Refactor: Extract dashboard services from Index page

Extract to separate files for better maintainability:
- Models/Dashboard/DashboardModels.cs - Dashboard DTOs
- Services/DashboardService.cs - All dashboard-related services
  - IDashboardService, IDashboardStatsCalculator
  - ITopCategoriesProvider, IRecentTransactionsProvider
  - ISpendTrendsProvider

Reduces Index.cshtml.cs from 355 lines to 37 lines.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

MoneyMap/Models/Dashboard/DashboardModels.cs

@@ -0,0 +1,62 @@
+namespace MoneyMap.Models.Dashboard
+{
+    /// <summary>
+    /// Statistics displayed on the dashboard.
+    /// </summary>
+    public record DashboardStats(
+        int TotalTransactions = 0,
+        int Credits = 0,
+        int Debits = 0,
+        int Uncategorized = 0,
+        int Receipts = 0,
+        int Cards = 0);
+
+    /// <summary>
+    /// Row representing spending in a category.
+    /// </summary>
+    public class TopCategoryRow
+    {
+        public string Category { get; set; } = "";
+        public decimal TotalSpend { get; set; }
+        public int Count { get; set; }
+        public decimal PercentageOfTotal { get; set; }
+        public decimal AveragePerTransaction { get; set; }
+    }
+
+    /// <summary>
+    /// Row representing a recent transaction.
+    /// </summary>
+    public class RecentTransactionRow
+    {
+        public long Id { get; set; }
+        public DateTime Date { get; set; }
+        public string Name { get; set; } = "";
+        public string Memo { get; set; } = "";
+        public decimal Amount { get; set; }
+        public string Category { get; set; } = "";
+        public string CardLabel { get; set; } = "";
+        public int ReceiptCount { get; set; }
+    }
+
+    /// <summary>
+    /// Spending trends over time.
+    /// </summary>
+    public class SpendTrends
+    {
+        public List<string> Labels { get; set; } = new();
+        public List<decimal> DebitsAbs { get; set; } = new();
+        public List<decimal> Credits { get; set; } = new();
+        public List<decimal> Net { get; set; } = new();
+    }
+
+    /// <summary>
+    /// Complete dashboard data package.
+    /// </summary>
+    public class DashboardData
+    {
+        public required DashboardStats Stats { get; init; }
+        public required List<TopCategoryRow> TopCategories { get; init; }
+        public required List<RecentTransactionRow> RecentTransactions { get; init; }
+        public required SpendTrends Trends { get; init; }
+    }
+}

MoneyMap/Pages/Index.cshtml.cs

@@ -1,7 +1,5 @@
 using Microsoft.AspNetCore.Mvc.RazorPages;
-using Microsoft.EntityFrameworkCore;
-using MoneyMap.Data;
-using MoneyMap.Models;
+using MoneyMap.Models.Dashboard;
 using MoneyMap.Services;
 
 namespace MoneyMap.Pages
@@ -17,7 +15,7 @@ namespace MoneyMap.Pages
 
         public DashboardStats Stats { get; set; } = new();
         public List<TopCategoryRow> TopCategories { get; set; } = new();
-        public List<RecentTxnRow> Recent { get; set; } = new();
+        public List<RecentTransactionRow> Recent { get; set; } = new();
         public List<string> TrendLabels { get; set; } = new();
         public List<decimal> TrendDebitsAbs { get; set; } = new();
         public List<decimal> TrendCredits { get; set; } = new();
@@ -35,321 +33,5 @@ namespace MoneyMap.Pages
             TrendCredits = dashboard.Trends.Credits;
             TrendNet = dashboard.Trends.Net;
         }
-
-        public record DashboardStats(
-            int TotalTransactions = 0,
-            int Credits = 0,
-            int Debits = 0,
-            int Uncategorized = 0,
-            int Receipts = 0,
-            int Cards = 0);
-
