"""向量知识库管理接口 - 直接操作 ChromaDB"""
from fastapi import APIRouter, HTTPException
from pydantic import BaseModel
from typing import Optional, List
import logging
import asyncio
import os

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/v1/knowledge-base", tags=["knowledge-base"])

# 后台同步任务引用
_sync_task = None


class DocumentInfo(BaseModel):
    id: str
    source: str
    title: str
    content: str = ""
    content_preview: str = ""
    metadata: dict = {}


class ListRequest(BaseModel):
    source: Optional[str] = None
    keyword: Optional[str] = None
    page: int = 1
    size: int = 20


class UpdateDocumentRequest(BaseModel):
    content: str
    title: Optional[str] = None
    metadata_override: Optional[dict] = None


@router.post("/stats")
async def get_stats():
    """获取向量库统计信息"""
    try:
        from app.rag.retriever import RagRetriever
        from app.rag.embeddings import get_embeddings
        from app.config import settings
        from langchain_chroma import Chroma

        retriever = RagRetriever()
        collection = retriever.vectorstore._collection
        count = collection.count()

        # 按 source 统计（兼容新旧两种 metadata 字段：source / type）
        all_data = collection.get(include=["metadatas"])
        metas = all_data.get("metadatas") or []
        source_counts = {}
        type_counts = {}
        for meta in metas:
            if not meta:
                continue
            src = meta.get("source") or meta.get("type") or "unknown"
            source_counts[src] = source_counts.get(src, 0) + 1
            doc_type = meta.get("type") or meta.get("source") or "unknown"
            type_counts[doc_type] = type_counts.get(doc_type, 0) + 1

        return {
            "total": count,
            "by_source": source_counts,
            "by_type": type_counts,
            "last_sync": _load_sync_state(),
        }
    except Exception as e:
        logger.error("获取向量库统计失败: %s", e)
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/documents")
async def list_documents(req: ListRequest):
    """分页列出向量库文档"""
    try:
        from app.rag.retriever import RagRetriever
        from app.rag.embeddings import get_embeddings
        from app.config import settings
        from langchain_chroma import Chroma

        retriever = RagRetriever()
        collection = retriever.vectorstore._collection

        # 构建过滤条件（兼容新旧两种 metadata 字段：source / type）
        where_filter = None
        if req.source:
            where_filter = {"$or": [{"source": req.source}, {"type": req.source}]}

        # 使用 get() 分页获取，避免加载全部 embedding
        limit = req.size
        offset = (req.page - 1) * req.size

        result = collection.get(
            where=where_filter,
            include=["documents", "metadatas"],
            limit=limit,
            offset=offset,
        )

        ids = result.get("ids") or []
        docs = result.get("documents") or []
        metas = result.get("metadatas") or []

        documents = []
        for i, doc_id in enumerate(ids):
            meta = metas[i] if i < len(metas) else {}
            content = docs[i] if i < len(docs) else ""
            # 截取内容预览
            preview = content[:200] + "..." if len(content) > 200 else content
            documents.append(DocumentInfo(
                id=doc_id,
                source=meta.get("source") or meta.get("type") or "unknown",
                title=meta.get("title", ""),
                content=content,
                content_preview=preview,
                metadata=meta,
            ))

        # 获取总数
        count_result = collection.get(
            where=where_filter,
            include=[],
        )
        total = len(count_result.get("ids", []))

        return {
            "total": total,
            "page": req.page,
            "size": req.size,
            "documents": documents,
        }
    except Exception as e:
        logger.error("列出文档失败: %s", e)
        raise HTTPException(status_code=500, detail=str(e))


@router.delete("/source/{source_prefix}")
async def delete_by_source(source_prefix: str):
    """删除指定 source 前缀的所有文档"""
    try:
        from app.rag.retriever import RagRetriever
        from app.rag.embeddings import get_embeddings
        from app.config import settings
        from langchain_chroma import Chroma

        retriever = RagRetriever()
        collection = retriever.vectorstore._collection

        # 兼容新旧两种 metadata 字段：source / type
        existing = collection.get(
            where={"$or": [{"source": source_prefix}, {"type": source_prefix}]},
            include=[],
        )
        ids = existing.get("ids", []) or []

        if not ids:
            return {"deleted": 0, "message": f"无 {source_prefix} 文档"}

        collection.delete(ids=ids)
        logger.info("已删除 source=%s 的 %d 个文档", source_prefix, len(ids))

        return {"deleted": len(ids), "source": source_prefix}
    except Exception as e:
        logger.error("删除文档失败: %s", e)
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/sync")
async def trigger_sync():
    """触发一次完整知识库同步"""
    global _sync_task

    try:
        # 如果已有同步任务在运行，返回提示
        if _sync_task and not _sync_task.done():
            return {"status": "running", "message": "同步任务已在运行中"}

        _sync_task = asyncio.create_task(_run_sync())
        return {"status": "started", "message": "已启动知识库同步任务"}
    except Exception as e:
        logger.error("触发同步失败: %s", e)
        raise HTTPException(status_code=500, detail=str(e))


async def _run_sync():
    """执行完整同步"""
    try:
        from app.tasks.knowledge_sync import sync_knowledge_base
        await sync_knowledge_base()
        logger.info("知识库同步完成")
    except Exception as e:
        logger.error("知识库同步失败: %s", e)


@router.put("/document/{doc_id}")
async def update_document(doc_id: str, req: UpdateDocumentRequest):
    """更新单个文档内容（先获取原 metadata，再删除重建，保持 ID 不变）"""
    try:
        from app.rag.retriever import RagRetriever
        from app.rag.embeddings import get_embeddings
        from app.config import settings
        from langchain_chroma import Chroma

        retriever = RagRetriever()
        collection = retriever.vectorstore._collection

        # 先获取原文档 metadata，避免删除后丢失
        old_result = collection.get(ids=[doc_id], include=["metadatas", "documents"])
        old_metas = old_result.get("metadatas") or []
        old_docs = old_result.get("documents") or []

        if not old_metas:
            raise HTTPException(status_code=404, detail="文档不存在")

        original_meta = old_metas[0]
        original_content = old_docs[0] if old_docs else ""

        # 删除旧文档
        collection.delete(ids=[doc_id])
        logger.info("已删除旧文档: %s", doc_id)

        # 构建新文档：保留原有 metadata，仅覆盖 content/title
        meta = req.metadata_override or {}
        # 保留原有 source/type/title 等字段，除非显式覆盖
        for k, v in original_meta.items():
            if k not in meta:
                meta[k] = v

        if req.title:
            meta["title"] = req.title

        # 使用原 ID 重新写入（显式传 ids，避免生成新 ID）
        from langchain_core.documents import Document
        doc = Document(page_content=req.content, metadata=meta)
        await retriever.vectorstore.aadd_documents([doc], ids=[doc_id])
        logger.info("已更新文档: %s", doc_id)

        return {"success": True, "message": "文档已更新", "doc_id": doc_id}
    except HTTPException:
        raise
    except Exception as e:
        logger.error("更新文档失败: %s", e)
        raise HTTPException(status_code=500, detail=str(e))


def _load_sync_state() -> str:
    """加载上次同步时间"""
    try:
        import json
        from app.config import settings
        import os
        sync_file = os.path.join(settings.chroma_db_path, ".sync_state")
        if os.path.exists(sync_file):
            with open(sync_file) as f:
                state = json.load(f)
                return state.get("last_sync", "未知")
    except Exception:
        pass
    return "未知"