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

[AddComponentMenu("UI/Effects/HorizontalColorGradual")]
public class HorizontalColorGradual:BaseMeshEffect {

    [SerializeField]
    private Color32 m_LeftColor = Color.white;
    public Color32 leftColor {
        get {
            return m_LeftColor;
        }
        set {
            m_LeftColor = value;
            this.graphic.SetVerticesDirty();
        }
    }

    [SerializeField]
    private Color32 m_RightColor = Color.black;
    public Color32 rightColor {
        get {
            return m_RightColor;
        }
        set {
            m_RightColor = value;
            this.graphic.SetVerticesDirty();
        }
    }

    [Range(-1,1)]
    [SerializeField]
    private float m_Center = 0f;
    public float center {
        get {
            return m_Center;
        }
        set {
            m_Center = value;
            this.graphic.SetVerticesDirty();
        }
    }

    public override void ModifyMesh(VertexHelper vh) {
        var vertexList = new List<UIVertex>();
        vh.GetUIVertexStream(vertexList);

        int count = vertexList.Count;
        if(count > 0) {
            var rightX = vertexList[0].position.y;
            var leftX = vertexList[0].position.y;

            for(int i = 1;i < count;i++) {
                var x = vertexList[i].position[0];
                if(x < leftX) {
                    leftX = x;
                }
                else if(x > rightX) {
                    rightX = x;
                }
            }

            var width = rightX - leftX;
            for(int i = 0;i < count;i++) {
                var vertex = vertexList[i];
                vertex.color = Color32.Lerp(leftColor,rightColor,Mathf.Clamp01((vertex.position[0] - (leftX + width * center)) / width));
                vertexList[i] = vertex;
            }
        }

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



}