-        public class TopCategoryRow
-        {
-            public string Category { get; set; } = "";
-            public decimal TotalSpend { get; set; }
-            public int Count { get; set; }
-            public decimal PercentageOfTotal { get; set; }
-            public decimal AveragePerTransaction { get; set; }
-        }
-
-        public class RecentTxnRow
-        {
-            public long Id { get; set; }
-            public DateTime Date { get; set; }
-            public string Name { get; set; } = "";
-            public string Memo { get; set; } = "";
-            public decimal Amount { get; set; }
-            public string Category { get; set; } = "";
-            public string CardLabel { get; set; } = "";
-            public int ReceiptCount { get; set; }
-        }
-    }
-
-    // ===== Service Layer =====
-
-    public interface IDashboardService
-    {
-        Task<DashboardData> GetDashboardDataAsync(int topCategoriesCount = 8, int recentTransactionsCount = 20);
-    }
-
-    public class DashboardService : IDashboardService
-    {
-        private readonly MoneyMapContext _db;
-        private readonly IDashboardStatsCalculator _statsCalculator;
-        private readonly ITopCategoriesProvider _topCategoriesProvider;
-        private readonly IRecentTransactionsProvider _recentTransactionsProvider;
-        private readonly ISpendTrendsProvider _spendTrendsProvider;
-
-        public DashboardService(
-            MoneyMapContext db,
-            IDashboardStatsCalculator statsCalculator,
-            ITopCategoriesProvider topCategoriesProvider,
-            IRecentTransactionsProvider recentTransactionsProvider,
-            ISpendTrendsProvider spendTrendsProvider)
-        {
-            _db = db;
-            _statsCalculator = statsCalculator;
-            _topCategoriesProvider = topCategoriesProvider;
-            _recentTransactionsProvider = recentTransactionsProvider;
-            _spendTrendsProvider = spendTrendsProvider;
-        }
-
-        public async Task<DashboardData> GetDashboardDataAsync(int topCategoriesCount = 8, int recentTransactionsCount = 20)
-        {
-            var stats = await _statsCalculator.CalculateAsync();
-            var topCategories = await _topCategoriesProvider.GetTopCategoriesAsync(topCategoriesCount);
-            var recent = await _recentTransactionsProvider.GetRecentTransactionsAsync(recentTransactionsCount);
-            var trends = await _spendTrendsProvider.GetDailyTrendsAsync(30);
-
-            return new DashboardData
-            {
-                Stats = stats,
-                TopCategories = topCategories,
-                RecentTransactions = recent,
-                Trends = trends
-            };
-        }
-    }
-
-    // ===== Stats Calculator =====
-
-    public interface IDashboardStatsCalculator
-    {
-        Task<IndexModel.DashboardStats> CalculateAsync();
-    }
-
-    public class DashboardStatsCalculator : IDashboardStatsCalculator
-    {
-        private readonly MoneyMapContext _db;
-
-        public DashboardStatsCalculator(MoneyMapContext db)
-        {
-            _db = db;
-        }
-
-        public async Task<IndexModel.DashboardStats> CalculateAsync()
-        {
-            var transactionStats = await GetTransactionStatsAsync();
-            var receiptsCount = await _db.Receipts.CountAsync();
-            var cardsCount = await _db.Cards.CountAsync();
-
-            return new IndexModel.DashboardStats(
-                transactionStats.Total,
-                transactionStats.Credits,
-                transactionStats.Debits,
-                transactionStats.Uncategorized,
-                receiptsCount,
-                cardsCount
