feat(api): include search result totals (#791)

Signed-off-by: phernandez <paul@basicmachines.co>

src/basic_memory/api/v2/routers/search_router.py

@@ -4,6 +4,8 @@ This router uses external_id UUIDs for stable, API-friendly routing.
 V1 uses string-based project names which are less efficient and less stable.
 """
 
+import asyncio
+
 from fastapi import APIRouter, HTTPException, Path
 
 import logfire
@@ -12,7 +14,7 @@ from basic_memory.repository.semantic_errors import (
     SemanticDependenciesMissingError,
     SemanticSearchDisabledError,
 )
-from basic_memory.schemas.search import SearchQuery, SearchResponse
+from basic_memory.schemas.search import SearchQuery, SearchResponse, SearchRetrievalMode
 from basic_memory.deps import (
     SearchServiceV2ExternalDep,
     EntityServiceV2ExternalDep,
@@ -65,7 +67,7 @@ async def search(
         has_filters=bool(query.note_types or query.entity_types or query.metadata_filters),
     ):
         offset = (page - 1) * page_size
-        fetch_limit = page_size + 1
+        exact_count_available = query.retrieval_mode == SearchRetrievalMode.FTS
         try:
             with logfire.span(
                 "api.search.search.execute_query",
@@ -75,7 +77,14 @@ async def search(
                 page=page,
                 page_size=page_size,
             ):
-                results = await search_service.search(query, limit=fetch_limit, offset=offset)
+                if exact_count_available:
+                    results, total = await asyncio.gather(
+                        search_service.search(query, limit=page_size, offset=offset),
+                        search_service.count(query),
+                    )
+                else:
+                    results = await search_service.search(query, limit=page_size + 1, offset=offset)
+                    total = 0
         except SemanticSearchDisabledError as exc:
             raise HTTPException(status_code=400, detail=str(exc)) from exc
         except SemanticDependenciesMissingError as exc:
@@ -90,9 +99,15 @@ async def search(
             phase="paginate_results",
             result_count=len(results),
         ):
-            has_more = len(results) > page_size
-            if has_more:
-                results = results[:page_size]
+            if exact_count_available:
+                has_more = offset + len(results) < total
+            else:
+                # Trigger: semantic modes would need another vector/hybrid retrieval to count.
+                # Why: search requests should not pay for a second semantic pass.
+                # Outcome: preserve probe pagination for semantic search and leave total at 0.
+                has_more = len(results) > page_size
+                if has_more:
+                    results = results[:page_size]
 
         with logfire.span(
             "api.search.search.hydrate_results",
@@ -113,6 +128,7 @@ async def search(
                 results=search_results,
                 current_page=page,
                 page_size=page_size,
+                total=total,
                 has_more=has_more,
             )