"""
GB 44721-2026 L3 接管流程模拟
国家标准要求的接管能力监测实现框架

关键时间节点：
- T-10s: 系统评估场景，决定需要接管
- T-7s: 发出接管请求（视觉+听觉+触觉）
- T-7s ~ T-0: 持续监测接管能力
- T-0: 接管超时，执行最小风险策略
"""

import numpy as np
from dataclasses import dataclass
from typing import Optional

@dataclass
class TakeoverRequest:
    """接管请求"""
    timestamp: float  # 发起时间（秒）
    reason: str       # 接管原因
    urgency: str      # 'normal' / 'urgent' / 'emergency'
    visual_alert: bool = True
    audio_alert: bool = True
    haptic_alert: bool = True

@dataclass
class DriverReadiness:
    """驾驶员就绪度评估"""
    timestamp: float
    eyes_on_road: bool
    gaze_forward: bool
    head_upright: bool
    hands_on_wheel: bool
    alertness_score: float  # 0-1
    readiness_score: float  # 0-1

class GB44721TakeoverMonitor:
    """
    GB 44721-2026 接管能力监测器
    
    标准要求：
    1. 持续监测驾驶员状态
    2. 评估接管能力
    3. 发出接管请求
    4. 超时执行最小风险策略
    
    技术实现：
    - PERCLOS 疲劳检测
    - 视线方向检测
    - 头部姿态检测
    - 手部位置检测
    - 综合就绪度评分
    """
    
    # 接管能力评估阈值
    READINESS_THRESHOLDS = {
        'ready': 0.80,       # 就绪
        'marginal': 0.50,    # 临界
        'not_ready': 0.0,    # 未就绪
    }
    
    # 接管超时（秒）
    TAKEOVER_TIMEOUT_NORMAL = 10.0
    TAKEOVER_TIMEOUT_URGENT = 5.0
    TAKEOVER_TIMEOUT_EMERGENCY = 3.0
    
    def __init__(self):
        self.driver_state_history = []
        self.takeover_request: Optional[TakeoverRequest] = None
        self.minimal_risk_triggered = False
        
    def assess_readiness(self, dms_data: dict) -> DriverReadiness:
        """
        评估驾驶员接管就绪度
        
        Args:
            dms_data: DMS 传感器数据
                - eye_openness: 0-1
                - gaze_direction: (x, y) degrees
                - head_pitch: degrees
                - hands_on_wheel: bool
                - perclos: %
                - reaction_time: seconds (如果可测)
        
        Returns:
            readiness: 就绪度评估
        """
        # 1. 眼睛状态
        eyes_open = dms_data.get('eye_openness', 0) > 0.3
        eyes_on_road = eyes_open and dms_data.get('gaze_direction', (0,0))[1] < 15
        
        # 2. 视线方向
        gaze_x, gaze_y = dms_data.get('gaze_direction', (0, 0))
        gaze_forward = abs(gaze_x) < 20 and abs(gaze_y) < 15
        
        # 3. 头部姿态
        head_pitch = dms_data.get('head_pitch', 0)
        head_upright = -15 < head_pitch < 15
        
        # 4. 手部位置
        hands_on_wheel = dms_data.get('hands_on_wheel', False)
        
        # 5. 警觉性评分
        perclos = dms_data.get('perclos', 0)
        alertness = max(0, 1.0 - perclos / 20.0)  # PERCLOS 20% = 0分
        
        # 6. 综合就绪度
        weights = {
            'eyes': 0.25,
            'gaze': 0.25,
            'head': 0.15,
            'hands': 0.15,
            'alertness': 0.20,
        }
        
        scores = {
            'eyes': 1.0 if eyes_on_road else 0.0,
            'gaze': 1.0 if gaze_forward else 0.3,
            'head': 1.0 if head_upright else 0.3,
            'hands': 1.0 if hands_on_wheel else 0.5,
            'alertness': alertness,
        }
        
        readiness_score = sum(scores[k] * weights[k] for k in weights)
        
        return DriverReadiness(
            timestamp=dms_data.get('timestamp', 0),
            eyes_on_road=eyes_on_road,
            gaze_forward=gaze_forward,
            head_upright=head_upright,
            hands_on_wheel=hands_on_wheel,
            alertness_score=alertness,
            readiness_score=readiness_score,
        )
    
    def monitor_takeover(self, readiness: DriverReadiness,
                          takeover_request: TakeoverRequest,
                          current_time: float) -> dict:
        """
        监测接管过程
        
        Returns:
            status: 接管状态和建议动作
        """
        elapsed = current_time - takeover_request.timestamp
        
        # 超时阈值
        timeout = {
            'normal': self.TAKEOVER_TIMEOUT_NORMAL,
            'urgent': self.TAKEOVER_TIMEOUT_URGENT,
            'emergency': self.TAKEOVER_TIMEOUT_EMERGENCY,
        }.get(takeover_request.urgency, 10.0)
        
