hyf-backend/th_agenter/services/document_processor.py

"""文档处理服务，负责文档的分段、向量化和索引"""

import os
from typing import List, Dict, Any, Optional
from pathlib import Path
from fastapi import HTTPException
from requests import Session
from sqlalchemy import text
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langchain_community.document_loaders import (
    TextLoader,
    PyPDFLoader,
    Docx2txtLoader,
    UnstructuredMarkdownLoader
)
import pdfplumber
from langchain_core.documents import Document
from langchain_postgres import PGVector
from typing import List


from ..core.config import BaseSettings, get_settings
from ..models.knowledge_base import Document as DocumentModel
from ..db.database import get_session
from loguru import logger

settings = get_settings()
class DocumentProcessor:
    """文档处理器，负责文档的加载、分段和向量化"""
    
    def __init__(self):
        # 初始化语义分割器配置
        self.embeddings = None
        self.semantic_splitter_enabled = settings.file.semantic_splitter_enabled
        self.text_splitter = RecursiveCharacterTextSplitter(
            chunk_size=settings.file.chunk_size,
            chunk_overlap=settings.file.chunk_overlap,
            length_function=len,
            separators=["\n\n", "\n", " ", ""]
        )
        
    async def initialize(self, session: Session = None):
        # 初始化嵌入模型 - 根据配置选择提供商
        await self._init_embeddings(session)
        
        # 初始化连接池（仅对PGVector）
        self.pgvector_pool = None
        
        # PostgreSQL pgvector连接配置
        # if settings.vector_db.type == "pgvector":
        #     # 新版本PGVector使用psycopg3连接字符串
        #     # 对密码进行URL编码以处理特殊字符（如@符号）
        #     encoded_password = quote(settings.vector_db.pgvector_password, safe="")
        #     self.connection_string = (
        #         f"postgresql+psycopg://{settings.vector_db.pgvector_user}:"
        #         f"{encoded_password}@"
        #         f"{settings.vector_db.pgvector_host}:"
        #         f"{settings.vector_db.pgvector_port}/"
        #         f"{settings.vector_db.pgvector_database}"
        #     )
        #     # 初始化连接池
        #     self.pgvector_pool = PGVectorConnectionPool()
        #     logger.info("新版本PGVector使用psycopg3连接字符串: %s", self.connection_string)
        # else:
            # 向量数据库存储路径（Chroma兼容）
        vector_db_path = settings.vector_db.persist_directory
        if not os.path.isabs(vector_db_path):
            # 如果是相对路径，则基于项目根目录计算绝对路径
            # 项目根目录是backend的父目录
            backend_dir = Path(__file__).parent.parent.parent
            vector_db_path = str(backend_dir / vector_db_path)
        self.vector_db_path = vector_db_path
        session.desc = f"初始化向量数据库 - 路径 = {self.vector_db_path}"
    
    async def _init_embeddings(self, session: Optional[Any] = None):
        """初始化嵌入模型。"""
        try:
            if not self.embeddings:
                # 使用llm_config_service获取嵌入配置
                from .llm_config_service import LLMConfigService
                llm_config_service = LLMConfigService()
                
                # 获取嵌入配置
                config = None
                if session:
                    config = await llm_config_service.get_default_embedding_config(session)
                    if config and session:
                        session.desc = f"获取默认嵌入模型配置: {config}"
                        # # 转换配置格式
                        # config = {
                        #     "provider": config.provider,
                        #     "api_key": config.api_key,
                        #     "model": config.model_name
                        # }
                
                # 如果未找到配置，使用默认配置
                if not config:
                    if session:
                        session.desc = f"ERROR: 未找到嵌入模型配置"
                    raise HTTPException(status_code=400, detail="未找到嵌入模型配置")
                if session:
                    session.desc = f"获取嵌入模型配置 > 结果：{config}"
                
