# -*- coding: utf-8 -*-
"""AgentMessenger - Pub/sub inter-agent communication.

Provides broadcast(), send(), and subscribe() for message passing
between agents using AgentScope's Msg format.
"""

from __future__ import annotations

import asyncio
import logging
from typing import Any, Callable, Dict, List, Optional, Set

from agentscope.message import Msg

logger = logging.getLogger(__name__)


class AgentMessenger:
    """Pub/sub messenger for inter-agent communication.

    Supports:
    - broadcast(): Send message to all subscribers
    - send(): Send message to specific agent
    - subscribe(): Register callback for agent messages
    - announce(): Send system-wide announcement
    - enable_auto_broadcast: Auto-broadcast agent replies to all participants

    Messages use AgentScope's Msg format for compatibility.
    """

    def __init__(self, enable_auto_broadcast: bool = False):
        """Initialize the messenger.

        Args:
            enable_auto_broadcast: If True, agent replies are automatically
                broadcast to all subscribed agents.
        """
        self._subscriptions: Dict[str, List[Callable[[Msg], None]]] = {}
        self._inbox: Dict[str, List[Msg]] = {}
        self._locks: Dict[str, asyncio.Lock] = {}
        self._enable_auto_broadcast = enable_auto_broadcast
        self._participants: Set[str] = set()

    def subscribe(
        self,
        agent_id: str,
        callback: Callable[[Msg], None],
    ) -> None:
        """Subscribe an agent to receive messages.

        Args:
            agent_id: Target agent identifier
            callback: Async function to call when message received
        """
        if agent_id not in self._subscriptions:
            self._subscriptions[agent_id] = []
        self._subscriptions[agent_id].append(callback)
        logger.debug("Agent %s subscribed to messages", agent_id)

    def unsubscribe(self, agent_id: str, callback: Callable[[Msg], None]) -> None:
        """Unsubscribe an agent from messages.

        Args:
            agent_id: Target agent identifier
            callback: Callback to remove
        """
        if agent_id in self._subscriptions:
            try:
                self._subscriptions[agent_id].remove(callback)
                logger.debug("Agent %s unsubscribed from messages", agent_id)
            except ValueError:
                pass

    async def send(
        self,
        to_agent: str,
        message: Msg,
    ) -> None:
        """Send message to specific agent.

        Args:
            to_agent: Target agent identifier
            message: Message to send (uses Msg format)
        """
        async def _deliver():
            if to_agent in self._subscriptions:
                for callback in self._subscriptions[to_agent]:
                    try:
                        if asyncio.iscoroutinefunction(callback):
                            await callback(message)
                        else:
                            callback(message)
                    except Exception as e:
                        logger.error(
                            "Error delivering message to %s: %s",
                            to_agent,
                            e,
                        )

        await _deliver()

    async def broadcast(self, message: Msg) -> None:
        """Broadcast message to all subscribed agents.

        Args:
            message: Message to broadcast (uses Msg format)
        """
        delivery_tasks = []
        for agent_id, callbacks in self._subscriptions.items():
            for callback in callbacks:
                async def _deliver(cb=callback, aid=agent_id):
                    try:
                        if asyncio.iscoroutinefunction(cb):
                            await cb(message)
                        else:
                            cb(message)
                    except Exception as e:
                        logger.error(
                            "Error broadcasting to %s: %s",
                            aid,
                            e,
                        )
                delivery_tasks.append(_deliver())

        if delivery_tasks:
            await asyncio.gather(*delivery_tasks)

    def inbox(self, agent_id: str) -> List[Msg]:
        """Get and clear inbox for agent.

        Args:
            agent_id: Agent identifier

        Returns:
            List of messages in inbox
        """
        messages = self._inbox.get(agent_id, [])
        self._inbox[agent_id] = []
        return messages

    def inbox_count(self, agent_id: str) -> int:
        """Count messages in agent's inbox without clearing.

        Args:
            agent_id: Agent identifier

        Returns:
            Number of messages waiting
        """
        return len(self._inbox.get(agent_id, []))

    def add_participant(self, agent_id: str) -> None:
        """Add a participant to the messenger.

        Participants are the agents that can receive auto-broadcast messages.

        Args:
            agent_id: Agent identifier to add
        """
        self._participants.add(agent_id)
        logger.debug("Agent %s added as participant", agent_id)

    def remove_participant(self, agent_id: str) -> None:
        """Remove a participant from the messenger.

        Args:
            agent_id: Agent identifier to remove
        """
        self._participants.discard(agent_id)
        logger.debug("Agent %s removed from participants", agent_id)

    @property
    def enable_auto_broadcast(self) -> bool:
        """Check if auto_broadcast is enabled."""
        return self._enable_auto_broadcast

    @enable_auto_broadcast.setter
    def enable_auto_broadcast(self, value: bool) -> None:
        """Enable or disable auto_broadcast."""
        self._enable_auto_broadcast = value
        logger.debug("Auto_broadcast set to %s", value)

    async def announce(self, message: Msg) -> None:
        """Send a system-wide announcement to all participants.

        Unlike broadcast(), announce() sends a message from the system/host
        to all participants without requiring prior subscription.

        Args:
            message: Announcement message (uses Msg format)
        """
        logger.info("System announcement: %s", message.content)
        await self.broadcast(message)

    async def auto_broadcast(self, message: Msg) -> None:
        """Auto-broadcast message to all participants.

        This is called internally when enable_auto_broadcast is True.
        Broadcasts to all registered participants.

        Args:
            message: Message to auto-broadcast (uses Msg format)
        """
        if not self._enable_auto_broadcast:
            return

        # Broadcast to all participants
        for participant_id in self._participants:
            if participant_id in self._subscriptions:
                for callback in self._subscriptions[participant_id]:
                    try:
                        if asyncio.iscoroutinefunction(callback):
                            await callback(message)
                        else:
                            callback(message)
                    except Exception as e:
                        logger.error(
                            "Error auto-broadcasting to %s: %s",
                            participant_id,
                            e,
                        )


__all__ = ["AgentMessenger"]