#!/usr/bin/env python3
"""
Maritime Compliance Module — Sanctions, AIS Anomaly, Dark Fleet Detection

Extracted from marinetraffic_parser.py for modularity.
All functions are self-contained with no dependencies on routing/ports/scraping.
"""

import logging
from datetime import datetime
from typing import Dict

logger = logging.getLogger('maritime_compliance')


# =============================================================================
# SANCTIONED FLAGS & ENTITIES
# =============================================================================

# Sanctioned flag states (OFAC, EU, UN — as of 2025-2026)
SANCTIONED_FLAGS = {
    'north korea': {'level': 'critical', 'lists': ['OFAC SDN', 'UN', 'EU'], 'code': 'KP'},
    'dprk': {'level': 'critical', 'lists': ['OFAC SDN', 'UN', 'EU'], 'code': 'KP'},
    'iran': {'level': 'critical', 'lists': ['OFAC SDN', 'EU'], 'code': 'IR'},
    'syria': {'level': 'critical', 'lists': ['OFAC SDN', 'EU'], 'code': 'SY'},
    'cuba': {'level': 'high', 'lists': ['OFAC SDN'], 'code': 'CU'},
    'crimea': {'level': 'high', 'lists': ['OFAC', 'EU'], 'code': '-'},
    'russia': {'level': 'elevated', 'lists': ['OFAC sectoral', 'EU partial'], 'code': 'RU'},
    'venezuela': {'level': 'elevated', 'lists': ['OFAC sectoral'], 'code': 'VE'},
    'myanmar': {'level': 'elevated', 'lists': ['OFAC targeted', 'EU targeted'], 'code': 'MM'},
    'belarus': {'level': 'elevated', 'lists': ['OFAC', 'EU'], 'code': 'BY'},
}

# High-risk company keywords (sanctioned entities)
SANCTIONED_ENTITIES = [
    'irisl', 'national iranian', 'cosco dalian', 'cosco shipping (dalian)',
    'ocean mighty', 'glory wealth', 'dark fleet', 'patriot',
    'korea ocean shipping', 'pyongyang', 'korea kumgang',
    'syria petroleum', 'sytrol',
    'rosneft trading', 'sovcomflot',  # Partial sanctions
    'pdvsa', 'petroleos de venezuela',
]

# Dark fleet indicators
DARK_FLEET_INDICATORS = [
    'ais_gaps',      # Frequent AIS switch-off
    'flag_changes',  # Multiple flag changes in short period
    'sts_transfers', # Ship-to-ship transfers in suspicious areas
    'age_25plus',    # Vessel age > 25 years (tankers)
    'unknown_owner', # Opaque ownership structure
]


# =============================================================================
# STS TRANSFER HOTSPOTS
# =============================================================================

# High-risk STS transfer zones
STS_HOTSPOTS = {
    'south_laconia_greece': {'lat_range': (36, 37), 'lon_range': (22, 24)},
    'off_ceuta': {'lat_range': (35, 36), 'lon_range': (-6, -5)},
    'malacca_strait': {'lat_range': (1, 4), 'lon_range': (101, 104)},
    'off_lomé_togo': {'lat_range': (5, 7), 'lon_range': (0, 2)},
    'east_malaysia': {'lat_range': (4, 7), 'lon_range': (110, 115)},
}


# =============================================================================
# HELPER FUNCTIONS
# =============================================================================

def _max_risk(current: str, new: str) -> str:
    """Return the higher of two risk levels."""
    levels = ['clear', 'low', 'elevated', 'high', 'critical']
    return new if levels.index(new) > levels.index(current) else current


# =============================================================================
# SANCTIONS & COMPLIANCE SCREENER
# =============================================================================

def screen_sanctions(vessel_name: str = None, imo: str = None, flag: str = None,
                     companies: list = None, vessel_type: str = None,
                     year_built: int = None) -> Dict:
    """
    Screen vessel/company against sanctions lists.
    Returns risk assessment with level, flags, and recommendations.
    """
    risks = []
    risk_level = 'clear'  # clear → low → elevated → high → critical

