"""
嵌入模型包装器，用于 llama.cpp 服务。
"""

import os
from .config import LLAMACPP_EMBEDDING_URL, LLAMACPP_API_KEY
import httpx
from typing import List

from langchain_core.embeddings import Embeddings


class LlamaCppEmbedder:
    """通过 OpenAI 兼容 API 封装 llama.cpp 嵌入服务。"""

    def __init__(self, model: str = "Qwen3-Embedding-0.6B-Q8_0"):
        """
        Args:
            model: 嵌入模型名称，默认 "Qwen3-Embedding-0.6B-Q8_0"。
        """
        self.base_url = LLAMACPP_EMBEDDING_URL
        self.api_key = LLAMACPP_API_KEY
        self.model = model
        print(f"初始化 base_url: { self.base_url}")



    def as_langchain_embeddings(self) -> Embeddings:
        """创建 LangChain 兼容的嵌入实例。"""
        return _LlamaCppLangchainAdapter(self)

    def embed_documents(self, texts: List[str]) -> List[List[float]]:
        """嵌入一批文档。"""
        return self._call_embedding_api(texts)

    def embed_query(self, text: str) -> List[List[float]]:
        """嵌入单个查询。"""
        return self._call_embedding_api([text])[0]

    def get_embedding_dimension(self) -> int:
        """通过嵌入测试字符串获取嵌入维度。"""
        test_embedding = self.embed_query("test")
        return len(test_embedding)

    def _call_embedding_api(self, texts: List[str]) -> List[List[float]]:
        """直接调用 llama.cpp 嵌入 API。"""
        headers = {"Content-Type": "application/json"}
        if self.api_key:
            headers["Authorization"] = f"Bearer {self.api_key}"

        base = self.base_url.rstrip("/")
        if not base.endswith("/v1"):
            base = base + "/v1"


        payload = {
            "input": texts,
            "model": self.model,
        }

        with httpx.Client(timeout=120) as client:
            response = client.post(
                f"{base}/embeddings",
                headers=headers,
                json=payload,
            )
            response.raise_for_status()
            data = response.json()

            if isinstance(data, list):
                return [item["embedding"] for item in data]
            elif isinstance(data, dict) and "data" in data:
                return [item["embedding"] for item in sorted(data["data"], key=lambda x: x["index"])]
            else:
                raise ValueError(f"未知的嵌入 API 响应格式: {data}")


class _LlamaCppLangchainAdapter(Embeddings):
    """将 LlamaCppEmbedder 适配为 LangChain Embeddings 接口。"""

    def __init__(self, embedder: LlamaCppEmbedder):
        self._embedder = embedder

    def embed_documents(self, texts: List[str]) -> List[List[float]]:
        return self._embedder.embed_documents(texts)

    def embed_query(self, text: str) -> List[List[float]]:
        return self._embedder.embed_query(text)