#30 - Weekday parser.

Author: techyian

src/ReportViewer.NET/Extensions/DateTimeExtensions.cs

@@ -208,6 +208,14 @@ public static int ParseDatePartShortString(this DateTime dtt, string dateInterva
             return 0;
         }
 
+        public static int ParseWeekday(this DateTime dtt, FirstDayOfWeek fdow)
+        {   
+            var currentDayOfWeek = (int)AdjustedDayOfWeek(dtt, fdow);
+
+            // TODO: Does SSRS increment by 1 to get a sane week number?
+            return currentDayOfWeek + 1;
+        }
+
         public static string FormatDateTime(this DateTime dtt, DateFormat format)
         {
             switch (format)
@@ -266,5 +274,29 @@ private static CalendarWeekRule FirstWeekOfYearToCalendarWeekRule(FirstWeekOfYea
                     return cultureInfo.DateTimeFormat.CalendarWeekRule;
             }
         }
+
+        private static int AdjustedDayOfWeek(DateTime dtt, FirstDayOfWeek fdow)
+        {
+            CultureInfo cultureInfo = CultureInfo.CurrentCulture;
+            Calendar calendar = cultureInfo.Calendar;
+
+            switch (fdow)
+            {                
+                case FirstDayOfWeek.Monday:
+                    return ((int)calendar.GetDayOfWeek(dtt) + 6) % 7;
+                case FirstDayOfWeek.Tuesday:
+                    return ((int)calendar.GetDayOfWeek(dtt) + 5) % 7;
+                case FirstDayOfWeek.Wednesday:
+                    return ((int)calendar.GetDayOfWeek(dtt) + 4) % 7;
+                case FirstDayOfWeek.Thursday:
+                    return ((int)calendar.GetDayOfWeek(dtt) + 3) % 7;
+                case FirstDayOfWeek.Friday:
+                    return ((int)calendar.GetDayOfWeek(dtt) + 2) % 7;
+                case FirstDayOfWeek.Saturday:
+                    return ((int)calendar.GetDayOfWeek(dtt) + 1) % 7;
+                default:
+                    return (int)calendar.GetDayOfWeek(dtt);
+            }
+        }
     }
 }

src/ReportViewer.NET/Parsers/DateAndTime/WeekdayParser.cs

@@ -0,0 +1,81 @@
+using Microsoft.VisualBasic;
+using ReportViewer.NET.DataObjects;
+using ReportViewer.NET.Extensions;
+using System;
+using System.Collections.Generic;
+using System.Text.RegularExpressions;
+
+namespace ReportViewer.NET.Parsers.DateAndTime
+{
+    public class WeekdayParser : BaseParser
+    {
+        public static Regex WeekdayRegex = RegexCommon.GenerateMultiParamParserRegex("Weekday");
+
+        public WeekdayParser(
+            string currentString,
+            ExpressionFieldOperator op,
+            ReportExpression currentExpression,
+            IEnumerable<IDictionary<string, object>> dataSetResults,
+            IDictionary<string, object> values,
+            int currentRowNumber,
+            IEnumerable<DataSet> dataSets,
+            DataSet activeDataset,
+            ReportRDL report
+        ) : base(currentString, op, currentExpression, dataSetResults, values, currentRowNumber, dataSets, activeDataset, WeekdayRegex, report)
+        {
+        }
+
+        public override (Type, object) ExtractExpressionValue(string fieldName, string dataSetName)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override void Parse()
+        {
+            var match = WeekdayRegex.Match(this.CurrentString);
+            var matchValue = match.Value;
+
+            // Remove the surrounding Weekday including open & close brace so we can inspect inner members and see if they too contain program flow expressions. 
+            matchValue = matchValue.MatchValueSubString(8);
+
+            var foundParameters = this.ParseParenthesis(matchValue);
+
+            if (foundParameters.Item2.Count < 1 || foundParameters.Item2.Count > 2)
+            {
+                // The Weekday function expects at least 1 parameter but no more than 2.
+                return;
+            }
+
+            // DateTime will either come directly from database or will be calculated from other expression.
+            var date = this.Report.Parser.ParseReportExpressionString(
+                foundParameters.Item2[0],
+                this.DataSetResults,
+                this.Values,
+                this.CurrentRowNumber,
+                this.DataSets,
+                this.ActiveDataset,
+                null
+            ).ExpressionAsDateTime();
+            
+            FirstDayOfWeek fdow = FirstDayOfWeek.System;
+          
+            if (foundParameters.Item2.Count > 1)
+            {
+                var fdowString = foundParameters.Item2[1].Trim();
+
+                if (int.TryParse(fdowString, out var fdowInt))
+                {
+                    fdow = (FirstDayOfWeek)fdowInt;
+                }
+                else
+                {
+                    fdow = (FirstDayOfWeek)Enum.Parse(typeof(FirstDayOfWeek), fdowString.Substring(15, fdowString.Length - 15));
+                }
+            }
+                        
+            this.CurrentExpression.Index = match.Index;
+            this.CurrentExpression.ResolvedType = typeof(int);
+            this.CurrentExpression.Value = date.ParseWeekday(fdow);
+        }
+    }
+}