    # 1. Flag screening
    if flag:
        flag_lower = flag.lower().strip()
        for sanctioned, info in SANCTIONED_FLAGS.items():
            if sanctioned in flag_lower or info['code'].lower() == flag_lower:
                risks.append({
                    'type': 'sanctioned_flag',
                    'severity': info['level'],
                    'detail': f"Flag state '{flag}' is on {', '.join(info['lists'])} sanctions lists",
                    'lists': info['lists'],
                })
                risk_level = _max_risk(risk_level, info['level'])

    # 2. Company screening
    if companies:
        for company in companies:
            c_name = ''
            if isinstance(company, dict):
                c_name = (company.get('name', '') or '').lower()
            elif isinstance(company, str):
                c_name = company.lower()

            for entity in SANCTIONED_ENTITIES:
                if entity in c_name:
                    risks.append({
                        'type': 'sanctioned_entity',
                        'severity': 'high',
                        'detail': f"Company '{c_name}' matches sanctioned entity pattern '{entity}'",
                    })
                    risk_level = _max_risk(risk_level, 'high')
                    break

    # 3. Dark fleet indicators
    dark_fleet_flags = []
    if vessel_type and vessel_type.lower() in ('tanker', 'oil tanker', 'crude oil tanker'):
        if year_built:
            try:
                age = 2026 - int(year_built)
                if age >= 25:
                    dark_fleet_flags.append('age_25plus')
                    risks.append({
                        'type': 'dark_fleet_indicator',
                        'severity': 'elevated',
                        'detail': f"Vessel is {age} years old — common in dark/shadow fleet operations",
                    })
                    risk_level = _max_risk(risk_level, 'elevated')
                elif age >= 20:
                    dark_fleet_flags.append('aging_vessel')
                    risks.append({
                        'type': 'dark_fleet_indicator',
                        'severity': 'low',
                        'detail': f"Vessel is {age} years old — monitor for fleet age concerns",
                    })
            except (ValueError, TypeError):
                pass

    # 4. Name-based heuristics (common in sanctioned fleets)
    if vessel_name:
        vn = vessel_name.lower()
        # Frequent name changes (vessels with very generic names)
        generic_names = ['glory', 'success', 'fortune', 'lucky', 'star', 'ocean', 'sea', 'diamond', 'golden']
        generic_count = sum(1 for g in generic_names if g in vn)
        if generic_count >= 2:
            risks.append({
                'type': 'name_pattern',
                'severity': 'low',
                'detail': 'Vessel name contains multiple generic keywords — common in dark fleet renaming patterns',
            })

    # Build result
    result = {
        'vessel_name': vessel_name,
        'imo': imo,
        'flag': flag,
        'risk_level': risk_level,
        'risk_count': len(risks),
        'risks': risks,
        'screened_against': ['OFAC SDN', 'OFAC Sectoral', 'EU Consolidated', 'UN Security Council'],
    }

    if risk_level == 'clear':
        result['recommendation'] = 'No sanctions flags detected. Standard due diligence applies.'
    elif risk_level == 'low':
        result['recommendation'] = 'Minor flags noted. Proceed with enhanced due diligence.'
    elif risk_level == 'elevated':
        result['recommendation'] = 'Elevated risk. Obtain legal counsel before proceeding. Check latest OFAC/EU advisories.'
    elif risk_level == 'high':
        result['recommendation'] = 'HIGH RISK — sanctioned entity match. Do NOT proceed without legal clearance. Report to compliance.'
    elif risk_level == 'critical':
        result['recommendation'] = 'CRITICAL — vessel/entity appears on primary sanctions lists. DO NOT ENGAGE. Report to compliance officer immediately.'

