"""运行时 LLM 配置：可由业务后端（管理端 AI 配置）动态下发，覆盖 .env。"""
from __future__ import annotations

from dataclasses import dataclass, field
from threading import RLock
from typing import Any


@dataclass
class RuntimeLlmConfig:
    """enabled=None 表示未由管理端覆盖，沿用 .env。"""

    enabled: bool | None = None
    api_base_url: str | None = None
    api_key: str | None = None
    model: str | None = None
    temperature: float | None = None
    source: str = "env"


_lock = RLock()
_runtime = RuntimeLlmConfig()


def get_runtime_llm() -> RuntimeLlmConfig:
    with _lock:
        return RuntimeLlmConfig(
            enabled=_runtime.enabled,
            api_base_url=_runtime.api_base_url,
            api_key=_runtime.api_key,
            model=_runtime.model,
            temperature=_runtime.temperature,
            source=_runtime.source,
        )


def update_runtime_llm(
    *,
    enabled: bool | None = None,
    api_base_url: str | None = None,
    api_key: str | None = None,
    model: str | None = None,
    temperature: float | None = None,
) -> RuntimeLlmConfig:
    """
    更新运行时配置。
    - api_key 为 None：不改密钥
    - api_key 为非空字符串：覆盖
    - api_key 为 ""：清空运行时密钥（回退 .env）
    """
    with _lock:
        if enabled is not None:
            _runtime.enabled = bool(enabled)
        if api_base_url is not None and api_base_url.strip():
            _runtime.api_base_url = api_base_url.strip()
        if api_key is not None:
            _runtime.api_key = api_key.strip() if api_key.strip() else None
        if model is not None and model.strip():
            _runtime.model = model.strip()
        if temperature is not None:
            t = float(temperature)
            _runtime.temperature = max(0.0, min(2.0, t))
        _runtime.source = "runtime"
        return get_runtime_llm()


def runtime_status(env_key_configured: bool, env_base: str, env_model: str) -> dict[str, Any]:
    rt = get_runtime_llm()
    key_ok = bool(rt.api_key) or env_key_configured
    enabled = False
    if key_ok:
        if rt.enabled is None:
            enabled = env_key_configured or bool(rt.api_key)
        else:
            enabled = bool(rt.enabled)
    return {
        "enabled": enabled,
        "configured": key_ok,
        "api_key_configured": key_ok,
        "api_base_url": rt.api_base_url or env_base,
        "model": rt.model or env_model,
        "temperature": rt.temperature,
        "source": rt.source if (rt.api_key or rt.enabled is not None or rt.api_base_url) else "env",
    }