-            );
-        }
-
-        private async Task<TransactionStats> GetTransactionStatsAsync()
-        {
-            var stats = await _db.Transactions
-                .GroupBy(_ => 1)
-                .Select(g => new TransactionStats
-                {
-                    Total = g.Count(),
-                    Credits = g.Count(t => t.Amount > 0),
-                    Debits = g.Count(t => t.Amount < 0),
-                    Uncategorized = g.Count(t => t.Category == null || t.Category == "")
-                })
-                .FirstOrDefaultAsync();
-
-            return stats ?? new TransactionStats();
-        }
-
-        private class TransactionStats
-        {
-            public int Total { get; set; }
-            public int Credits { get; set; }
-            public int Debits { get; set; }
-            public int Uncategorized { get; set; }
-        }
-    }
-
-    // ===== Top Categories Provider =====
-
-    public interface ITopCategoriesProvider
-    {
-        Task<List<IndexModel.TopCategoryRow>> GetTopCategoriesAsync(int count = 8, int lastDays = 90);
-    }
-
-    public class TopCategoriesProvider : ITopCategoriesProvider
-    {
-        private readonly MoneyMapContext _db;
-
-        public TopCategoriesProvider(MoneyMapContext db)
-        {
-            _db = db;
-        }
-
-        public async Task<List<IndexModel.TopCategoryRow>> GetTopCategoriesAsync(int count = 8, int lastDays = 90)
-        {
-            var since = DateTime.UtcNow.Date.AddDays(-lastDays);
-
-            // Get all expense transactions for the period
-            var expenseTransactions = await _db.Transactions
-                .Where(t => t.Date >= since && t.Amount < 0)
-                .ExcludeTransfers() // Exclude credit card payments and transfers
-                .ToListAsync();
-
-            // Calculate total spend
-            var totalSpend = expenseTransactions.Sum(t => -t.Amount);
-
-            // Group by category and calculate percentages
-            var topCategories = expenseTransactions
-                .GroupBy(t => t.Category ?? "")
-                .Select(g => new IndexModel.TopCategoryRow
-                {
-                    Category = g.Key,
-                    TotalSpend = g.Sum(x => -x.Amount),
-                    Count = g.Count(),
-                    PercentageOfTotal = totalSpend > 0 ? (g.Sum(x => -x.Amount) / totalSpend) * 100 : 0,
-                    AveragePerTransaction = g.Count() > 0 ? g.Sum(x => -x.Amount) / g.Count() : 0
-                })
-                .OrderByDescending(x => x.TotalSpend)
-                .Take(count)
-                .ToList();
-
-            return topCategories;
-        }
-    }
-
-    // ===== Recent Transactions Provider =====
-
-    public interface IRecentTransactionsProvider
-    {
-        Task<List<IndexModel.RecentTxnRow>> GetRecentTransactionsAsync(int count = 20);
-    }
-
-    public class RecentTransactionsProvider : IRecentTransactionsProvider
-    {
-        private readonly MoneyMapContext _db;
-
-        public RecentTransactionsProvider(MoneyMapContext db)
-        {
-            _db = db;
-        }
-
-        public async Task<List<IndexModel.RecentTxnRow>> GetRecentTransactionsAsync(int count = 20)
-        {
-            return await _db.Transactions
-                .Include(t => t.Card)
-                .OrderByDescending(t => t.Date)
-                .ThenByDescending(t => t.Id)
-                .Select(t => new IndexModel.RecentTxnRow
-                {
-                    Id = t.Id,
-                    Date = t.Date,
-                    Name = t.Name,
-                    Memo = t.Memo,
-                    Amount = t.Amount,
