fix(scheduler): added better error messages and regular expression for numerical paths

src/MfGames.Nitride.Temporal.Schedules/NumericalPathSchedule.cs

@@ -21,7 +21,7 @@ public partial class NumericalPathSchedule : ISchedule
 {
     public NumericalPathSchedule()
     {
-        this.PathRegex = @"^.*(\d+)";
+        this.PathRegex = @"^.*?(\d+)[^\d]*$";
         this.GetPath = entity => entity.Get<UPath>().ToString();
         this.CaptureGroup = 1;
         this.CaptureOffset = -1;
@@ -61,13 +61,17 @@ public partial class NumericalPathSchedule : ISchedule
     /// <summary>
     /// Gets or sets the schedule period as a TimeSpan object. This is converted
     /// from SchedulePeriod using https://github.com/pengowray/TimeSpanParser.
-    /// If the value is null, then this will be instant (TimeSpan.Zero).
+    /// If the value is null or blank or "immediate", then this will be instant
+    /// (TimeSpan.Zero).
     /// </summary>
     public virtual TimeSpan SchedulePeriodTimeSpan
     {
-        get => this.SchedulePeriod == null
+        get => string.IsNullOrWhiteSpace(this.SchedulePeriod)
-            ? TimeSpan.Zero
+            || this.SchedulePeriod.Equals(
-            : TimeSpanParser.Parse(this.SchedulePeriod);
+                "immediate",
+                StringComparison.InvariantCultureIgnoreCase)
+                ? TimeSpan.Zero
+                : TimeSpanParser.Parse(this.SchedulePeriod);
         set => this.SchedulePeriod = value.ToString();
     }
 
@@ -95,9 +99,24 @@ public partial class NumericalPathSchedule : ISchedule
             return entity;
         }
 
+        if (match.Groups.Count < 2)
+        {
+            throw new InvalidOperationException(
+                "There must be at least one capture group in '"
+                + this.PathRegex
+                + "'.");
+        }
+
         // Figure out the index/number of this entry.
-        int number = int.Parse(match.Groups[this.CaptureGroup].Value)
+        string numberValue = match.Groups[this.CaptureGroup].Value;
-            + this.CaptureOffset;
+
+        if (!int.TryParse(numberValue, out int number))
+        {
+            throw new FormatException(
+                path + ": Cannot parse '" + numberValue + "' as integer.");
+        }
+
+        number += this.CaptureOffset;
 
         // Figure out the time from the start.
         DateTime start = this.ScheduleStart

src/MfGames.Nitride.Temporal.Schedules/README.md

@@ -103,7 +103,7 @@ chapter will be set to 2023-01-08, and the third at 2023-01-15.
     - Defaults to `entity.Get<UPath>().ToString()`
 - `Regex PathRegex`
     - The regular expression that retrieves the number.
-    - Defaults to `^.*(\d+)` which grabs the last number found.
+    - Defaults to `^.*?(\d+)[^\d]*$` which grabs the last number found.
 - `DateTime ScheduleStart`
     - The date that the schedule starts.
     - No default.

tests/MfGames.Nitride.Temporal.Schedules.Tests/NumericalPathScheduleTests.cs

@@ -49,6 +49,7 @@ public class NumericalPathScheduleTests : TemporalSchedulesTestBase
                     "schedules:",
                     "  - pathRegex: chapter-(\\d+)",
                     "    scheduleStart: 2023-01-01",
+                    "    schedulePeriod: 1 week",
                     "    access: public",
                     ""));
         List<TestSchedule>? schedules = model.Schedules!;
@@ -141,6 +142,62 @@ public class NumericalPathScheduleTests : TemporalSchedulesTestBase
         TestHelper.CompareObjects(expected, actual);
     }
 
+    [Fact]
+    public void ScheduleOffsetWorks()
+    {
+        using TemporalSchedulesTestContext context = this.CreateContext();
+
+        // Create a numerical series of entities.
+        var input = new List<Entity>
+        {
+            new Entity().SetAll((UPath)"/chapter-11.md", new TestModel()),
+            new Entity().SetAll((UPath)"/chapter-12.md", new TestModel()),
+            new Entity().SetAll((UPath)"/chapter-13.md", new TestModel()),
+        };
+
+        var schedules = new List<TestSchedule>
+        {
+            new()
+            {
+                ScheduleStart = DateTime.Parse("2023-01-01"),
+                CaptureOffset = -11,
+                Access = "public",
+            },
+        };
+
+        // Create the operation and run it, but treat it as being set after the
+        // second but before the third item.
+        Timekeeper time = context.Resolve<Timekeeper>();
+        ApplySchedules op = context.Resolve<ApplySchedules>()
+            .WithGetSchedules(_ => schedules);
+        var now = