"""
Communication network — manages agent connectivity and message delivery.
"""

from __future__ import annotations
from typing import Any, Dict, List, Optional
from .protocol import Message, CommunicationProtocol


class CommunicationNetwork:
    """Manages the topology and message delivery between agents."""

    def __init__(self) -> None:
        self._protocol = CommunicationProtocol()
        self._connections: Dict[str, List[str]] = {}  # agent_id -> [peer_ids]
        self._message_log: List[Message] = []

    def connect(self, agent_a: str, agent_b: str) -> None:
        self._connections.setdefault(agent_a, []).append(agent_b)
        self._connections.setdefault(agent_b, []).append(agent_a)

    def disconnect(self, agent_a: str, agent_b: str) -> None:
        for peer in (agent_a, agent_b):
            if peer in self._connections:
                self._connections[peer] = [
                    p for p in self._connections[peer] if p != agent_b
                ]

    def deliver(self, message: Message) -> bool:
        if message.recipient in self._connections.get(message.sender, []):
            self._message_log.append(message)
            return self._protocol.send(message)
        return False

    def broadcast(self, sender: str, payload: Any) -> int:
        peers = self._connections.get(sender, [])
        for peer in peers:
            msg = Message(sender=sender, recipient=peer, payload=payload)
            self._message_log.append(msg)
        return len(peers)

    def get_peers(self, agent_id: str) -> List[str]:
        return self._connections.get(agent_id, [])

    def get_message_log(self, limit: int = 100) -> List[Message]:
        return self._message_log[-limit:]