Add support for Dataverse custom PowerFx functions

src/XrmMockup365/Core.cs

@@ -1361,7 +1361,7 @@ internal async System.Threading.Tasks.Task ExecuteFormulaFields(EntityMetadata e
                     continue;
                 }
 
-                entity[attr.LogicalName] = await FormulaFieldEvaluator.Evaluate(definition, entity);
+                entity[attr.LogicalName] = await FormulaFieldEvaluator.Evaluate(definition, entity, TimeOffset);
             }
         }
 

src/XrmMockup365/CustomFunction/ISOWeekNumFunction.cs

@@ -0,0 +1,45 @@
+using Microsoft.PowerFx;
+using Microsoft.PowerFx.Interpreter;
+using Microsoft.PowerFx.Types;
+using System;
+using System.Globalization;
+
+namespace DG.Tools.XrmMockup.CustomFunction
+{
+    internal class ISOWeekNumFunction : ReflectionFunction
+    {
+        private readonly TimeSpan timeOffset;
+
+        public ISOWeekNumFunction(TimeSpan timeOffset)
+            : base("ISOWeekNum", FormulaType.Decimal, FormulaType.DateTime)
+        {
+            this.timeOffset = timeOffset;
+        }
+        public DecimalValue Execute(DateTimeValue date)
+        {
+            var utcDate = date?.GetConvertedValue(TimeZoneInfo.Utc);
+            if (utcDate == null || utcDate.Value <= DateTime.MinValue)
+                throw new CustomFunctionErrorException("Invalid date or time value", ErrorKind.InvalidArgument);
+
+            utcDate = utcDate.Value.Add(timeOffset);
+
+#if DATAVERSE_SERVICE_CLIENT
+            var weekNumber = ISOWeek.GetWeekOfYear(utcDate.Value);
+#else
+            // .NET Framework does not have ISOWeek class
+            // Implementing ISO 8601 week date algorithm
+            // https://learn.microsoft.com/en-us/archive/blogs/shawnste/iso-8601-week-of-year-format-in-microsoft-net
+
+            var dayOfWeek = utcDate.Value.DayOfWeek;
+            if (dayOfWeek >= DayOfWeek.Monday && dayOfWeek <= DayOfWeek.Wednesday)
+            {
+                utcDate = utcDate.Value.AddDays(3);
+            }
+
+            var weekNumber = CultureInfo.InvariantCulture.Calendar.GetWeekOfYear(utcDate.Value, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
+#endif
+
+            return FormulaValue.New(weekNumber);
+        }
+    }
+}

src/XrmMockup365/CustomFunction/IsUTCTodayFunction.cs

@@ -0,0 +1,27 @@
+using Microsoft.PowerFx;
+using Microsoft.PowerFx.Interpreter;
+using Microsoft.PowerFx.Types;
+using System;
+
+namespace DG.Tools.XrmMockup.CustomFunction
+{
+    internal class IsUTCTodayFunction : ReflectionFunction
+    {
+        private readonly TimeSpan timeOffset;
+
+        public IsUTCTodayFunction(TimeSpan timeOffset)
+            : base("IsUTCToday", FormulaType.Boolean, FormulaType.DateTime)
+        {
+            this.timeOffset = timeOffset;
+        }
+        public BooleanValue Execute(DateTimeValue date)
+        {
+            var utcDate = date?.GetConvertedValue(TimeZoneInfo.Utc);
+            if (utcDate == null || utcDate <= DateTime.MinValue)
+                throw new CustomFunctionErrorException("Invalid date or time value", ErrorKind.InvalidArgument);
+
+            var utcToday = DateTime.UtcNow.Add(timeOffset).Date;
+            return FormulaValue.New(utcDate.Value.Date == utcToday);
+        }
+    }
+}

src/XrmMockup365/CustomFunction/UTCNowFunction.cs

@@ -0,0 +1,22 @@
+using Microsoft.PowerFx;
+using Microsoft.PowerFx.Types;
+using System;
+
+namespace DG.Tools.XrmMockup.CustomFunction
+{
+    internal class UTCNowFunction : ReflectionFunction
+    {
+        private readonly TimeSpan timeOffset;
+
+        public UTCNowFunction(TimeSpan timeOffset)
+            : base("UTCNow", FormulaType.DateTime)
+        {
+            this.timeOffset = timeOffset;
+        }
+        public DateTimeValue Execute()
+        {
+            var utcNow = DateTime.UtcNow.Add(timeOffset);
+            return FormulaValue.New(utcNow);
+        }
+    }
+}

src/XrmMockup365/CustomFunction/UTCTodayFunction.cs

@@ -0,0 +1,23 @@
+using Microsoft.PowerFx;
+using Microsoft.PowerFx.Types;
+using System;
+
+namespace DG.Tools.XrmMockup.CustomFunction
+{
+    internal class UTCTodayFunction : ReflectionFunction
+    {
+        private readonly TimeSpan timeOffset;
+
+        public UTCTodayFunction(TimeSpan timeOffset)
+            : base("UTCToday", FormulaType.DateTime)
+        {
+            this.timeOffset = timeOffset;
+        }
+
+        public DateTimeValue Execute()
+        {
+            var utcNow = DateTime.UtcNow.Add(timeOffset);
+            return FormulaValue.New(utcNow.Date);
+        }
+    }
+}

src/XrmMockup365/FormulaFieldEvaluator.cs

@@ -1,9 +1,12 @@
-using Microsoft.PowerFx.Dataverse;
+using DG.Tools.XrmMockup.CustomFunction;
 using Microsoft.PowerFx;
+using Microsoft.PowerFx.Dataverse;
 using Microsoft.Xrm.Sdk;
-using System.Threading.Tasks;
-using System.Threading;
+using System;
+using System.Collections.Generic;
 using System.Globalization;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace DG.Tools.XrmMockup
 {
@@ -18,11 +21,18 @@ public FormulaFieldEvaluator(IOrganizationServiceFactory serviceFactory)
             _dataverseConnection = SingleOrgPolicy.New(_organizationService);
         }
 
-        public async Task<object> Evaluate(string formula, Entity thisEntity)
+        public async Task<object> Evaluate(string formula, Entity thisEntity, TimeSpan timeOffset)
         {
             var rowScopeSymbols = _dataverseConnection.GetRowScopeSymbols(thisEntity.LogicalName, true);
 
-            var engine = new RecalcEngine();
+            var config = new PowerFxConfig();
+            config.AddFunction(new UTCTodayFunction(timeOffset));
+            config.AddFunction(new UTCNowFunction(timeOffset));
+            config.AddFunction(new IsUTCTodayFunction(timeOffset));
+            config.AddFunction(new ISOWeekNumFunction(timeOffset));
+
+            var engine = new RecalcEngine(config);
+
             var combinedSymbols = ReadOnlySymbolTable.Compose(rowScopeSymbols, _dataverseConnection.Symbols);
             var checkResult = engine.Check(formula, new ParserOptions(CultureInfo.InvariantCulture), combinedSymbols);
             checkResult.ThrowOnErrors();