                # 根据配置创建嵌入模型
                if config.provider == "openai":
                    from langchain_openai import OpenAIEmbeddings
                    self.embeddings = OpenAIEmbeddings(
                        model=config.model_name or "text-embedding-3-small",
                        api_key=config.api_key
                    )
                    if session:
                        session.desc = f"创建嵌入模型 - OpenAIEmbeddings(model={config.model_name or 'text-embedding-3-small'})"
                elif config.provider == "zhipu":
                    from .zhipu_embeddings import ZhipuOpenAIEmbeddings
                    self.embeddings = ZhipuOpenAIEmbeddings(
                        api_key=config.api_key,
                        base_url=config.base_url or "https://open.bigmodel.cn/api/paas/v4",
                        model=config.model_name or "embedding-3",
                        dimensions=settings.vector_db.embedding_dimension
                    )
                    if session:
                        session.desc = f"创建嵌入模型 - ZhipuOpenAIEmbeddings(model={config.model_name or 'embedding-3'}, base_url={config.base_url})"
                elif config.provider == "ollama":
                    from langchain_ollama import OllamaEmbeddings
                    self.embeddings = OllamaEmbeddings(
                        model=config.model_name,
                        base_url=config.base_url
                    )
                    if session:
                        session.desc = f"创建嵌入模型 - OllamaEmbeddings({self.embeddings.base_url} - {self.embeddings.model})"
                elif config.provider == "local":
                    from langchain_huggingface import HuggingFaceEmbeddings
                    self.embeddings = HuggingFaceEmbeddings(
                        model_name=config.model_name or "sentence-transformers/all-MiniLM-L6-v2"
                    )
                    if session:
                        session.desc = f"创建嵌入模型 - HuggingFaceEmbeddings(model={config.model_name or 'sentence-transformers/all-MiniLM-L6-v2'})"
                else:
                    # 默认使用OpenAI
                    from langchain_openai import OpenAIEmbeddings
                    self.embeddings = OpenAIEmbeddings(
                        model=config.model_name or "text-embedding-3-small",
                        api_key=config.api_key
                    )
                    if session:
                        session.desc = f"ERROR: 未支持的嵌入提供者: {config.provider}，已使用默认的 OpenAIEmbeddings - 可能不正确或无效"
                
            return self.embeddings
        except Exception as e:
            logger.error(f"初始化嵌入模型时出错: {e}")
            raise
    
    def load_document(self, session: Session, file_path: str) -> List[Document]:
        """根据文件类型加载文档"""
        file_extension = Path(file_path).suffix.lower()
        try:
            if file_extension == '.txt':
                session.desc = f"加载文档 - 文件路径: {file_path} - 类型: txt"
                loader = TextLoader(file_path, encoding='utf-8')
                documents = loader.load()
            elif file_extension == '.pdf':
                # 使用pdfplumber处理PDF文件，更稳定
                session.desc = f"加载文档 - 文件路径: {file_path} - 类型: pdf"
                from langchain_community.document_loaders import PyPDFLoader
                loader = PyPDFLoader(file_path)
                documents = loader.load()
                # documents = self._load_pdf_with_pdfplumber(file_path)
            elif file_extension == '.docx':
                session.desc = f"加载文档 - 文件路径: {file_path} - 类型: docx"
                loader = Docx2txtLoader(file_path)
                documents = loader.load()
            elif file_extension == '.md':
                session.desc = f"加载文档 - 文件路径: {file_path} - 类型: md"
                loader = UnstructuredMarkdownLoader(file_path)
                documents = loader.load()
            else:
                raise ValueError(f"不支持的文件类型: {file_extension}")
            
            session.desc = f"已载文档: {file_path}, 页数: {len(documents)}"
            # if len(documents) > 0:
            #     session.desc = f"文档内容示例: {type(documents[0])} - {documents[0]}"
            return documents
            
        except Exception as e:
            session.desc = f"ERROR: 加载文档失败 {file_path}: {str(e)}"
            raise e
    
