using System;

namespace Models;

/// <summary>
/// 状态值 (StatusValue)
/// 维护当前状态值以及上限和下限阈值。
/// </summary>
public class StatusValue
{
    private PropertyValue _current;
    private PropertyValue _upperThreshold;
    private PropertyValue _lowerThreshold;

    /// <summary>
    /// 当 Current >= UpperThreshold 时触发此事件
    /// </summary>
    public event Action OnUpperThresholdReached;

    /// <summary>
    /// 当 Current <= LowerThreshold 时触发此事件
    /// </summary>
    public event Action OnLowerThresholdReached;

    /// <summary>
    /// 当前状态值
    /// 修改时会自动检测阈值。
    /// </summary>
    public PropertyValue Current
    {
        get => _current;
        set
        {
            _current = value;
            CheckThresholds();
        }
    }

    /// <summary>
    /// 上限阈值
    /// </summary>
    public PropertyValue UpperThreshold
    {
        get => _upperThreshold;
        set
        {
            _upperThreshold = value;
            CheckThresholds();
        }
    }

    /// <summary>
    /// 下限阈值
    /// </summary>
    public PropertyValue LowerThreshold
    {
        get => _lowerThreshold;
        set
        {
            _lowerThreshold = value;
            CheckThresholds();
        }
    }

    public StatusValue(int current = 0, int upper = 100, int lower = 0)
    {
        _current = new PropertyValue(current);
        _upperThreshold = new PropertyValue(upper);
        _lowerThreshold = new PropertyValue(lower);
    }
    
    public StatusValue(PropertyValue current, PropertyValue upper, PropertyValue lower)
    {
        _current = current ?? new PropertyValue(0);
        _upperThreshold = upper ?? new PropertyValue(100);
        _lowerThreshold = lower ?? new PropertyValue(0);
    }

    private void CheckThresholds()
    {
        if ((int)_current >= (int)_upperThreshold)
        {
            OnUpperThresholdReached?.Invoke();
        }

        if ((int)_current <= (int)_lowerThreshold)
        {
            OnLowerThresholdReached?.Invoke();
        }
    }

    public void Add(int value)
    {
        Current += value; // 触发 setter -> CheckThresholds
    }
    
    public void Subtract(int value)
    {
        Current -= value; // 触发 setter -> CheckThresholds
    }
}