using System;
using System.Collections.Generic;
using System.Linq;
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;

namespace Pong
{
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;

        Texture2D pongPaddle1;
        Texture2D pongPaddle2;
        Texture2D pongBall;

        Vector2 PongPaddle1;
        Vector2 PongPaddle2;
        Vector2 Ball;
        Vector2 BallStartPosition;
        Vector2 BallVelocity;
        Vector2 BallRebound;
        Vector2 BallInboundL;
        Vector2 BallInboundR;

        Random r = new Random();

        const int paddleSpeed = 10;

        float SafeAreaZone = 0.05f;

        Rectangle safeBounds;

        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }

        protected override void Initialize()
        {
            graphics.PreferredBackBufferWidth = 1280;
            graphics.PreferredBackBufferHeight = 720;
            graphics.ApplyChanges();

            base.Initialize();
        }

        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

            Viewport viewport = graphics.GraphicsDevice.Viewport;
            safeBounds = new Rectangle(
               (int)(viewport.Width * SafeAreaZone),
               (int)(viewport.Height * SafeAreaZone),
               (int)(viewport.Width * (1 - 2 * SafeAreaZone)),
               (int)(viewport.Height * (1 - 2 * SafeAreaZone)));

            pongPaddle1 = Content.Load<Texture2D>("pongpaddle1");
            pongPaddle2 = Content.Load<Texture2D>("pongpaddle2");
            pongBall = Content.Load<Texture2D>("PongBall");

            PongPaddle1 = new Vector2();
            PongPaddle1.X = graphics.GraphicsDevice.Viewport.Width / 100 * 5;
            PongPaddle1.Y = graphics.GraphicsDevice.Viewport.Height / 2 - pongPaddle1.Height / 2;

            PongPaddle2 = new Vector2();
            PongPaddle2.X = graphics.GraphicsDevice.Viewport.Width / 100 * 97;
            PongPaddle2.Y = graphics.GraphicsDevice.Viewport.Height / 2 - pongPaddle2.Height / 2;

            BallInboundL = new Vector2();
            BallInboundL.X = r.Next(-14, -10);
            BallInboundL.Y = 0;

            BallInboundR = new Vector2();
            BallInboundR.X = r.Next(10, 14);
            BallInboundR.Y = 0;

            Ball = new Vector2();
            Ball.X = graphics.GraphicsDevice.Viewport.Width / 2 - (pongBall.Width / 2);
            Ball.Y = graphics.GraphicsDevice.Viewport.Height / 2 - (pongBall.Height / 2);

            BallStartPosition = new Vector2();
            BallStartPosition.X = graphics.GraphicsDevice.Viewport.Width / 2 - (pongBall.Width / 2);
            BallStartPosition.Y = graphics.GraphicsDevice.Viewport.Height / 2 - (pongBall.Height / 2);

            BallVelocity = new Vector2();
            BallVelocity.X = r.Next(11, 16);
            BallVelocity.Y = 0;

            BallRebound = new Vector2();
            BallRebound.X = r.Next(12, 16);
            BallRebound.Y = r.Next(12, 16);
        }

        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
        }

        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();

            PongPaddle1.Y = MathHelper.Clamp(PongPaddle1.Y,
                safeBounds.Top - 30, safeBounds.Bottom - 70);

            PongPaddle2.Y = MathHelper.Clamp(PongPaddle2.Y,
                safeBounds.Top - 30, safeBounds.Bottom - 70);

            if (Keyboard.GetState().IsKeyDown(Keys.Up) == true)
            {
                PongPaddle1.Y -= paddleSpeed;
            }

            if (Keyboard.GetState().IsKeyDown(Keys.Down) == true)
            {
                PongPaddle1.Y += paddleSpeed;
            }

            base.Update(gameTime);
        }

        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.Black);

            spriteBatch.Begin();
            spriteBatch.Draw(pongPaddle1, PongPaddle1, Color.White);
            spriteBatch.Draw(pongPaddle2, PongPaddle2, Color.White);
            spriteBatch.Draw(pongBall, Ball, Color.White);
            spriteBatch.End();

            base.Draw(gameTime);
        }
    }
}