    def _load_pdf_with_pdfplumber(self, file_path: str) -> List[Document]:
        """使用pdfplumber加载PDF文档"""
        documents = []
        try:
            with pdfplumber.open(file_path) as pdf:
                for page_num, page in enumerate(pdf.pages):
                    text = page.extract_text()
                    if text and text.strip():  # 只处理有文本内容的页面
                        doc = Document(
                            page_content=text,
                            metadata={
                                "source": file_path,
                                "page": page_num + 1
                            }
                        )
                        documents.append(doc)
            return documents
        except Exception as e:
            logger.error(f"使用pdfplumber加载PDF失败 {file_path}: {str(e)}")
            # 如果pdfplumber失败，回退到PyPDFLoader
            try:
                loader = PyPDFLoader(file_path)
                return loader.load()
            except Exception as fallback_e:
                logger.error(f"PyPDFLoader回退也失败 {file_path}: {str(fallback_e)}")
                raise fallback_e
    
    def _merge_documents(self, documents: List[Document]) -> Document:
        """将多个文档合并成一个文档"""
        merged_text = ""
        merged_metadata = {}
        
        for doc in documents:
            if merged_text:
                merged_text += "\n\n"
            merged_text += doc.page_content
            # 合并元数据
            merged_metadata.update(doc.metadata)
        
        return Document(page_content=merged_text, metadata=merged_metadata)
    
    def _split_by_semantic_points(self, text: str, split_points: List[str]) -> List[str]:
        """根据语义分割点切分文本"""
        chunks = []
        current_pos = 0

        # 按顺序查找每个分割点并切分文本
        for point in split_points:
            pos = text.find(point, current_pos)
            if pos != -1:
                # 添加当前位置到分割点位置的文本块
                if pos > current_pos:
                    chunk = text[current_pos:pos].strip()
                    if chunk:
                        chunks.append(chunk)
                current_pos = pos

        # 添加最后一个文本块
        if current_pos < len(text):
            chunk = text[current_pos:].strip()
            if chunk:
                chunks.append(chunk)

        return chunks

    async def split_documents(self, session: Session, documents: List[Document]) -> List[Document]:
        """将文档分割成小块（含短段落合并和超长强制分割功能）"""
        try:
            chunks = self.text_splitter.split_documents(documents)

            session.desc = f"文档分割完成，共生成 {len(chunks)} 个文档块"
            if len(chunks) > 0:
                session.desc = f"文档块内容示例: {type(chunks[0])} - {chunks[0]}"
            return chunks

        except Exception as e:
            session.desc = f"ERROR: 文档分割失败: {str(e)}"
            raise e

    def _force_split_long_chunk(self, chunk: str) -> List[str]:
        """强制分割超长段落（超过1000字符）"""
        max_length = 1000
        chunks = []

        # 先尝试按换行符分割
        if '\n' in chunk:
            lines = chunk.split('\n')
            current_chunk = ""
            for line in lines:
                if len(current_chunk) + len(line) + 1 > max_length:
                    if current_chunk:
                        chunks.append(current_chunk)
                        current_chunk = line
                    else:
                        chunks.append(line[:max_length])
                        current_chunk = line[max_length:]
                else:
                    if current_chunk:
                        current_chunk += "\n" + line
                    else:
                        current_chunk = line
            if current_chunk:
                chunks.append(current_chunk)
        else:
            # 没有换行符则直接按长度分割
            chunks = [chunk[i:i + max_length] for i in range(0, len(chunk), max_length)]

        return chunks
    
    def create_vector_store(self, knowledge_base_id: int, documents: List[Document], document_id: int = None) -> str:
        """为知识库创建向量存储"""
        try:
            # if settings.vector_db.type == "pgvector":
            #     # 添加元数据
            #     for i, doc in enumerate(documents):
            #         doc.metadata.update({
            #             "knowledge_base_id": knowledge_base_id,
            #             "document_id": str(document_id) if document_id else "unknown",
            #             "chunk_id": f"{knowledge_base_id}_{document_id}_{i}",
            #             "chunk_index": i
            #         })
                
            #     # 创建PostgreSQL pgvector存储
            #     collection_name = f"{settings.vector_db.pgvector_table_name}_kb_{knowledge_base_id}"
                
            #     # 创建新版本PGVector实例
            #     vector_store = PGVector(
            #         connection=self.connection_string,
            #         embeddings=self.embeddings,
            #         collection_name=collection_name,
            #         use_jsonb=True  # 使用JSONB存储元数据
            #     )
                
