
                x += 5;
            }
        }
        public void snake_draw(Graphics g)//调用Block中的Draw方法绘制Snake 
        {
            for (int i = 0; i < snake_block.Count;i++ )
            {
                Block block=(Block)snake_block[i];
                block.block_draw(g);
            }

        }
        public void snake_moveup() 
        {
            for (int i = snake_block.Count - 1; i >= 1; i--)
            {
                snake_block[i] = snake_block[i - 1];
            }
            Block block_temp = (Block)snake_block[0];
            block_temp.block_point = new Point(block_temp.block_point.X, block_temp.block_point.Y - 5);
            snake_block[0] = block_temp;
         }
        public void snake_movedown()
        {
            for (int i = snake_block.Count - 1; i >= 1; i--)
            {
                snake_block[i] = snake_block[i - 1];
            }
            Block block_temp = (Block)snake_block[0];
            block_temp.block_point = new Point(block_temp.block_point.X , block_temp.block_point.Y+5);
            snake_block[0] = block_temp;
        }
        public void snake_moveleft()
        {
            for (int i = snake_block.Count - 1; i >= 1;i-- )
            {
                snake_block[i] = snake_block[i - 1];
            }
            Block block_temp=(Block)snake_block[0];
            block_temp.block_point = new Point(block_temp.block_point.X-5,block_temp.block_point.Y);
            snake_block[0] = block_temp;
        }
        public void snake_moveright()
        {
            for (int i = snake_block.Count - 1; i >= 1; i--)
            {
                snake_block[i] = snake_block[i - 1];
            }
            Block block_temp = (Block)snake_block[0];
            block_temp.block_point = new Point(block_temp.block_point.X +5, block_temp.block_point.Y);
            snake_block[0] = block_temp;
        }
    }
    class Food { }
}