using BEPUphysics.Entities.Prefabs;
using Microsoft.Xna.Framework;
using Microsoft.Devices.Sensors;
using System;

namespace BEPUphysicsPhoneDemo.Demos
{
    /// <summary>
    /// Demo of a wall of blocks.
    /// </summary>
    public class ShakeMotionDemo : StandardDemo
    {
        /// <summary>
        /// Constructs the demo.
        /// </summary>
        /// <param name="game">Game that owns the demo.</param>
        public ShakeMotionDemo(PhoneGame game)
            : base(game)
        {
        }

        /// <summary>
        /// Gets the name of the simulation.
        /// </summary>
        public override string Name
        {
            get { return "Shakyshake"; }
        }


        /// <summary>
        /// Initializes the demo.
        /// </summary>
        public override void Initialize()
        {
            base.Initialize();

            Game.Camera.Position = new Vector3(0, 6, 18);

            Space.Add(new Box(Vector3.Zero, 30, 10, 30));
            Space.Add(new Box(new Vector3(0, 30, 0), 30, 10, 30));
            Space.Add(new Box(new Vector3(15, 15, 0), 10, 30, 30));
            Space.Add(new Box(new Vector3(-15, 15, 0), 10, 30, 30));
            Space.Add(new Box(new Vector3(0, 15, 15), 30, 30, 10));
            Space.Add(new Box(new Vector3(0, 15, -15), 30, 30, 10));
            
            float horizontalSpacing = 2;
            float verticalSpacing = 2f;
            int rowCount = 3;
            int columnCount = 3;
            for (int i = 0; i < rowCount; i++)
            {
                for (int j = 0; j < columnCount; j++)
                {
                    var toAdd = new Box(new Vector3(
                                          j * horizontalSpacing - (columnCount - i % 2) * horizontalSpacing * .5f,
                                          verticalSpacing * (i + 1),
                                          0),
                                      1, 1, 1, 20);
                    toAdd.ActivityInformation.IsAlwaysActive = true;
                    Space.Add(toAdd);
                }
            }
            motion = new Motion();


            try
            {
                motion.Start();
                motionAvailable = true;
            }
            catch (Exception e)
            {
                motionAvailable = false;
            }
        }

        Motion motion;
        bool motionAvailable;


        public override void Update(float dt)
        {
            if (motionAvailable)
            {
                Vector3 gravity = motion.CurrentValue.Gravity;
                Vector3 externalAcceleration = motion.CurrentValue.DeviceAcceleration;
                
                //Check the external acceleration magnitude against a threshold to avoid using every single tiny shake.
                if (externalAcceleration.LengthSquared() > .3f * .3f)
                {
                    //If the external acceleration is significant, include it for shakey purposes.
                    Space.ForceUpdater.Gravity = gravity * 20 - externalAcceleration * 300;
                }
                else
                {
                    //If the external acceleration is tiny, don't bother including it.
                    Space.ForceUpdater.Gravity = gravity * 20;
                }
            }
            base.Update(dt);
        }

        public override void DrawUI()
        {
            if (!motionAvailable)
            {
                Game.SpriteBatch.DrawString(Game.ButtonFont, "Motion unavailable.", new Vector2(100, 100), Color.White);
            }
            else
            {
                Game.SpriteBatch.DrawString(Game.ButtonFont, Space.ForceUpdater.Gravity.X.ToString(), new Vector2(0, 100), Color.White);
                Game.SpriteBatch.DrawString(Game.ButtonFont, Space.ForceUpdater.Gravity.Y.ToString(), new Vector2(0, 120), Color.White);
                Game.SpriteBatch.DrawString(Game.ButtonFont, Space.ForceUpdater.Gravity.Z.ToString(), new Vector2(0, 140), Color.White);
            }
            base.DrawUI();
        }

        public override void CleanUp()
        {
            motion.Stop();
            base.CleanUp();
        }

    }
}