Try to reuse existing chunks (#3983)

### What problem does this PR solve?

Try to reuse existing chunks. Close #3793
### Type of change

- [x] New Feature (non-breaking change which adds functionality)

api/db/services/document_service.py

@@ -282,6 +282,31 @@ class DocumentService(CommonService):
             return
         return docs[0]["embd_id"]
 
+    @classmethod
+    @DB.connection_context()
+    def get_chunking_config(cls, doc_id):
+        configs = (
+            cls.model.select(
+                cls.model.id,
+                cls.model.kb_id,
+                cls.model.parser_id,
+                cls.model.parser_config,
+                Knowledgebase.language,
+                Knowledgebase.embd_id,
+                Tenant.id.alias("tenant_id"),
+                Tenant.img2txt_id,
+                Tenant.asr_id,
+                Tenant.llm_id,
+            )
+            .join(Knowledgebase, on=(cls.model.kb_id == Knowledgebase.id))
+            .join(Tenant, on=(Knowledgebase.tenant_id == Tenant.id))
+            .where(cls.model.id == doc_id)
+        )
+        configs = configs.dicts()
+        if not configs:
+            return None
+        return configs[0]
+
     @classmethod
     @DB.connection_context()
     def get_doc_id_by_doc_name(cls, doc_name):