using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;

namespace BouncyCatIsBouncy
{
    class PhysicsBody
    {
        public Vector2 Position {get; set;}
        public float Mass {get; set;}
        public float CoeffRestitution { get; set; }
        public Vector2 Velocity { get; internal set; }
        public bool CollisionResponseEnable { get; set; }
        public delegate void CollisionEventHandler(PhysicsBody other);
        public event CollisionEventHandler OnCollision;
        public Vector2 Gravity { get; set; }

        public Object Tag;

        bool m_isColliding, m_wasColliding;

        public PhysicsBody()
        {
            CoeffRestitution = 1.0f;
            CollisionResponseEnable = true;
        }

        //This isn't close to correct, impulses should be gathered and applied during Update
        public void ApplyImpulse(Vector2 impulse)
        {
            Velocity += impulse;
        }

        List<PhysicsGeom> m_geometry = new List<PhysicsGeom>();
        public List<PhysicsGeom> Geometry
        {
            get { return m_geometry; }
        }

        public void Update(float dt)
        {
            Velocity += Gravity * dt;
            Position += Velocity * dt;
            if (m_isColliding)
            {
                m_isColliding = false;
            }
            else if (m_wasColliding)
            {
                m_wasColliding = false;
            }
        }

        public void Collision(PhysicsBody other)
        {
            if (!m_wasColliding && OnCollision != null)
            {
                OnCollision(other);
            }
            m_wasColliding = m_isColliding = true;
        }
    }
}