using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Sprites;
using UnityEngine.UI;

/* Author: Josh H.
 * Procedural UI Image
 * assetstore.joshh@gmail.com for feedback or questions
 */

namespace UnityEngine.UI {

    [ExecuteInEditMode]
    [AddComponentMenu("UI/Procedural Image")]
	public class ProceduralImage : ImageProxy {
        [SerializeField]private float borderWidth;
		private ProceduralImageModifier modifier;
        public  Material materialInstance;
        public Material materialInstanceClip;
		[SerializeField]private float falloffDistance = 1;
        public bool needClipping = false;
        public float BorderWidth {
			get {
				return borderWidth;
			}
			set {
				borderWidth = value;
				this.SetMaterialDirty();
			}
		}

		public float FalloffDistance {
			get {
				return falloffDistance;
			}
			set {
				falloffDistance = value;
				this.SetMaterialDirty();
			}
		}

		protected ProceduralImageModifier Modifier {
			get {
				if (modifier == null) {
					//try to get the modifier on the object.
					modifier = this.GetComponent<ProceduralImageModifier>();
					//if we did not find any modifier
					if(modifier == null){
						//Add free modifier
						ModifierType = typeof(FreeModifier);
					}
				}
				return modifier;
			}
			set{
				modifier = value;
			}
		}

		/// <summary>
		/// Gets or sets the type of the modifier. Adds a modifier of that type.
		/// </summary>
		/// <value>The type of the modifier.</value>
		public System.Type ModifierType {
			get {
				return Modifier.GetType();
			}
			set {
				if(this.GetComponent<ProceduralImageModifier>()!=null){
					Destroy(this.GetComponent<ProceduralImageModifier>());
				}
				this.gameObject.AddComponent(value);
				Modifier = this.GetComponent<ProceduralImageModifier>();
				this.SetAllDirty();
			}
		}

		override protected void OnEnable()
        {
            base.OnEnable ();
          //  ScenceMain.MainUpdateEvent += MainUpdate;
            this.Init ();
		}

		/// <summary>
		/// Initializes this instance.
		/// </summary>
		public void Init (){
        //    materialInstance = Image.defaultGraphicMaterial;
        //    materialInstanceClip = Image.defaultETC1GraphicMaterial;
         //   this.material = materialInstance;
        }

        protected override void OnDisable()
        {
            base.OnDisable();
          //  ScenceMain.MainUpdateEvent -= MainUpdate;
        }
        public void Update(){
			if (needClipping) {
			//	this.material = materialInstanceClip;
			} else {
				//this.material = materialInstance;
			}
			this.UpdateMaterial ();
		}
		/// <summary>
		/// Prevents radius to get bigger than rect size
		/// </summary>
		/// <returns>The fixed radius.</returns>
		/// <param name="vec">border-radius as Vector4 (starting upper-left, clockwise)</param>
		private Vector4 FixRadius(Vector4 vec){
			Rect r = this.rectTransform.rect;
			vec = new Vector4 (Mathf.Max(vec.x,0),Mathf.Max(vec.y,0),Mathf.Max(vec.z,0),Mathf.Max(vec.w,0));
			//float maxRadiusSums = Mathf.Max (vec.x,vec.z) + Mathf.Max (vec.y,vec.w);
			float scaleFactor = Mathf.Min(r.width/(vec.x+vec.y),r.width/(vec.z+vec.w),r.height/(vec.x+vec.w),r.height/(vec.z+vec.y),1);
			return vec*scaleFactor;
		}
		protected override void OnPopulateMesh(VertexHelper toFill)
		{
			//note: Sliced and Tiled have no effect to this currently.

