fix 文档管理模块 & 法规对话模块

backend/app/application/knowledge/services.py

@@ -3,17 +3,24 @@
 from __future__ import annotations
 
 from app.domain.retrieval import RetrievalQuery, Retriever, RetrievedChunk
+from app.domain.retrieval.ports import Reranker
 # Keep orchestration logic centralized so use-case flow stays easy to trace.
 
 
-
 class KnowledgeRetrievalService:
     """Provide the Knowledge Retrieval Service service."""
-    def __init__(self, *, retriever: Retriever) -> None:
+
+    def __init__(self, *, retriever: Retriever, reranker: Reranker | None = None, reranker_top_k: int = 5) -> None:
         """Initialize the Knowledge Retrieval Service instance."""
         self.retriever = retriever
+        self.reranker = reranker
+        self.reranker_top_k = reranker_top_k
 
     def retrieve(self, *, query: str, top_k: int, filters: str | None = None) -> list[RetrievedChunk]:
-        """Handle retrieve for the Knowledge Retrieval Service instance."""
-        retrieval_query = RetrievalQuery(query=query, top_k=top_k, filters=filters)
-        return self.retriever.retrieve(retrieval_query)
+        """Retrieve and optionally rerank chunks for a query."""
+        candidate_k = top_k if self.reranker is None else max(top_k * 4, 20)
+        retrieval_query = RetrievalQuery(query=query, top_k=candidate_k, filters=filters)
+        candidates = self.retriever.retrieve(retrieval_query)
+        if self.reranker and candidates:
+            return self.reranker.rerank(query, candidates, top_k=self.reranker_top_k)
+        return candidates[:top_k]