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

namespace TyphoonUI
{
    public class RhombusProgress : Image
    {
        [Range(0, 1)] [SerializeField] private float m_Progress = 1.0f;

        [Range(0, 90f)] [SerializeField] private float m_Angle = 30f;

        private static List<int> indices = new List<int>() { 0, 1, 2, 2, 3, 0 };

        private List<UIVertex> _rendererVertex = new List<UIVertex>() { default, default, default, default };


        public float angle
        {
            get { return m_Angle; }
            set
            {
                if (m_Angle == value)
                {
                    return;
                }

                m_Angle = value;
                SetVerticesDirty();
            }
        }

        public float progress
        {
            get { return m_Progress; }
            set
            {
                if (m_Progress == value)
                {
                    return;
                }

                m_Progress = value;
                SetVerticesDirty();
            }
        }

        protected List<UIVertex> _vertices = new List<UIVertex>();


        protected override void OnPopulateMesh(VertexHelper toFill)
        {
            base.OnPopulateMesh(toFill);
            if (overrideSprite == null)
            {
                base.OnPopulateMesh(toFill);
                return;
            }

            if (type == Type.Simple)
            {
                //读取当前顶点
                toFill.GetUIVertexStream(_vertices);
                var rect = rectTransform.rect;
                var width = rect.width;
                var height = rect.height;
                var offset = Mathf.Tan(Mathf.Deg2Rad * m_Angle) * height;
                var process = Mathf.InverseLerp(0, width, offset);
                var v1 = _vertices[0];
                var v2 = _vertices[1];
                var v3 = _vertices[2];
                var v4 = _vertices[4];
                var vert1 = v1;
                var vert2 = SampleVertex(v2, v3, process);
                var vert3 = v3;
                var vert4 = SampleVertex(v4, v1, process);
                var finalVert3 = SampleVertex(vert2, vert3, m_Progress);
                var finalVert4 = SampleVertex(vert1, vert4, m_Progress);
                _rendererVertex[0] = vert1;
                _rendererVertex[1] = vert2;
                _rendererVertex[2] = finalVert3;
                _rendererVertex[3] = finalVert4;
                toFill.Clear();
                toFill.AddUIVertexStream(_rendererVertex, indices);
            }
        }

        private UIVertex SampleVertex(UIVertex start, UIVertex end, float process)
        {
            return new UIVertex()
            {
                position = Vector3.Lerp(start.position, end.position, process),
                color = Color.Lerp(start.color, end.color, process),
                uv0 = Vector4.Lerp(start.uv0, end.uv0, process),
            };
        }
    }
}