			if (overrideSprite == null)
			{
				base.OnPopulateMesh(toFill);
				return;
			}
			
			switch (type)
			{
			case Type.Simple:
				GenerateSimpleSprite(toFill);
				break;
			case Type.Sliced:
				GenerateSimpleSprite(toFill);
				break;
			case Type.Tiled:
				GenerateSimpleSprite(toFill);
				break;
			case Type.Filled:
				base.OnPopulateMesh(toFill);
				break;
			}
		}
		#if UNITY_EDITOR
		protected override void Reset (){
			base.Reset ();
			OnEnable ();
		}
#endif
        private Vector4 GetDrawingDimensions(bool shouldPreserveAspect)
        {
            var padding = overrideSprite == null ? Vector4.zero : DataUtility.GetPadding(overrideSprite);
            Rect r = GetPixelAdjustedRect();
            var size = overrideSprite == null ? new Vector2(r.width, r.height) : new Vector2(overrideSprite.rect.width, overrideSprite.rect.height);
            //Debug.Log(string.Format("r:{2}, size:{0}, padding:{1}", size, padding, r));

            int spriteW = Mathf.RoundToInt(size.x);
            int spriteH = Mathf.RoundToInt(size.y);

            if (shouldPreserveAspect && size.sqrMagnitude > 0.0f)
            {
                var spriteRatio = size.x / size.y;
                var rectRatio = r.width / r.height;

                if (spriteRatio > rectRatio)
                {
                    var oldHeight = r.height;
                    r.height = r.width * (1.0f / spriteRatio);
                    r.y += (oldHeight - r.height) * rectTransform.pivot.y;
                }
                else
                {
                    var oldWidth = r.width;
                    r.width = r.height * spriteRatio;
                    r.x += (oldWidth - r.width) * rectTransform.pivot.x;
                }
            }

            var v = new Vector4(
                    padding.x / spriteW,
                    padding.y / spriteH,
                    (spriteW - padding.z) / spriteW,
                    (spriteH - padding.w) / spriteH);

            v = new Vector4(
                    r.x + r.width * v.x,
                    r.y + r.height * v.y,
                    r.x + r.width * v.z,
                    r.y + r.height * v.w
                    );

            return v;
        }

        //每个角最大的三角形数，一般5-8个就有不错的圆角效果，设置Max防止不必要的性能浪费
        const int MaxTriangleNum = 20;
        const int MinTriangleNum = 1;

        public float Radius=10;
        //使用几个三角形去填充每个角的四分之一圆
        [Range(MinTriangleNum, MaxTriangleNum)]
        public int TriangleNum=6;
        /// <summary>
        /// Generates the Verticies needed.
        /// </summary>
        /// <param name="vh">vertex helper</param>
        void GenerateSimpleSprite(VertexHelper vh){

            Vector4 v = GetDrawingDimensions(false);
            Vector4 uv = overrideSprite != null ? DataUtility.GetOuterUV(overrideSprite) : Vector4.zero;

            var color32 = color;
            vh.Clear();
            //对radius的值做限制，必须在0-较小的边的1/2的范围内
            float radius = Radius;
            if (radius > (v.z - v.x) / 2) radius = (v.z - v.x) / 2;
            if (radius > (v.w - v.y) / 2) radius = (v.w - v.y) / 2;
            if (radius < 0) radius = 0;
            //计算出uv中对应的半径值坐标轴的半径
            float uvRadiusX = radius / (v.z - v.x);
            float uvRadiusY = radius / (v.w - v.y);

                //0，1
                vh.AddVert(new Vector3(v.x, v.w - radius), color32, new Vector2(uv.x, uv.w - uvRadiusY));
                vh.AddVert(new Vector3(v.x, v.y + radius), color32, new Vector2(uv.x, uv.y + uvRadiusY));

                //2，3，4，5
                vh.AddVert(new Vector3(v.x + radius, v.w), color32, new Vector2(uv.x + uvRadiusX, uv.w));
                vh.AddVert(new Vector3(v.x + radius, v.w - radius), color32, new Vector2(uv.x + uvRadiusX, uv.w - uvRadiusY));
                vh.AddVert(new Vector3(v.x + radius, v.y + radius), color32, new Vector2(uv.x + uvRadiusX, uv.y + uvRadiusY));
                vh.AddVert(new Vector3(v.x + radius, v.y), color32, new Vector2(uv.x + uvRadiusX, uv.y));

                //6，7，8，9
                vh.AddVert(new Vector3(v.z - radius, v.w), color32, new Vector2(uv.z - uvRadiusX, uv.w));
                vh.AddVert(new Vector3(v.z - radius, v.w - radius), color32, new Vector2(uv.z - uvRadiusX, uv.w - uvRadiusY));
                vh.AddVert(new Vector3(v.z - radius, v.y + radius), color32, new Vector2(uv.z - uvRadiusX, uv.y + uvRadiusY));
                vh.AddVert(new Vector3(v.z - radius, v.y), color32, new Vector2(uv.z - uvRadiusX, uv.y));

