"""
Cloudflare DNS Intelligence

Advanced intelligence for Cloudflare DNS and domain management
providing intelligent DNS optimization, security, and performance recommendations.
"""

from typing import Dict, Any, List, Optional, Tuple
from datetime import datetime, timedelta
import json

from .cloudflare_intelligence_base import CloudflareIntelligenceBase
from .stateless_intelligence import (
    ResourceType, ResourceFingerprint, ChangeImpactAnalysis, 
    ResourceHealth, HealthStatus
)


class CloudflareDNSIntelligence(CloudflareIntelligenceBase):
    """
    Cloudflare DNS Intelligence Engine
    
    Provides intelligent DNS management including:
    - DNS record optimization and validation
    - Security configuration (DNSSEC, CAA records)
    - Performance optimization (TTL tuning, load balancing)
    - Global traffic management
    - SSL/TLS certificate management
    - WAF and security policy optimization
    """
    
    def __init__(self):
        super().__init__(ResourceType.DNS)
        
        # DNS-specific optimization rules
        self.dns_rules = {
            "ttl_recommendations": {
                "a_record": 300,        # 5 minutes for A records
                "aaaa_record": 300,     # 5 minutes for AAAA records
                "cname_record": 1800,   # 30 minutes for CNAME records
                "mx_record": 3600,      # 1 hour for MX records
                "txt_record": 3600,     # 1 hour for TXT records
                "srv_record": 1800      # 30 minutes for SRV records
            },
            "security_requirements": {
                "dnssec_required": True,
                "caa_records_required": True,
                "spf_required": True,
                "dkim_required": True,
                "dmarc_required": True
            },
            "performance_thresholds": {
                "dns_response_time": 0.050,    # 50ms DNS response time
                "query_success_rate": 0.999,   # 99.9% query success rate
                "global_coverage_zones": 5     # Minimum 5 global zones
            }
        }
    
    def _discover_existing_resources(self) -> Dict[str, Dict[str, Any]]:
        """Discover existing Cloudflare DNS zones and records"""
        
