using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;

namespace Demo
{
    /// <summary>
    /// This is the main type for your game.
    /// </summary>
    public class Demo : Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;

        BasicEffect basicEffect;
        VertexPositionColor[] vertices;

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

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            // TODO: Add your initialization logic here
            basicEffect = new BasicEffect(GraphicsDevice);
            basicEffect.View = Matrix.CreateLookAt(new Vector3(graphics.PreferredBackBufferWidth/2f, graphics.PreferredBackBufferHeight/2f, 1f), Vector3.Forward, Vector3.Up);
            basicEffect.World = Matrix.Identity;
            basicEffect.Projection = Matrix.CreateOrthographic(GraphicsDevice.Viewport.Width, GraphicsDevice.Viewport.Height, 0, 1);
            basicEffect.VertexColorEnabled = true;

            vertices = new VertexPositionColor[5];
            vertices[0] = new VertexPositionColor(new Vector3(5, 5, 0), Color.Red);
            vertices[1] = new VertexPositionColor(new Vector3(10, 5, 0), Color.Red);
            vertices[2] = new VertexPositionColor(new Vector3(10, 10, 0), Color.Red);
            vertices[3] = new VertexPositionColor(new Vector3(5, 10, 0), Color.Red);
            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

            // TODO: use this.Content to load your game content here
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// game-specific content.
        /// </summary>
        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed || Keyboard.GetState().IsKeyDown(Keys.Escape))
                Exit();

            // TODO: Add your update logic here

            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);

            foreach (EffectPass effectPass in basicEffect.CurrentTechnique.Passes)
            {
                effectPass.Apply();
                GraphicsDevice.DrawUserPrimitives(PrimitiveType.LineStrip, vertices, 0, 4);
            }
            // TODO: Add your drawing code here

            base.Draw(gameTime);
        }
    }
}