Refactor search architecture: move integer ID enhancement to NoteService

- Add SearchUserNotes method to INoteService and NoteService
- Move integer ID enhancement logic from SearchService to NoteService
- Remove INoteRepository dependency from SearchService
- Update NotesController to use SearchUserNotes method
- Clean up SearchService to focus purely on search index operations
- Update SearchServiceTests to remove repository-related tests
- Add comprehensive tests for SearchUserNotes method

Fixes #11

Author: davidwei

src/HappyNotes.Api/Controllers/NotesController.cs

@@ -79,7 +79,7 @@ public async Task<ApiResult> PurgeDeleted()
     public async Task<ApiResult<PageData<NoteDto>>> Search(string query, int pageNumber = 1, int pageSize = 10, string filter = "normal")
     {
         var filterType = filter.ToLower() == "deleted" ? NoteFilterType.Deleted : NoteFilterType.Normal;
-        var results = await noteService.GetUserKeywordNotes(currentUser.Id, pageSize, pageNumber, query, filterType);
+        var results = await noteService.SearchUserNotes(currentUser.Id, pageSize, pageNumber, query, filterType);
         return new SuccessfulResult<PageData<NoteDto>>(mapper.Map<PageData<NoteDto>>(results));
     }
 }

src/HappyNotes.Services/NoteService.cs

@@ -182,6 +182,62 @@ public async Task<PageData<Note>> GetUserKeywordNotes(long userId, int pageSize,
         };
     }
 
+    public async Task<PageData<Note>> SearchUserNotes(long userId, int pageSize, int pageNumber, string keyword, NoteFilterType filter = NoteFilterType.Normal)
+    {
+        keyword = keyword?.Trim() ?? string.Empty;
+        if (keyword.Length == 0)
+        {
+            return new PageData<Note>()
+            {
+                DataList = [],
+                PageIndex = pageNumber,
+                PageSize = pageSize,
+                TotalCount = 0,
+            };
+        }
+
+        // Bigram indexing requires at least 2 characters to generate valid tokens
+        if (keyword.Length == 1)
+        {
+            return new PageData<Note>()
+            {
+                DataList = [],
+                PageIndex = pageNumber,
+                PageSize = pageSize,
+                TotalCount = 0,
+            };
+        }
+
+        // Get search results from SearchService
+        var (noteIds, total) = await searchService.GetNoteIdsByKeywordAsync(userId, keyword, pageNumber, pageSize, filter);
+        var noteIdList = noteIds.ToList();
+
+        // Enhancement: if keyword is an integer and this is the first page,
+        // check if the note ID belongs to the current user and prepend it to results
+        if (pageNumber == 1 && long.TryParse(keyword, out long noteId))
+        {
+            // Check if this note ID belongs to the current user
+            var note = await noteRepository.GetFirstOrDefaultAsync(n => n.Id == noteId);
+
+            if (note != null && note.UserId == userId)
+            {
+                // Remove the note from the list if it's already there to avoid duplication
+                noteIdList.RemoveAll(id => id == noteId);
+                // Prepend it to the beginning
+                noteIdList.Insert(0, noteId);
+            }
+        }
+
+        var notes = await _GetNotesByIds(noteIdList);
+        return new PageData<Note>()
+        {
+            DataList = notes,
+            PageIndex = pageNumber,
+            PageSize = pageSize,
+            TotalCount = total,
+        };
+    }
+
     public async Task<PageData<Note>> GetLinkedNotes(long userId, long noteId)
     {
         return await noteRepository.GetLinkedNotes(userId, noteId);

src/HappyNotes.Services/SearchService.cs

@@ -7,7 +7,6 @@
 using HappyNotes.Entities;
 using HappyNotes.Models.Search;
 using HappyNotes.Services.interfaces;
-using HappyNotes.Repositories.interfaces;
 using SqlSugar;
 
 namespace HappyNotes.Services;
@@ -16,13 +15,11 @@ public class SearchService : ISearchService
 {
     private readonly IDatabaseClient _client;
     private readonly HttpClient _httpClient;
-    private readonly INoteRepository _noteRepository;
 
-    public SearchService(IDatabaseClient client, HttpClient httpClient, ManticoreConnectionOptions options, INoteRepository noteRepository)
+    public SearchService(IDatabaseClient client, HttpClient httpClient, ManticoreConnectionOptions options)
     {
         _client = client;
         _httpClient = httpClient;
-        _noteRepository = noteRepository;
         _httpClient.BaseAddress = new Uri(options.HttpEndpoint);
         _httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
     }
@@ -69,22 +66,6 @@ public SearchService(IDatabaseClient client, HttpClient httpClient, ManticoreCon
             }
         }
 
-        // Enhancement: if query is an integer and this is the first page,
-        // check if the note ID belongs to the current user and prepend it to results
-        if (pageNumber == 1 && long.TryParse(query, out long noteId))
-        {
-            // Check if this note ID belongs to the current user
-            var note = await _noteRepository.GetFirstOrDefaultAsync(n => n.Id == noteId);
-
-            if (note != null && note.UserId == userId)
-            {
-                // Remove the note from the list if it's already there to avoid duplication
-                noteIdList.RemoveAll(id => id == noteId);
-                // Prepend it to the beginning
-                noteIdList.Insert(0, noteId);
-            }
-        }
-
         return (noteIdList, (int)total);
     }
 

src/HappyNotes.Services/interfaces/INoteService.cs

@@ -24,6 +24,7 @@ public interface INoteService
 
     Task<PageData<Note>> GetUserTagNotes(long userId, int pageSize, int pageNumber, string tag);
     Task<PageData<Note>> GetUserKeywordNotes(long userId, int pageSize, int pageNumber, string keyword, NoteFilterType filter = NoteFilterType.Normal);
+    Task<PageData<Note>> SearchUserNotes(long userId, int pageSize, int pageNumber, string keyword, NoteFilterType filter = NoteFilterType.Normal);
 
     Task<PageData<Note>> GetLinkedNotes(long userId, long noteId);
     Task<IList<Note>> Memories(long userId, string localTimezone);