add csharp-es sample

2026-04-27 23:09:38 +01:00
parent cb06d80d6a
commit d785852c1c
8 changed files with 509 additions and 0 deletions
@@ -0,0 +1,84 @@
+using System.Collections.Immutable;
+using CsharpEs.Domain;
+using CsharpEs.Infrastructure;
+using CsharpEs.Library;
+
+public abstract record DemoError
+{
+    public sealed record Account(AccountError Error) : DemoError;
+
+    public sealed record ReadModel(ReadModelError Error) : DemoError;
+}
+
+public class Program
+{
+    private static Guid accountId;
+    private static ImmutableList<AccountCommand> demoCommands = ImmutableList<AccountCommand>.Empty;
+
+    static Program()
+    {
+        accountId = Guid.NewGuid();
+        demoCommands = demoCommands.AddRange([
+            new AccountCommand.OpenAccount(accountId, new Money(-200m)),
+            //            new AccountCommand.OpenAccount(accountId, new Money(200m)),
+            new AccountCommand.WithdrawMoney(accountId, new Money(100m)),
+            new AccountCommand.WithdrawMoney(accountId, new Money(200m)),
+            new AccountCommand.DepositMoney(accountId, new Money(500m)),
+        ]);
+    }
+
+    static ImmutableList<AccountEvent> eventStore = ImmutableList<AccountEvent>.Empty;
+
+    static Result<AccountState?, DemoError> ApplyEvent(
+        AccountBalanceReadModel balanceProjection,
+        AccountState? state,
+        AccountEvent @event
+    )
+    {
+        eventStore = eventStore.Add(@event);
+        Logging.Output(
+            "ae",
+            $"Applying event {Logging.Format(@event)} to state {Logging.Format(state)}"
+        );
+        return AccountDecider
+            .Evolve(state, @event)
+            .MapError(e => (DemoError)new DemoError.Account(e))
+            .Bind(newState =>
+                balanceProjection
+                    .Project(@event)
+                    .MapError(e => (DemoError)new DemoError.ReadModel(e))
+                    .Log("ae ad", "Account details")
+                    .Map(_ => newState)
+            )
+            .Log("ae", $"Applied and projected {Logging.Format(@event)}");
+    }
+
+    public static void Main(string[] args)
+    {
+        Logging.Output("csharp-es", "Starting money handling demo...");
+
+        AccountBalanceReadModelModule
+            .Create()
+            .MapError(e => (DemoError)new DemoError.ReadModel(e))
+            .Bind(readModel =>
+                demoCommands
+                    .Aggregate(
+                        Result<AccountState?, DemoError>.Ok(null),
+                        (stateResult, command) =>
+                            stateResult.Bind(state =>
+                                AccountDecider
+                                    .Decide(state, command)
+                                    .MapError(e => (DemoError)new DemoError.Account(e))
+                                    .Bind(@event => ApplyEvent(readModel, state, @event))
+                            )
+                    )
+                    .Bind(s =>
+                        readModel
+                            .Query()
+                            .Log("query", "Read model data")
+                            .MapError(e => (DemoError)new DemoError.ReadModel(e))
+                    )
+            )
+            .Log("csharp-es done", "Demo completed.");
+    }
+}