"""
Cluster Registration Service
Handles registration-based cluster management for Hive-Bzzz integration.
"""
import asyncpg
import secrets
import json
import socket
from datetime import datetime, timedelta
from typing import Dict, List, Optional, Any
from dataclasses import dataclass
from ipaddress import IPv4Network, IPv6Network, ip_address
import logging

logger = logging.getLogger(__name__)

@dataclass
class ClusterToken:
    id: int
    token: str
    description: str
    created_at: datetime
    expires_at: Optional[datetime]
    is_active: bool
    max_registrations: Optional[int]
    current_registrations: int
    allowed_ip_ranges: Optional[List[str]]

@dataclass
class ClusterNode:
    id: int
    node_id: str
    hostname: str
    ip_address: str
    registration_token: str
    cpu_info: Optional[Dict[str, Any]]
    memory_info: Optional[Dict[str, Any]]
    gpu_info: Optional[Dict[str, Any]]
    disk_info: Optional[Dict[str, Any]]
    os_info: Optional[Dict[str, Any]]
    platform_info: Optional[Dict[str, Any]]
    status: str
    last_heartbeat: datetime
    first_registered: datetime
    services: Optional[Dict[str, Any]]
    capabilities: Optional[Dict[str, Any]]
    ports: Optional[Dict[str, Any]]
    client_version: Optional[str]
    registration_metadata: Optional[Dict[str, Any]]

@dataclass
class RegistrationRequest:
    token: str
    node_id: str
    hostname: str
    ip_address: str
    system_info: Dict[str, Any]
    client_version: Optional[str] = None
    services: Optional[Dict[str, Any]] = None
    capabilities: Optional[Dict[str, Any]] = None
    ports: Optional[Dict[str, Any]] = None
    metadata: Optional[Dict[str, Any]] = None

@dataclass
class HeartbeatRequest:
    node_id: str
    status: str = "online"
    cpu_usage: Optional[float] = None
    memory_usage: Optional[float] = None
    disk_usage: Optional[float] = None
    gpu_usage: Optional[float] = None
    services_status: Optional[Dict[str, Any]] = None
    network_metrics: Optional[Dict[str, Any]] = None
    custom_metrics: Optional[Dict[str, Any]] = None

class ClusterRegistrationService:
    def __init__(self, database_url: str):
        self.database_url = database_url
        self._conn_cache = None
    
    async def get_connection(self) -> asyncpg.Connection:
        """Get database connection with caching."""
        if not self._conn_cache or self._conn_cache.is_closed():
            try:
                self._conn_cache = await asyncpg.connect(self.database_url)
            except Exception as e:
                logger.error(f"Failed to connect to database: {e}")
                raise
        return self._conn_cache
    
    async def close_connection(self):
        """Close database connection."""
        if self._conn_cache and not self._conn_cache.is_closed():
            await self._conn_cache.close()
    
    # Token Management
    async def generate_cluster_token(
        self, 
        description: str,
        created_by_user_id: str,
        expires_in_days: Optional[int] = None,
        max_registrations: Optional[int] = None,
        allowed_ip_ranges: Optional[List[str]] = None
    ) -> ClusterToken:
        """Generate a new cluster registration token."""
        conn = await self.get_connection()
        
        # Generate secure token  
        token = f"hive_cluster_{secrets.token_urlsafe(32)}"
        expires_at = datetime.now() + timedelta(days=expires_in_days) if expires_in_days else None
        
        try:
            result = await conn.fetchrow("""
                INSERT INTO cluster_tokens (
                    token, description, created_by, expires_at, 
                    max_registrations, allowed_ip_ranges
                ) VALUES ($1, $2, $3, $4, $5, $6)
                RETURNING id, token, description, created_at, expires_at, 
                         is_active, max_registrations, current_registrations, allowed_ip_ranges
            """, token, description, created_by_user_id, expires_at, max_registrations, allowed_ip_ranges)
            
            return ClusterToken(**dict(result))
        except Exception as e:
            logger.error(f"Failed to generate cluster token: {e}")
            raise
    
    async def validate_token(self, token: str, client_ip: str) -> Optional[ClusterToken]:
        """Validate a cluster registration token."""
        conn = await self.get_connection()
        
        try:
            result = await conn.fetchrow("""
                SELECT id, token, description, created_at, expires_at, 
                       is_active, max_registrations, current_registrations, allowed_ip_ranges
                FROM cluster_tokens 
                WHERE token = $1 AND is_active = true
            """, token)
            
            if not result:
                return None
            
            cluster_token = ClusterToken(**dict(result))
            
