using UnityEngine;
using UnityEngine.UI;

namespace Coffee.UIExtensions
{
	/// <summary>
	/// Area for effect.
	/// </summary>
	public enum EffectArea
	{
		RectTransform,
		Fit,
		Character,
	}

	public static class EffectAreaExtensions
	{
		static readonly Rect rectForCharacter = new Rect(0, 0, 1, 1);
		static readonly Vector2 [] splitedCharacterPosition = { Vector2.up, Vector2.one, Vector2.right, Vector2.zero };

		/// <summary>
		/// Gets effect for area.
		/// </summary>
		public static Rect GetEffectArea (this EffectArea area, VertexHelper vh, Rect rectangle, float aspectRatio = -1)
		{
			Rect rect = default(Rect);
			switch (area)
			{
				case EffectArea.RectTransform:
					rect = rectangle;
					break;
				case EffectArea.Character:
					rect = rectForCharacter;
					break;
				case EffectArea.Fit:
					// Fit to contents.
					UIVertex vertex = default (UIVertex);
					float xMin = float.MaxValue;
					float yMin = float.MaxValue;
					float xMax = float.MinValue;
					float yMax = float.MinValue;
					for (int i = 0; i < vh.currentVertCount; i++)
					{
						vh.PopulateUIVertex(ref vertex, i);
						float x = vertex.position.x;
						float y = vertex.position.y;
						xMin = Mathf.Min(xMin, x);
						yMin = Mathf.Min(yMin, y);
						xMax = Mathf.Max(xMax, x);
						yMax = Mathf.Max(yMax, y);
					}
					rect.Set (xMin, yMin, xMax - xMin, yMax - yMin);
					break;
				default:
					rect = rectangle;
					break;
			}


			if(0 < aspectRatio)
			{
				if (rect.width < rect.height)
				{
					rect.width =  rect.height * aspectRatio;
				}
				else
				{
					rect.height = rect.width / aspectRatio;
				}
			}
			return rect;
		}

		/// <summary>
		/// Gets position factor for area.
		/// </summary>
		public static void GetPositionFactor (this EffectArea area, int index, Rect rect, Vector2 position, bool isText, bool isTMPro, out float x, out float y)
		{
			if (isText && area == EffectArea.Character)
			{
				index = isTMPro ? (index + 3) % 4 : index % 4;
				x = splitedCharacterPosition [index].x;
				y = splitedCharacterPosition [index].y;
			}
			else if (area == EffectArea.Fit)
			{
				x = Mathf.Clamp01 ((position.x - rect.xMin) / rect.width);
				y = Mathf.Clamp01 ((position.y - rect.yMin) / rect.height);
			}
			else
			{
				x = Mathf.Clamp01 (position.x / rect.width + 0.5f);
				y = Mathf.Clamp01 (position.y / rect.height + 0.5f);
			}
		}

		/// <summary>
		/// Normalize vertex position by local matrix.
		/// </summary>
		public static void GetNormalizedFactor (this EffectArea area, int index, Matrix2x3 matrix, Vector2 position, bool isText, out Vector2 nomalizedPos)
		{
			if (isText && area == EffectArea.Character)
			{
				nomalizedPos = matrix * splitedCharacterPosition [(index + 3) % 4];
			}
			else
			{
				nomalizedPos = matrix * position;
			}
		}
	}
}