using System;

namespace Spine {
	/** Attachment that displays a texture region. */
	public class RegionAttachment : Attachment {
		public const int X1 = 0;
		public const int Y1 = 1;
		public const int X2 = 2;
		public const int Y2 = 3;
		public const int X3 = 4;
		public const int Y3 = 5;
		public const int X4 = 6;
		public const int Y4 = 7;

		public float X { get; set; }
		public float Y { get; set; }
		public float ScaleX { get; set; }
		public float ScaleY { get; set; }
		public float Rotation { get; set; }
		public float Width { get; set; }
		public float Height { get; set; }

		public float[] Offset { get; private set; }
		public float[] Vertices { get; private set; }
		public float[] UVs { get; private set; }

		private AtlasRegion region;
		public AtlasRegion Region {
			get {
				return region;
			}
			set {
				region = value;
				float[] uvs = UVs;
				if (value.Rotate) {
					uvs[X2] = value.U;
					uvs[Y2] = value.V2;
					uvs[X3] = value.U;
					uvs[Y3] = value.V;
					uvs[X4] = value.U2;
					uvs[Y4] = value.V;
					uvs[X1] = value.U2;
					uvs[Y1] = value.V2;
				} else {
					uvs[X1] = value.U;
					uvs[Y1] = value.V2;
					uvs[X2] = value.U;
					uvs[Y2] = value.V;
					uvs[X3] = value.U2;
					uvs[Y3] = value.V;
					uvs[X4] = value.U2;
					uvs[Y4] = value.V2;
				}
			}
		}

		public RegionAttachment (string name)
			: base(name) {
			Offset = new float[8];
			Vertices = new float[8];
			UVs = new float[8];
			ScaleX = 1;
			ScaleY = 1;
		}

		public void UpdateOffset () {
			float width = Width;
			float height = Height;
			float localX2 = width / 2;
			float localY2 = height / 2;
			float localX = -localX2;
			float localY = -localY2;
			AtlasRegion region = Region;
			if (region.Rotate) {
				localX += region.OffsetX / region.OriginalWidth * height;
				localY += region.OffsetY / region.OriginalHeight * width;
				localX2 -= (region.OriginalWidth - region.OffsetX - region.Height) / region.OriginalWidth * width;
				localY2 -= (region.OriginalHeight - region.OffsetY - region.Width) / region.OriginalHeight * height;
			} else {
				localX += region.OffsetX / region.OriginalWidth * width;
				localY += region.OffsetY / region.OriginalHeight * height;
				localX2 -= (region.OriginalWidth - region.OffsetX - region.Width) / region.OriginalWidth * width;
				localY2 -= (region.OriginalHeight - region.OffsetY - region.Height) / region.OriginalHeight * height;
			}
			float scaleX = ScaleX;
			float scaleY = ScaleY;
			localX *= scaleX;
			localY *= scaleY;
			localX2 *= scaleX;
			localY2 *= scaleY;
			float radians = Rotation * (float)Math.PI / 180;
			float cos = (float)Math.Cos(radians);
			float sin = (float)Math.Sin(radians);
			float x = X;
			float y = Y;
			float localXCos = localX * cos + x;
			float localXSin = localX * sin;
			float localYCos = localY * cos + y;
			float localYSin = localY * sin;
			float localX2Cos = localX2 * cos + x;
			float localX2Sin = localX2 * sin;
			float localY2Cos = localY2 * cos + y;
			float localY2Sin = localY2 * sin;
			float[] offset = Offset;
			offset[X1] = localXCos - localYSin;
			offset[Y1] = localYCos + localXSin;
			offset[X2] = localXCos - localY2Sin;
			offset[Y2] = localY2Cos + localXSin;
			offset[X3] = localX2Cos - localY2Sin;
			offset[Y3] = localY2Cos + localX2Sin;
			offset[X4] = localX2Cos - localYSin;
			offset[Y4] = localYCos + localX2Sin;
		}

		public void UpdateVertices (Bone bone) {
			float x = bone.WorldX;
			float y = bone.WorldY;
			float m00 = bone.M00;
			float m01 = bone.M01;
			float m10 = bone.M10;
			float m11 = bone.M11;
			float[] vertices = Vertices;
			float[] offset = Offset;
			vertices[X1] = offset[X1] * m00 + offset[Y1] * m01 + x;
			vertices[Y1] = offset[X1] * m10 + offset[Y1] * m11 + y;
			vertices[X2] = offset[X2] * m00 + offset[Y2] * m01 + x;
			vertices[Y2] = offset[X2] * m10 + offset[Y2] * m11 + y;
			vertices[X3] = offset[X3] * m00 + offset[Y3] * m01 + x;
			vertices[Y3] = offset[X3] * m10 + offset[Y3] * m11 + y;
			vertices[X4] = offset[X4] * m00 + offset[Y4] * m01 + x;
			vertices[Y4] = offset[X4] * m10 + offset[Y4] * m11 + y;
		}
	}
}