using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DyeingComputer.UserClass
{
    /// <summary>
    /// 加注曲线类型
    /// </summary>
    public enum DosingCurveType
    {
        Linear,      // 线性曲线
        Parabolic,   // 抛物线曲线（开始快，后来慢）
        Exponential  // 指数曲线（开始慢，后来快）
    }

    /// <summary>
    /// 液体加注PID控制器
    /// </summary>
    public class LiquidDosingController
    {
        private DateTime _startTime;
        private DateTime _lastUpdateTime;
        private double _lastLevel;
        private bool _isDosingActive;

        // PID控制器参数
        private double _proportionalGain;
        private double _integralGain;
        private double _derivativeGain;
        private double _integralTerm;
        private double _lastError;

        /// <summary>
        /// 当前比例阀开度 (0-100%)
        /// </summary>
        public double CurrentValveOpening { get; private set; }

        /// <summary>
        /// 目标完成时间 (秒)
        /// </summary>
        public double TargetTime { get; set; }

        /// <summary>
        /// 加注曲线类型
        /// </summary>
        public DosingCurveType CurveType { get; set; }

        /// <summary>
        /// 容器最大容量
        /// </summary>
        public double MaxCapacity { get; set; }

        /// <summary>
        /// 当前液位
        /// </summary>
        public double CurrentLevel { get; private set; }

        /// <summary>
        /// 已加注体积
        /// </summary>
        public double DosedVolume { get; private set; }

        /// <summary>
        /// 液体加注事件
        /// </summary>
        public event Action<double> OnDosingUpdate;

        /// <summary>
        /// 初始化液体加注控制器
        /// </summary>
        /// <param name="targetTime">目标加注时间(秒)</param>
        /// <param name="maxCapacity">容器最大容量</param>
        /// <param name="curveType">加注曲线类型</param>
        /// <param name="kP">比例增益</param>
        /// <param name="kI">积分增益</param>
        /// <param name="kD">微分增益</param>
        public LiquidDosingController(double targetTime, double maxCapacity,
                                    DosingCurveType curveType = DosingCurveType.Linear,
                                    double kP = 1.0, double kI = 0.1, double kD = 0.01)
        {
            TargetTime = targetTime;
            MaxCapacity = maxCapacity;
            CurveType = curveType;

            _proportionalGain = kP;
            _integralGain = kI;
            _derivativeGain = kD;

            _isDosingActive = false;
            CurrentValveOpening = 0;
        }

        /// <summary>
        /// 开始加注过程
        /// </summary>
        /// <param name="initialLevel">初始液位</param>
        public void StartDosing(double initialLevel)
        {
            if (_isDosingActive) return;

            _lastLevel = initialLevel;
            CurrentLevel = initialLevel;
            DosedVolume = 0;
            _integralTerm = 0;
            _lastError = 0;
            CurrentValveOpening = 0;

            _startTime = DateTime.Now;
            _lastUpdateTime = _startTime;

            _isDosingActive = true;

            OnDosingUpdate?.Invoke(CurrentValveOpening);
        }

        /// <summary>
        /// 停止加注过程
        /// </summary>
        public void StopDosing()
        {
            _isDosingActive = false;
            CurrentValveOpening = 0;
            OnDosingUpdate?.Invoke(0);
        }

        /// <summary>
        /// 更新当前液位并计算新的阀门开度
        /// </summary>
        /// <param name="currentLevel">当前液位</param>
        /// <returns>新的阀门开度</returns>
        public double UpdateLevel(double currentLevel)
        {
            if (!_isDosingActive) return 0;

            // 获取当前时间
            DateTime currentTime = DateTime.Now;

            // 计算时间间隔
            double timeInterval = (currentTime - _lastUpdateTime).TotalSeconds;

            // 如果时间间隔太小，避免计算过于频繁
            if (timeInterval < 0.1) return CurrentValveOpening;

            // 更新液位
            CurrentLevel = currentLevel;

            // 计算这段时间内的液体减少量
            double volumeDosedInInterval = _lastLevel - currentLevel;
            DosedVolume += volumeDosedInInterval;
            _lastLevel = currentLevel;

            // 计算已用时间和剩余时间
            double elapsedTime = (currentTime - _startTime).TotalSeconds;
            double remainingTime = TargetTime - elapsedTime;

            // 如果已超过目标时间，完全关闭阀门
            if (remainingTime <= 0)
            {
                StopDosing();
                return 0;
            }

            // 计算期望的加注速率（基于所选曲线类型）
            double desiredDosingRate = CalculateDesiredDosingRate(elapsedTime, remainingTime);

            // 计算实际加注速率（升/秒）
            double actualDosingRate = volumeDosedInInterval / timeInterval;

            // 计算误差（期望速率与实际速率之差）
            double error = desiredDosingRate - actualDosingRate;

            // PID计算
            double proportionalTerm = _proportionalGain * error;

            _integralTerm += _integralGain * error * timeInterval;
            // 积分项抗饱和
            _integralTerm = Math.Max(Math.Min(_integralTerm, 100), 0);

            double derivativeTerm = _derivativeGain * (error - _lastError) / timeInterval;
            _lastError = error;

            // 计算新的阀门开度
            double newValveOpening = CurrentValveOpening + proportionalTerm + _integralTerm + derivativeTerm;

            // 限制阀门开度在0-100%范围内
            newValveOpening = Math.Max(Math.Min(newValveOpening, 100), 0);

            CurrentValveOpening = newValveOpening;

            // 更新最后更新时间
            _lastUpdateTime = currentTime;

            // 触发更新事件
            OnDosingUpdate?.Invoke(CurrentValveOpening);

            // 检查是否已完成加注
            if (CurrentLevel <= 0)
            {
                StopDosing();
            }

            return CurrentValveOpening;
        }

        /// <summary>
        /// 根据曲线类型计算期望的加注速率
        /// </summary>
        private double CalculateDesiredDosingRate(double elapsedTime, double remainingTime)
        {
            double remainingVolume = CurrentLevel;

            // 确保不会除零
            if (remainingTime <= 0) return 0;

            double progress = elapsedTime / TargetTime;

            switch (CurveType)
            {
                case DosingCurveType.Linear:
                    // 线性：恒定速率
                    return remainingVolume / remainingTime;

                case DosingCurveType.Parabolic:
                    // 抛物线：开始快，后来慢
                    // 使用二次函数减少速率
                    double parabolicFactor = 1.0 - Math.Pow(progress, 2);
                    return (remainingVolume / remainingTime) * parabolicFactor;

                case DosingCurveType.Exponential:
                    // 指数：开始慢，后来快
                    // 使用指数函数增加速率
                    double exponentialFactor = Math.Exp(progress) / Math.Exp(1);
                    return (remainingVolume / remainingTime) * exponentialFactor;

                default:
                    return remainingVolume / remainingTime;
            }
        }

        /// <summary>
        /// 设置PID参数
        /// </summary>
        public void SetPIDParameters(double kP, double kI, double kD)
        {
            _proportionalGain = kP;
            _integralGain = kI;
            _derivativeGain = kD;

            // 重置积分项和误差
            _integralTerm = 0;
            _lastError = 0;
        }

        /// <summary>
        /// 检查加注是否正在进行中
        /// </summary>
        public bool IsDosingActive => _isDosingActive;
    }
}