        # Mock implementation - in production would use Cloudflare API
        return {
            "example.com": {
                "zone_id": "zone-123456",
                "name": "example.com",
                "status": "active",
                "name_servers": [
                    "ns1.cloudflare.com",
                    "ns2.cloudflare.com"
                ],
                "plan": "pro",
                "account_id": "account-789",
                "created_on": "2024-01-01T00:00:00Z",
                "modified_on": "2024-03-01T12:00:00Z",
                "settings": {
                    "ssl": "full",
                    "security_level": "medium",
                    "cache_level": "aggressive",
                    "browser_cache_ttl": 14400,
                    "always_online": "on",
                    "development_mode": "off",
                    "ipv6": "on",
                    "websockets": "on",
                    "pseudo_ipv4": "off",
                    "ip_geolocation": "on",
                    "email_obfuscation": "on",
                    "server_side_exclude": "on",
                    "hotlink_protection": "off",
                    "security_header": {
                        "strict_transport_security": {
                            "enabled": True,
                            "max_age": 31536000,
                            "include_subdomains": True
                        }
                    },
                    "minify": {
                        "css": "on",
                        "html": "on",
                        "js": "on"
                    },
                    "dnssec": "active",
                    "cname_flattening": "flatten_at_root"
                },
                "dns_records": [
                    {
                        "id": "record-001",
                        "type": "A",
                        "name": "example.com",
                        "content": "203.0.113.1",
                        "ttl": 300,
                        "proxied": True,
                        "created_on": "2024-01-01T00:00:00Z",
                        "modified_on": "2024-02-01T00:00:00Z"
                    },
                    {
                        "id": "record-002",
                        "type": "A",
                        "name": "www.example.com",
                        "content": "203.0.113.1",
                        "ttl": 300,
                        "proxied": True,
                        "created_on": "2024-01-01T00:00:00Z",
                        "modified_on": "2024-02-01T00:00:00Z"
                    },
                    {
                        "id": "record-003",
                        "type": "CNAME",
                        "name": "api.example.com",
                        "content": "api-server.example.com",
                        "ttl": 1800,
                        "proxied": True,
                        "created_on": "2024-01-15T00:00:00Z",
                        "modified_on": "2024-02-15T00:00:00Z"
                    },
                    {
                        "id": "record-004",
                        "type": "MX",
                        "name": "example.com",
                        "content": "10 mail.example.com",
                        "ttl": 3600,
                        "proxied": False,
                        "created_on": "2024-01-01T00:00:00Z"
                    },
                    {
                        "id": "record-005",
                        "type": "TXT",
                        "name": "example.com",
                        "content": "v=spf1 include:_spf.google.com ~all",
                        "ttl": 3600,
                        "proxied": False,
                        "created_on": "2024-01-01T00:00:00Z"
                    },
                    {
                        "id": "record-006",
                        "type": "CAA",
                        "name": "example.com",
                        "content": "0 issue \"letsencrypt.org\"",
                        "ttl": 3600,
                        "proxied": False,
                        "created_on": "2024-01-01T00:00:00Z"
                    }
                ],
                "page_rules": [
                    {
                        "id": "rule-001",
                        "targets": [{"target": "url", "constraint": {"operator": "matches", "value": "*.example.com/api/*"}}],
                        "actions": [
                            {"id": "cache_level", "value": "bypass"},
                            {"id": "security_level", "value": "high"}
                        ],
                        "status": "active",
                        "priority": 1
                    }
                ],
                "ssl_certificates": [
                    {
                        "id": "cert-001",
                        "type": "universal",
                        "hosts": ["example.com", "*.example.com"],
                        "status": "active",
                        "validation_method": "http",
                        "validity_days_left": 85,
                        "certificate_authority": "lets_encrypt"
                    }
                ],
                "analytics": {
                    "requests": {
                        "all": 2500000,
                        "cached": 1875000,
                        "uncached": 625000,
                        "ssl": {
                            "encrypted": 2450000,
                            "unencrypted": 50000
                        }
                    },
                    "bandwidth": {
                        "all": 125000000000,  # 125 GB
                        "cached": 100000000000,
                        "uncached": 25000000000,
                        "ssl": {
                            "encrypted": 122500000000,
                            "unencrypted": 2500000000
                        }
                    },
                    "threats": {
                        "all": 15000,
                        "type": {
                            "country": 5000,
                            "hotlink": 2000,
                            "security_level": 3000,
                            "rate_limit": 1000,
                            "waf": 4000
                        }
                    },
                    "pageviews": {
                        "all": 500000,
                        "search_engines": {
                            "googlebot": 50000,
                            "bingbot": 15000
                        }
                    },
                    "uniques": {
                        "all": 125000
                    },
                    "cache_hit_ratio": 0.75,
                    "response_time_avg": 0.145,
                    "ssl_handshake_time": 0.089
                },
                "security_events": {
                    "threats_blocked": 15000,
                    "attack_types": {
                        "sql_injection": 3000,
                        "xss": 2500,
                        "bot_attack": 5000,
                        "ddos": 1500,
                        "malicious_upload": 1000,
                        "brute_force": 2000
                    },
                    "threat_countries": ["CN", "RU", "BR", "IN", "US"]
                }
            },
            "test-domain.net": {
                "zone_id": "zone-789456",
                "name": "test-domain.net",
                "status": "active",
                "name_servers": [
                    "ns3.cloudflare.com",
                    "ns4.cloudflare.com"
                ],
                "plan": "free",
                "account_id": "account-789",
                "created_on": "2024-02-15T00:00:00Z",
                "modified_on": "2024-03-01T12:00:00Z",
                "settings": {
                    "ssl": "flexible",
                    "security_level": "medium",
                    "cache_level": "standard",
                    "browser_cache_ttl": 4800,
                    "always_online": "off",
                    "development_mode": "off",
                    "ipv6": "off",
                    "websockets": "off",
                    "dnssec": "disabled",
                    "cname_flattening": "flatten_at_root"
                },
                "dns_records": [
                    {
                        "id": "record-101",
                        "type": "A",
                        "name": "test-domain.net",
                        "content": "203.0.113.100",
                        "ttl": 1,  # Auto TTL
                        "proxied": True,
                        "created_on": "2024-02-15T00:00:00Z"
                    },
                    {
                        "id": "record-102",
                        "type": "A",
                        "name": "mail.test-domain.net",
                        "content": "203.0.113.101",
                        "ttl": 3600,
                        "proxied": False,
                        "created_on": "2024-02-15T00:00:00Z"
                    }
                ],
                "page_rules": [],
                "ssl_certificates": [
                    {
                        "id": "cert-101",
                        "type": "universal",
                        "hosts": ["test-domain.net", "*.test-domain.net"],
                        "status": "active",
                        "validation_method": "http",
                        "validity_days_left": 45,
                        "certificate_authority": "lets_encrypt"
                    }
                ],
                "analytics": {
                    "requests": {"all": 50000, "cached": 25000, "uncached": 25000},
                    "bandwidth": {"all": 2500000000},  # 2.5 GB
                    "threats": {"all": 150},
                    "cache_hit_ratio": 0.50,
                    "response_time_avg": 0.300
                }
            }
        }
    