            #     # 手动添加文档
            #     vector_store.add_documents(documents)
                
            #     logger.info(f"PostgreSQL pgvector存储创建成功: {collection_name}")
            #     return collection_name
            # else:
            # Chroma兼容模式
            from langchain_chroma import Chroma
            kb_vector_path = os.path.join(self.vector_db_path, f"kb_{knowledge_base_id}")
            
            # 添加元数据
            for i, doc in enumerate(documents):
                doc.metadata.update({
                    "knowledge_base_id": knowledge_base_id,
                    "document_id": str(document_id) if document_id else "unknown",
                    "chunk_id": f"{knowledge_base_id}_{document_id}_{i}",
                    "chunk_index": i
                })
            
            # 创建向量存储
            vector_store = Chroma.from_documents(
                documents=documents,
                embedding=self.embeddings,
                persist_directory=kb_vector_path
            )
            
            logger.info(f"向量存储创建成功: {kb_vector_path}")
            return kb_vector_path
            
        except Exception as e:
            logger.error(f"创建向量存储失败: {str(e)}")
            raise
    
    def add_documents_to_vector_store(self, session: Session, knowledge_base_id: int, documents: List[Document], document_id: int = None) -> None:
        """向现有向量存储添加文档"""
        if len(documents) == 0:
            session.desc = f"WARNING: 文档列表为空，不执行添加操作"
            return
        from langchain_chroma import Chroma
        
        kb_vector_path = os.path.join(self.vector_db_path, f"kb_{knowledge_base_id}")
        session.desc = f"添加文档到向量存储: {kb_vector_path} - documents number: {len(documents)}"
        # 检查向量存储是否存在
        if not os.path.exists(kb_vector_path):
            # 如果不存在，创建新的向量存储
            session.desc = f"WARNING: 向量存储不存在，创建新的向量存储"
            self.create_vector_store(knowledge_base_id, documents, document_id)
            return
        session.desc = f"添加文档到向量存储: exists"
        # 添加元数据
        for i, doc in enumerate(documents):
            doc.metadata.update({
                "knowledge_base_id": knowledge_base_id,
                "document_id": str(document_id) if document_id else "unknown",
                "chunk_id": f"{knowledge_base_id}_{document_id}_{i}",
                "chunk_index": i
            })

        session.desc = f"添加文档到向量存储: enumerate"
        # 加载现有向量存储
        vector_store = Chroma(
            persist_directory=kb_vector_path,
            embedding_function=self.embeddings
        )

        session.desc = f"添加文档到向量存储: Chroma"
        # 添加新文档
        ids = vector_store.add_documents(documents)
        session.desc = f"文档已添加到向量存储: {kb_vector_path} -> {len(ids)} IDS - \n{ids}"
    
    async def process_document(self, session: Session, document_id: int, file_path: str, knowledge_base_id: int) -> Dict[str, Any]:
        """处理单个文档：加载、分段、向量化"""
        try:
            session.desc = f"处理文档 ID: {document_id} 文件路径: {file_path}"
            
            # 1. 加载文档
            documents = self.load_document(session, file_path)
            
            # 2. 分割文档
            chunks = await self.split_documents(session, documents)
            
            # 3. 添加到向量存储
            self.add_documents_to_vector_store(session, knowledge_base_id, chunks, document_id)
            
            # 4. 更新文档状态
            # Python 3.9 兼容：使用 async for 替代 anext
            async for db_session in get_session():
                try:
                    from sqlalchemy import select
                    document = await db_session.scalar(select(DocumentModel).where(DocumentModel.id == document_id))
                    
                    if document:
                        document.is_processed = True
                        document.chunk_count = len(chunks)
                        await db_session.commit()
                finally:
                    await db_session.close()
                break  # 只取第一个 session
            
            result = {
                "document_id": document_id,
                "status": "success",
                "chunks_count": len(chunks),
                "message": "文档处理完成"
            }
            