                //10，11
                vh.AddVert(new Vector3(v.z, v.w - radius), color32, new Vector2(uv.z, uv.w - uvRadiusY));
                vh.AddVert(new Vector3(v.z, v.y + radius), color32, new Vector2(uv.z, uv.y + uvRadiusY));

            //左边的矩形
            vh.AddTriangle(1, 0, 3);
            vh.AddTriangle(1, 4, 3);
            //中间的矩形
            vh.AddTriangle(5, 2, 6);
            vh.AddTriangle(5, 9, 6);
            //右边的矩形
            vh.AddTriangle(8, 7, 10);
            vh.AddTriangle(8, 11, 10);

            //开始构造四个角
            List<Vector2> vCenterList = new List<Vector2>();
            List<Vector2> uvCenterList = new List<Vector2>();
            List<int> vCenterVertList = new List<int>();

            //右上角的圆心
            vCenterList.Add(new Vector2(v.z - radius, v.w - radius));
            uvCenterList.Add(new Vector2(uv.z - uvRadiusX, uv.w - uvRadiusY));
            vCenterVertList.Add(7);

            //左上角的圆心
            vCenterList.Add(new Vector2(v.x + radius, v.w - radius));
            uvCenterList.Add(new Vector2(uv.x + uvRadiusX, uv.w - uvRadiusY));
            vCenterVertList.Add(3);

            //左下角的圆心
            vCenterList.Add(new Vector2(v.x + radius, v.y + radius));
            uvCenterList.Add(new Vector2(uv.x + uvRadiusX, uv.y + uvRadiusY));
            vCenterVertList.Add(4);

            //右下角的圆心
            vCenterList.Add(new Vector2(v.z - radius, v.y + radius));
            uvCenterList.Add(new Vector2(uv.z - uvRadiusX, uv.y + uvRadiusY));
            vCenterVertList.Add(8);

            //每个三角形的顶角
            float degreeDelta = (float)(Mathf.PI / 2 / TriangleNum);
            //当前的角度
            float curDegree = 0;

            for (int i = 0; i < vCenterVertList.Count; i++)
            {
                int preVertNum = vh.currentVertCount;
                for (int j = 0; j <= TriangleNum; j++)
                {
                    float cosA = Mathf.Cos(curDegree);
                    float sinA = Mathf.Sin(curDegree);
                    Vector3 vPosition = new Vector3(vCenterList[i].x + cosA * radius, vCenterList[i].y + sinA * radius);
                    Vector3 uvPosition = new Vector2(uvCenterList[i].x + cosA * uvRadiusX, uvCenterList[i].y + sinA * uvRadiusY);
                    vh.AddVert(vPosition, color32, uvPosition);
                    curDegree += degreeDelta;
                }
                curDegree -= degreeDelta;
                for (int j = 0; j <= TriangleNum - 1; j++)
                {
                    vh.AddTriangle(vCenterVertList[i], preVertNum + j + 1, preVertNum + j);
                }
            }
        }
        /// <summary>
        /// Sets the material values of shader.
        /// Implementation of IMaterialModifier
        /// </summary>
        public override Material GetModifiedMaterial (Material baseMaterial){
            return base.GetModifiedMaterial(baseMaterial);
            Rect rect = this.GetComponent<RectTransform> ().rect;
			//get world-space corners of rect
			Vector3[] corners = new Vector3[4];
			rectTransform.GetWorldCorners (corners);
			float pixelSize = Vector3.Distance (corners [1], corners [2]) / rect.width;
			pixelSize = pixelSize/falloffDistance;

			Vector4 radius = FixRadius (Modifier.CalculateRadius (rect));
			Material m = MaterialHelper.SetMaterialValues (new ProceduralImageMaterialInfo(rect.width+falloffDistance,rect.height+falloffDistance,1,radius,Mathf.Max(borderWidth,0)),baseMaterial);
			return base.GetModifiedMaterial (m);
		}
	}
}