    def _extract_resource_config(self, cloud_state: Dict[str, Any]) -> Dict[str, Any]:
        """Extract DNS zone configuration from cloud state"""
        
        return {
            "name": cloud_state.get("name"),
            "status": cloud_state.get("status"),
            "plan": cloud_state.get("plan"),
            "name_servers": cloud_state.get("name_servers", []),
            "settings": cloud_state.get("settings", {}),
            "dns_records": cloud_state.get("dns_records", []),
            "page_rules": cloud_state.get("page_rules", []),
            "ssl_certificates": cloud_state.get("ssl_certificates", []),
            "analytics": cloud_state.get("analytics", {}),
            "security_events": cloud_state.get("security_events", {})
        }
    
    def _calculate_config_hash(self, config: Dict[str, Any]) -> str:
        """Generate hash for DNS zone configuration"""
        
        # Focus on key configuration elements
        key_config = {
            "name": config.get("name"),
            "settings": {
                "ssl": config.get("settings", {}).get("ssl"),
                "security_level": config.get("settings", {}).get("security_level"),
                "cache_level": config.get("settings", {}).get("cache_level"),
                "dnssec": config.get("settings", {}).get("dnssec")
            },
            "dns_records": [
                {
                    "type": record.get("type"),
                    "name": record.get("name"),
                    "content": record.get("content"),
                    "proxied": record.get("proxied")
                }
                for record in config.get("dns_records", [])
            ],
            "page_rules_count": len(config.get("page_rules", [])),
            "ssl_certificates_count": len(config.get("ssl_certificates", []))
        }
        
        return str(hash(json.dumps(key_config, sort_keys=True)))
    
    def analyze_dns_optimization(self, zone_data: Dict[str, Any]) -> Dict[str, Any]:
        """
        Analyze DNS zone for optimization opportunities
        """
        
        optimization_analysis = {
            "zone_name": zone_data.get("name"),
            "plan": zone_data.get("plan"),
            "recommendations": [],
            "dns_record_recommendations": [],
            "security_recommendations": [],
            "performance_recommendations": [],
            "ssl_recommendations": []
        }
        
        # DNS record analysis
        dns_analysis = self._analyze_dns_records(zone_data)
        optimization_analysis["dns_record_recommendations"] = dns_analysis
        
        # Security analysis
        security_analysis = self.analyze_cf_security_posture(zone_data)
        optimization_analysis["security_recommendations"] = security_analysis["recommendations"]
        
        # Performance analysis
        performance_analysis = self.analyze_cf_performance_optimization(zone_data)
        optimization_analysis["performance_recommendations"] = performance_analysis["recommendations"]
        
        # SSL/TLS analysis
        ssl_analysis = self._analyze_ssl_configuration(zone_data)
        optimization_analysis["ssl_recommendations"] = ssl_analysis
        
        # General recommendations
        general_recommendations = self._generate_general_dns_recommendations(zone_data)
        optimization_analysis["recommendations"].extend(general_recommendations)
        
        return optimization_analysis
    
    def _analyze_dns_records(self, zone_data: Dict[str, Any]) -> List[Dict[str, Any]]:
        """Analyze DNS records for optimization opportunities"""
        
        recommendations = []
        dns_records = zone_data.get("dns_records", [])
        