            # Check expiration
            if cluster_token.expires_at and datetime.now() > cluster_token.expires_at:
                logger.warning(f"Token {token[:20]}... has expired")
                return None
            
            # Check registration limit
            if (cluster_token.max_registrations and 
                cluster_token.current_registrations >= cluster_token.max_registrations):
                logger.warning(f"Token {token[:20]}... has reached registration limit")
                return None
            
            # Check IP restrictions
            if cluster_token.allowed_ip_ranges:
                client_ip_obj = ip_address(client_ip)
                allowed = False
                for ip_range in cluster_token.allowed_ip_ranges:
                    try:
                        network = IPv4Network(ip_range, strict=False) if ':' not in ip_range else IPv6Network(ip_range, strict=False)
                        if client_ip_obj in network:
                            allowed = True
                            break
                    except Exception as e:
                        logger.warning(f"Invalid IP range {ip_range}: {e}")
                
                if not allowed:
                    logger.warning(f"IP {client_ip} not allowed for token {token[:20]}...")
                    return None
            
            return cluster_token
            
        except Exception as e:
            logger.error(f"Failed to validate token: {e}")
            return None
    
    async def list_tokens(self) -> List[ClusterToken]:
        """List all cluster tokens."""
        conn = await self.get_connection()
        
        try:
            results = await conn.fetch("""
                SELECT id, token, description, created_at, expires_at, 
                       is_active, max_registrations, current_registrations, allowed_ip_ranges
                FROM cluster_tokens 
                ORDER BY created_at DESC
            """)
            
            return [ClusterToken(**dict(result)) for result in results]
            
        except Exception as e:
            logger.error(f"Failed to list tokens: {e}")
            raise
    
    async def revoke_token(self, token: str) -> bool:
        """Revoke a cluster token."""
        conn = await self.get_connection()
        
        try:
            result = await conn.execute("""
                UPDATE cluster_tokens 
                SET is_active = false 
                WHERE token = $1
            """, token)
            
            return result != "UPDATE 0"
            
        except Exception as e:
            logger.error(f"Failed to revoke token: {e}")
            return False
    
    # Node Registration
    async def register_node(self, request: RegistrationRequest, client_ip: str) -> Dict[str, Any]:
        """Register a new cluster node."""
        conn = await self.get_connection()
        
        # Log registration attempt
        await self._log_registration_attempt(
            client_ip, request.token, request.node_id, 
            request.hostname, True, None, request.metadata
        )
        
        try:
            # Validate token
            token_info = await self.validate_token(request.token, client_ip)
            if not token_info:
                await self._log_registration_attempt(
                    client_ip, request.token, request.node_id, 
                    request.hostname, False, "Invalid or expired token", request.metadata
                )
                raise ValueError("Invalid or expired registration token")
            
            # Extract system info components
            system_info = request.system_info or {}
            cpu_info = system_info.get('cpu', {})
            memory_info = system_info.get('memory', {})
            gpu_info = system_info.get('gpu', {})
            disk_info = system_info.get('disk', {})
            os_info = system_info.get('os', {})
            platform_info = system_info.get('platform', {})
            
            # Register or update node
            result = await conn.fetchrow("""
                INSERT INTO cluster_nodes (
                    node_id, hostname, ip_address, registration_token,
                    cpu_info, memory_info, gpu_info, disk_info, os_info, platform_info,
                    services, capabilities, ports, client_version, registration_metadata
                ) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15)
                ON CONFLICT (node_id) DO UPDATE SET
                    hostname = EXCLUDED.hostname,
                    ip_address = EXCLUDED.ip_address,
                    cpu_info = EXCLUDED.cpu_info,
                    memory_info = EXCLUDED.memory_info,
                    gpu_info = EXCLUDED.gpu_info,
                    disk_info = EXCLUDED.disk_info,
                    os_info = EXCLUDED.os_info,
                    platform_info = EXCLUDED.platform_info,
                    services = EXCLUDED.services,
                    capabilities = EXCLUDED.capabilities,
                    ports = EXCLUDED.ports,
                    client_version = EXCLUDED.client_version,
                    registration_metadata = EXCLUDED.registration_metadata,
                    status = 'online',
                    last_heartbeat = NOW()
                RETURNING id, node_id, hostname, ip_address, first_registered
            """, 
                request.node_id, request.hostname, request.ip_address, request.token,
                json.dumps(cpu_info) if cpu_info else None,
                json.dumps(memory_info) if memory_info else None,
                json.dumps(gpu_info) if gpu_info else None,
                json.dumps(disk_info) if disk_info else None,
                json.dumps(os_info) if os_info else None,
                json.dumps(platform_info) if platform_info else None,
                json.dumps(request.services) if request.services else None,
                json.dumps(request.capabilities) if request.capabilities else None,
                json.dumps(request.ports) if request.ports else None,
                request.client_version,
                json.dumps(request.metadata) if request.metadata else None
            )
            
