feat(server): add api to fetch entity context entities

memos/crud.py

@@ -596,3 +596,58 @@ async def list_entities(
     entities = query.order_by(EntityModel.file_created_at.desc()).limit(limit).all()
 
     return [Entity(**entity.__dict__) for entity in entities]
+
+
+def get_entity_context(
+    db: Session, library_id: int, entity_id: int, prev: int = 0, next: int = 0
+) -> Tuple[List[Entity], List[Entity]]:
+    """
+    Get the context (previous and next entities) for a given entity.
+    Returns a tuple of (previous_entities, next_entities).
+    """
+    # First get the target entity to get its timestamp
+    target_entity = (
+        db.query(EntityModel)
+        .filter(
+            EntityModel.id == entity_id,
+            EntityModel.library_id == library_id,
+        )
+        .first()
+    )
+    
+    if not target_entity:
+        return [], []
+        
+    # Get previous entities
+    prev_entities = []
+    if prev > 0:
+        prev_entities = (
+            db.query(EntityModel)
+            .filter(
+                EntityModel.library_id == library_id,
+                EntityModel.file_created_at < target_entity.file_created_at
+            )
+            .order_by(EntityModel.file_created_at.desc())
+            .limit(prev)
+            .all()
+        )
+        # Reverse the list to get chronological order and convert to Entity models
+        prev_entities = [Entity(**entity.__dict__) for entity in prev_entities][::-1]
+    
+    # Get next entities
+    next_entities = []
+    if next > 0:
+        next_entities = (
+            db.query(EntityModel)
+            .filter(
+                EntityModel.library_id == library_id,
+                EntityModel.file_created_at > target_entity.file_created_at
+            )
+            .order_by(EntityModel.file_created_at.asc())
+            .limit(next)
+            .all()
+        )
+        # Convert to Entity models
+        next_entities = [Entity(**entity.__dict__) for entity in next_entities]
+    
+    return prev_entities, next_entities

memos/schemas.py

@@ -292,3 +292,8 @@ class SearchResult(BaseModel):
     request_params: RequestParams
     search_cutoff: bool
     search_time_ms: int
+
+
+class EntityContext(BaseModel):
+    prev: List[Entity]
+    next: List[Entity]

memos/server.py

@@ -46,6 +46,7 @@ from .schemas import (
     SearchResult,
     SearchHit,
     RequestParams,
+    EntityContext,
 )
 from .read_metadata import read_metadata
 from .logging_config import LOGGING_CONFIG
@@ -886,6 +887,54 @@ async def search_entities_v2(
         )
 
 
+@app.get(
+    "/libraries/{library_id}/entities/{entity_id}/context",
+    response_model=EntityContext,
+    tags=["entity"],
+)
+def get_entity_context(
+    library_id: int,
+    entity_id: int,
+    prev: Annotated[int | None, Query(ge=0, le=100)] = None,
+    next: Annotated[int | None, Query(ge=0, le=100)] = None,
+    db: Session = Depends(get_db),
+):
+    """
+    Get the context (previous and next entities) for a given entity.
+    
+    Args:
+        library_id: The ID of the library
+        entity_id: The ID of the target entity
+        prev: Number of previous entities to fetch (optional)
+        next: Number of next entities to fetch (optional)
+    
+    Returns:
+        EntityContext object containing prev and next lists of entities
+    """
+    # If both prev and next are None, return empty lists
+    if prev is None and next is None:
+        return EntityContext(prev=[], next=[])
+        
+    # Convert None to 0 for the crud function
+    prev_count = prev if prev is not None else 0
+    next_count = next if next is not None else 0
+    
+    # Get the context entities
+    prev_entities, next_entities = crud.get_entity_context(
+        db=db,
+        library_id=library_id,
+        entity_id=entity_id,
+        prev=prev_count,
+        next=next_count
+    )
+    
+    # Return the context object
+    return EntityContext(
+        prev=prev_entities,
+        next=next_entities
+    )
+
+
 def run_server():
     logging.info("Database path: %s", get_database_path())
     if settings.typesense.enabled: