Add booking-text charts to the transactions page

Adds two charts to the per-account transactions view: a stacked bar
chart of monthly totals and a pie chart of overall totals, both
grouped by booking text, so recurring bookings (rent, subscriptions,
etc.) are visible at a glance. Chart components are keyed on the
account id so switching accounts remounts them instead of reusing a
stale Plotly instance.

Schaad.Accounting.Common/Datasets/Charts/CategoryTotal.cs

@@ -0,0 +1,4 @@
+namespace Schaad.Accounting.Datasets.Charts
+{
+    public record CategoryTotal(string Name, decimal Value);
+}

Schaad.Accounting.Common/Datasets/TransactionDataset.cs

@@ -33,5 +33,15 @@ namespace Schaad.Accounting.Datasets
             else
                 return Value;
         }
+
+        public decimal GetValue(bool withFxRate, string accountId)
+        {
+            if (accountId == OriginAccountId)
+            {
+                return -1 * GetValue(withFxRate);
+            }
+
+            return GetValue(withFxRate);
+        }
     }
 }

Schaad.Accounting.Services/ChartService.cs

@@ -95,6 +95,49 @@ namespace Schaad.Accounting.Services
             return list;
         }
 
+        public async Task<IReadOnlyList<DataSerie>> GetBookingTextExpensesPerMonthAsync(string accountId)
+        {
+            var account = await viewService.GetAccountViewAsync(accountId);
+            var transactions = await viewService.GetTransactionViewListAsync(accountId);
+            if (transactions.Count == 0)
+            {
+                return new List<DataSerie>();
+            }
+
+            var year = settingsService.GetYear();
+            var maxMonth = transactions.Max(t => t.ValueDate.Month);
+
+            var list = new List<DataSerie>();
+            foreach (var grp in transactions.GroupBy(t => t.Text))
+            {
+                var groupedByMonth = grp
+                    .GroupBy(t => t.ValueDate.Month)
+                    .ToDictionary(g => g.Key, g => g.Sum(t => t.GetValue(account.IsFxAccount, accountId)));
+                EnsureEntryForEveryMonth(groupedByMonth, maxMonth);
+
+                list.Add(new DataSerie(
+                    Id: grp.Key,
+                    Name: grp.Key,
+                    X: groupedByMonth.OrderBy(g => g.Key).Select(g => new DateOnly(year, g.Key, 1)).ToList(),
+                    Y: groupedByMonth.OrderBy(g => g.Key).Select(g => g.Value).ToList()
+                ));
+            }
+            return list;
+        }
+
+        public async Task<IReadOnlyList<CategoryTotal>> GetBookingTextTotalsAsync(string accountId)
+        {
+            var account = await viewService.GetAccountViewAsync(accountId);
+            var transactions = await viewService.GetTransactionViewListAsync(accountId);
+
+            return transactions
+                .Where(t => t.TargetAccountId == accountId)
+                .GroupBy(t => t.Text)
+                .Select(g => new CategoryTotal(g.Key, g.Sum(t => t.GetValue(account.IsFxAccount, accountId))))
+                .Where(c => c.Value != 0)
+                .ToList();
+        }
+
         private static void EnsureEntryForEveryMonth(Dictionary<int, decimal> values, int maxMonth = 12)
         {
             for (int i = 1; i <= maxMonth; i++)

Schaad.Accounting.Services/Interfaces/IChartService.cs

@@ -7,5 +7,9 @@ namespace Schaad.Accounting.Interfaces
     public interface IChartService
     {
         Task<IReadOnlyList<DataSerie>> GetExpensesPerMonthAsync();
+
+        Task<IReadOnlyList<DataSerie>> GetBookingTextExpensesPerMonthAsync(string accountId);
+
+        Task<IReadOnlyList<CategoryTotal>> GetBookingTextTotalsAsync(string accountId);
     }
 }