            logger.info(f"Node {request.node_id} registered successfully from {client_ip}")
            
            return {
                "node_id": result["node_id"],
                "registration_status": "success",
                "heartbeat_interval": 30,  # seconds
                "registered_at": result["first_registered"].isoformat(),
                "cluster_info": {
                    "coordinator_version": "1.0.0",
                    "features": ["heartbeat", "dynamic_scaling", "service_discovery"]
                }
            }
            
        except Exception as e:
            logger.error(f"Failed to register node {request.node_id}: {e}")
            await self._log_registration_attempt(
                client_ip, request.token, request.node_id, 
                request.hostname, False, str(e), request.metadata
            )
            raise
    
    async def update_heartbeat(self, request: HeartbeatRequest) -> Dict[str, Any]:
        """Update node heartbeat and metrics."""
        conn = await self.get_connection()
        
        try:
            # Update node status and heartbeat
            result = await conn.fetchrow("""
                UPDATE cluster_nodes 
                SET status = $2, last_heartbeat = NOW()
                WHERE node_id = $1
                RETURNING node_id, status, last_heartbeat
            """, request.node_id, request.status)
            
            if not result:
                raise ValueError(f"Node {request.node_id} not found")
            
            # Record heartbeat metrics
            await conn.execute("""
                INSERT INTO node_heartbeats (
                    node_id, cpu_usage, memory_usage, disk_usage, gpu_usage,
                    services_status, network_metrics, custom_metrics
                ) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
            """, 
                request.node_id, request.cpu_usage, request.memory_usage,
                request.disk_usage, request.gpu_usage,
                json.dumps(request.services_status) if request.services_status else None,
                json.dumps(request.network_metrics) if request.network_metrics else None,
                json.dumps(request.custom_metrics) if request.custom_metrics else None
            )
            
            return {
                "node_id": result["node_id"],
                "status": result["status"],
                "heartbeat_received": result["last_heartbeat"].isoformat(),
                "next_heartbeat_in": 30,  # seconds
                "commands": []  # Future: cluster management commands
            }
            
        except Exception as e:
            logger.error(f"Failed to update heartbeat for {request.node_id}: {e}")
            raise
    
    async def get_registered_nodes(self, include_offline: bool = True) -> List[ClusterNode]:
        """Get all registered cluster nodes."""
        conn = await self.get_connection()
        
        try:
            query = """
                SELECT id, node_id, hostname, ip_address, registration_token,
                       cpu_info, memory_info, gpu_info, disk_info, os_info, platform_info,
                       status, last_heartbeat, first_registered,
                       services, capabilities, ports, client_version, registration_metadata
                FROM cluster_nodes
            """
            
            if not include_offline:
                query += " WHERE status != 'offline'"
            
            query += " ORDER BY first_registered DESC"
            
            results = await conn.fetch(query)
            
            nodes = []
            for result in results:
                node_dict = dict(result)
                # Parse JSON fields
                for json_field in ['cpu_info', 'memory_info', 'gpu_info', 'disk_info', 
                                 'os_info', 'platform_info', 'services', 'capabilities', 
                                 'ports', 'registration_metadata']:
                    if node_dict[json_field]:
                        try:
                            node_dict[json_field] = json.loads(node_dict[json_field])
                        except json.JSONDecodeError:
                            node_dict[json_field] = None
                
                nodes.append(ClusterNode(**node_dict))
            
            return nodes
            
        except Exception as e:
            logger.error(f"Failed to get registered nodes: {e}")
            raise
    
    async def get_node_details(self, node_id: str) -> Optional[ClusterNode]:
        """Get detailed information about a specific node."""
        nodes = await self.get_registered_nodes()
        return next((node for node in nodes if node.node_id == node_id), None)
    
    async def remove_node(self, node_id: str) -> bool:
        """Remove a node from the cluster."""
        conn = await self.get_connection()
        
        try:
            result = await conn.execute("""
                DELETE FROM cluster_nodes WHERE node_id = $1
            """, node_id)
            
            if result != "DELETE 0":
                logger.info(f"Node {node_id} removed from cluster")
                return True
            return False
            
        except Exception as e:
            logger.error(f"Failed to remove node {node_id}: {e}")
            return False
    