src/ReportViewer.NET/Parsers/ExpressionFieldOperator.cs

@@ -70,6 +70,7 @@ public enum ExpressionFieldOperator
         TimeString,
         TimeValue,
         Today,
+        Weekday,
         FormatCurrency,
         RowNumber
     }

src/ReportViewer.NET/Parsers/ExpressionParser.cs

@@ -516,6 +516,7 @@ ref string proposedString
             }
 
             if (DayParser.DayRegex.IsMatch(currentString) &&
+                ((WeekdayParser.WeekdayRegex.IsMatch(currentString) && DayParser.DayRegex.Match(currentString).Index < WeekdayParser.WeekdayRegex.Match(currentString).Index) || !WeekdayParser.WeekdayRegex.IsMatch(currentString)) &&
                 (currentExpression.Operator == ExpressionFieldOperator.None || DayParser.DayRegex.Match(currentString).Index < currentExpression.Index)
             )
             {
@@ -640,6 +641,15 @@ ref string proposedString
                 todayParser.Parse();
                 proposedString = todayParser.GetProposedString();
             }
+
+            if (WeekdayParser.WeekdayRegex.IsMatch(currentString) &&
+                (currentExpression.Operator == ExpressionFieldOperator.None || WeekdayParser.WeekdayRegex.Match(currentString).Index < currentExpression.Index)
+            )
+            {
+                var weekdayParser = new WeekdayParser(currentString, ExpressionFieldOperator.Weekday, currentExpression, dataSetResults, values, currentRowNumber, dataSets, activeDataset, _report);
+                weekdayParser.Parse();
+                proposedString = weekdayParser.GetProposedString();
+            }
         }
 
         private void SearchMathFunctions()

test/ReportViewer.NET.Tests/Parsers/DateAndTime/WeekdayParserTests.cs

@@ -0,0 +1,73 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using ReportViewer.NET.DataObjects;
+using ReportViewer.NET.Extensions;
+using ReportViewer.NET.Parsers;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ReportViewer.NET.Tests.Parsers.DateAndTime
+{
+    [TestClass]
+    public class WeekdayParserTests
+    {
+        private ExpressionParser _expressionParser;
+        private ReportRDL _report;
+
+        public WeekdayParserTests()
+        {
+            var report = TestHelper.PrimeReport();
+
+            _report = report;
+            _expressionParser = new ExpressionParser(report);
+        }
+
+        [TestMethod]
+        public void Weekday_Returns_Integer()
+        {
+            // System defaults first day to Sunday, January 15 2010 is a Friday so this will be 6.
+
+            // Arrange
+            var expr = "=Weekday(\"January 15, 2010 14:15:30\")";
+
+            // Act
+            var result = _expressionParser.ParseReportExpressionString(
+                expr,
+                null,
+                null,
+                1,
+                _report.DataSets,
+                null,
+                null
+            ).ExpressionAsInt();
+
+            // Assert
+            Assert.AreEqual(6, result);
+        }
+
+        [TestMethod]
+        public void Weekday_Returns_Integer_First_Day_Tuesday()
+        {
+            // January 15 2010 is a Friday. Setting first day to Tuesday will make this 4.
+
+            // Arrange
+            var expr = "=Weekday(\"January 15, 2010 14:15:30\", FirstDayOfWeek.Tuesday)";
+
+            // Act
+            var result = _expressionParser.ParseReportExpressionString(
+                expr,
+                null,
+                null,
+                1,
+                _report.DataSets,
+                null,
+                null
+            ).ExpressionAsInt();
+
+            // Assert
+            Assert.AreEqual(4, result);
+        }
+    }
+}