Handling of english number parsing for reminders

DeukBot4/MessageHandlers/ReminderHandler.cs

@@ -8,7 +8,7 @@ namespace DeukBot4.MessageHandlers
 {
     public static class ReminderHandler
     {
-        private static Regex ReminderMatcher =
+        private static readonly Regex ReminderMatcher =
             new Regex(
                 @".*(remind\s*((?<recipient>me)|<@!*(?<recipient>\d*)>)\s*to)(?<action>.*)(in\s+)(?<time>.*)",
                 RegexOptions.IgnoreCase);
@@ -49,7 +49,7 @@ namespace DeukBot4.MessageHandlers
         }
 
         private static Regex TimespanMatcher =
-            new Regex(@"(?<timeNumber>\d+.?\d*)\s*(?<timeId>minutes*|hours*|days*|weeks*|months*|years*)\W*(and )*",
+            new Regex(@"(?<timeNumber>\d+.?\d*|[\w\s-]+)\s*(?<timeId>minutes*|hours*|days*|weeks*|months*|years*)\W*(and )*",
                 RegexOptions.IgnoreCase);
         private static TimeSpan? ParseTime(string message)
         {
@@ -62,7 +62,14 @@ namespace DeukBot4.MessageHandlers
                 if (!match.Success)
                     continue;
                 var timeId = match.Groups["timeId"].Value.ToLowerInvariant();
-                var timeAmount = double.Parse(match.Groups["timeNumber"].Value);
+                var amountString = match.Groups["timeNumber"].Value;
+                if (!double.TryParse(amountString, out var timeAmount))
+                {
+                    if (!EnglishNumberParser.ConvertNumberString(amountString, out timeAmount))
+                    {
+                        return null;
+                    }
+                }
                 if (timeId.StartsWith("minute"))
                     timespan += TimeSpan.FromMinutes(timeAmount);
                 else if (timeId.StartsWith("hour"))
@@ -93,5 +100,6 @@ namespace DeukBot4.MessageHandlers
 
             return timespan;
         }
+
     }
 }

DeukBot4/Utilities/EnglishNumberParser.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Collections.Generic;
+
+namespace DeukBot4.Utilities
+{
+    public class EnglishNumberParser
+    {
+        private static readonly Dictionary<string, int> OneValues = new Dictionary<string, int>()
+        {
+            {"zero", 0}, {"a", 1}, {"an", 1}, {"one", 1}, {"two", 2}, {"three", 3}, {"four",4}, {"five", 5}, {"six", 6}, {"seven", 7},
+            {"eight", 8}, {"nine", 9}
+        };
+        private static readonly Dictionary<string, int> TenValues = new Dictionary<string, int>()
+        {
+            {"ten", 10}, {"eleven", 11}, {"twelve", 12}, {"thirteen", 13}, {"fourteen", 14}, {"fifteen", 15},
+            {"sixteen", 16}, {"seventeen", 17}, {"eighteen", 18}, {"nineteen", 19},
+
+            {"twenty", 20}, {"thirty", 30}, {"forty",40}, {"fifty", 50}, {"sixty", 60}, {"seventy", 70},
+            {"eighty", 80}, {"ninety", 90}
+        };
+        private static readonly Dictionary<string, int> HundredsValues = new Dictionary<string, int>()
+        {
+            {"hundred", 100}, {"thousand",1000}, {"million", 1_000_000}
+        };
+
+
+        public static bool ConvertNumberString(string numberString, out double number)
+        {
+            numberString = numberString.Replace("-", "").Replace(" ", "");
+            var i = 0;
+            while (numberString.Length > 0)
+            {
+                var next = ConvertNextNumber(ref numberString);
+                if (!next.HasValue)
+                {
+                    number = 0;
+                    return false;
+                }
+                i += next.Value;
+            }
+            number = i;
+            return true;
+        }
+
+        private static int? ConvertNextNumber(ref string numberString)
+        {
+            foreach (var oneValue in OneValues)
+            {
+                if (numberString.EndsWith(oneValue.Key, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    numberString =  numberString.Substring(0, numberString.Length - oneValue.Key.Length);
+                    return oneValue.Value;
+                }
+            }
+            foreach (var oneValue in TenValues)
+            {
+                if (numberString.EndsWith(oneValue.Key, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    numberString =  numberString.Substring(0, numberString.Length - oneValue.Key.Length);
+                    return oneValue.Value;
+                }
+            }
+            foreach (var oneValue in HundredsValues)
+            {
+                if (numberString.EndsWith(oneValue.Key, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    numberString =  numberString.Substring(0, numberString.Length - oneValue.Key.Length);
+                    var value = oneValue.Value;
+                    var next = ConvertNextNumber(ref numberString);
+                    if (next.HasValue)
+                    {
+                        if ((int)Math.Log10(next.Value) <= (int)Math.Log10(value))
+                            value *= next.Value;
+                        else
+                        {
+                            value += next.Value;
+                        }
+                    }
+                    return value;
+                }
+            }
+
+            return null;
+        }
+
+    }
+}