using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using System.Timers;

namespace Snakes_on_a_Game
{
    class Snake
    {
        static Rectangle BLOCK_SIZE = new Rectangle(0, 0, 40, 40);
        List<Vector2> SnakePositions = new List<Vector2>();
        Vector2 snakeVelocity;
        int snakeLength = 5;
        Texture2D snaketexture;
        private Game1 game1;

        public Snake(Game1 game1)
        {
            // TODO: Complete member initialization
            snaketexture = game1.Content.Load<Texture2D>(@"Square");
            this.game1 = game1;
            snakeVelocity = new Vector2(1, 0);
            for(int i = 0; i < snakeLength; i++)
                SnakePositions.Add(new Vector2(i, i)*snakeVelocity);
        }

        public void Draw(GameTime gameTime)
        {
            for (int i = 0; i < SnakePositions.Count; i++)
            {
                Vector2 v = SnakePositions[i];
                Rectangle pos = new Rectangle((int)(BLOCK_SIZE.Width*v.X), (int)(BLOCK_SIZE.Height*v.Y),
                    (int)(BLOCK_SIZE.Width), (int)(BLOCK_SIZE.Height));
                game1.spriteBatch.Draw(snaketexture, pos, Color.Green);
            }
        }

        const double UPDATE_TIME = 500;
        double lastMoveTime;
        public void Update(GameTime gameTime)
        {


            KeyboardState keystate = Keyboard.GetState();
            if (keystate.IsKeyDown(Keys.Up))
            {
                snakeVelocity = new Vector2(0, 1);
            }
            else if (keystate.IsKeyDown(Keys.Down))
            {
                snakeVelocity = new Vector2(0, -1);
            }
            else if (keystate.IsKeyDown(Keys.Left))
            {
                snakeVelocity = new Vector2(-1, 0);
            }
            else if (keystate.IsKeyDown(Keys.Right))
            {
                snakeVelocity = new Vector2(-1, 0);
            }

            double l = gameTime.TotalGameTime.TotalMilliseconds;

            //gotta check if 500ms has elapsed since lastMoveTime
            if (l - lastMoveTime < UPDATE_TIME)
                return;
            lastMoveTime = l;
            //You also need to use some time check otherwise it's gonna be extremely fast
            //you'll want to remove the latest vector of the list and then place a new one in front
            Vector2 newPos = SnakePositions[SnakePositions.Count-1] + snakeVelocity;
            SnakePositions.RemoveAt(0);
            if (SnakePositions.Contains(newPos))
            {
                //game over because we hit ourself
            } else
                SnakePositions.Add(newPos);

            //check if you hit a food or w/e they are called (or possibly do this in Game1 class.. dunno)
            //but thats it i guess
        }

    }
}