from __future__ import annotations

from dataclasses import dataclass, field
from time import time


@dataclass
class ChatTurn:
    role: str
    content: str
    ts: float = field(default_factory=time)


class ChatStore:
    """In-memory chat history for the DJ panel."""

    def __init__(self, max_turns: int = 40) -> None:
        self._turns: list[ChatTurn] = []
        self._max = max_turns
        self.pending_vibe: str = ""

    def add(self, role: str, content: str) -> None:
        self._turns.append(ChatTurn(role=role, content=content))
        if len(self._turns) > self._max:
            self._turns = self._turns[-self._max :]

    def history(self) -> list[dict]:
        return [{"role": t.role, "content": t.content} for t in self._turns]

    def public_log(self) -> list[dict]:
        return [
            {"role": t.role, "content": t.content, "ts": t.ts}
            for t in self._turns
            if t.role in ("user", "dj")
        ]

    def take_vibe_hint(self) -> str:
        hint = self.pending_vibe.strip()
        self.pending_vibe = ""
        return hint