"""
Swarm Client (MVP) - P2P Threat Intelligence Sharing

UPGRADE: P0 Fix - Distributed Defense Network
Uses libp2p for peer-to-peer threat intelligence sharing.

Status: MVP Implementation (Fallback to Stub if libp2p not available)
"""

import time
import logging
from typing import Any, Dict, List, Optional, Callable
from dataclasses import dataclass

logger = logging.getLogger(__name__)

# Try to import libp2p (may not be available)
try:
    # Note: libp2p-py is not a standard package, this is a placeholder
    # In production, use: pip install libp2p
    # For now, we use a stub implementation
    LIBP2P_AVAILABLE = False
    logger.warning("libp2p-py not available, using stub implementation")
except ImportError:
    LIBP2P_AVAILABLE = False
    logger.warning("libp2p-py not available, using stub implementation")


@dataclass
class ThreatUpdate:
    """Threat intelligence update from peer."""

    embedding_hash: str
    signature: str
    timestamp: float
    peer_id: str


class SwarmClient:
    """
    Swarm Client for P2P threat intelligence sharing.

    MVP Implementation:
    - GossipSub for threat updates
    - Kademlia DHT for peer discovery
    - Local DB for threat storage

    Status: Stub implementation (libp2p integration pending)
    """

    def __init__(self, bootstrap_nodes: Optional[List[str]] = None):
        """
        Initialize Swarm Client.

        Args:
            bootstrap_nodes: List of bootstrap node addresses (e.g., ["/ip4/swarm.hak-gal.org/tcp/4001"])
        """
        self.bootstrap_nodes = bootstrap_nodes or []
        self.is_connected = False
        self.peer_count = 0
        self.threat_db: List[ThreatUpdate] = []

        # Callback for threat updates
        self.on_threat_callback: Optional[Callable[[ThreatUpdate], None]] = None

        if LIBP2P_AVAILABLE:
            self._initialize_libp2p()
        else:
            logger.warning(
                "Swarm Client: Using stub implementation (libp2p not available)"
            )
            self._initialize_stub()

    def _initialize_libp2p(self):
        """Initialize libp2p host and protocols."""
        # TODO: Implement when libp2p-py is available
        # self.host = Host.new(keys.generate_keypair(keys.KeyType.RSA))
        # self.gossip = GossipSub([self.host], flood_publish=True)
        # self.gossip.subscribe("threats/new", self.on_threat_update)
        # self.dht = KademliaDHT()
        # self.dht.bootstrap(self.bootstrap_nodes)
        pass

    def _initialize_stub(self):
        """Initialize stub implementation (no-op for now)."""
        logger.info("Swarm Client: Stub mode active (no P2P connectivity)")
        self.is_connected = False
        self.peer_count = 0

    def on_threat_update(self, msg: Dict):
        """
        Handle threat update from peer.

        Args:
            msg: Gossip message with threat data
        """
        try:
            threat = ThreatUpdate(
                embedding_hash=msg.get("embedding_hash", ""),
                signature=msg.get("signature", ""),
                timestamp=msg.get("timestamp", time.time()),
                peer_id=msg.get("peer_id", ""),
            )

            # Validate signature (in production, verify against root guardians)
            if self.is_valid_signature(threat):
                self.threat_db.append(threat)

                # Call callback if registered
                if self.on_threat_callback:
                    self.on_threat_callback(threat)

                logger.info(
                    f"Swarm: Received threat update from peer {threat.peer_id[:8]}..."
                )
            else:
                logger.warning(
                    f"Swarm: Invalid signature for threat update from {threat.peer_id[:8]}..."
                )
        except Exception as e:
            logger.error(f"Swarm: Error processing threat update: {e}")

    def publish_threat(self, embedding_hash: str):
        """
        Publish threat to swarm.

        Args:
            embedding_hash: Hash of adversarial embedding to share
        """
        if not LIBP2P_AVAILABLE:
            logger.debug(f"Swarm (stub): Would publish threat {embedding_hash[:16]}...")
            return

        msg = {
            "embedding_hash": embedding_hash,
            "signature": self.sign(embedding_hash),
            "timestamp": time.time(),
            "peer_id": self.get_peer_id(),
        }

        # In production: self.gossip.publish("threats/new", json.dumps(msg).encode())
        logger.info(f"Swarm: Published threat {embedding_hash[:16]}...")

    def is_valid_signature(self, threat: ThreatUpdate) -> bool:
        """
        Validate threat signature against root guardians.

        Args:
            threat: Threat update to validate

        Returns:
            True if signature is valid
        """
        # TODO: Implement Web of Trust verification
        # For now, accept all (stub)
        return True

    def sign(self, data: str) -> str:
        """
        Sign data with local peer key.

        Args:
            data: Data to sign

        Returns:
            Signature string
        """
        # TODO: Implement actual signing
        return f"stub_signature_{hash(data)}"

    def get_peer_id(self) -> str:
        """Get local peer ID."""
        # TODO: Return actual peer ID from libp2p host
        return "stub_peer_id"

    def get_peers(self) -> Dict[str, Any]:
        """
        Get list of connected peers.

        Returns:
            Dictionary with peer count and peer IDs
        """
        return {
            "peer_count": self.peer_count,
            "peers": [] if not LIBP2P_AVAILABLE else [],  # TODO: Return actual peer IDs
            "status": "connected" if self.is_connected else "stub",
        }
