"""具体 LLM Provider 实现：DashScope（公网千问，仅 dev）、vLLM（本地，prod）。

两者均走 OpenAI 兼容的 /chat/completions 协议。
"""

from __future__ import annotations

import httpx

from app.llm.base import ChatMessage, LLMProvider, LLMResponse


class DashScopeProvider(LLMProvider):
    """公网千问（DashScope，OpenAI 兼容模式）。仅限开发测试，且只允许脱敏/样例假数据。"""

    name = "dashscope"
    egress = True  # 走公网，出域

    _BASE_URL = "https://dashscope.aliyuncs.com/compatible-mode/v1"

    def __init__(self, api_key: str, model: str, timeout: float = 30.0) -> None:
        self._api_key = api_key
        self._model = model
        self._timeout = timeout

    def chat(self, messages: list[ChatMessage], **kwargs) -> LLMResponse:
        payload = {
            "model": self._model,
            "messages": [{"role": m.role, "content": m.content} for m in messages],
            **kwargs,
        }
        headers = {"Authorization": f"Bearer {self._api_key}"}
        with httpx.Client(timeout=self._timeout) as client:
            resp = client.post(
                f"{self._BASE_URL}/chat/completions", json=payload, headers=headers
            )
            resp.raise_for_status()
            data = resp.json()
        content = data["choices"][0]["message"]["content"]
        return LLMResponse(
            content=content, model=self._model, provider=self.name, egress=True, raw=data
        )

    def health(self) -> bool:
        return bool(self._api_key)


class VllmProvider(LLMProvider):
    """本地 vLLM（OpenAI 兼容）。生产使用，数据不出域。"""

    name = "vllm"
    egress = False

    def __init__(self, base_url: str, model: str, timeout: float = 60.0) -> None:
        self._base_url = base_url.rstrip("/")
        self._model = model
        self._timeout = timeout

    def chat(self, messages: list[ChatMessage], **kwargs) -> LLMResponse:
        payload = {
            "model": self._model,
            "messages": [{"role": m.role, "content": m.content} for m in messages],
            **kwargs,
        }
        with httpx.Client(timeout=self._timeout) as client:
            resp = client.post(f"{self._base_url}/chat/completions", json=payload)
            resp.raise_for_status()
            data = resp.json()
        content = data["choices"][0]["message"]["content"]
        return LLMResponse(
            content=content, model=self._model, provider=self.name, egress=False, raw=data
        )

    def health(self) -> bool:
        try:
            with httpx.Client(timeout=5.0) as client:
                resp = client.get(f"{self._base_url}/models")
                return resp.status_code == 200
        except httpx.HTTPError:
            return False