class CabinAirQualityMonitor:
    """
    座舱空气质量监测系统
    
    基于 Garmin Unified Cabin 的空气质量集成理念
    CO2 浓度直接影响驾驶员警觉性
    """
    
    # CO2 浓度与警觉性关系
    CO2_THRESHOLDS = {
        'excellent': (400, 600, '空气清新，警觉性最佳'),
        'good': (600, 800, '空气良好，警觉性正常'),
        'moderate': (800, 1000, '空气一般，建议通风'),
        'poor': (1000, 1500, 'CO2偏高，警觉性可能下降'),
        'bad': (1500, 2500, 'CO2过高，困倦风险增加'),
        'dangerous': (2500, float('inf'), '严重超标，立即通风'),
    }
    
    def __init__(self):
        self.co2_history = []
        self.temp_history = []
        self.humidity_history = []
        self.recirculation_mode = False
        self.recirculation_duration = 0  # 分钟
    
    def update(self, co2_ppm: float, temp_c: float, 
               humidity_pct: float, is_recirc: bool):
        """更新传感器读数"""
        self.co2_history.append(co2_ppm)
        self.temp_history.append(temp_c)
        self.humidity_history.append(humidity_pct)
        
        if is_recirc:
            self.recirculation_duration += 1
        else:
            self.recirculation_duration = 0
        
        self.recirculation_mode = is_recirc
    
    def assess_alertness_risk(self) -> dict:
        """评估CO2对驾驶员警觉性的影响"""
        if not self.co2_history:
            return {'risk': 'unknown'}
        
        current_co2 = self.co2_history[-1]
        
        # 确定等级
        for level, (low, high, desc) in self.CO2_THRESHOLDS.items():
            if low <= current_co2 < high:
                risk_level = level
                description = desc
                break
        else:
            risk_level = 'dangerous'
            description = '严重超标'
        
        # 内循环风险
        recirc_risk = 'high' if self.recirculation_duration > 30 else \
                      'moderate' if self.recirculation_duration > 15 else 'low'
        
        # 趋势分析
        if len(self.co2_history) >= 5:
            recent = self.co2_history[-5:]
            trend = 'rising' if recent[-1] > recent[0] + 50 else \
                    'falling' if recent[-1] < recent[0] - 50 else 'stable'
        else:
            trend = 'unknown'
        
        # 建议动作
        if current_co2 > 1000:
            action = '切换外循环+开窗通风'
        elif current_co2 > 800 and self.recirculation_duration > 15:
            action = '建议切换外循环'
        else:
            action = '保持当前状态'
        
        return {
            'co2_ppm': current_co2,
            'risk_level': risk_level,
            'description': description,
            'recirculation_risk': recirc_risk,
            'recirculation_duration_min': self.recirculation_duration,
            'trend': trend,
            'recommendation': action,
        }


# 测试
if __name__ == "__main__":
    monitor = CabinAirQualityMonitor()
    
    print("=== 模拟长途驾驶 CO2 变化 ===")
    
    # 场景1: 外循环
    print("\n--- 外循环模式 ---")
    for minute in range(10):
        co2 = 500 + minute * 2  # 缓慢上升
        monitor.update(co2, 22, 45, is_recirc=False)
    
    result = monitor.assess_alertness_risk()
    print(f"CO2: {result['co2_ppm']} ppm ({result['risk_level']})")
    print(f"建议: {result['recommendation']}")
    
    # 场景2: 切换内循环
    print("\n--- 切换内循环 ---")
    for minute in range(40):
        co2 = 520 + minute * 40  # 快速上升
        monitor.update(co2, 23, 47, is_recirc=True)
    
    result = monitor.assess_alertness_risk()
    print(f"CO2: {result['co2_ppm']} ppm ({result['risk_level']})")
    print(f"内循环时长: {result['recirculation_duration_min']} 分钟")
    print(f"趋势: {result['trend']}")
    print(f"建议: {result['recommendation']}")
    
    # 场景3: 危险水平
    print("\n--- 长时间内循环（CO2达危险水平）---")
    for minute in range(30):
        co2 = 2120 + minute * 30
        monitor.update(co2, 24, 50, is_recirc=True)
    
    result = monitor.assess_alertness_risk()
    print(f"CO2: {result['co2_ppm']} ppm ({result['risk_level']})")
    print(f"描述: {result['description']}")
    print(f"建议: {result['recommendation']}")