import numpy as np
from typing import List, Tuple
from dataclasses import dataclass

@dataclass
class MaritimeTarget:
    """海上目标数据结构"""
    target_id: str
    distance: float        # 距离 (海里)
    bearing: float         # 方位角 (度)
    speed: float           # 速度 (节)
    course: float          # 航向 (度)
    is_ais: bool           # 是否AIS目标
    target_type: str       # 船舶/浮标/碍航物
    risk_level: int        # 风险等级 0-3


class OrcaAIBridgeMonitor:
    """
    Orca AI SeaPod 桥楼监控核心逻辑复现
    
    关键功能：
    1. 多传感器融合目标检测
    2. 碰撞风险评估（DCPA/TCPA）
    3. 非AIS目标识别与告警
    4. 值班员状态推断
    """
    
    def __init__(self, config: dict = None):
        config = config or {}
        self.dcpa_threshold = config.get('dcpa_threshold', 0.5)  # 最近会遇距离 (海里)
        self.tcpa_threshold = config.get('tcpa_threshold', 15)   # 到最近会遇点时间 (分钟)
        self.alert_history = []
        
    def assess_collision_risk(
        self,
        own_ship: Tuple[float, float, float, float],  # (lat, lon, speed, course)
        targets: List[MaritimeTarget]
    ) -> List[dict]:
        """
        碰撞风险评估
        
        基于 DCPA (Distance at Closest Point of Approach) 和 
        TCPA (Time to Closest Point of Approach) 计算
        
        Args:
            own_ship: 本船 (纬度, 经度, 速度, 航向)
            targets: 周围目标列表
            
        Returns:
            risk_assessments: 每个目标的风险评估
        """
        assessments = []
        
        for target in targets:
            # 计算 DCPA 和 TCPA
            dcpa, tcpa = self._calculate_cpa(own_ship, target)
            
            # 风险等级判定
            if dcpa < self.dcpa_threshold and tcpa < self.tcpa_threshold:
                risk_level = 3  # 高危
            elif dcpa < self.dcpa_threshold * 2 and tcpa < self.tcpa_threshold * 2:
                risk_level = 2  # 中危
            elif dcpa < self.dcpa_threshold * 3:
                risk_level = 1  # 低危
            else:
                risk_level = 0  # 安全
            
            # 非AIS目标加权
            risk_score = risk_level
            if not target.is_ais and risk_level > 0:
                risk_score += 1  # 非AIS目标更危险
                risk_score = min(risk_score, 3)
            
            assessments.append({
                'target_id': target.target_id,
                'dcpa': dcpa,
                'tcpa': tcpa,
                'risk_level': risk_score,
                'is_ais': target.is_ais,
                'alert': risk_score >= 2
            })
        
        return assessments
    
    def _calculate_cpa(
        self,
        own_ship: Tuple[float, float, float, float],
        target: MaritimeTarget
    ) -> Tuple[float, float]:
        """
        计算 CPA (Closest Point of Approach)
        
        简化版相对运动计算
        """
        # 本船速度分量
        own_speed = own_ship[2]
        own_course = np.radians(own_ship[3])
        own_vx = own_speed * np.sin(own_course)
        own_vy = own_speed * np.cos(own_course)
        
        # 目标船速度分量
        tgt_course = np.radians(target.course)
        tgt_vx = target.speed * np.sin(tgt_course)
        tgt_vy = target.speed * np.cos(tgt_course)
        
        # 相对速度
        rel_vx = tgt_vx - own_vx
        rel_vy = tgt_vy - own_vy
        rel_speed = np.sqrt(rel_vx**2 + rel_vy**2)
        
        if rel_speed < 0.01:
            return target.distance, float('inf')
        
        # DCPA = 目标距离 * sin(目标方位-相对运动方向)
        rel_bearing = np.radians(target.bearing)
        rel_course = np.arctan2(rel_vx, rel_vy)
        
        dcpa = abs(target.distance * np.sin(rel_bearing - rel_course))
        tcpa = target.distance * np.cos(rel_bearing - rel_course) / rel_speed
        
        # 转换为分钟
        tcpa = tcpa * 60 / rel_speed if rel_speed > 0 else float('inf')
        
        return dcpa, tcpa
    
    def detect_watchkeeping_failure(
        self,
        bridge_activity: List[dict],
        window_sec: int = 300
    ) -> dict:
        """
        值班缺失检测
        
        ShipIn FleetVision 的核心能力之一：
        检测桥楼是否无人值班
        
        Args:
            bridge_activity: 桥楼活动记录序列
            window_sec: 检测窗口（秒）
            
        Returns:
            result: 值班状态
        """
        recent = bridge_activity[-window_sec:]
        
        # 统计人员检测帧
        person_detected = sum(1 for a in recent if a.get('person_present', False))
        presence_ratio = person_detected / len(recent) if recent else 0
        
        if presence_ratio < 0.3:
            return {
                'status': 'UNATTENDED',
                'confidence': 1 - presence_ratio,
                'duration': len(recent),
                'alert_level': 3
            }
        elif presence_ratio < 0.6:
            return {
                'status': 'INTERMITTENT',
                'confidence': 0.7,
                'duration': len(recent),
                'alert_level': 2
            }
        else:
            return {
                'status': 'ATTENDED',
                'confidence': presence_ratio,
                'duration': len(recent),
                'alert_level': 0
            }


if __name__ == "__main__":
    monitor = OrcaAIBridgeMonitor()
    
    # 模拟本船：北纬35°, 东经122°, 速度12节, 航向045°
    own_ship = (35.0, 122.0, 12.0, 45.0)
    
    # 模拟目标
    targets = [
        MaritimeTarget("T1", 3.0, 30, 10, 60, True, "vessel", 1),
        MaritimeTarget("T2", 1.5, 15, 8, 200, False, "vessel", 2),  # 非AIS!
        MaritimeTarget("T3", 8.0, 90, 15, 270, True, "vessel", 0),
    ]
    
    # 风险评估
    assessments = monitor.assess_collision_risk(own_ship, targets)
    print("=== 碰撞风险评估 ===")
    for a in assessments:
        print(f"目标 {a['target_id']}: DCPA={a['dcpa']:.2f}nm, "
              f"TCPA={a['tcpa']:.1f}min, "
              f"风险={a['risk_level']}, AIS={a['is_ais']}, "
              f"告警={'是' if a['alert'] else '否'}")
    
    # 值班检测
    activity = [{'person_present': True} if i % 3 != 0 else {'person_present': False} 
                for i in range(300)]
    watch = monitor.detect_watchkeeping_failure(activity)
    print(f"\n=== 值班状态 ===")
    print(f"状态: {watch['status']}")
    print(f"置信度: {watch['confidence']:.2f}")
    print(f"告警等级: {watch['alert_level']}")