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


/// <summary>
/// UGUI描边
/// </summary>
public class OutlineEx : BaseMeshEffect
{
    [Header("新shader描边")]
    public Color OutlineColor = new Color(0, 0, 0, 0.5f);// Color.black;

    QualityTextColType m_ColorType = QualityTextColType.None;
    public QualityTextColType colorType
    {
        get { return m_ColorType; }
        set
        {
            if (m_ColorType != value)
            {
                m_ColorType = value;
                OutlineColor = UIHelper.GetUIOutlineColor(value);
                this._Refresh();
            }
        }
    }


    [Range(0, 30)]
    //默认10，不同的颜色（包括调整alpha）视觉上描边粗细有差异，故shader里乘以0.2适应不同情况
    public int OutlineWidth = 10;    

    private static List<UIVertex> m_VetexList = new List<UIVertex>();
    // 材质池：Key为"颜色_宽度"格式的字符串，Value为对应的材质; 减少合批问题，又能保持不同的描边；共用材质会同时改变参数
    private static Dictionary<string, Material> m_MaterialPool = new Dictionary<string, Material>();

    static Shader m_tmpShader;
    private static Shader m_Shader
    {
        get
        {
            if (m_tmpShader == null)
            {
                m_tmpShader = Shader.Find("TSF Shaders/UI/OutlineEx");
            }
            return m_tmpShader;
        }
    }

    protected override void Start()
    {
        base.Start();

        // 使用材质池获取或创建材质
        string key = GetMaterialKey(OutlineColor, OutlineWidth);
        if (!m_MaterialPool.TryGetValue(key, out Material material))
        {
            material = new Material(m_Shader);
            material.SetColor("_OutlineColor", this.OutlineColor);
            material.SetInt("_OutlineWidth", this.OutlineWidth);
            m_MaterialPool[key] = material;
        }
        base.graphic.material = material;

        var v1 = base.graphic.canvas.additionalShaderChannels;
        var v2 = AdditionalCanvasShaderChannels.TexCoord1;
        if ((v1 & v2) != v2)
        {
            base.graphic.canvas.additionalShaderChannels |= v2;
        }
        v2 = AdditionalCanvasShaderChannels.TexCoord2;
        if ((v1 & v2) != v2)
        {
            base.graphic.canvas.additionalShaderChannels |= v2;
        }

        this._Refresh();
    }

#if UNITY_EDITOR
    //在编辑器下打开也刷新下
    // protected override void OnEnable()
    // {
    //     base.OnEnable();
    //     this._Refresh();
    // }

    protected override void OnValidate()
    {
        base.OnValidate();

        if (base.graphic.material != null)
        {
            this._Refresh();
        }
    }
#endif


    private void _Refresh()
    {
        // 检查当前材质是否与所需属性匹配，如果不匹配则从池中获取或创建新材质
        string key = GetMaterialKey(OutlineColor, OutlineWidth);
        Material material;
        if (!m_MaterialPool.TryGetValue(key, out material))
        {
            // 如果池中没有对应的材质，创建新材质
            var shader = Shader.Find("TSF Shaders/UI/OutlineEx");
            material = new Material(shader);
            m_MaterialPool[key] = material;
        }

        if (material == null)
        {
            // 防范材质被删的情况，创建新材质
            material = new Material(m_Shader);
            m_MaterialPool[key] = material;
        }

        material.SetColor("_OutlineColor", this.OutlineColor);
        material.SetInt("_OutlineWidth", this.OutlineWidth);
        
        // 更新图形材质
        base.graphic.material = material;
        base.graphic.SetVerticesDirty();
    }


    public override void ModifyMesh(VertexHelper vh)
    {
        vh.GetUIVertexStream(m_VetexList);

        this._ProcessVertices();

