from __future__ import annotations

from typing import Any


class TopicRouter:
    def __init__(self, config: dict[str, Any] | None = None):
        cfg = config or {}
        self._groups_config = cfg.get("groups", {})
        self._default_agent_id = cfg.get("default_agent_id", "default")

    def resolve_topic_agent(self, chat_id: str, thread_id: str) -> str:
        chat_config = self._groups_config.get(chat_id, {})
        topics_config = chat_config.get("topics", {})

        topic_config = topics_config.get(thread_id)
        if topic_config and "agent_id" in topic_config:
            return topic_config["agent_id"]

        group_agent = chat_config.get("agent_id")
        return group_agent or self._default_agent_id

    def resolve_group_agent(self, chat_id: str) -> str:
        chat_config = self._groups_config.get(chat_id, {})
        group_agent = chat_config.get("agent_id")
        return group_agent or self._default_agent_id

    def resolve_route(
        self,
        chat_id: str,
        chat_type: str,
        thread_id: str | None = None,
    ) -> str:
        agent_id = self._resolve_agent(chat_id, chat_type, thread_id)

        if chat_type == "private":
            return f"agent:{agent_id}:telegram:direct:{chat_id}"
        if thread_id:
            return f"agent:{agent_id}:telegram:group:{chat_id}:topic:{thread_id}"
        return f"agent:{agent_id}:telegram:group:{chat_id}"

    def _resolve_agent(self, chat_id: str, chat_type: str, thread_id: str | None) -> str:
        if chat_type == "private":
            return self._default_agent_id
        if thread_id:
            return self.resolve_topic_agent(chat_id, thread_id)
        return self.resolve_group_agent(chat_id)