from fastapi import APIRouter, HTTPException, Query
from pydantic import BaseModel
from app.core.embedding import embedder
from app.core.config import settings
from llama_index.vector_stores.faiss import FaissVectorStore
from llama_index import VectorStoreIndex, ServiceContext, StorageContext
import os
import logging
import chardet

router = APIRouter()

# 设置日志记录器
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class QueryRequest(BaseModel):
    query: str

# 自动检测文件编码并加载
def read_file_with_detected_encoding(file_path: str):
    with open(file_path, "rb") as f:
        raw_data = f.read()
        result = chardet.detect(raw_data)
        encoding = result['encoding']  # 获取检测到的编码
    try:
        with open(file_path, "r", encoding=encoding, errors='ignore') as f:
            return f.read()
    except UnicodeDecodeError:
        logger.error(f"UnicodeDecodeError: Unable to decode the file using {encoding}.")
        raise HTTPException(status_code=500, detail="Error reading the file due to encoding issues.")

@router.post("/search")
def search_docs(request: QueryRequest, user_id: str = Query(..., description="用户ID")):
    try:
        logger.info(f"Received search request from user: {user_id} with query: {request.query}")

        # 修正后的索引路径，确保指向整个目录，而不是单个文件
        index_path = os.path.join("index_data", user_id)  # 使用整个目录路径
        logger.info(f"Looking for index at path: {index_path}")

        # 检查索引目录是否存在
        if not os.path.exists(index_path):
            logger.error(f"Index not found for user: {user_id} at {index_path}")
            raise HTTPException(status_code=404, detail="用户索引不存在")

        # 创建 StorageContext 并加载 Faiss 向量存储目录
        logger.info(f"Loading Faiss vector store from path: {index_path}")
        storage_context = StorageContext.from_defaults(persist_dir=index_path)

        # 自动读取 docstore.json 文件内容并解码
        docstore_file = os.path.join(index_path, "docstore.json")
        if os.path.exists(docstore_file):
            file_content = read_file_with_detected_encoding(docstore_file)
            logger.info(f"Successfully read docstore.json with detected encoding.")
        else:
            logger.error(f"docstore.json not found at {docstore_file}")
            raise HTTPException(status_code=404, detail="docstore.json not found")

        # 加载 Faiss 向量存储
        faiss_store = FaissVectorStore.from_persist_path(storage_context)
        service_context = ServiceContext.from_defaults(embed_model=embedder, llm=None)
        logger.info("Service context created successfully.")

        index = VectorStoreIndex.from_vector_store(faiss_store, service_context=service_context)
        logger.info("VectorStoreIndex created successfully.")

        # 检索结果（真实文本）
        retriever = index.as_retriever(similarity_top_k=settings.TOP_K)
        logger.info(f"Retrieving top {settings.TOP_K} results for query: {request.query}")
        nodes = retriever.retrieve(request.query)

        # 返回检索结果
        result = {
            "user_id": user_id,
            "query": request.query,
            "results": [
                {"score": float(node.score or 0), "text": node.get_content()}
                for node in nodes
            ]
        }

        logger.info(f"Search results for user {user_id}: {result}")
        return result

    except Exception as e:
        logger.error(f"Error processing search request: {e}", exc_info=True)
        raise HTTPException(status_code=500, detail=str(e))