#if UNITY_EDITOR
using UnityEditor;
#endif
using UnityEngine;

[ExecuteInEditMode]
public class DayNightAnimator : MonoBehaviour
{
    const float SUNSET_BEGIN = 0.1f;
    const float SUNSET_END = 0.4f;
    const float SUNRISE_BEGIN = 0.6f;
    const float SUNRISE_END = 0.9f;
    const float LIGHT_BEGIN = 0.2f;
    const float LIGHT_END = 0.7f;

    private Light light0 = null;

    void Awake()
    {
        if (light0 == null)
        {
            light0 = GetComponent<Light>();
        }
    }

    void OnValidate()
    {
        Awake();
    }

    private void Update()
    {
        float time = Mathf.Repeat(Time.fixedTime / 5f, 1f);
        if (SUNSET_BEGIN < time && time < SUNSET_END) // 夕焼けタイム
        {
            float rate = (time - SUNSET_BEGIN) / (SUNSET_END - SUNSET_BEGIN);
            light0.color = new Color(1f, 0.3f, 0f, rate);
        }
        bool nightTex = LIGHT_BEGIN < time && time < LIGHT_END;
        Shader.SetGlobalFloat("_NightTexEnabled", nightTex ? 1f : 0f);
        if (SUNRISE_BEGIN < time && time < SUNRISE_END) // 夜明け前タイム
        {
            float rate = (time - SUNRISE_BEGIN) / (SUNRISE_END - SUNRISE_BEGIN);
            light0.color = new Color(0.2f, 0.6f, 1.0f, 1 - rate);
        }
    }
}