from services.model.base import AbstractModelService
from services.chat.history_service import HistoryService
from services.events.event_bus import EventBus


class ChatService:
    """대화 오케스트레이션 서비스."""

    EVENT_TOKEN = "stream.token"
    EVENT_END = "stream.end"

    def __init__(
        self,
        model: AbstractModelService,
        history: HistoryService,
        event_bus: EventBus,
        max_tokens: int,
    ):
        self._model = model
        self._history = history
        self._event_bus = event_bus
        self._max_tokens = max_tokens

    def respond(self, user_input: str) -> str:
        self._history.add("user", user_input)
        prompt = self._model.build_prompt(self._history.get())

        response_text = ""
        for token in self._model.stream(prompt, self._max_tokens):
            self._event_bus.publish(self.EVENT_TOKEN, token)
            response_text += token

        self._event_bus.publish(self.EVENT_END)
        self._history.add("assistant", response_text)
        return response_text