            
            session.desc = f"文档处理完成: {result}"
            return result
            
        except Exception as e:
            session.desc = f"ERROR: 文档处理失败 ID: {document_id}: {str(e)}"
            
            # 更新文档状态为失败
            try:
                # Python 3.9 兼容：使用 async for 替代 anext
                async for db_session in get_session():
                    try:
                        from sqlalchemy import select
                        document = await db_session.scalar(select(DocumentModel).where(DocumentModel.id == document_id))
                        if document:
                            document.is_processed = False
                            document.processing_error = str(e)
                            await db_session.commit()
                    finally:
                        await db_session.close()
                    break  # 只取第一个 session
            except Exception as db_error:
                session.desc = f"ERROR: 更新文档状态失败: {str(db_error)}"
            
            return {
                "document_id": document_id,
                "status": "failed",
                "error": str(e),
                "message": "文档处理失败"
            }
      
    def delete_document_from_vector_store(self, knowledge_base_id: int, document_id: int) -> None:
        """从向量存储中删除文档"""
        try:
            # Chroma兼容模式
            from langchain_chroma import Chroma
            kb_vector_path = os.path.join(self.vector_db_path, f"kb_{knowledge_base_id}")
            
            if not os.path.exists(kb_vector_path):
                logger.warning(f"向量存储不存在: {kb_vector_path}")
                return
            
            chunks = self.get_document_chunks(knowledge_base_id, document_id)
            # 加载向量存储
            vector_store = Chroma(
                persist_directory=kb_vector_path,
                embedding_function=self.embeddings
            )
            
            count_before = vector_store._collection.count()
            count_after = count_before
            
            if len(chunks) > 0:
                where_filter = {"document_id": str(document_id)}
                vector_store.delete(where=where_filter)
                count_after = vector_store._collection.count()
            
            # 注意：Chroma的删除功能可能需要特定的实现方式
            logger.info(f"文档已从向量存储中删除: document_id={document_id}，删除前有 {count_before} 个向量，删除后有 {count_after} 个向量")
            
        except Exception as e:
            logger.error(f"从向量存储删除文档失败: {str(e)}")
            raise
    
    def get_document_chunks(self, knowledge_base_id: int, document_id: int) -> List[Dict[str, Any]]:
        """获取文档的所有分段内容
        
        改进说明:
        - 避免使用空查询进行相似性搜索，防止触发不必要的embedding API调用
        - 优先使用直接SQL查询，提高性能
        - 确保结果按chunk_index排序
        """
        try:
            return self._get_chunks_chroma(knowledge_base_id, document_id)
                
        except Exception as e:
            logger.error(f"获取文档分段失败 document_id: {document_id}, kb_id: {knowledge_base_id}: {str(e)}")
            return []
    
    def _get_chunks_by_sql(self, knowledge_base_id: int, document_id: int) -> List[Dict[str, Any]]:
        """使用SQLAlchemy连接池查询获取文档分段（推荐方法）"""
        try:
            if not self.pgvector_pool:
                logger.error("PGVector连接池未初始化")
                return []
            
            # 直接SQL查询，避免相似性搜索和embedding计算
            query = """
                SELECT 
                    id,
                    document,
                    cmetadata
                FROM langchain_pg_embedding 
                WHERE cmetadata->>'document_id' = :document_id
                  AND cmetadata->>'knowledge_base_id' = :knowledge_base_id
                ORDER BY 
                    CAST(cmetadata->>'chunk_index' AS INTEGER) ASC;
            """
            
            # 使用连接池执行查询
            session = self.pgvector_pool.get_session()
            try:
                result = session.execute(
                    text(query), 
                    {
                        'document_id': str(document_id), 
                        'knowledge_base_id': str(knowledge_base_id)
                    }
                )
                results = result.fetchall()
                
                chunks = []
                for row in results:
                    # SQLAlchemy结果行访问
                    metadata = row.cmetadata
                    chunk = {
                        "id": f"chunk_{document_id}_{metadata.get('chunk_index', 0)}",
                        "content": row.document,
                        "metadata": metadata,
                        "page_number": metadata.get("page"),
                        "chunk_index": metadata.get("chunk_index", 0),
                        "start_char": metadata.get("start_char"),
                        "end_char": metadata.get("end_char")
                    }
                    chunks.append(chunk)
                