-                    Category = t.Category ?? "",
-                    CardLabel = t.PaymentMethodLabel,
-                    ReceiptCount = t.Receipts.Count()
-                })
-                .Take(count)
-                .AsNoTracking()
-                .ToListAsync();
-        }
-
-        private static string FormatCardLabel(Card? card, string? cardLast4)
-        {
-            if (card != null)
-                return $"{card.Issuer} {card.Last4}";
-
-            if (string.IsNullOrEmpty(cardLast4))
-                return "";
-
-            return $"<22><><EFBFBD><EFBFBD> {cardLast4}";
-        }
-    }
-
-    // ===== Data Transfer Objects =====
-
-    public class DashboardData
-    {
-        public required IndexModel.DashboardStats Stats { get; init; }
-        public required List<IndexModel.TopCategoryRow> TopCategories { get; init; }
-        public required List<IndexModel.RecentTxnRow> RecentTransactions { get; init; }
-        public required SpendTrends Trends { get; init; }
-    }
-
-    // ===== Spend Trends Provider =====
-
-    public interface ISpendTrendsProvider
-    {
-        Task<SpendTrends> GetDailyTrendsAsync(int lastDays = 30);
-    }
-
-    public class SpendTrendsProvider : ISpendTrendsProvider
-    {
-        private readonly MoneyMapContext _db;
-
-        public SpendTrendsProvider(MoneyMapContext db)
-        {
-            _db = db;
-        }
-
-        public async Task<SpendTrends> GetDailyTrendsAsync(int lastDays = 30)
-        {
-            var today = DateTime.UtcNow.Date;
-            var since = today.AddDays(-(lastDays - 1));
-
-            var raw = await _db.Transactions
-                .Where(t => t.Date >= since)
-                .ExcludeTransfers()
-                .GroupBy(t => t.Date.Date)
-                .Select(g => new
-                {
-                    Date = g.Key,
-                    Debits = g.Where(t => t.Amount < 0).Sum(t => t.Amount),
-                    Credits = g.Where(t => t.Amount > 0).Sum(t => t.Amount)
-                })
-                .ToListAsync();
-
-            var dict = raw.ToDictionary(x => x.Date, x => x);
-            var labels = new List<string>();
-            var debitsAbs = new List<decimal>();
-            var credits = new List<decimal>();
-            var net = new List<decimal>();
-
-            for (var d = since; d <= today; d = d.AddDays(1))
-            {
-                labels.Add(d.ToString("yyyy-MM-dd"));
-                if (dict.TryGetValue(d, out var v))
-                {
-                    var debit = v.Debits;
-                    var credit = v.Credits;
-                    debitsAbs.Add(Math.Abs(debit));
-                    credits.Add(credit);
-                    net.Add(credit + debit);
-                }
-                else
-                {
-                    debitsAbs.Add(0);
-                    credits.Add(0);
-                    net.Add(0);
-                }
-            }
-
-            return new SpendTrends
-            {
-                Labels = labels,
-                DebitsAbs = debitsAbs,
-                Credits = credits,
-                Net = net
-            };
-        }
-    }
-
-    public class SpendTrends
-    {
-        public List<string> Labels { get; set; } = new();
-        public List<decimal> DebitsAbs { get; set; } = new();
-        public List<decimal> Credits { get; set; } = new();
-        public List<decimal> Net { get; set; } = new();
     }
 }

MoneyMap/Services/DashboardService.cs

@@ -0,0 +1,263 @@
+using Microsoft.EntityFrameworkCore;
+using MoneyMap.Data;
+using MoneyMap.Models.Dashboard;
+
+namespace MoneyMap.Services
+{
+    /// <summary>
+    /// Service for retrieving dashboard data.
