duempelkas/tests/Duempelkas.Tests/YearlyStatementCalculationTests.cs

using Duempelkas.Domain.Entities;
using Duempelkas.Domain.Enums;
using Duempelkas.Infrastructure.Persistence;
using Duempelkas.Infrastructure.Services;
using FluentAssertions;
using Microsoft.EntityFrameworkCore;
using Xunit;

namespace Duempelkas.Tests;

public class BalanceCalculationTests : IDisposable
{
    private readonly FinanceDbContext _db;
    private readonly BalanceQueryService _balanceQueryService;
    private readonly EntryService _entryService;
    private readonly string _connectionString = $"Data Source=duempelkas-balance-tests-{Guid.NewGuid():N};Mode=Memory;Cache=Shared";

    public BalanceCalculationTests()
    {
        var options = new DbContextOptionsBuilder<FinanceDbContext>()
            .UseSqlite(_connectionString)
            .Options;

        _db = new FinanceDbContext(options);
        _db.Database.OpenConnection();
        _db.Database.EnsureCreated();

        var dbFactory = new TestDbContextFactory(options);

        _balanceQueryService = new BalanceQueryService(dbFactory);
        _entryService = new EntryService(dbFactory);
    }

    [Fact]
    public async Task AccountBalance_CalculatesCorrectTotals()
    {
        var account = new Account { Name = "Test Account", CarryoverBalance = 500.00m };
        _db.Accounts.Add(account);
        await _db.SaveChangesAsync();

        _db.Entries.AddRange(
            new Entry { AccountId = account.Id, DisplayId = "2026-001", Type = EntryType.Income, Date = new DateTime(2026, 1, 15), Title = "Gehalt", Amount = 800.00m },
            new Entry { AccountId = account.Id, DisplayId = "2026-002", Type = EntryType.Income, Date = new DateTime(2026, 2, 15), Title = "Bonus", Amount = 400.00m },
            new Entry { AccountId = account.Id, DisplayId = "2026-003", Type = EntryType.Expense, Date = new DateTime(2026, 1, 20), Title = "Miete", Amount = 200.00m },
            new Entry { AccountId = account.Id, DisplayId = "2026-004", Type = EntryType.Expense, Date = new DateTime(2026, 2, 20), Title = "Lebensmittel", Amount = 250.00m }
        );
        await _db.SaveChangesAsync();

        var balance = await _balanceQueryService.GetAccountBalanceAsync(account.Id);

        balance.CarryoverBalance.Should().Be(500.00m);
        balance.TotalIncome.Should().Be(1200.00m);
        balance.TotalExpense.Should().Be(450.00m);
        balance.TotalBalance.Should().Be(1250.00m);
    }

    [Fact]
    public async Task AccountBalance_IncludesTransfersCorrectly()
    {
        var accountA = new Account { Name = "Account A", CarryoverBalance = 500.00m };
        var accountB = new Account { Name = "Account B" };
        _db.Accounts.AddRange(accountA, accountB);
        await _db.SaveChangesAsync();

        _db.Entries.Add(new Entry
        {
            AccountId = accountA.Id,
            DisplayId = "2026-001",
            Type = EntryType.Income,
            Date = new DateTime(2026, 1, 10),
            Title = "Gehalt",
            Amount = 1000.00m
        });
        await _db.SaveChangesAsync();

        await _entryService.CreateTransferAsync(accountA.Id, accountB.Id, new DateTime(2026, 2, 1), "Umbuchung nach B", 300.00m);

        var balanceA = await _balanceQueryService.GetAccountBalanceAsync(accountA.Id);

        balanceA.CarryoverBalance.Should().Be(500.00m);
        balanceA.TotalIncome.Should().Be(1000.00m);
        balanceA.TotalExpense.Should().Be(300.00m);
        balanceA.TotalBalance.Should().Be(1200.00m);
    }

    [Fact]
    public async Task AccountBalance_WithCarryover()
    {
        var account = new Account { Name = "Konto mit Übertrag", CarryoverBalance = 1000.00m };
        _db.Accounts.Add(account);
        await _db.SaveChangesAsync();

        _db.Entries.AddRange(
            new Entry { AccountId = account.Id, DisplayId = "2025-001", Type = EntryType.Income, Date = new DateTime(2025, 6, 1), Title = "Einnahme 2025", Amount = 500.00m },
            new Entry { AccountId = account.Id, DisplayId = "2026-001", Type = EntryType.Income, Date = new DateTime(2026, 6, 1), Title = "Einnahme 2026", Amount = 300.00m },
            new Entry { AccountId = account.Id, DisplayId = "2026-002", Type = EntryType.Expense, Date = new DateTime(2026, 7, 1), Title = "Ausgabe 2026", Amount = 150.00m }
        );
        await _db.SaveChangesAsync();

        var balance = await _balanceQueryService.GetAccountBalanceAsync(account.Id);

        // 1000 + 500 + 300 - 150 = 1650
        balance.TotalBalance.Should().Be(1650.00m);
        balance.CarryoverBalance.Should().Be(1000.00m);
    }

    public void Dispose()
    {
        _db.Database.CloseConnection();
        _db.Dispose();
    }

    private sealed class TestDbContextFactory : IDbContextFactory<FinanceDbContext>
    {
        private readonly DbContextOptions<FinanceDbContext> _options;

        public TestDbContextFactory(DbContextOptions<FinanceDbContext> options)
        {
            _options = options;
        }

        public FinanceDbContext CreateDbContext() => new(_options);

        public Task<FinanceDbContext> CreateDbContextAsync(CancellationToken cancellationToken = default)
            => Task.FromResult(new FinanceDbContext(_options));
    }
}