    return result


# =============================================================================
# AIS ANOMALY DETECTOR
# =============================================================================

def detect_ais_anomalies(vessel_name: str = None, imo: str = None,
                          mmsi: str = None, flag: str = None,
                          vessel_type: str = None, year_built: int = None,
                          last_known_lat: float = None, last_known_lon: float = None,
                          ais_gap_hours: float = None) -> Dict:
    """Detect AIS behavioral anomalies for compliance screening."""
    anomalies = []
    risk_score = 0  # 0-100

    # 1. AIS gap detection
    if ais_gap_hours and ais_gap_hours > 12:
        severity = 'critical' if ais_gap_hours > 72 else 'high' if ais_gap_hours > 48 else 'elevated' if ais_gap_hours > 24 else 'moderate'
        risk_score += min(30, int(ais_gap_hours / 2))
        anomalies.append({
            'type': 'ais_gap',
            'severity': severity,
            'detail': f"AIS signal gap of {ais_gap_hours:.0f} hours detected",
            'implication': 'Possible intentional AIS switch-off — common indicator of sanctions evasion or illicit STS transfer',
        })

    # 2. Location in STS hotspot
    if last_known_lat is not None and last_known_lon is not None:
        for zone_name, zone in STS_HOTSPOTS.items():
            lat_min, lat_max = zone['lat_range']
            lon_min, lon_max = zone['lon_range']
            if lat_min <= last_known_lat <= lat_max and lon_min <= last_known_lon <= lon_max:
                risk_score += 20
                anomalies.append({
                    'type': 'sts_hotspot',
                    'severity': 'high',
                    'detail': f"Vessel located in known STS transfer zone: {zone_name.replace('_', ' ').title()}",
                    'implication': 'Ship-to-ship transfers in this area are flagged for potential sanctions evasion',
                })

    # 3. Flag risk
    if flag:
        flag_lower = flag.lower()
        for sanctioned, info in SANCTIONED_FLAGS.items():
            if sanctioned in flag_lower:
                risk_score += 15
                anomalies.append({
                    'type': 'flag_risk',
                    'severity': info['level'],
                    'detail': f"Flag state '{flag}' on {', '.join(info['lists'])} lists",
                    'implication': 'Enhanced due diligence required for all commercial engagements',
                })
                break

    # 4. Vessel age risk (for tankers especially)
    if year_built and vessel_type:
        age = datetime.now().year - year_built
        vtype = vessel_type.lower()
        if 'tanker' in vtype and age > 20:
            risk_score += 10
            anomalies.append({
                'type': 'aged_tanker',
                'severity': 'elevated',
                'detail': f"Tanker vessel aged {age} years (built {year_built})",
                'implication': 'Aged tankers are commonly used in dark fleet operations. Check P&I coverage and ownership history.',
            })

    # 5. Spoofing indicators (if position seems wrong for vessel type)
    if last_known_lat is not None and last_known_lon is not None:
        if abs(last_known_lat) > 80:
            risk_score += 15
            anomalies.append({
                'type': 'position_anomaly',
                'severity': 'high',
                'detail': f"Position reported in extreme latitude ({last_known_lat:.1f}\u00b0)",
                'implication': 'Possible AIS spoofing or GPS manipulation',
            })

    # Determine overall risk level
    if risk_score >= 60:
        risk_level = 'critical'
    elif risk_score >= 40:
        risk_level = 'high'
    elif risk_score >= 20:
        risk_level = 'elevated'
    elif risk_score > 0:
        risk_level = 'low'
    else:
        risk_level = 'clear'

    recommendations = []
    if risk_level in ('critical', 'high'):
        recommendations.extend([
            'Do NOT engage commercially without enhanced due diligence',
            'Verify vessel ownership chain and beneficial owner',
            'Check P&I club status and insurance coverage',
            'Request recent port state control inspection reports',
            'Monitor for further AIS anomalies over next 7 days',
        ])
    elif risk_level == 'elevated':
        recommendations.extend([
            'Enhanced monitoring recommended',
            'Verify P&I and H&M insurance status',
            'Request vessel particulars and ownership documentation',
        ])
    else:
        recommendations.append('No significant anomalies detected — standard monitoring sufficient')