Schaad.Accounting.Services/ViewService.cs

@@ -132,8 +132,9 @@ namespace Schaad.Accounting.Services
         }
 
         /// <summary>
-        /// Get transaction list filtered to a single account, with values sign-flipped
+        /// Get transaction list filtered to a single account. Sign is not baked in here -
-        /// when the requested account is the origin of an activa booking.
+        /// callers use <see cref="TransactionDataset.GetValue(bool, string)"/> with this
+        /// account's id to get a value that's negative when the account is paying out.
         /// </summary>
         public async Task<List<TransactionDataset>> GetTransactionViewListAsync(string accountId)
         {
@@ -143,22 +144,10 @@ namespace Schaad.Accounting.Services
 
             return transactionList.Select(t =>
                     new TransactionDataset(
-                        WithDisplaySign(t),
+                        t,
                         accountsById[t.OriginAccountId],
                         accountsById[t.TargetAccountId]))
                 .ToList();
-
-            Transaction WithDisplaySign(Transaction t)
-            {
-                var originAccount = accountsById[t.OriginAccountId];
-                if (originAccount.Class == ClassIds.Activa && accountId == t.OriginAccountId)
-                {
-                    var copy = t.Clone();
-                    copy.Value *= -1;
-                    return copy;
-                }
-                return t;
-            }
         }
 
         /// <summary>

Schaad.Accounting.Tests/ChartServiceTestShould.cs

@@ -118,7 +118,7 @@ public class ChartServiceTestShould
     private static AccountDataset AsDataset(Account a, string subClassName = "") =>
         new(a, balance: 0, balanceCHF: 0, startBalanceCHF: 0, className: "", subClassName: subClassName);
 
-    private static TransactionDataset MakeTransaction(Account origin, Account target, decimal value, DateTime valueDate, decimal? fxRate = null) =>
+    private static TransactionDataset MakeTransaction(Account origin, Account target, decimal value, DateTime valueDate, decimal? fxRate = null, string text = "") =>
         new(
             new Transaction
             {
@@ -127,6 +127,7 @@ public class ChartServiceTestShould
                 TargetAccountId = target.Id,
                 Value = value,
                 FxRate = fxRate,
+                Text = text,
                 ValueDate = valueDate,
                 BookingDate = valueDate
             },
@@ -168,4 +169,113 @@ public class ChartServiceTestShould
 
