Add FlowDecision activity

src/modules/Elsa.Workflows.Core/Activities/Flowchart/Activities/FlowDecision.cs

@@ -7,7 +7,7 @@ using Elsa.Workflows.Core.Models;
 namespace Elsa.Workflows.Core.Activities.Flowchart.Activities;
 
 [FlowNode("True", "False")]
-[Activity("Elsa", "Flow", "Continues on either the True or False branch, depending on the result of a specified condition")]
+[Activity("Elsa", "Flow", "Evaluate a Boolean condition to determine which path to execute next.")]
 public class FlowDecision : ActivityBase
 {
     /// <summary>

src/modules/Elsa.Workflows.Core/Activities/Flowchart/Activities/FlowSwitch.cs

@@ -0,0 +1,79 @@
+using System.Text.Json.Serialization;
+using Elsa.Expressions;
+using Elsa.Expressions.Models;
+using Elsa.Expressions.Services;
+using Elsa.Workflows.Core.Activities.Flowchart.Attributes;
+using Elsa.Workflows.Core.Attributes;
+using Elsa.Workflows.Core.Models;
+
+namespace Elsa.Workflows.Core.Activities.Flowchart.Activities;
+
+[FlowNode("Default")]
+[Activity("Elsa", "Flow", "Evaluate a set of case conditions and schedule the activity for a matching case.")]
+public class FlowSwitch : ActivityBase
+{
+    [Input(UIHint = "flow-switch-editor")] public ICollection<FlowSwitchCase> Cases { get; set; } = new List<FlowSwitchCase>();
+
+    protected override async ValueTask ExecuteAsync(ActivityExecutionContext context)
+    {
+        var matchingCase = await FindMatchingCaseAsync(context.ExpressionExecutionContext);
+        var outcome = matchingCase?.Label ?? "Default";
+
+        await context.CompleteActivityAsync(outcome);
+    }
+
+    private async Task<FlowSwitchCase?> FindMatchingCaseAsync(ExpressionExecutionContext context)
+    {
+        var expressionEvaluator = context.GetRequiredService<IExpressionEvaluator>();
+
+        foreach (var switchCase in Cases)
+        {
+            var result = await expressionEvaluator.EvaluateAsync<bool?>(switchCase.Condition, context);
+
+            if (result == true)
+                return switchCase;
+        }
+
+        return null;
+    }
+}
+
+/// <summary>
+/// Represents an individual case of the <see cref="FlowSwitch"/> activity.
+/// </summary>
+public class FlowSwitchCase
+{
+    [JsonConstructor]
+    public FlowSwitchCase()
+    {
+    }
+
+    public FlowSwitchCase(string label, IExpression condition)
+    {
+        Label = label;
+        Condition = condition;
+    }
+
+    public FlowSwitchCase(string label, DelegateBlockReference<bool> condition) : this(label, new DelegateExpression(condition))
+    {
+    }
+
+    public FlowSwitchCase(string label, Func<ExpressionExecutionContext, ValueTask<bool>> condition) : this(label, new DelegateBlockReference<bool>(condition))
+    {
+    }
+
+    public FlowSwitchCase(string label, Func<ValueTask<bool>> condition) : this(label, new DelegateBlockReference<bool>(condition))
+    {
+    }
+
+    public FlowSwitchCase(string label, Func<ExpressionExecutionContext, bool> condition) : this(label, new DelegateBlockReference<bool>(condition))
+    {
+    }
+
+    public FlowSwitchCase(string label, Func<bool> condition) : this(label, new DelegateBlockReference<bool>(condition))
+    {
+    }
+
+    public string Label { get; set; } = default!;
+    public IExpression Condition { get; set; } = new LiteralExpression(false);
+}