        # Group records by type
        records_by_type = {}
        for record in dns_records:
            record_type = record.get("type")
            if record_type not in records_by_type:
                records_by_type[record_type] = []
            records_by_type[record_type].append(record)
        
        # Analyze each record type
        for record_type, records in records_by_type.items():
            type_recommendations = self._analyze_record_type(record_type, records)
            recommendations.extend(type_recommendations)
        
        # Check for missing important records
        missing_records = self._check_missing_records(zone_data)
        recommendations.extend(missing_records)
        
        return recommendations
    
    def _analyze_record_type(self, record_type: str, records: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
        """Analyze specific DNS record type"""
        
        recommendations = []
        optimal_ttl = self.dns_rules["ttl_recommendations"].get(record_type.lower() + "_record", 3600)
        
        for record in records:
            record_name = record.get("name")
            ttl = record.get("ttl", 1)
            proxied = record.get("proxied", False)
            
            record_recommendations = {
                "record": f"{record_type} {record_name}",
                "recommendations": []
            }
            
            # TTL optimization
            if ttl == 1:  # Auto TTL
                record_recommendations["recommendations"].append("Using Auto TTL - consider setting specific TTL for better control")
            elif ttl != optimal_ttl:
                if ttl > optimal_ttl * 2:
                    record_recommendations["recommendations"].append(f"TTL too high ({ttl}s) - consider reducing to {optimal_ttl}s")
                elif ttl < optimal_ttl / 2:
                    record_recommendations["recommendations"].append(f"TTL too low ({ttl}s) - consider increasing to {optimal_ttl}s")
            
            # Proxy status optimization
            if record_type in ["A", "AAAA", "CNAME"] and not proxied:
                if not record_name.startswith("mail.") and not record_name.startswith("ftp."):
                    record_recommendations["recommendations"].append("Consider enabling Cloudflare proxy for security and performance benefits")
            
            # Record-specific analysis
            if record_type == "MX" and proxied:
                record_recommendations["recommendations"].append("MX records should not be proxied through Cloudflare")
            
            if record_recommendations["recommendations"]:
                recommendations.append(record_recommendations)
        
        return recommendations
    
    def _check_missing_records(self, zone_data: Dict[str, Any]) -> List[Dict[str, Any]]:
        """Check for missing important DNS records"""
        
        recommendations = []
        dns_records = zone_data.get("dns_records", [])
        zone_name = zone_data.get("name")
        
        # Check existing record types
        existing_types = {}
        for record in dns_records:
            record_type = record.get("type")
            record_name = record.get("name")
            
            if record_type not in existing_types:
                existing_types[record_type] = []
            existing_types[record_type].append(record_name)
        
        # Check for missing security records
        if "CAA" not in existing_types:
            recommendations.append({
                "record": "CAA records",
                "recommendations": ["Add CAA records to specify authorized Certificate Authorities"]
            })
        
        # Check for missing SPF record
        txt_records = existing_types.get("TXT", [])
        has_spf = any("v=spf1" in record.get("content", "") for record in dns_records if record.get("type") == "TXT")
        
        if not has_spf:
            recommendations.append({
                "record": "SPF record",
                "recommendations": ["Add SPF record to prevent email spoofing"]
            })
        
        # Check for DMARC record
        has_dmarc = any(record.get("name", "").startswith("_dmarc.") for record in dns_records)
        if not has_dmarc:
            recommendations.append({
                "record": "DMARC record",
                "recommendations": ["Add DMARC record for email authentication policy"]
            })
        
        return recommendations
    
    def _analyze_ssl_configuration(self, zone_data: Dict[str, Any]) -> List[str]:
        """Analyze SSL/TLS configuration"""
        
        recommendations = []
        settings = zone_data.get("settings", {})
        ssl_certificates = zone_data.get("ssl_certificates", [])
        
