"""
Per-user conversation history store.

Each Discord user gets their own isolated message list.  Only the last
`max_history` messages are kept — older ones are silently dropped so the
LLM context stays small.
"""

from __future__ import annotations

import logging
from typing import Dict, List

logger = logging.getLogger("bot.conversation")

# role we assign to user messages inside the OpenAI-style message list
_USER_ROLE = "user"
# role we assign to bot responses
_ASSISTANT_ROLE = "assistant"


class ConversationStore:
    """Thread-safe-ish in-memory store keyed by Discord user ID (int)."""

    def __init__(self, max_history: int = 7) -> None:
        self._max = max_history
        self._store: Dict[int, List[dict]] = {}

    # ------------------------------------------------------------------
    # public API
    # ------------------------------------------------------------------

    def get_history(self, user_id: int) -> list[dict]:
        """Return the last *max_history* messages for *user_id*."""
        return list(self._store.get(user_id, []))

    def append(self, user_id: int, user_msg: str, assistant_reply: str) -> None:
        """Store the user message + assistant reply, then trim to max."""
        if user_id not in self._store:
            self._store[user_id] = []

        history = self._store[user_id]
        history.append({"role": _USER_ROLE, "content": user_msg})
        history.append({"role": _ASSISTANT_ROLE, "content": assistant_reply})

        # Trim oldest messages if we exceeded the limit
        while len(history) > self._max:
            history.pop(0)

    def clear(self, user_id: int) -> None:
        """Wipe the conversation for a user."""
        self._store.pop(user_id, None)
        logger.info("Cleared conversation for user %s", user_id)

    # ------------------------------------------------------------------
    # debug / introspection
    # ------------------------------------------------------------------

    @property
    def user_count(self) -> int:
        return len(self._store)