using Games.Events;
using Games.Scene;
using UnityEngine;

/// <summary>
/// 设置当前场景方向光到全局参数上
/// </summary>
// 注：因为美术效果很多时候阴影方向和镜面反射所需光线方向冲突，因此修改组件为可自由旋转
// 注：现在这个工具也用于处理平行光动态阴影开关
public class DirectionalLightSetter : MonoBehaviour
{
    private const string _dirPropertyName = "_DirectionalLight";
    // 镜面反射单独使用一个方向
    private const string _specularPropertyName = "_SpecularLight";
    private const string _colorPropertyName = "_DirectionalLightColor";
    private const string _attenPropertyName = "_DirectionalLightAtten";
    // 欧拉角度表示的镜面反射方向
    public Quaternion specularRotation = Quaternion.identity;

    private Light _lightComponent;

    private void Start()
    {
        _lightComponent = GetComponent<Light>();
        PlayerPreferenceData.SystemQualityDymShadow.onSettingUpdate += OnDynamicShadowToggle;
        OnDynamicShadowToggle(PlayerPreferenceData.SystemQualityDymShadow);
        EventDispatcher.Instance.Add(Games.Events.EventId.PostMainCameraMove, OnCameraMove);
        SetLight();
    }

    private void OnDestroy()
    {
        if (!GameManager.applicationQuit)
        {
            PlayerPreferenceData.SystemQualityDymShadow.onSettingUpdate -= OnDynamicShadowToggle;
            EventDispatcher.Instance.Remove(Games.Events.EventId.PostMainCameraMove, OnCameraMove);
        }
    }

    private void OnDynamicShadowToggle(bool isOn)
    {
        _lightComponent.enabled = isOn;
    }

    public void SetLight(Light light)
    {
        Shader.SetGlobalVector(_dirPropertyName, transform.rotation * Vector3.back);
        Shader.SetGlobalColor(_colorPropertyName, light.color);
        Shader.SetGlobalFloat(_attenPropertyName, light.intensity);
        Shader.SetGlobalVector(_specularPropertyName, specularRotation * Vector3.back);
    }

    public void SetLight()
    {
        SetLight(_lightComponent);
    }

    private float? _baseYaw;
    private float _lastYaw;
    private void OnCameraMove(object args)
    {
        if (_baseYaw == null)
        {
            _lastYaw = SceneLogic.CameraController.Yaw;
            _baseYaw = _lastYaw;
        }
        else if (_lastYaw != SceneLogic.CameraController.Yaw)
        {
            var yaw = SceneLogic.CameraController.Yaw;
            var deltaYaw = yaw - _baseYaw.Value;
            _lastYaw = yaw;
            var rotation = Quaternion.Euler(0f, deltaYaw, 0f) * specularRotation;
            Shader.SetGlobalVector(_specularPropertyName, rotation * Vector3.back);
        }
    }
}