"""ModelAdapter — 범용 OpenAI-compat 모델 어댑터."""

from __future__ import annotations

import json
import logging
from collections.abc import AsyncGenerator

import httpx

logger = logging.getLogger(__name__)


class ModelAdapter:
    """OpenAI-compatible /v1/chat/completions 백엔드 범용 어댑터.
    Ollama, MLX 등 모두 동일 인터페이스로 호출."""

    def __init__(
        self,
        name: str,
        base_url: str,
        model: str,
        system_prompt: str,
        temperature: float = 0.7,
        timeout: float = 120.0,
        max_tokens: int = 4096,
    ):
        self.name = name
        self.base_url = base_url
        self.model = model
        self.system_prompt = system_prompt
        self.temperature = temperature
        self.timeout = timeout
        self.max_tokens = max_tokens

    async def stream_chat(self, message: str, *, messages: list[dict] | None = None) -> AsyncGenerator[str, None]:
        """스트리밍 호출. content chunk를 yield. messages 직접 전달 가능."""
        if messages is None:
            messages = [
                {"role": "system", "content": self.system_prompt},
                {"role": "user", "content": message},
            ]
        payload = {
            "model": self.model,
            "messages": messages,
            "stream": True,
            "temperature": self.temperature,
            "max_tokens": self.max_tokens,
        }

        async with httpx.AsyncClient(timeout=self.timeout) as client:
            try:
                async with client.stream(
                    "POST",
                    f"{self.base_url}/v1/chat/completions",
                    json=payload,
                ) as resp:
                    if resp.status_code != 200:
                        body = await resp.aread()
                        logger.error("%s error %d: %s", self.name, resp.status_code, body.decode())
                        raise RuntimeError(f"{self.name} 응답 실패 ({resp.status_code})")

                    async for line in resp.aiter_lines():
                        line = line.strip()
                        if not line or not line.startswith("data: "):
                            continue
                        payload_str = line[len("data: "):]
                        if payload_str == "[DONE]":
                            return
                        try:
                            chunk = json.loads(payload_str)
                            delta = chunk.get("choices", [{}])[0].get("delta", {})
                            content = delta.get("content", "")
                            if content:
                                yield content
                        except (json.JSONDecodeError, IndexError, KeyError):
                            continue

            except httpx.ConnectError:
                logger.error("%s connection failed: %s", self.name, self.base_url)
                raise
            except httpx.ReadTimeout:
                logger.error("%s read timeout", self.name)
                raise

    async def complete_chat(self, message: str, *, messages: list[dict] | None = None) -> str:
        """비스트리밍 호출. 전체 응답 텍스트 반환. messages 직접 전달 가능."""
        if messages is None:
            messages = [
                {"role": "system", "content": self.system_prompt},
                {"role": "user", "content": message},
            ]
        payload = {
            "model": self.model,
            "messages": messages,
            "stream": False,
            "temperature": self.temperature,
            "max_tokens": self.max_tokens,
        }

        async with httpx.AsyncClient(timeout=self.timeout) as client:
            resp = await client.post(
                f"{self.base_url}/v1/chat/completions",
                json=payload,
            )
            resp.raise_for_status()
            data = resp.json()
            return data["choices"][0]["message"]["content"]

    async def health_check(self) -> bool:
        """GET /v1/models — 5초 timeout."""
        try:
            async with httpx.AsyncClient(timeout=5.0) as client:
                resp = await client.get(f"{self.base_url}/v1/models")
                return resp.status_code < 500
        except Exception:
            return False