         series.Single(s => s.Id == "42").Y[0].ShouldBe(200m);
     }
+
+    [Fact]
+    public async Task GroupBookingTextExpensesByTextWhenBuildingMonthlySeriesForAccount()
+    {
+        var checking = MakeAccount("chk", 1010);
+        var groceries = MakeAccount("groc", 4200);
+        viewService.GetAccountViewAsync("chk").Returns(AsDataset(checking));
+        viewService.GetTransactionViewListAsync("chk").Returns(new List<TransactionDataset>
+        {
+            MakeTransaction(checking, groceries, value: 50m, valueDate: new DateTime(2026, 1, 5), text: "Migros"),
+            MakeTransaction(checking, groceries, value: 20m, valueDate: new DateTime(2026, 2, 3), text: "Coop")
+        });
+
+        var series = await BuildService().GetBookingTextExpensesPerMonthAsync("chk");
+
+        series.Count.ShouldBe(2);
+        var migros = series.Single(s => s.Name == "Migros");
+        migros.Y[0].ShouldBe(-50m);
+        migros.Y[1].ShouldBe(0m);
+        var coop = series.Single(s => s.Name == "Coop");
+        coop.Y[0].ShouldBe(0m);
+        coop.Y[1].ShouldBe(-20m);
+    }
+
+    [Fact]
+    public async Task ShowPositiveValueWhenAccountIsTargetOfBookingTextTransaction()
+    {
+        var checking = MakeAccount("chk", 1010);
+        var salary = MakeAccount("sal", 3000);
+        viewService.GetAccountViewAsync("chk").Returns(AsDataset(checking));
+        viewService.GetTransactionViewListAsync("chk").Returns(new List<TransactionDataset>
+        {
+            MakeTransaction(salary, checking, value: 5000m, valueDate: new DateTime(2026, 1, 5), text: "Lohn")
+        });
+
+        var series = await BuildService().GetBookingTextExpensesPerMonthAsync("chk");
+
+        series.Single().Y.Single().ShouldBe(5000m);
+    }
+
+    [Fact]
+    public async Task ConvertFxAccountValuesWhenBuildingBookingTextSeries()
+    {
+        var usChecking = MakeAccount("chk", 1010, currency: "USD");
+        var groceries = MakeAccount("groc", 4200);
+        viewService.GetAccountViewAsync("chk").Returns(AsDataset(usChecking));
+        viewService.GetTransactionViewListAsync("chk").Returns(new List<TransactionDataset>
+        {
+            MakeTransaction(usChecking, groceries, value: 100m, valueDate: new DateTime(2026, 1, 5), fxRate: 0.5m, text: "Migros")
+        });
+
+        var series = await BuildService().GetBookingTextExpensesPerMonthAsync("chk");
+
+        series.Single().Y.Single().ShouldBe(-200m);
+    }
+
+    [Fact]
+    public async Task SumBookingTextTotalsAcrossMonthsWhenBuildingTotalsForAccount()
+    {
+        var checking = MakeAccount("chk", 1010);
+        var groceries = MakeAccount("groc", 4200);
+        viewService.GetAccountViewAsync("chk").Returns(AsDataset(checking));
+        viewService.GetTransactionViewListAsync("chk").Returns(new List<TransactionDataset>
+        {
+            MakeTransaction(checking, groceries, value: 50m, valueDate: new DateTime(2026, 1, 5), text: "Migros"),
+            MakeTransaction(checking, groceries, value: 30m, valueDate: new DateTime(2026, 2, 3), text: "Migros"),
+            MakeTransaction(checking, groceries, value: 20m, valueDate: new DateTime(2026, 2, 4), text: "Coop")
+        });
+
+        var totals = await BuildService().GetBookingTextTotalsAsync("chk");
+
+        totals.Count.ShouldBe(2);
+        totals.ShouldContain(t => t.Name == "Migros" && t.Value == -80m);
+        totals.ShouldContain(t => t.Name == "Coop" && t.Value == -20m);
+    }
+
+    [Fact]
+    public async Task NetOutgoingAndIncomingBookingsWithTheSameTextWhenBuildingTotalsForAccount()
+    {
+        var checking = MakeAccount("chk", 1010);
+        var groceries = MakeAccount("groc", 4200);
+        viewService.GetAccountViewAsync("chk").Returns(AsDataset(checking));
+        viewService.GetTransactionViewListAsync("chk").Returns(new List<TransactionDataset>
+        {
+            MakeTransaction(checking, groceries, value: 50m, valueDate: new DateTime(2026, 1, 5), text: "Migros"),
+            MakeTransaction(groceries, checking, value: 20m, valueDate: new DateTime(2026, 1, 6), text: "Migros")
+        });
+
+        var totals = await BuildService().GetBookingTextTotalsAsync("chk");
+
+        totals.Single().Value.ShouldBe(-30m);
+    }
+
+    [Fact]
+    public async Task ExcludeZeroNetBookingTextsWhenBuildingTotalsForAccount()
+    {
+        var checking = MakeAccount("chk", 1010);
+        var groceries = MakeAccount("groc", 4200);
+        viewService.GetAccountViewAsync("chk").Returns(AsDataset(checking));
+        viewService.GetTransactionViewListAsync("chk").Returns(new List<TransactionDataset>
+        {
+            MakeTransaction(checking, groceries, value: 50m, valueDate: new DateTime(2026, 1, 5), text: "Migros"),
+            MakeTransaction(checking, groceries, value: -50m, valueDate: new DateTime(2026, 1, 6), text: "Migros")
+        });
+
+        var totals = await BuildService().GetBookingTextTotalsAsync("chk");
+
+        totals.ShouldBeEmpty();
+    }
 }

