Merge pull request #87 from Tr1sma/bolt/optimize-stats-service-14777551252098779145

⚡ Bolt: Optimize StatsService aggregation queries

Author: Tr1sma

BookLoggerApp.Infrastructure/Services/StatsService.cs

@@ -24,14 +24,16 @@ public async Task<int> GetTotalBooksReadAsync(CancellationToken ct = default)
 
     public async Task<int> GetTotalPagesReadAsync(CancellationToken ct = default)
     {
-        var completedBooks = await _unitOfWork.Books.GetBooksByStatusAsync(ReadingStatus.Completed);
-        return completedBooks.Where(b => b.PageCount.HasValue).Sum(b => b.PageCount!.Value);
+        // Optimized: Calculate sum in database to avoid loading all completed books into memory.
+        return await _unitOfWork.Context.Set<Book>()
+            .Where(b => b.Status == ReadingStatus.Completed && b.PageCount.HasValue)
+            .SumAsync(b => b.PageCount!.Value, ct);
     }
 
     public async Task<int> GetTotalMinutesReadAsync(CancellationToken ct = default)
     {
-        var allSessions = await _unitOfWork.ReadingSessions.GetAllAsync();
-        return allSessions.Sum(s => s.Minutes);
+        // Optimized: Calculate sum in database using existing repository method.
+        return await _unitOfWork.ReadingSessions.GetTotalMinutesAsync(ct);
     }
 
     public async Task<int> GetCurrentStreakAsync(CancellationToken ct = default)

BookLoggerApp.Tests/Services/StatsServicePerformanceTests.cs

@@ -0,0 +1,83 @@
+using FluentAssertions;
+using BookLoggerApp.Core.Models;
+using BookLoggerApp.Infrastructure.Data;
+using BookLoggerApp.Infrastructure.Services;
+using BookLoggerApp.Infrastructure.Repositories;
+using BookLoggerApp.Tests.TestHelpers;
+using Xunit;
+using Microsoft.EntityFrameworkCore;
+
+namespace BookLoggerApp.Tests.Services;
+
+public class StatsServicePerformanceTests : IDisposable
+{
+    private readonly AppDbContext _context;
+    private readonly IUnitOfWork _unitOfWork;
+    private readonly StatsService _service;
+
+    public StatsServicePerformanceTests()
+    {
+        _context = TestDbContext.Create();
+        _unitOfWork = new UnitOfWork(_context);
+        _service = new StatsService(_unitOfWork);
+    }
+
+    public void Dispose()
+    {
+        _context.Dispose();
+    }
+
+    [Fact]
+    public async Task GetTotalMinutesReadAsync_ShouldCalculateSumDatabaseSide_AndBeCorrect()
+    {
+        // Arrange
+        await _unitOfWork.ReadingSessions.AddAsync(new ReadingSession
+        {
+            Minutes = 60,
+            StartedAt = DateTime.UtcNow
+        });
+        await _unitOfWork.ReadingSessions.AddAsync(new ReadingSession
+        {
+            Minutes = 30,
+            StartedAt = DateTime.UtcNow
+        });
+        await _context.SaveChangesAsync();
+
+        // Act
+        var totalMinutes = await _service.GetTotalMinutesReadAsync();
+
+        // Assert
+        totalMinutes.Should().Be(90);
+    }
+
+    [Fact]
+    public async Task GetTotalPagesReadAsync_ShouldCalculateSumDatabaseSide_AndBeCorrect()
+    {
+        // Arrange
+        await _unitOfWork.Books.AddAsync(new Book
+        {
+            Title = "Book 1",
+            Status = ReadingStatus.Completed,
+            PageCount = 100
+        });
+        await _unitOfWork.Books.AddAsync(new Book
+        {
+            Title = "Book 2",
+            Status = ReadingStatus.Completed,
+            PageCount = 200
+        });
+        await _unitOfWork.Books.AddAsync(new Book
+        {
+            Title = "Book 3",
+            Status = ReadingStatus.Reading, // Should be ignored
+            PageCount = 50
+        });
+        await _context.SaveChangesAsync();
+
+        // Act
+        var totalPages = await _service.GetTotalPagesReadAsync();
+
+        // Assert
+        totalPages.Should().Be(300);
+    }
+}