        vh.Clear();
        vh.AddUIVertexTriangleStream(m_VetexList);
    }


    private void _ProcessVertices()
    {
        for (int i = 0, count = m_VetexList.Count - 3; i <= count; i += 3)
        {
            var v1 = m_VetexList[i];
            var v2 = m_VetexList[i + 1];
            var v3 = m_VetexList[i + 2];
            // 计算原顶点坐标中心点
            //
            var minX = _Min(v1.position.x, v2.position.x, v3.position.x);
            var minY = _Min(v1.position.y, v2.position.y, v3.position.y);
            var maxX = _Max(v1.position.x, v2.position.x, v3.position.x);
            var maxY = _Max(v1.position.y, v2.position.y, v3.position.y);
            var posCenter = new Vector2(minX + maxX, minY + maxY) * 0.5f;
            // 计算原始顶点坐标和UV的方向
            //
            Vector2 triX, triY, uvX, uvY;
            Vector2 pos1 = v1.position;
            Vector2 pos2 = v2.position;
            Vector2 pos3 = v3.position;
            if (Mathf.Abs(Vector2.Dot((pos2 - pos1).normalized, Vector2.right))
                > Mathf.Abs(Vector2.Dot((pos3 - pos2).normalized, Vector2.right)))
            {
                triX = pos2 - pos1;
                triY = pos3 - pos2;
                uvX = v2.uv0 - v1.uv0;
                uvY = v3.uv0 - v2.uv0;
            }
            else
            {
                triX = pos3 - pos2;
                triY = pos2 - pos1;
                uvX = v3.uv0 - v2.uv0;
                uvY = v2.uv0 - v1.uv0;
            }
            // 计算原始UV框
            //
            var uvMin = _Min(v1.uv0, v2.uv0, v3.uv0);
            var uvMax = _Max(v1.uv0, v2.uv0, v3.uv0);
            var uvOrigin = new Vector4(uvMin.x, uvMin.y, uvMax.x, uvMax.y);
            // 为每个顶点设置新的Position和UV，并传入原始UV框
            //
            v1 = _SetNewPosAndUV(v1, this.OutlineWidth, posCenter, triX, triY, uvX, uvY, uvOrigin);
            v2 = _SetNewPosAndUV(v2, this.OutlineWidth, posCenter, triX, triY, uvX, uvY, uvOrigin);
            v3 = _SetNewPosAndUV(v3, this.OutlineWidth, posCenter, triX, triY, uvX, uvY, uvOrigin);
            // 应用设置后的UIVertex
            //
            m_VetexList[i] = v1;
            m_VetexList[i + 1] = v2;
            m_VetexList[i + 2] = v3;
        }
    }


    private static UIVertex _SetNewPosAndUV(UIVertex pVertex, int pOutLineWidth,
        Vector2 pPosCenter,
        Vector2 pTriangleX, Vector2 pTriangleY,
        Vector2 pUVX, Vector2 pUVY,
        Vector4 pUVOrigin)
    {
        // Position
        var pos = pVertex.position;
        var posXOffset = pos.x > pPosCenter.x ? pOutLineWidth : -pOutLineWidth;
        var posYOffset = pos.y > pPosCenter.y ? pOutLineWidth : -pOutLineWidth;
        pos.x += posXOffset;
        pos.y += posYOffset;
        pVertex.position = pos;
        // UV
        var uv = pVertex.uv0;
        uv += new Vector4((pUVX / pTriangleX.magnitude * posXOffset * (Vector2.Dot(pTriangleX, Vector2.right) > 0 ? 1 : -1)).x, (pUVX / pTriangleX.magnitude * posXOffset * (Vector2.Dot(pTriangleX, Vector2.right) > 0 ? 1 : -1)).y, 0, 0);
        uv += new Vector4((pUVY / pTriangleY.magnitude * posYOffset * (Vector2.Dot(pTriangleY, Vector2.up) > 0 ? 1 : -1)).x, (pUVY / pTriangleY.magnitude * posYOffset * (Vector2.Dot(pTriangleY, Vector2.up) > 0 ? 1 : -1)).y, 0, 0);
        pVertex.uv0 = uv;
        // 原始UV框
        pVertex.uv1 = new Vector2(pUVOrigin.x, pUVOrigin.y);
        pVertex.uv2 = new Vector2(pUVOrigin.z, pUVOrigin.w);

        return pVertex;
    }


    private static float _Min(float pA, float pB, float pC)
    {
        return Mathf.Min(Mathf.Min(pA, pB), pC);
    }


    private static float _Max(float pA, float pB, float pC)
    {
        return Mathf.Max(Mathf.Max(pA, pB), pC);
    }


    private static Vector2 _Min(Vector2 pA, Vector2 pB, Vector2 pC)
    {
        return new Vector2(_Min(pA.x, pB.x, pC.x), _Min(pA.y, pB.y, pC.y));
    }


    private static Vector2 _Max(Vector2 pA, Vector2 pB, Vector2 pC)
    {
        return new Vector2(_Max(pA.x, pB.x, pC.x), _Max(pA.y, pB.y, pC.y));
    }


    // 生成材质池的键
    private string GetMaterialKey(Color color, int width)
    {
        // 使用颜色的RGBA值和宽度生成唯一键
        return string.Format("{0}_{1}_{2}_{3}_{4}", 
            color.r, color.g, color.b, color.a, width);
    }
}