using UnityEngine;
// using UniTask;

namespace BrewMonster.Scripts
{
    public class CECSunMoon : MonoSingleton<CECSunMoon>
    {
        private const float TIME_SCALE = 6f;
        private const float NIGHT_DAY_START = (3.0f / 24.0f);
        private const float NIGHT_DAY_END = (7.0f / 24.0f);
        private const float DAY_NIGHT_START = (18.0f / 24.0f);
        private const float DAY_NIGHT_END = (21.0f / 24.0f);

        public double m_vTimeOfTheDay;		// time of the day 0.0f means 00:00, 1.0f means 24:00 (4h-cycle phase, matches C++ CECSunMoon)
        public double m_vRealPhase;			// 真实服务器时间对应的24h相位（用于 nightControl shader）// real 24h phase from server time, used for nightControl shader (not the 4h-wrapped cycle)
        public float m_fDNFactor;			// day or night factor
        public float m_fDNFactorDest;		// day or night factor dest

        [SerializeField] GlobalShaderVariableSetting _globalShaderVariables;

        protected override void Initialize()
        {
            base.Initialize();

            // keep this alive when scene is loaded
            DontDestroyOnLoad(gameObject);
            RefreshDayNightFactorsFromPhase();
        }

        public void Update()
        {
            double advance = Time.deltaTime / 3600.0 / 24.0;
            // 4h cycle — same as C++ Tick(): drives sun/moon visual animation
            m_vTimeOfTheDay += advance * TIME_SCALE;
            while (m_vTimeOfTheDay > 1.0)
                m_vTimeOfTheDay -= 1.0;
            // 24h real-time phase — used for nightControl shader (not TIME_SCALE-sped-up)
            m_vRealPhase += advance;
            while (m_vRealPhase > 1.0)
                m_vRealPhase -= 1.0;
            RefreshDayNightFactorsFromPhase();
        }

        public float GetTimeOfTheDay() => (float)m_vTimeOfTheDay;
        public float GetDNFactor() => m_fDNFactor;
        public float GetDNFactorDest() => m_fDNFactorDest;

        /// <summary>
        /// 设置一天中的时刻（与 PC 版 CECSunMoon::SetTimeOfTheDay 对齐） // Set time-of-day phase [0,1), aligned with PC CECSunMoon::SetTimeOfTheDay
        /// 仅设置4h动画相位；用 SetTimeOfTheDayFull 同时设置真实24h相位 // Sets 4h animation phase only; use SetTimeOfTheDayFull to also set the real 24h phase
        /// </summary>
        public bool SetTimeOfTheDay(float vTime)
        {
            while (vTime < 0f)
                vTime += 1f;
            while (vTime > 1f)
                vTime -= 1f;
            m_vTimeOfTheDay = vTime;
            RefreshDayNightFactorsFromPhase();
            return true;
        }

        /// <summary>
        /// 同时设置4h动画相位（C++公式）和24h真实相位（shader nightControl用） // Set both the 4h animation phase (C++ formula) and the real 24h phase (for shader nightControl)
        /// </summary>
        /// <param name="phase4h">nTimeInDay / (4f*3600f) — wrap to [0,1), drives sun/moon animation</param>
        /// <param name="phase24h">nTimeInDay / (24f*3600f) — [0,1), drives nightControl shader (0=day 1=night based on real server time)</param>
        public bool SetTimeOfTheDayFull(float phase4h, float phase24h)
        {
            while (phase4h < 0f) phase4h += 1f;
            while (phase4h > 1f) phase4h -= 1f;
            m_vTimeOfTheDay = phase4h;

            phase24h = Mathf.Clamp01(phase24h);
            m_vRealPhase = phase24h;

            RefreshDayNightFactorsFromPhase();
            return true;
        }

        /// <summary>
        /// PC EC_SunMoon::UpdateWithTime 中昼夜因子段（供 minimap 与场景一致） // DN factor block from PC EC_SunMoon::UpdateWithTime
        /// m_fDNFactor 由4h相位驱动（与C++一致，用于太阳/月亮视觉）; nightControl 由24h真实相位驱动（shader正确反映服务器白天/黑夜）
        /// m_fDNFactor is driven by the 4h phase (C++ compatible, for sun/moon visuals); nightControl is driven by the real 24h phase (shader correctly reflects server day/night)
        /// </summary>
        void RefreshDayNightFactorsFromPhase()
        {
            float v = (float)m_vTimeOfTheDay;

            // m_fDNFactor — 4h cycle phase, same as C++ EC_SunMoon::UpdateWithTime lines 894-918
            if (v < NIGHT_DAY_START)
            {
                m_fDNFactor = 1.0f;
                m_fDNFactorDest = 1.0f;
            }
            else if (v < NIGHT_DAY_END)
            {
                m_fDNFactor = 1.0f - (v - NIGHT_DAY_START) / (NIGHT_DAY_END - NIGHT_DAY_START);
                m_fDNFactorDest = 0.0f;
            }
            else if (m_vTimeOfTheDay < DAY_NIGHT_START)
            {
                // PC 使用 m_vTimeOfTheDay 与 DAY_NIGHT_START 比较 // PC compares m_vTimeOfTheDay to DAY_NIGHT_START (see EC_SunMoon.cpp)
                m_fDNFactor = 0.0f;
                m_fDNFactorDest = 0.0f;
            }
            else if (v < DAY_NIGHT_END)
            {
                m_fDNFactor = (v - DAY_NIGHT_START) / (DAY_NIGHT_END - DAY_NIGHT_START);
                m_fDNFactorDest = 1.0f;
            }
            else
            {
                m_fDNFactor = 1.0f;
                m_fDNFactorDest = 1.0f;
            }

            // nightControl shader — driven by m_vRealPhase (24h real server time, 0=day 1=night)
            // 用真实24h相位计算 nightControl，确保正午=白天(0)，午夜=黑夜(1)，不受4h周期wrap影响
            // Real 24h phase ensures noon=day(0), midnight=night(1), unaffected by 4h cycle wrapping
            _globalShaderVariables?.Apply(ComputeNightControlFromRealPhase((float)m_vRealPhase));
        }

        /// <summary>
        /// 用24h真实相位计算 nightControl（与相同阈值，但基于实际服务器时间） // Compute nightControl from real 24h phase using same thresholds
        /// </summary>
        static float ComputeNightControlFromRealPhase(float r)
        {
            if (r < NIGHT_DAY_START)      return 1.0f;
            if (r < NIGHT_DAY_END)        return 1.0f - (r - NIGHT_DAY_START) / (NIGHT_DAY_END - NIGHT_DAY_START);
            if (r < DAY_NIGHT_START)      return 0.0f;
            if (r < DAY_NIGHT_END)        return (r - DAY_NIGHT_START) / (DAY_NIGHT_END - DAY_NIGHT_START);
            return 1.0f;
        }
    }
}