        # 评估状态
        if readiness.readiness_score >= self.READINESS_THRESHOLDS['ready']:
            status = 'takeover_complete'
            action = '移交控制权'
            confidence = readiness.readiness_score
            
        elif readiness.readiness_score >= self.READINESS_THRESHOLDS['marginal']:
            if elapsed < timeout:
                status = 'monitoring'
                action = '继续监测+加强提醒'
                confidence = readiness.readiness_score
            else:
                status = 'timeout_warning'
                action = '即将超时+加强警告'
                confidence = 0.5
            
        else:
            if elapsed < timeout:
                status = 'not_ready'
                action = '加强唤醒+升级警告'
                confidence = 0.3
            else:
                status = 'minimal_risk'
                action = '执行最小风险策略（靠边停车）'
                confidence = 0.0
                self.minimal_risk_triggered = True
        
        return {
            'status': status,
            'action': action,
            'elapsed_sec': elapsed,
            'timeout_sec': timeout,
            'remaining_sec': max(0, timeout - elapsed),
            'readiness_score': readiness.readiness_score,
            'confidence': confidence,
        }


# ==================== 测试 ====================
if __name__ == "__main__":
    np.random.seed(42)
    monitor = GB44721TakeoverMonitor()
    
    print("=== GB 44721-2026 接管能力监测器 ===")
    print(f"就绪阈值: {monitor.READINESS_THRESHOLDS}")
    print(f"超时时间: 正常={monitor.TAKEOVER_TIMEOUT_NORMAL}s, "
          f"紧急={monitor.TAKEOVER_TIMEOUT_EMERGENCY}s")
    
    # 场景1：驾驶员快速接管（理想）
    print("\n--- 场景1：理想接管 ---")
    request = TakeoverRequest(
        timestamp=0, reason='前方施工', urgency='normal'
    )
    
    # 模拟驾驶员响应
    for t in [1, 3, 5, 7]:
        dms = {
            'timestamp': t,
            'eye_openness': 0.9,
            'gaze_direction': (5, 10),
            'head_pitch': 5,
            'hands_on_wheel': True,
            'perclos': 5,
        }
        readiness = monitor.assess_readiness(dms)
        status = monitor.monitor_takeover(readiness, request, t)
        print(f"  T+{t}s: 就绪度={readiness.readiness_score:.2f}, "
              f"状态={status['status']}, 建议={status['action']}")
    
    # 场景2：驾驶员未接管（疲劳）
    print("\n--- 场景2：疲劳驾驶员未接管 ---")
    monitor2 = GB44721TakeoverMonitor()
    request2 = TakeoverRequest(
        timestamp=0, reason='前方事故', urgency='urgent'
    )
    
    for t in [1, 3, 5, 7]:
        dms = {
            'timestamp': t,
            'eye_openness': 0.2,  # 闭眼
            'gaze_direction': (30, 20),  # 偏离
            'head_pitch': 25,  # 低头
            'hands_on_wheel': False,
            'perclos': 35,  # 高 PERCLOS
        }
        readiness = monitor2.assess_readiness(dms)
        status = monitor2.monitor_takeover(readiness, request2, t)
        print(f"  T+{t}s: 就绪度={readiness.readiness_score:.2f}, "
              f"状态={status['status']}, 建议={status['action']}, "
              f"剩余={status['remaining_sec']:.1f}s")
    
    print(f"\n  最小风险策略触发: {monitor2.minimal_risk_triggered}")
    
    # 合规清单
    print("\n=== GB 44721-2026 合规清单 ===")
    checklist = [
        ('驾驶人接管能力监测', 'L3必须', '2027.07前实现'),
        ('接管请求系统', '视觉+听觉+触觉', '2027.07前实现'),
        ('最小风险策略', '超时自动执行', '2027.07前实现'),
        ('系统状态显示', 'HUD/仪表显示', '2027.07前实现'),
        ('数据记录功能', 'DSS存储', '2027.07前实现'),
        ('功能安全认证', 'ASIL B/D', '型式批准前'),
        ('测试验证数据', '接管场景测试', '型式批准前'),
    ]
    
    for item, req, deadline in checklist:
        print(f"  [ ] {item}: {req} ({deadline})")
    
    # 时间线
    print("\n=== 实施时间线 ===")
    timeline = [
        ('2026.08', 'GB 44721-2026 发布'),
        ('2026.09-2027.06', '开发&验证期（10个月）'),
        ('2027.07.01', '新车型式批准执行'),
        ('2027.07-2028.06', '已批准车型缓冲期'),
        ('2028.07.01', '全面覆盖所有车型'),
    ]
    
    for date, event in timeline:
        print(f"  {date}: {event}")