        # SSL mode analysis
        ssl_mode = settings.get("ssl", "off")
        if ssl_mode == "off":
            recommendations.append("Enable SSL encryption - at minimum Flexible SSL")
        elif ssl_mode == "flexible":
            recommendations.append("Upgrade from Flexible to Full or Full (Strict) SSL for end-to-end encryption")
        elif ssl_mode == "full":
            recommendations.append("Consider Full (Strict) SSL for maximum security")
        
        # Certificate analysis
        for cert in ssl_certificates:
            validity_days = cert.get("validity_days_left", 0)
            
            if validity_days < 30:
                recommendations.append(f"SSL certificate expires in {validity_days} days - renewal needed soon")
            elif validity_days < 7:
                recommendations.append(f"SSL certificate expires in {validity_days} days - immediate renewal required")
        
        # HSTS analysis
        hsts = settings.get("security_header", {}).get("strict_transport_security", {})
        if not hsts.get("enabled", False):
            recommendations.append("Enable HTTP Strict Transport Security (HSTS)")
        else:
            max_age = hsts.get("max_age", 0)
            if max_age < 31536000:  # 1 year
                recommendations.append("Increase HSTS max-age to at least 1 year (31536000 seconds)")
        
        return recommendations
    
    def _generate_general_dns_recommendations(self, zone_data: Dict[str, Any]) -> List[str]:
        """Generate general DNS optimization recommendations"""
        
        recommendations = []
        settings = zone_data.get("settings", {})
        plan = zone_data.get("plan", "free")
        analytics = zone_data.get("analytics", {})
        
        # DNSSEC recommendation
        if settings.get("dnssec") != "active":
            recommendations.append("Enable DNSSEC for improved DNS security")
        
        # IPv6 recommendation
        if not settings.get("ipv6", False):
            recommendations.append("Enable IPv6 support for better global accessibility")
        
        # Plan optimization
        if plan == "free":
            requests = analytics.get("requests", {}).get("all", 0)
            if requests > 5000000:  # 5M requests
                recommendations.append("High traffic volume - consider upgrading to Pro plan for better performance")
        
        # Cache optimization
        cache_level = settings.get("cache_level", "standard")
        if cache_level == "basic":
            recommendations.append("Consider upgrading cache level to Standard or Aggressive")
        
        # Development mode check
        if settings.get("development_mode") == "on":
            recommendations.append("Development mode is enabled - disable for production")
        
        return recommendations
    
    def predict_dns_performance(self, zone_name: str, metrics_history: List[Dict[str, Any]]) -> Dict[str, Any]:
        """
        Predict DNS performance and optimization needs
        """
        
        if not metrics_history:
            return {"prediction": "insufficient_data", "confidence": 0.0}
        
        # Analyze performance trends
        response_times = [m.get("response_time_avg", 0) for m in metrics_history]
        cache_hit_ratios = [m.get("cache_hit_ratio", 0) for m in metrics_history]
        request_counts = [m.get("requests", {}).get("all", 0) for m in metrics_history]
        
        avg_response_time = sum(response_times) / len(response_times)
        avg_cache_hit_ratio = sum(cache_hit_ratios) / len(cache_hit_ratios)
        avg_requests = sum(request_counts) / len(request_counts)
        
        # Trend analysis
        if len(request_counts) >= 7:
            recent_requests = sum(request_counts[-7:]) / 7
            earlier_requests = sum(request_counts[:7]) / 7
            traffic_trend = "increasing" if recent_requests > earlier_requests * 1.1 else "stable"
        else:
            traffic_trend = "stable"
        
        prediction = {
            "zone_name": zone_name,
            "performance_analysis": {
                "average_response_time": avg_response_time,
                "average_cache_hit_ratio": avg_cache_hit_ratio,
                "average_daily_requests": avg_requests,
                "traffic_trend": traffic_trend
            },
            "optimization_prediction": self._generate_performance_prediction(
                avg_response_time, avg_cache_hit_ratio, traffic_trend
            ),
            "capacity_recommendations": self._generate_dns_capacity_recommendations(
                avg_requests, traffic_trend
            ),
            "confidence_score": min(len(metrics_history) / 30.0, 1.0)  # 30 days = 100%
        }
        
