using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System;

namespace RecrownedAthenaeum.Camera
{
    /// <summary>
    /// A virtual 2D camera that wraps the normal <see cref="Camera"/>. Default projection is orthographic.
    /// </summary>
    public class Camera2D : Camera
    {

        /// <summary>
        /// The 2D position.
        /// </summary>
        public Vector2 Position { get { return new Vector2(position.X, position.Y); } set { position.X = value.X; position.Y = value.Y; } }

        /// <summary>
        /// A 2D camera from the generic <see cref="Camera"/>.
        /// </summary>
        public Camera2D() : base()
        {

        }

        /// <summary>
        /// Lerps to the given position.
        /// </summary>
        /// <param name="alpha">The multiplier for difference in distance.</param>
        /// <param name="targetPosition">The target position to lerp to.</param>
        /// <param name="delta">Time between this frame and the previous frame.</param>
        public void LinearInterpolationToPosition(float alpha, Vector2 targetPosition, float delta)
        {
            if (alpha <= 0 && alpha > 1f) throw new ArgumentException("Alpha can't be greater than 1f, less than or equal to 0.");

            Vector2 distance = targetPosition - Position;
            distance *= (float)(1.0f - Math.Pow(1 - alpha, delta / 0.02f));

            Position += distance;

            Apply();
        }

        private Matrix BasicOrthographic()
        {
            return Matrix.CreateOrthographic(graphicsDevice.Viewport.Width, graphicsDevice.Viewport.Height, 0, 1);
        }
    }
}