"""
DMS 分心类型细分：恢复性走神 vs 危险分心

核心思路：
- 恢复性走神：视线短暂偏离（<5s）+ 无手机操作 → 可能有益
- 危险分心：视线长期偏离（>5s）或手机操作 → 有害
"""

from dataclasses import dataclass
from typing import Optional
from enum import Enum

class MindWanderType(Enum):
    RECOVERING = "recovering"    # 恢复性走神（有益）
    DANGEROUS = "dangerous"      # 危险分心
    NEUTRAL = "neutral"          # 中性

@dataclass
class MindWanderAssessment:
    wander_type: MindWanderType
    gaze_off_duration: float      # 视线偏离时长
    phone_in_hand: bool          # 是否手持手机
    steering_stability: float     # 转向稳定性（0-1）
    recommendation: str          # DMS 建议

class AdaptiveDistractionDetector:
    """
    自适应分心检测器
    
    区分"恢复性走神"和"危险分心"：
    - 恢复性走神：短暂视线偏离 + 无手机操作 + 转向稳定 → 不警告
    - 危险分心：长时间偏离 或 手机操作 → 警告
    """
    
    def __init__(self):
        self.recovery_wander_threshold = 5.0  # 秒，恢复性走神上限
        self.phone_use_threshold = 3.5        # 秒，手机使用警告阈值
        self.stability_threshold = 0.7        # 转向稳定性阈值
    
    def assess(self, gaze_off_duration: float, phone_in_hand: bool,
               steering_stability: float) -> MindWanderAssessment:
        
        # 手机操作 → 危险
        if phone_in_hand and gaze_off_duration > self.phone_use_threshold:
            return MindWanderAssessment(
                wander_type=MindWanderType.DANGEROUS,
                gaze_off_duration=gaze_off_duration,
                phone_in_hand=phone_in_hand,
                steering_stability=steering_stability,
                recommendation="立即警告（手机操作+视线偏离）"
            )
        
        # 短暂走神 + 转向稳定 → 恢复性
        if gaze_off_duration < self.recovery_wander_threshold and \
           steering_stability > self.stability_threshold and \
           not phone_in_hand:
            return MindWanderAssessment(
                wander_type=MindWanderType.RECOVERING,
                gaze_off_duration=gaze_off_duration,
                phone_in_hand=phone_in_hand,
                steering_stability=steering_stability,
                recommendation="不警告（可能是恢复性走神）"
            )
        
        # 长时间偏离 → 危险
        if gaze_off_duration > self.phone_use_threshold:
            return MindWanderAssessment(
                wander_type=MindWanderType.DANGEROUS,
                gaze_off_duration=gaze_off_duration,
                phone_in_hand=phone_in_hand,
                steering_stability=steering_stability,
                recommendation="一级警告"
            )
        
        return MindWanderAssessment(
            wander_type=MindWanderType.NEUTRAL,
            gaze_off_duration=gaze_off_duration,
            phone_in_hand=phone_in_hand,
            steering_stability=steering_stability,
            recommendation="持续监测"
        )


# 测试
if __name__ == "__main__":
    detector = AdaptiveDistractionDetector()
    
    # 场景1：短暂看窗外3秒 + 转向稳定
    r1 = detector.assess(3.0, False, 0.85)
    print(f"短暂走神: {r1.wander_type.name} → {r1.recommendation}")
    
    # 场景2：手机操作4秒
    r2 = detector.assess(4.0, True, 0.6)
    print(f"手机操作: {r2.wander_type.name} → {r2.recommendation}")
    
    # 场景3：视线偏离6秒 + 无手机
    r3 = detector.assess(6.0, False, 0.75)
    print(f"长偏离: {r3.wander_type.name} → {r3.recommendation}")