    return {
        'vessel': vessel_name or 'Unknown',
        'imo': imo or '',
        'mmsi': mmsi or '',
        'flag': flag or '',
        'risk_score': risk_score,
        'risk_level': risk_level,
        'anomalies_found': len(anomalies),
        'anomalies': anomalies,
        'recommendations': recommendations,
        'screened_against': [
            'AIS gap detection (>12h threshold)',
            'STS transfer hotspot zones (5 regions)',
            'Sanctions flag screening (OFAC/EU/UN)',
            'Dark fleet age profiling',
            'Position anomaly / spoofing detection',
        ],
        'note': 'AIS anomaly assessment based on available data points. For real-time monitoring, integrate with live AIS feed (Spire, Kpler, MarineTraffic).',
    }


# =============================================================================
# DARK FLEET DETECTOR
# =============================================================================

def detect_dark_fleet(vessel_name: str = None, imo: str = None,
                      flag: str = None, year_built: int = None,
                      owner: str = None, vessel_type: str = None,
                      dwt: float = None, previous_flags: list = None,
                      p_and_i_club: str = None, ais_gaps_30d: int = None) -> Dict:
    """Screen vessel for dark/shadow fleet indicators."""
    indicators = []
    score = 0  # 0-100

    vtype = (vessel_type or '').lower()
    age = (datetime.now().year - year_built) if year_built else 0

    # 1. Vessel age (critical for tankers)
    if age > 25 and 'tanker' in vtype:
        score += 20
        indicators.append({
            'indicator': 'Aged tanker (>25 years)',
            'severity': 'high',
            'detail': f"Built {year_built}, age {age} years. Tankers >20 years are predominant in dark fleet.",
            'weight': 20,
        })
    elif age > 20 and 'tanker' in vtype:
        score += 12
        indicators.append({
            'indicator': 'Aging tanker (>20 years)',
            'severity': 'elevated',
            'detail': f"Built {year_built}, age {age} years. Approaching dark fleet age profile.",
            'weight': 12,
        })
    elif age > 15:
        score += 5
        indicators.append({
            'indicator': 'Older vessel',
            'severity': 'low',
            'detail': f"Built {year_built}, age {age} years.",
            'weight': 5,
        })

    # 2. Flag state risk
    if flag:
        flag_lower = flag.lower()
        for sanctioned, info in SANCTIONED_FLAGS.items():
            if sanctioned in flag_lower:
                weight = {'critical': 25, 'high': 20, 'elevated': 10}.get(info['level'], 5)
                score += weight
                indicators.append({
                    'indicator': f"Sanctioned flag state ({flag})",
                    'severity': info['level'],
                    'detail': f"On {', '.join(info['lists'])} lists. Dark fleet commonly uses sanctioned or FOC flags.",
                    'weight': weight,
                })
                break
        else:
            # Flags of Convenience (FOC) commonly used by dark fleet
            foc_flags = ['cameroon', 'palau', 'gabon', 'togo', 'tanzania', 'comoros', 'equatorial guinea', 'sao tome']
            if flag_lower in foc_flags:
                score += 15
                indicators.append({
                    'indicator': f"High-risk Flag of Convenience ({flag})",
                    'severity': 'elevated',
                    'detail': 'Flag commonly associated with dark fleet operations and limited regulatory oversight.',
                    'weight': 15,
                })

    # 3. Flag changes
    if previous_flags and len(previous_flags) >= 3:
        score += 15
        indicators.append({
            'indicator': f"Multiple flag changes ({len(previous_flags)} flags)",
            'severity': 'high',
            'detail': f"Previous flags: {', '.join(previous_flags)}. Frequent flag-hopping is a dark fleet indicator.",
            'weight': 15,
        })

