from __future__ import annotations

from dataclasses import dataclass, field
from typing import Any


@dataclass(slots=True)
class ChatParams:
    max_tokens: int = 512
    temperature: float = 0.7
    top_p: float = 0.95
    top_k: int = 40
    min_p: float = 0.05
    repeat_penalty: float = 1.05
    seed: int | None = None
    stop: list[str] = field(default_factory=list)
    enable_thinking: bool | None = None
    extra: dict[str, Any] = field(default_factory=dict)
    response_format: str | dict[str, Any] | None = None
    tools: list[dict[str, Any]] = field(default_factory=list)
    tool_choice: Any = None
    keep_alive: str | int | float | None = None

    def as_generation_kwargs(self) -> dict[str, Any]:
        result: dict[str, Any] = {
            "max_tokens": self.max_tokens,
            "temperature": self.temperature,
            "top_p": self.top_p,
            "top_k": self.top_k,
            "min_p": self.min_p,
            "repeat_penalty": self.repeat_penalty,
        }
        if self.seed is not None:
            result["seed"] = self.seed
        if self.stop:
            result["stop"] = self.stop
        return result


@dataclass(slots=True)
class ChatChunk:
    text: str = ""
    done: bool = False
    finish_reason: str | None = None
    metadata: dict[str, Any] = field(default_factory=dict)
    delta: dict[str, Any] = field(default_factory=dict)


class BackendError(RuntimeError):
    """An expected model backend failure with a user-facing message."""