    # Maintenance and Monitoring
    async def cleanup_offline_nodes(self, offline_threshold_minutes: int = 10) -> int:
        """Mark nodes as offline if they haven't sent heartbeats."""
        conn = await self.get_connection()
        
        try:
            result = await conn.execute("""
                UPDATE cluster_nodes 
                SET status = 'offline'
                WHERE status = 'online' 
                AND last_heartbeat < NOW() - INTERVAL '%s minutes'
            """ % offline_threshold_minutes)
            
            # Extract number from result like "UPDATE 3"
            count = int(result.split()[-1]) if result.split()[-1].isdigit() else 0
            if count > 0:
                logger.info(f"Marked {count} nodes as offline due to missing heartbeats")
            
            return count
            
        except Exception as e:
            logger.error(f"Failed to cleanup offline nodes: {e}")
            return 0
    
    async def cleanup_old_heartbeats(self, retention_days: int = 30) -> int:
        """Remove old heartbeat data for storage management."""
        conn = await self.get_connection()
        
        try:
            result = await conn.execute("""
                DELETE FROM node_heartbeats 
                WHERE heartbeat_time < NOW() - INTERVAL '%s days'
            """ % retention_days)
            
            count = int(result.split()[-1]) if result.split()[-1].isdigit() else 0
            if count > 0:
                logger.info(f"Cleaned up {count} old heartbeat records")
            
            return count
            
        except Exception as e:
            logger.error(f"Failed to cleanup old heartbeats: {e}")
            return 0
    
    async def _log_registration_attempt(
        self, 
        ip_address: str, 
        token: str, 
        node_id: str,
        hostname: str, 
        success: bool, 
        failure_reason: Optional[str] = None,
        metadata: Optional[Dict[str, Any]] = None
    ):
        """Log registration attempts for security monitoring."""
        conn = await self.get_connection()
        
        try:
            await conn.execute("""
                INSERT INTO node_registration_attempts (
                    ip_address, token_used, node_id, hostname, 
                    success, failure_reason, request_metadata
                ) VALUES ($1, $2, $3, $4, $5, $6, $7)
            """, ip_address, token, node_id, hostname, success, failure_reason,
                json.dumps(metadata) if metadata else None)
        except Exception as e:
            logger.error(f"Failed to log registration attempt: {e}")
    
    async def get_cluster_statistics(self) -> Dict[str, Any]:
        """Get cluster statistics and health metrics."""
        conn = await self.get_connection()
        
        try:
            # Node statistics
            node_stats = await conn.fetchrow("""
                SELECT 
                    COUNT(*) as total_nodes,
                    COUNT(*) FILTER (WHERE status = 'online') as online_nodes,
                    COUNT(*) FILTER (WHERE status = 'offline') as offline_nodes,
                    COUNT(*) FILTER (WHERE status = 'maintenance') as maintenance_nodes
                FROM cluster_nodes
            """)
            
            # Token statistics
            token_stats = await conn.fetchrow("""
                SELECT 
                    COUNT(*) as total_tokens,
                    COUNT(*) FILTER (WHERE is_active = true) as active_tokens,
                    COUNT(*) FILTER (WHERE expires_at IS NOT NULL AND expires_at < NOW()) as expired_tokens
                FROM cluster_tokens
            """)
            
            return {
                "cluster_health": {
                    "total_nodes": node_stats["total_nodes"],
                    "online_nodes": node_stats["online_nodes"],
                    "offline_nodes": node_stats["offline_nodes"],
                    "maintenance_nodes": node_stats["maintenance_nodes"],
                    "health_percentage": (node_stats["online_nodes"] / max(node_stats["total_nodes"], 1)) * 100
                },
                "token_management": {
                    "total_tokens": token_stats["total_tokens"],
                    "active_tokens": token_stats["active_tokens"],
                    "expired_tokens": token_stats["expired_tokens"]
                },
                "last_updated": datetime.now().isoformat()
            }
            
        except Exception as e:
            logger.error(f"Failed to get cluster statistics: {e}")
            return {
                "error": str(e),
                "last_updated": datetime.now().isoformat()
            }