+    /// </summary>
+    public interface IDashboardService
+    {
+        Task<DashboardData> GetDashboardDataAsync(int topCategoriesCount = 8, int recentTransactionsCount = 20);
+    }
+
+    public class DashboardService : IDashboardService
+    {
+        private readonly IDashboardStatsCalculator _statsCalculator;
+        private readonly ITopCategoriesProvider _topCategoriesProvider;
+        private readonly IRecentTransactionsProvider _recentTransactionsProvider;
+        private readonly ISpendTrendsProvider _spendTrendsProvider;
+
+        public DashboardService(
+            IDashboardStatsCalculator statsCalculator,
+            ITopCategoriesProvider topCategoriesProvider,
+            IRecentTransactionsProvider recentTransactionsProvider,
+            ISpendTrendsProvider spendTrendsProvider)
+        {
+            _statsCalculator = statsCalculator;
+            _topCategoriesProvider = topCategoriesProvider;
+            _recentTransactionsProvider = recentTransactionsProvider;
+            _spendTrendsProvider = spendTrendsProvider;
+        }
+
+        public async Task<DashboardData> GetDashboardDataAsync(int topCategoriesCount = 8, int recentTransactionsCount = 20)
+        {
+            var stats = await _statsCalculator.CalculateAsync();
+            var topCategories = await _topCategoriesProvider.GetTopCategoriesAsync(topCategoriesCount);
+            var recent = await _recentTransactionsProvider.GetRecentTransactionsAsync(recentTransactionsCount);
+            var trends = await _spendTrendsProvider.GetDailyTrendsAsync(30);
+
+            return new DashboardData
+            {
+                Stats = stats,
+                TopCategories = topCategories,
+                RecentTransactions = recent,
+                Trends = trends
+            };
+        }
+    }
+
+    /// <summary>
+    /// Calculates dashboard statistics.
+    /// </summary>
+    public interface IDashboardStatsCalculator
+    {
+        Task<DashboardStats> CalculateAsync();
+    }
+
+    public class DashboardStatsCalculator : IDashboardStatsCalculator
+    {
+        private readonly MoneyMapContext _db;
+
+        public DashboardStatsCalculator(MoneyMapContext db)
+        {
+            _db = db;
+        }
+
+        public async Task<DashboardStats> CalculateAsync()
+        {
+            var transactionStats = await GetTransactionStatsAsync();
+            var receiptsCount = await _db.Receipts.CountAsync();
+            var cardsCount = await _db.Cards.CountAsync();
+
+            return new DashboardStats(
+                transactionStats.Total,
+                transactionStats.Credits,
+                transactionStats.Debits,
+                transactionStats.Uncategorized,
+                receiptsCount,
+                cardsCount
+            );
+        }
+
+        private async Task<TransactionStatsInternal> GetTransactionStatsAsync()
+        {
+            var stats = await _db.Transactions
+                .GroupBy(_ => 1)
+                .Select(g => new TransactionStatsInternal
+                {
+                    Total = g.Count(),
+                    Credits = g.Count(t => t.Amount > 0),
+                    Debits = g.Count(t => t.Amount < 0),
+                    Uncategorized = g.Count(t => t.Category == null || t.Category == "")
+                })
+                .FirstOrDefaultAsync();
+
+            return stats ?? new TransactionStatsInternal();
+        }
+
+        private class TransactionStatsInternal
+        {
+            public int Total { get; set; }
+            public int Credits { get; set; }
+            public int Debits { get; set; }
+            public int Uncategorized { get; set; }
+        }
+    }
+
+    /// <summary>
+    /// Provides top spending categories.
+    /// </summary>
+    public interface ITopCategoriesProvider
+    {
+        Task<List<TopCategoryRow>> GetTopCategoriesAsync(int count = 8, int lastDays = 90);
+    }
+
+    public class TopCategoriesProvider : ITopCategoriesProvider
+    {
+        private readonly MoneyMapContext _db;
+
+        public TopCategoriesProvider(MoneyMapContext db)
+        {
+            _db = db;
+        }
+
+        public async Task<List<TopCategoryRow>> GetTopCategoriesAsync(int count = 8, int lastDays = 90)
+        {
+            var since = DateTime.UtcNow.Date.AddDays(-lastDays);
+
+            var expenseTransactions = await _db.Transactions
+                .Where(t => t.Date >= since && t.Amount < 0)
+                .ExcludeTransfers()
+                .ToListAsync();
+
+            var totalSpend = expenseTransactions.Sum(t => -t.Amount);
+
+            var topCategories = expenseTransactions
+                .GroupBy(t => t.Category ?? "")
+                .Select(g => new TopCategoryRow
+                {
+                    Category = g.Key,
+                    TotalSpend = g.Sum(x => -x.Amount),
+                    Count = g.Count(),
+                    PercentageOfTotal = totalSpend > 0 ? (g.Sum(x => -x.Amount) / totalSpend) * 100 : 0,
+                    AveragePerTransaction = g.Count() > 0 ? g.Sum(x => -x.Amount) / g.Count() : 0
+                })
+                .OrderByDescending(x => x.TotalSpend)
+                .Take(count)
+                .ToList();
+
+            return topCategories;
+        }
+    }
+
+    /// <summary>
+    /// Provides recent transactions.