    # 4. P&I club status
    if p_and_i_club:
        reputable_clubs = ['gard', 'britannia', 'standard', 'steamship mutual', 'north', 'skuld',
                           'swedish', 'west of england', 'japan', 'london', 'american', 'shipowners', 'uk p&i']
        if not any(club in p_and_i_club.lower() for club in reputable_clubs):
            score += 15
            indicators.append({
                'indicator': f"Non-IG P&I club ({p_and_i_club})",
                'severity': 'elevated',
                'detail': 'Not a member of International Group of P&I Clubs. Dark fleet vessels often lack reputable P&I coverage.',
                'weight': 15,
            })
    else:
        score += 10
        indicators.append({
            'indicator': 'P&I club status unknown',
            'severity': 'moderate',
            'detail': 'Unable to verify P&I coverage. Vessels without proper insurance are high risk.',
            'weight': 10,
        })

    # 5. Ownership opacity
    if owner:
        owner_lower = owner.lower()
        suspicious_keywords = ['single purpose', 'one ship', 'special purpose', 'unknown', 'nominee']
        if any(kw in owner_lower for kw in suspicious_keywords):
            score += 15
            indicators.append({
                'indicator': 'Opaque ownership structure',
                'severity': 'high',
                'detail': f"Owner '{owner}' suggests single-purpose entity — common dark fleet structure to limit liability.",
                'weight': 15,
            })
        # Check sanctioned entities
        for entity in SANCTIONED_ENTITIES:
            if entity in owner_lower:
                score += 25
                indicators.append({
                    'indicator': f"Owner matches sanctioned entity",
                    'severity': 'critical',
                    'detail': f"Owner '{owner}' matches known sanctioned entity pattern.",
                    'weight': 25,
                })
                break

    # 6. AIS behavior
    if ais_gaps_30d and ais_gaps_30d > 5:
        score += 15
        indicators.append({
            'indicator': f"Frequent AIS gaps ({ais_gaps_30d} in 30 days)",
            'severity': 'high',
            'detail': 'Frequent AIS switch-offs are primary indicator of sanctions-evading dark fleet operations.',
            'weight': 15,
        })

    # Overall assessment
    score = min(100, score)
    if score >= 70:
        risk_level = 'critical'
        classification = 'HIGH PROBABILITY dark fleet vessel'
    elif score >= 50:
        risk_level = 'high'
        classification = 'LIKELY dark fleet / shadow fleet vessel'
    elif score >= 30:
        risk_level = 'elevated'
        classification = 'POSSIBLE dark fleet — enhanced due diligence required'
    elif score >= 10:
        risk_level = 'low'
        classification = 'LOW risk — minor indicators present'
    else:
        risk_level = 'clear'
        classification = 'No dark fleet indicators detected'

    compliance = {
        'can_engage': risk_level in ('clear', 'low'),
        'requires_due_diligence': risk_level in ('elevated',),
        'do_not_engage': risk_level in ('high', 'critical'),
    }

    return {
        'vessel': vessel_name or 'Unknown',
        'imo': imo or '',
        'vessel_type': vtype or 'unknown',
        'dwt': dwt,
        'flag': flag or 'Unknown',
        'year_built': year_built,
        'age_years': age,
        'dark_fleet_score': score,
        'risk_level': risk_level,
        'classification': classification,
        'indicators_found': len(indicators),
        'indicators': indicators,
        'compliance_status': compliance,
        'screened_against': [
            'Vessel age profiling (>20yr tankers)',
            'OFAC/EU/UN sanctions flag screening',
            'Flag-hopping detection',
            'P&I club verification (IG membership)',
            'Beneficial ownership opacity check',
            'Sanctioned entity matching',
            'AIS behavior analysis',
        ],
        'recommendation': (
            'DO NOT ENGAGE — vessel shows multiple dark fleet indicators. Report to compliance team.'
            if risk_level in ('critical', 'high') else
            'ENHANCED DUE DILIGENCE required before engagement. Verify ownership, insurance, and recent trading history.'
            if risk_level == 'elevated' else
            'Standard due diligence sufficient. Monitor for changes.'
        ),
        'note': 'Dark fleet screening based on publicly available indicators. For comprehensive screening, cross-reference with Windward, Kpler, or IHS Markit databases.',
    }