Add project files.

BudgetApp/Data/Account.cs

@@ -0,0 +1,39 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace BudgetApp.Data;
+
+public class Account
+{
+    public int Id { get; set; }
+
+    [Required, MaxLength(100)]
+    public string Name { get; set; } = string.Empty;
+
+    public decimal CurrentBalance { get; set; }
+
+    [Required, MaxLength(7)]
+    public string Color { get; set; } = "#1b6ec2";
+
+    [Required, MaxLength(3)]
+    public string CurrencyCode { get; set; } = "GBP";
+
+    [Required]
+    public string UserId { get; set; } = string.Empty;
+
+    public ApplicationUser User { get; set; } = default!;
+
+    public List<Transaction> Transactions { get; set; } = [];
+
+    public static readonly Dictionary<string, string> CurrencySymbols = new()
+    {
+        ["USD"] = "$", ["EUR"] = "€", ["GBP"] = "£", ["JPY"] = "¥",
+        ["CAD"] = "C$", ["AUD"] = "A$", ["CHF"] = "CHF", ["CNY"] = "¥",
+        ["INR"] = "₹", ["BRL"] = "R$", ["KRW"] = "₩", ["MXN"] = "MX$",
+        ["SEK"] = "kr", ["NOK"] = "kr", ["DKK"] = "kr", ["NZD"] = "NZ$",
+        ["ZAR"] = "R", ["PLN"] = "zł", ["TRY"] = "₺", ["THB"] = "฿"
+    };
+
+    public string GetSymbol() => CurrencySymbols.GetValueOrDefault(CurrencyCode, CurrencyCode);
+
+    public string FormatAmount(decimal amount) => $"{GetSymbol()}{amount:N2}";
+}

BudgetApp/Data/ApplicationDbContext.cs

@@ -0,0 +1,59 @@
+using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore;
+
+namespace BudgetApp.Data;
+
+public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
+{
+    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
+        : base(options)
+    {
+    }
+
+    public DbSet<Account> Accounts => Set<Account>();
+    public DbSet<Transaction> Transactions => Set<Transaction>();
+    public DbSet<Category> Categories => Set<Category>();
+
+    protected override void OnModelCreating(ModelBuilder builder)
+    {
+        base.OnModelCreating(builder);
+
+        builder.Entity<Account>(e =>
+        {
+            e.HasOne(a => a.User)
+             .WithMany()
+             .HasForeignKey(a => a.UserId)
+             .OnDelete(DeleteBehavior.Cascade);
+
+            e.Property(a => a.CurrentBalance).HasColumnType("decimal(18,2)");
+        });
+
+        builder.Entity<Transaction>(e =>
+        {
+            e.HasOne(t => t.Account)
+             .WithMany(a => a.Transactions)
+             .HasForeignKey(t => t.AccountId)
+             .OnDelete(DeleteBehavior.Cascade);
+
+            e.HasOne(t => t.Category)
+             .WithMany(c => c.Transactions)
+             .HasForeignKey(t => t.CategoryId)
+             .OnDelete(DeleteBehavior.SetNull);
+
+            e.HasOne(t => t.ParentTransaction)
+             .WithMany()
+             .HasForeignKey(t => t.ParentTransactionId)
+             .OnDelete(DeleteBehavior.SetNull);
+
+            e.Property(t => t.Amount).HasColumnType("decimal(18,2)");
+        });
+
+        builder.Entity<Category>(e =>
+        {
+            e.HasOne(c => c.User)
+             .WithMany()
+             .HasForeignKey(c => c.UserId)
+             .OnDelete(DeleteBehavior.Cascade);
+        });
+    }
+}

BudgetApp/Data/ApplicationUser.cs

@@ -0,0 +1,7 @@
+using Microsoft.AspNetCore.Identity;
+
+namespace BudgetApp.Data;
+
+public class ApplicationUser : IdentityUser
+{
+}

BudgetApp/Data/Category.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace BudgetApp.Data;
+
+public class Category
+{
+    public int Id { get; set; }
+
+    [Required, MaxLength(100)]
+    public string Name { get; set; } = string.Empty;
+
+    [MaxLength(10)]
+    public string Icon { get; set; } = string.Empty;
+
+    [Required]
+    public string UserId { get; set; } = string.Empty;
+
+    public ApplicationUser User { get; set; } = default!;
+
+    public List<Transaction> Transactions { get; set; } = [];
+}

BudgetApp/Data/Transaction.cs

@@ -0,0 +1,45 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace BudgetApp.Data;
+
+public enum TransactionType
+{
+    Income,
+    Expense
+}
+
+public enum RecurrenceType
+{
+    None,
+    Daily,
+    Weekly,
+    Monthly,
+    Yearly
+}
+
+public class Transaction
+{
+    public int Id { get; set; }
+
+    [Required, MaxLength(200)]
+    public string Description { get; set; } = string.Empty;
+
+    public decimal Amount { get; set; }
+
+    public DateTime Date { get; set; } = DateTime.Today;
+
+    public TransactionType Type { get; set; } = TransactionType.Expense;
+
+    public RecurrenceType RecurrenceType { get; set; } = RecurrenceType.None;
+
+    public DateTime? RecurrenceEndDate { get; set; }
+
+    public int? ParentTransactionId { get; set; }
+    public Transaction? ParentTransaction { get; set; }
+
+    public int AccountId { get; set; }
+    public Account Account { get; set; } = default!;
+
+    public int? CategoryId { get; set; }
+    public Category? Category { get; set; }
+}