                logger.info(f"通过SQLAlchemy连接池查询获取到文档 {document_id} 的 {len(chunks)} 个分段")
                return chunks
                
            finally:
                session.close()
            
        except Exception as e:
            logger.error(f"SQLAlchemy连接池查询失败: {e}")
            return []
    
    def _get_chunks_by_langchain_improved(self, knowledge_base_id: int, document_id: int, collection_name: str) -> List[Dict[str, Any]]:
        """改进的LangChain查询方法（回退方案）"""
        try:
            vector_store = PGVector(
                connection=self.connection_string,
                embeddings=self.embeddings,
                collection_name=collection_name,
                use_jsonb=True
            )
            
            # 使用有意义的查询而不是空查询，避免触发embedding API错误
            # 先尝试获取少量结果来构造查询
            try:
                sample_results = vector_store.similarity_search(
                    query="文档内容",  # 使用通用查询词而非空字符串
                    k=5,
                    filter={"document_id": {"$eq": str(document_id)}}
                )
                
                if sample_results:
                    # 使用第一个结果的内容片段作为查询
                    first_content = sample_results[0].page_content[:50]
                    results = vector_store.similarity_search(
                        query=first_content,
                        k=1000,
                        filter={"document_id": {"$eq": str(document_id)}}
                    )
                else:
                    # 如果没有结果，尝试不使用filter的查询
                    results = vector_store.similarity_search(
                        query="文档",
                        k=1000
                    )
                    # 手动过滤结果
                    results = [doc for doc in results if doc.metadata.get("document_id") == str(document_id)]
                
            except Exception as e:
                logger.warning(f"改进的相似性搜索失败: {e}")
                return []
            
            chunks = []
            for i, doc in enumerate(results):
                chunk = {
                    "id": f"chunk_{document_id}_{i}",
                    "content": doc.page_content,
                    "metadata": doc.metadata,
                    "page_number": doc.metadata.get("page"),
                    "chunk_index": doc.metadata.get("chunk_index", i),
                    "start_char": doc.metadata.get("start_char"),
                    "end_char": doc.metadata.get("end_char")
                }
                chunks.append(chunk)
            
            # 按chunk_index排序
            chunks.sort(key=lambda x: x.get("chunk_index", 0))
            
            logger.info(f"通过改进的LangChain方法获取到文档 {document_id} 的 {len(chunks)} 个分段")
            return chunks
            
        except Exception as e:
            logger.error(f"LangChain改进方法失败: {e}")
            return []
    
    def _get_chunks_chroma(self, knowledge_base_id: int, document_id: int) -> List[Dict[str, Any]]:
        """Chroma存储的处理逻辑"""
        from langchain_chroma import Chroma
        # 构建向量数据库路径
        vector_db_path = os.path.join(self.vector_db_path, f"kb_{knowledge_base_id}")
        
        if not os.path.exists(vector_db_path):
            logger.warning(f"向量数据库不存在: {vector_db_path}")
            return []
        
        # 加载向量数据库
        vectorstore = Chroma(
            persist_directory=vector_db_path,
            embedding_function=self.embeddings
        )
        
        # 获取所有文档的元数据，筛选出指定文档的分段
        collection = vectorstore._collection
        all_docs = collection.get(include=["metadatas", "documents"])
        all_ids_data = collection.get()
        
        chunks = []
        chunk_index = 0
        
        for i, metadata in enumerate(all_docs["metadatas"]):
            if metadata.get("document_id") == str(document_id):
                chunk_content = all_docs["documents"][i]
                vector_id = all_ids_data["ids"][i]
                
                chunk = {
                    "id": f"chunk_{document_id}_{chunk_index}",
                    "content": chunk_content,
                    "metadata": metadata,
                    "page_number": metadata.get("page"),
                    "chunk_index": chunk_index,
                    "start_char": metadata.get("start_char"),
                    "end_char": metadata.get("end_char"),
                    "vector_id": vector_id
                }
                chunks.append(chunk)
                chunk_index += 1
        
        return chunks
    
    def search_similar_documents(self, knowledge_base_id: int, query: str, k: int = 5) -> List[Dict[str, Any]]:
        """在知识库中搜索相似文档"""
        try:
            # if settings.vector_db.type == "pgvector":
            #     # PostgreSQL pgvector存储
            #     collection_name = f"{settings.vector_db.pgvector_table_name}_kb_{knowledge_base_id}"
                
