MoneyMap/MoneyMap.Tests/Services/MerchantServiceTests.cs

using MoneyMap.Models;
using MoneyMap.Services;
using MoneyMap.Tests.TestHelpers;
using Xunit;

namespace MoneyMap.Tests.Services;

public class MerchantServiceTests
{
    [Fact]
    public async Task GetOrCreateAsync_CreatesNewMerchant_WhenDoesNotExist()
    {
        // Arrange
        using var context = DbContextHelper.CreateInMemoryContext();
        var service = new MerchantService(context);

        // Act
        var result = await service.GetOrCreateAsync("Walmart");

        // Assert
        Assert.NotNull(result);
        Assert.Equal("Walmart", result.Name);
        Assert.Single(context.Merchants);
    }

    [Fact]
    public async Task GetOrCreateAsync_ReturnsExistingMerchant_WhenExists()
    {
        // Arrange
        using var context = DbContextHelper.CreateInMemoryContext();
        var service = new MerchantService(context);

        var existingMerchant = new Merchant { Id = 1, Name = "Walmart" };
        context.Merchants.Add(existingMerchant);
        await context.SaveChangesAsync();

        // Act
        var result = await service.GetOrCreateAsync("Walmart");

        // Assert
        Assert.NotNull(result);
        Assert.Equal(1, result.Id);
        Assert.Single(context.Merchants);
    }

    [Fact]
    public async Task GetAllMerchantsWithStatsAsync_ReturnsMerchantsWithStats()
    {
        // Arrange
        using var context = DbContextHelper.CreateInMemoryContext();
        var service = new MerchantService(context);

        var account = new Account
        {
            Id = 1,
            Institution = "Test Bank",
            AccountType = AccountType.Checking,
            Last4 = "1234",
            Owner = "Test Owner"
        };
        context.Accounts.Add(account);

        var merchant1 = new Merchant { Id = 1, Name = "Walmart" };
        var merchant2 = new Merchant { Id = 2, Name = "Target" };
        context.Merchants.AddRange(merchant1, merchant2);

        var transaction = new Transaction
        {
            Date = DateTime.Now,
            Amount = -50.00m,
            Name = "Test",
            Memo = "Test",
            AccountId = 1,
            MerchantId = 1
        };
        context.Transactions.Add(transaction);
        await context.SaveChangesAsync();

        // Act
        var result = await service.GetAllMerchantsWithStatsAsync();

        // Assert
        Assert.Equal(2, result.Count);
        var walmart = result.First(m => m.Name == "Walmart");
        Assert.Equal(1, walmart.TransactionCount);
        var target = result.First(m => m.Name == "Target");
        Assert.Equal(0, target.TransactionCount);
    }

    [Fact]
    public async Task UpdateMerchantAsync_SuccessfullyUpdatesName()
    {
        // Arrange
        using var context = DbContextHelper.CreateInMemoryContext();
        var service = new MerchantService(context);

        var merchant = new Merchant { Id = 1, Name = "Walmart" };
        context.Merchants.Add(merchant);
        await context.SaveChangesAsync();

        // Act
        var result = await service.UpdateMerchantAsync(1, "Walmart Supercenter");

        // Assert
        Assert.True(result.Success);
        var updated = await context.Merchants.FindAsync(1);
        Assert.Equal("Walmart Supercenter", updated!.Name);
    }

    [Fact]
    public async Task UpdateMerchantAsync_FailsWhenDuplicateName()
    {
        // Arrange
        using var context = DbContextHelper.CreateInMemoryContext();
        var service = new MerchantService(context);

        var merchant1 = new Merchant { Id = 1, Name = "Walmart" };
        var merchant2 = new Merchant { Id = 2, Name = "Target" };
        context.Merchants.AddRange(merchant1, merchant2);
        await context.SaveChangesAsync();

        // Act
        var result = await service.UpdateMerchantAsync(1, "Target");

        // Assert
        Assert.False(result.Success);
        Assert.Contains("already exists", result.Message);
    }

    [Fact]
    public async Task DeleteMerchantAsync_SuccessfullyDeletes()
    {
        // Arrange
        using var context = DbContextHelper.CreateInMemoryContext();
        var service = new MerchantService(context);

        var merchant = new Merchant { Id = 1, Name = "Walmart" };
        context.Merchants.Add(merchant);
        await context.SaveChangesAsync();

        // Act
        var result = await service.DeleteMerchantAsync(1);

        // Assert
        Assert.True(result.Success);
        Assert.Empty(context.Merchants);
    }

    [Fact]
    public async Task DeleteMerchantAsync_ReportsTransactionAndMappingCounts()
    {
        // Arrange
        using var context = DbContextHelper.CreateInMemoryContext();
        var service = new MerchantService(context);

        var account = new Account
        {
            Id = 1,
            Institution = "Test Bank",
            AccountType = AccountType.Checking,
            Last4 = "1234",
            Owner = "Test Owner"
        };
        context.Accounts.Add(account);

        var merchant = new Merchant { Id = 1, Name = "Walmart" };
        context.Merchants.Add(merchant);

        var transaction = new Transaction
        {
            Date = DateTime.Now,
            Amount = -50.00m,
            Name = "Test",
            Memo = "Test",
            AccountId = 1,
            MerchantId = 1
        };
        context.Transactions.Add(transaction);
        await context.SaveChangesAsync();

        // Act
        var result = await service.DeleteMerchantAsync(1);

        // Assert
        Assert.True(result.Success);
        Assert.Equal(1, result.TransactionCount);
        Assert.Contains("1 transaction", result.Message);
    }
}