using Entitas;
using UnityEngine;
using Game;
using Vector3 = UnityEngine.Vector3;

// view 需要在update后 渲染前处理的
public class ViewLateSystem : IExecuteSystem, IInitializeSystem
{
    private IGroup<GameEntity> _entities;
    private static readonly int Flash = Shader.PropertyToID("_Flash");
    private static readonly int Color = Shader.PropertyToID("_Color");
    private static readonly int UV = Shader.PropertyToID("_UV");
    private static readonly int Direction = Shader.PropertyToID("_Direction");
    private static readonly int Intensity = Shader.PropertyToID("_Intensity");

    public void Initialize()
    {
        _entities = Util.GetGroup(GameMatcher.View);
    }

    public void Execute()
    {
        foreach (var entity in _entities)
        {
            UpdateUV(entity); //更新uv坐标
            if (Util.IsPause(entity))
            {
                continue;
            }

            UpdateFlash(entity); //更新闪白
            UpdateScale(entity); //更新缩放
        }
    }

    private static void UpdateUV(GameEntity entity)
    {
        var view = entity.view;
        if (view.SpriteRenderer == null)
        {
            return;
        }

        if (view.SpriteRenderer.sprite == null)
        {
            return;
        }

        var (xMin, yMin, xMax, yMax) = (1f, 1f, 0f, 0f);
        foreach (var uv in view.SpriteRenderer.sprite.uv)
        {
            xMin = Mathf.Min(xMin, uv.x);
            yMin = Mathf.Min(yMin, uv.y);
            xMax = Mathf.Max(xMax, uv.x);
            yMax = Mathf.Max(yMax, uv.y);
        }

        var (widthHalf, heightHalf) = ((xMax - xMin) / 2, (yMax - yMin) / 2);
        var (centerX, centerY) = (xMin + widthHalf, yMin + heightHalf);
        var param = new Vector4(centerX, centerY, widthHalf, heightHalf);
        view.Material.SetVector(UV, param);
    }

    private static void UpdateFlash(GameEntity entity)
    {
        var view = entity.view;
        if (view.FlashTimeLeft == 0)
        {
            return;
        }

        view.FlashTimeLeft -= Time.deltaTime;
        if (view.FlashTimeLeft < 0)
        {
            view.FlashTimeLeft = 0;
            view.FlashColor = UnityEngine.Color.white;
        }

        var flashRate = view.FlashTimeLeft / GameConst.FlashTerm;
        view.Material.SetFloat(Flash, flashRate);
        view.Material.SetColor(Color, view.FlashColor);
    }

    private static void UpdateScale(GameEntity entity)
    {
        var view = entity.view;
        if (view.ScaleTimeLeft == 0)
        {
            return;
        }

        view.ScaleTimeLeft -= Time.deltaTime;
        if (view.ScaleTimeLeft < 0)
        {
            view.ScaleTimeLeft = 0;
            view.ScaleDir = Vector3.zero;
        }

        var scaleRate = view.ScaleTimeLeft / GameConst.ScaleTerm;
        view.Material.SetVector(Direction, view.ScaleDir);
        view.Material.SetFloat(Intensity, scaleRate * view.ScaleRate);
    }
}