app/api/graph.py

from fastapi import APIRouter, Query, HTTPException, status
from fastapi.responses import JSONResponse
from app.services.graph_service import graph_service
from app.cache import cache
import time
from app.database.neo4j_driver import Neo4jDriver, get_neo4j_driver

router = APIRouter(
    prefix="/api",
    tags=["knowledge graph"]
)

@router.get("/graph")
async def get_graph(
        limit: int = Query(100, ge=1, le=1000),
        database: str = Query("u0-ss-math-rjb-bx3", description="要查询的Neo4j数据库名称")
):
    """
    获取知识图谱数据

    Args:
        limit: 每类最多返回的节点数量
        database: Neo4j数据库名称，默认为"u0-ss-math-rjb-bx3"

    Returns:
        包含节点和关系的图谱数据
    """
    try:
        result, is_cached = graph_service.get_knowledge_graph(limit, database)
        return JSONResponse(
            content=result,
            headers={"X-From-Cache": "true" if is_cached else "false"}
        )
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"获取知识图谱失败: {str(e)}"
        )


@router.delete("/graph/cache")
async def clear_graph_cache():
    """
    清除知识图谱缓存
    """
    try:
        cache.clear_by_prefix("knowledge_graph")
        return {"message": "缓存已清除"}
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"清除缓存失败: {str(e)}"
        )

@router.get("/graph/cache-status")
async def get_cache_status(limit: int = Query(100, ge=1, le=1000)):
    """
    获取缓存状态
    """
    cache_key = f"knowledge_graph:{limit}"
    cache_info = cache.get_cache_info(cache_key)

    if cache_info["exists"]:
        return {
            "cached": True,
            "limit": limit,
            "expires_in_seconds": cache_info["expires_in"],
            "expires_in_minutes": cache_info["expires_in"] // 60,
            "expires_at": time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(cache_info["expires_at"]))
        }
    else:
        return {
            "cached": False,
            "limit": limit
        }

@router.get("/health")
async def health_check():
    """
    健康检查路由，检查数据库连接状态
    """
    driver = Neo4jDriver()
    if driver.check_connection():
        return {"status": "ok", "message": "数据库连接正常"}
    else:
        return {"status": "error", "message": "数据库连接失败"}, 500


@router.get("/graph/node/{node_id}")
async def get_node(node_id: str):
    """
    查询特定 ID 的节点

    Args:
        node_id: 节点的唯一标识符

    Returns:
        包含节点属性的字典
    """
    # 使用 get_neo4j_driver 函数获取驱动
    driver = get_neo4j_driver()

    try:
        with driver.session() as session:
            # 使用参数化查询，避免 SQL 注入
            query = """
            MATCH (n)
            WHERE n.id = $node_id
            RETURN n
            """
            result = session.run(query, node_id=node_id)  # 将 node_id 转为整数
            record = result.single()

            if not record:
                raise HTTPException(
                    status_code=status.HTTP_404_NOT_FOUND,
                    detail=f"未找到节点: {node_id}"
                )

            node_data = record["n"]
            return {
                "id": node_data.id,
                **dict(node_data)  # 返回属性
            }
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"查询节点失败: {str(e)}"
        )