From 10d77b7365d4c75cd7fe344827f7159e27d0563a Mon Sep 17 00:00:00 2001
From: Sipke Schoorstra <sipkeschoorstra@outlook.com>
Date: Mon, 26 Apr 2021 13:28:20 +0200
Subject: [PATCH] Add "workflow_definition_id" liquid filter

---
 .../LiquidServiceCollectionExtensions.cs      |  3 +-
 .../Filters/WorkflowDefinitionIdFilter.cs     | 38 +++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 src/scripting/Elsa.Scripting.Liquid/Filters/WorkflowDefinitionIdFilter.cs

diff --git a/src/scripting/Elsa.Scripting.Liquid/Extensions/LiquidServiceCollectionExtensions.cs b/src/scripting/Elsa.Scripting.Liquid/Extensions/LiquidServiceCollectionExtensions.cs
index e7253eed3..1868fef9a 100644
--- a/src/scripting/Elsa.Scripting.Liquid/Extensions/LiquidServiceCollectionExtensions.cs
+++ b/src/scripting/Elsa.Scripting.Liquid/Extensions/LiquidServiceCollectionExtensions.cs
@@ -18,7 +18,8 @@ namespace Elsa.Scripting.Liquid.Extensions
                 .AddScoped<ILiquidTemplateManager, LiquidTemplateManager>()
                 .AddSingleton<LiquidParser>()
                 .AddLiquidFilter<JsonFilter>("json")
-                .AddLiquidFilter<Base64Filter>("base64");
+                .AddLiquidFilter<Base64Filter>("base64")
+                .AddLiquidFilter<WorkflowDefinitionIdFilter>("workflow_definition_id");
         }
         
         public static IServiceCollection AddLiquidFilter<T>(this IServiceCollection services, string name) where T : class, ILiquidFilter
diff --git a/src/scripting/Elsa.Scripting.Liquid/Filters/WorkflowDefinitionIdFilter.cs b/src/scripting/Elsa.Scripting.Liquid/Filters/WorkflowDefinitionIdFilter.cs
new file mode 100644
index 000000000..9b68e0bab
--- /dev/null
+++ b/src/scripting/Elsa.Scripting.Liquid/Filters/WorkflowDefinitionIdFilter.cs
@@ -0,0 +1,38 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using Elsa.Scripting.Liquid.Services;
+using Elsa.Services;
+using Elsa.Services.Models;
+using Fluid;
+using Fluid.Values;
+
+namespace Elsa.Scripting.Liquid.Filters
+{
+    public class WorkflowDefinitionIdFilter : ILiquidFilter
+    {
+        private readonly IWorkflowRegistry _workflowRegistry;
+
+        public WorkflowDefinitionIdFilter(IWorkflowRegistry workflowRegistry) => _workflowRegistry = workflowRegistry;
+
+        public async ValueTask<FluidValue> ProcessAsync(FluidValue input, FilterArguments arguments, TemplateContext context)
+        {
+            if (input.Type != FluidValues.String)
+                throw new NotSupportedException("Unrecognized FluidValue");
+
+            var queryType = arguments.Values.FirstOrDefault()?.ToStringValue() ?? "name";
+            var queryValue = input.ToStringValue().ToLowerInvariant();
+
+            Func<IWorkflowBlueprint, bool> predicate = queryType switch
+            {
+                "name" => x => string.Equals(x.Name, queryValue, StringComparison.OrdinalIgnoreCase),
+                "tag" => x => string.Equals(x.Tag, queryValue, StringComparison.OrdinalIgnoreCase),
+                _ => throw new ArgumentOutOfRangeException()
+            };
+
+            var workflowBlueprint = await _workflowRegistry.FindAsync(predicate);
+            var workflowDefinitionId = workflowBlueprint?.Id;
+            return new StringValue(workflowDefinitionId);
+        }
+    }
+}
\ No newline at end of file