Schaad.Accounting.Tests/TransactionDatasetTestShould.cs

@@ -0,0 +1,54 @@
+using Schaad.Accounting.Datasets;
+using Schaad.Accounting.Models;
+using Shouldly;
+
+namespace Schaad.Accounting.Tests;
+
+public class TransactionDatasetTestShould
+{
+    private static Account MakeAccount(string id) => new() { Id = id, Name = id, Currency = "CHF" };
+
+    private static TransactionDataset MakeTransaction(Account origin, Account target, decimal value, decimal? fxRate = null) =>
+        new(
+            new Transaction
+            {
+                Id = Guid.NewGuid().ToString(),
+                OriginAccountId = origin.Id,
+                TargetAccountId = target.Id,
+                Value = value,
+                FxRate = fxRate,
+                ValueDate = DateTime.Now,
+                BookingDate = DateTime.Now
+            },
+            origin, target);
+
+    [Fact]
+    public void ReturnNegativeValueWhenAccountIsOrigin()
+    {
+        var checking = MakeAccount("chk");
+        var groceries = MakeAccount("groc");
+        var transaction = MakeTransaction(checking, groceries, value: 50m);
+
+        transaction.GetValue(withFxRate: false, accountId: "chk").ShouldBe(-50m);
+    }
+
+    [Fact]
+    public void ReturnPositiveValueWhenAccountIsTarget()
+    {
+        var checking = MakeAccount("chk");
+        var groceries = MakeAccount("groc");
+        var transaction = MakeTransaction(groceries, checking, value: 50m);
+
+        transaction.GetValue(withFxRate: false, accountId: "chk").ShouldBe(50m);
+    }
+
+    [Fact]
+    public void ApplyFxConversionBeforeApplyingSignWhenAccountIsOrigin()
+    {
+        var checking = MakeAccount("chk");
+        var groceries = MakeAccount("groc");
+        var transaction = MakeTransaction(checking, groceries, value: 100m, fxRate: 0.5m);
+
+        transaction.GetValue(withFxRate: true, accountId: "chk").ShouldBe(-200m);
+    }
+}

Schaad.Accounting.UI/Components/Pages/Charts/BookingTextBreakdown.razor

@@ -0,0 +1,8 @@
+@if (config is not null && layout is not null && data is not null)
+{
+    <PlotlyChart style="height: 400px; min-height: 300px" @bind-Config="config" @bind-Layout="layout" @bind-Data="data" @ref="chart" />
+}
+else
+{
+    <Loading/>
+}

Schaad.Accounting.UI/Components/Pages/Charts/BookingTextBreakdown.razor.cs

@@ -0,0 +1,44 @@
+using Microsoft.AspNetCore.Components;
+using Plotly.Blazor;
+using Plotly.Blazor.Traces;
+using Schaad.Accounting.Interfaces;
+
+namespace Schaad.Accounting.UI.Components.Pages.Charts;
+
+public partial class BookingTextBreakdown : ComponentBase
+{
+    private PlotlyChart chart = null!;
+    private Config? config;
+    private Plotly.Blazor.Layout? layout;
+    private IList<ITrace>? data;
+
+    [Parameter, EditorRequired]
+    public string AccountId { get; set; } = null!;
+
+    [Inject]
+    private IChartService chartService { get; set; } = null!;
+
+    protected override async Task OnInitializedAsync()
+    {
+        config = new Config
+        {
+            Responsive = true
+        };
+
+        layout = new Plotly.Blazor.Layout
+        {
+            Title = new Plotly.Blazor.LayoutLib.Title { Text = "Nach Buchungstext" }
+        };
+
+        var totals = await chartService.GetBookingTextTotalsAsync(AccountId);
+        data = new List<ITrace>
+        {
+            new Pie
+            {
+                // Values are shown as their absolute magnitude - a pie slice can't represent a signed amount.
+                Values = totals.Select(t => (object)Math.Abs(t.Value)).ToList(),
+                Labels = totals.Select(t => (object)t.Name).ToList()
+            }
+        };
+    }
+}

Schaad.Accounting.UI/Components/Pages/Charts/BookingTextOverTime.razor

@@ -0,0 +1,8 @@
+@if (config is not null && layout is not null)
+{
+    <PlotlyChart style="height: 400px; min-height: 300px" @bind-Config="config" @bind-Layout="layout" @bind-Data="data" @ref="chart" />
+}
+else
+{
+    <Loading/>
+}