            #     try:
            #         vector_store = PGVector(
            #             connection=self.connection_string,
            #             embeddings=self.embeddings,
            #             collection_name=collection_name,
            #             use_jsonb=True
            #         )
                    
            #         # 执行相似性搜索
            #         results = vector_store.similarity_search_with_score(query, k=k)
                    
            #         # 格式化结果
            #         formatted_results = []
            #         for doc, distance_score in results:
            #             # pgvector使用余弦距离，距离越小相似度越高
            #             # 将距离转换为0-1之间的相似度分数
            #             similarity_score = 1.0 / (1.0 + distance_score)
                        
            #             formatted_results.append({
            #                 "content": doc.page_content,
            #                 "metadata": doc.metadata,
            #                 "similarity_score": distance_score,  # 保留原始距离分数
            #                 "normalized_score": similarity_score,  # 归一化相似度分数
            #                 "source": doc.metadata.get('filename', 'unknown'),
            #                 "document_id": doc.metadata.get('document_id', 'unknown'),
            #                 "chunk_id": doc.metadata.get('chunk_id', 'unknown')
            #             })
                    
            #         # 按相似度分数排序（距离越小越相似）
            #         formatted_results.sort(key=lambda x: x['similarity_score'])
                    
            #         logger.info(f"PostgreSQL pgvector搜索完成，找到 {len(formatted_results)} 个相关文档")
            #         return formatted_results
                    
            #     except Exception as e:
            #         logger.warning(f"PostgreSQL pgvector存储不存在: {collection_name}, {str(e)}")
            #         return []
            # else:
            # Chroma兼容模式
            from langchain_chroma import Chroma
            kb_vector_path = os.path.join(self.vector_db_path, f"kb_{knowledge_base_id}")
            
            if not os.path.exists(kb_vector_path):
                logger.warning(f"向量存储不存在: {kb_vector_path}")
                return []
            
            # 加载向量存储
            vector_store = Chroma(
                persist_directory=kb_vector_path,
                embedding_function=self.embeddings
            )
            
            # 执行相似性搜索
            results = vector_store.similarity_search_with_score(query, k=k)
            
            # 格式化结果
            formatted_results = []
            for doc, distance_score in results:
                # Chroma使用欧几里得距离，距离越小相似度越高
                # 将距离转换为0-1之间的相似度分数
                similarity_score = 1.0 / (1.0 + distance_score)
                
                formatted_results.append({
                    "content": doc.page_content,
                    "metadata": doc.metadata,
                    "similarity_score": distance_score,  # 保留原始距离分数
                    "normalized_score": similarity_score,  # 归一化相似度分数
                    "source": doc.metadata.get('filename', 'unknown'),
                    "document_id": doc.metadata.get('document_id', 'unknown'),
                    "chunk_id": doc.metadata.get('chunk_id', 'unknown')
                })
            
            # 按相似度分数排序（距离越小越相似）
            formatted_results.sort(key=lambda x: x['similarity_score'])
            
            logger.info(f"搜索完成，找到 {len(formatted_results)} 个相关文档")
            return formatted_results
            
        except Exception as e:
            logger.error(f"搜索文档失败: {str(e)}")
            return []  # 返回空列表而不是抛出异常

# 全局文档处理器实例（延迟初始化）
document_processor = None

async def get_document_processor(session: Session = None):
    """获取文档处理器实例（延迟初始化）"""
    global document_processor
    if session:
        session.desc = "获取文档处理器实例"
    if document_processor is None:
        document_processor = DocumentProcessor()
        await document_processor.initialize(session)
    return document_processor