        return prediction
    
    def _generate_performance_prediction(self, avg_response_time: float, 
                                       avg_cache_hit_ratio: float, traffic_trend: str) -> Dict[str, Any]:
        """Generate DNS performance predictions"""
        
        if avg_response_time > 0.200:  # 200ms
            return {
                "action": "optimize_performance",
                "confidence": "high",
                "recommendation": "High response times detected - optimize caching and origin",
                "suggested_actions": ["Optimize cache settings", "Review origin server performance"]
            }
        elif avg_cache_hit_ratio < 0.70:
            return {
                "action": "improve_caching",
                "confidence": "medium",
                "recommendation": "Low cache hit ratio - optimize caching strategy",
                "suggested_actions": ["Review page rules", "Optimize TTL settings", "Enable aggressive caching"]
            }
        elif traffic_trend == "increasing":
            return {
                "action": "prepare_for_growth",
                "confidence": "medium",
                "recommendation": "Traffic growing - prepare for increased load",
                "suggested_actions": ["Monitor performance metrics", "Consider plan upgrade", "Review cache policies"]
            }
        else:
            return {
                "action": "maintain",
                "confidence": "medium",
                "recommendation": "Performance appears optimal",
                "suggested_actions": ["Continue monitoring", "Regular performance reviews"]
            }
    
    def _generate_dns_capacity_recommendations(self, avg_requests: float, traffic_trend: str) -> List[str]:
        """Generate DNS capacity planning recommendations"""
        
        recommendations = []
        
        if avg_requests > 50000000:  # 50M requests per month
            recommendations.append("Very high traffic volume - consider Enterprise plan for dedicated support")
            recommendations.append("Implement advanced load balancing for global distribution")
        elif avg_requests > 10000000:  # 10M requests per month
            recommendations.append("High traffic volume - ensure adequate plan limits")
            recommendations.append("Monitor rate limiting and implement if necessary")
        
        if traffic_trend == "increasing":
            recommendations.append("Traffic trending upward - monitor plan limits and upgrade if necessary")
            recommendations.append("Consider implementing more aggressive caching")
        
        recommendations.extend([
            "Regular monitoring of DNS query patterns",
            "Implement geographic load balancing for global users",
            "Review and optimize page rules for performance"
        ])
        
        return recommendations
    
    def generate_security_audit(self, zone_data: Dict[str, Any]) -> Dict[str, Any]:
        """
        Generate comprehensive security audit for DNS zone
        """
        
        audit_result = {
            "zone_name": zone_data.get("name"),
            "audit_timestamp": datetime.now().isoformat(),
            "overall_security_score": 0.0,
            "security_findings": [],
            "threat_analysis": {},
            "recommendations": []
        }
        
        # Perform security analysis
        security_analysis = self.analyze_cf_security_posture(zone_data)
        audit_result.update(security_analysis)
        
        # DNS-specific security checks
        dns_security = self._audit_dns_security(zone_data)
        audit_result["security_findings"].extend(dns_security)
        
        # Threat analysis from security events
        security_events = zone_data.get("security_events", {})
        audit_result["threat_analysis"] = security_events
        
        return audit_result
    
    def _audit_dns_security(self, zone_data: Dict[str, Any]) -> List[str]:
        """Audit DNS-specific security configurations"""
        
        findings = []
        settings = zone_data.get("settings", {})
        dns_records = zone_data.get("dns_records", [])
        
        # DNSSEC check
        if settings.get("dnssec") != "active":
            findings.append("DNSSEC not enabled - DNS responses are not cryptographically signed")
        
        # CAA records check
        has_caa = any(record.get("type") == "CAA" for record in dns_records)
        if not has_caa:
            findings.append("No CAA records found - unauthorized certificate issuance possible")
        
        # SPF record check
        has_spf = any("v=spf1" in record.get("content", "") for record in dns_records if record.get("type") == "TXT")
        if not has_spf:
            findings.append("No SPF record found - email spoofing protection missing")
        
        # Wildcard record security
        wildcard_records = [r for r in dns_records if r.get("name", "").startswith("*")]
        if wildcard_records:
            findings.append(f"Wildcard DNS records detected ({len(wildcard_records)}) - review for security implications")
        
        return findings