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

namespace ShootEmUp.Animations
{
	class Animation
	{
		public Texture2D GetSpriteSheet { get; }
		public Rectangle GetSourceRectangle { get; set; }
		public Point GetSpriteCount { get; private set; }

		private Point mySpriteSize;
		private float myElapsedTime;
		private float myTimeBetweenFrames;

		public Animation(Texture2D aSpriteSheet, Point someSpriteSize, Point someSpriteCount, float someTimeBetweenFrames)
		{
			GetSpriteSheet = aSpriteSheet;
			mySpriteSize = someSpriteSize;
			GetSpriteCount = someSpriteCount;
			myTimeBetweenFrames = someTimeBetweenFrames;
		}

		public void Update(GameTime someGameTime)
		{
			if (GetSpriteCount.X * GetSpriteCount.Y == 1)
			{
				GetSourceRectangle = new Rectangle(0, 0, mySpriteSize.X, mySpriteSize.Y);
				return;
			}

			int tempTargetSpriteIndex = GetTargetSpriteIndex(someGameTime);

			Point tempTargetImage = GetTargetImage(tempTargetSpriteIndex);
			Point tempTargetImagePosition = new Point(tempTargetImage.X * mySpriteSize.X, tempTargetImage.Y * mySpriteSize.Y);

			Rectangle tempTargetRectangle = new Rectangle(tempTargetImagePosition.X, tempTargetImagePosition.Y, mySpriteSize.X, mySpriteSize.Y);

			GetSourceRectangle = tempTargetRectangle;
		}

		private int GetTargetSpriteIndex(GameTime someGameTime)
		{
			int tempTargetSpriteIndex = 0;

			do
			{
				tempTargetSpriteIndex = (int)(myElapsedTime / (myTimeBetweenFrames <= 0 ? 1 : myTimeBetweenFrames));
				myElapsedTime += (float)someGameTime.ElapsedGameTime.TotalSeconds;

				if (tempTargetSpriteIndex >= GetSpriteCount.X * GetSpriteCount.Y)
				{
					myElapsedTime = 0;
				}

			} while (tempTargetSpriteIndex >= GetSpriteCount.X * GetSpriteCount.Y);

			return tempTargetSpriteIndex;
		}

		private Point GetTargetImage(int someTargetSpriteIndex)
		{
			return new Point(someTargetSpriteIndex % GetSpriteCount.X, (int)(someTargetSpriteIndex / GetSpriteCount.X));
		}
	}
}