+    /// </summary>
+    public interface IRecentTransactionsProvider
+    {
+        Task<List<RecentTransactionRow>> GetRecentTransactionsAsync(int count = 20);
+    }
+
+    public class RecentTransactionsProvider : IRecentTransactionsProvider
+    {
+        private readonly MoneyMapContext _db;
+
+        public RecentTransactionsProvider(MoneyMapContext db)
+        {
+            _db = db;
+        }
+
+        public async Task<List<RecentTransactionRow>> GetRecentTransactionsAsync(int count = 20)
+        {
+            return await _db.Transactions
+                .Include(t => t.Card)
+                .OrderByDescending(t => t.Date)
+                .ThenByDescending(t => t.Id)
+                .Select(t => new RecentTransactionRow
+                {
+                    Id = t.Id,
+                    Date = t.Date,
+                    Name = t.Name,
+                    Memo = t.Memo,
+                    Amount = t.Amount,
+                    Category = t.Category ?? "",
+                    CardLabel = t.PaymentMethodLabel,
+                    ReceiptCount = t.Receipts.Count()
+                })
+                .Take(count)
+                .AsNoTracking()
+                .ToListAsync();
+        }
+    }
+
+    /// <summary>
+    /// Provides spending trends over time.
+    /// </summary>
+    public interface ISpendTrendsProvider
+    {
+        Task<SpendTrends> GetDailyTrendsAsync(int lastDays = 30);
+    }
+
+    public class SpendTrendsProvider : ISpendTrendsProvider
+    {
+        private readonly MoneyMapContext _db;
+
+        public SpendTrendsProvider(MoneyMapContext db)
+        {
+            _db = db;
+        }
+
+        public async Task<SpendTrends> GetDailyTrendsAsync(int lastDays = 30)
+        {
+            var today = DateTime.UtcNow.Date;
+            var since = today.AddDays(-(lastDays - 1));
+
+            var raw = await _db.Transactions
+                .Where(t => t.Date >= since)
+                .ExcludeTransfers()
+                .GroupBy(t => t.Date.Date)
+                .Select(g => new
+                {
+                    Date = g.Key,
+                    Debits = g.Where(t => t.Amount < 0).Sum(t => t.Amount),
+                    Credits = g.Where(t => t.Amount > 0).Sum(t => t.Amount)
+                })
+                .ToListAsync();
+
+            var dict = raw.ToDictionary(x => x.Date, x => x);
+            var labels = new List<string>();
+            var debitsAbs = new List<decimal>();
+            var credits = new List<decimal>();
+            var net = new List<decimal>();
+
+            for (var d = since; d <= today; d = d.AddDays(1))
+            {
+                labels.Add(d.ToString("yyyy-MM-dd"));
+                if (dict.TryGetValue(d, out var v))
+                {
+                    var debit = v.Debits;
+                    var credit = v.Credits;
+                    debitsAbs.Add(Math.Abs(debit));
+                    credits.Add(credit);
+                    net.Add(credit + debit);
+                }
+                else
+                {
+                    debitsAbs.Add(0);
+                    credits.Add(0);
+                    net.Add(0);
+                }
+            }
+
+            return new SpendTrends
+            {
+                Labels = labels,
+                DebitsAbs = debitsAbs,
+                Credits = credits,
+                Net = net
+            };
+        }
+    }
+}