Schaad.Accounting.UI/Components/Pages/Charts/BookingTextOverTime.razor.cs

@@ -0,0 +1,57 @@
+using Microsoft.AspNetCore.Components;
+using Plotly.Blazor;
+using Plotly.Blazor.LayoutLib;
+using Plotly.Blazor.Traces;
+using Schaad.Accounting.Interfaces;
+
+namespace Schaad.Accounting.UI.Components.Pages.Charts;
+
+public partial class BookingTextOverTime : ComponentBase
+{
+    private PlotlyChart chart = null!;
+    private Config? config;
+    private Plotly.Blazor.Layout? layout;
+    private IList<ITrace> data = new List<ITrace>();
+
+    [Parameter, EditorRequired]
+    public string AccountId { get; set; } = null!;
+
+    [Inject]
+    private IChartService chartService { get; set; } = null!;
+
+    protected override async Task OnInitializedAsync()
+    {
+        config = new Config
+        {
+            Responsive = true
+        };
+
+        layout = new Plotly.Blazor.Layout
+        {
+            Title = new Title { Text = "Nach Buchungstext im Verlauf" },
+            BarMode = BarModeEnum.Stack,
+            XAxis = new List<XAxis>
+            {
+                new()
+                {
+                    Type = Plotly.Blazor.LayoutLib.XAxisLib.TypeEnum.Date
+                }
+            }
+        };
+
+        var newData = new List<ITrace>();
+        var dataSeries = await chartService.GetBookingTextExpensesPerMonthAsync(AccountId);
+        foreach (var dataSerie in dataSeries)
+        {
+            newData.Add(new Bar
+            {
+                Name = dataSerie.Name,
+                X = dataSerie.X.Select(d => (object)d).ToList(),
+                Y = dataSerie.Y.Select(d => (object)d).ToList(),
+            });
+        }
+        data = newData;
+
+        await base.OnInitializedAsync();
+    }
+}

Schaad.Accounting.UI/Components/Pages/Transactions.razor

@@ -1,5 +1,6 @@
 @page "/transactions"
 @rendermode InteractiveServer
+@using Schaad.Accounting.UI.Components.Pages.Charts
 
 <PageTitle>Transaktionen</PageTitle>
 
@@ -43,6 +44,18 @@
                 </FluentGridItem>
             </FluentGrid>
             
+            @if (selectedAccount.Class == ClassIds.Expenses)
+            {
+                <FluentGrid Justify="JustifyContent.FlexStart">
+                    <FluentGridItem xs="6">
+                        <BookingTextOverTime @key="selectedAccount.Id" AccountId="@selectedAccount.Id"/>
+                    </FluentGridItem>
+                    <FluentGridItem xs="6">
+                        <BookingTextBreakdown @key="selectedAccount.Id" AccountId="@selectedAccount.Id"/>
+                    </FluentGridItem>
+                </FluentGrid>
+            }
+
             <FluentPaginator State="@pagination" SummaryTemplate="@template"/>
             <FluentDataGrid Items="@transactionList" Pagination="@pagination" RowSize="DataGridRowSize.Medium">
                 <PropertyColumn Property="@(p => p.BookingDate)" Format="dd.MM.yyyy" Sortable="true" IsDefaultSortColumn="true" InitialSortDirection="SortDirection.Descending"/>
@@ -52,7 +65,7 @@
                     @GetAccountName(context)
                 </TemplateColumn>
                 <TemplateColumn Title="Betrag" Align="Align.End">
-                    @context.GetValue(selectedAccount.IsFxAccount).ToString("N2") @selectedAccount.Currency
+                    @context.GetValue(selectedAccount.IsFxAccount, selectedAccountId).ToString("N2") @selectedAccount.Currency
                 </TemplateColumn>
                 <TemplateColumn Align="Align.Center" Width="50px">
                     <FluentButton IconEnd="@(new Icons.Regular.Size16.Delete())" Appearance="Appearance.Neutral" title="Löschen" aria-label="Löschen" OnClick="@(() => DeleteAsync(context.Id))"/>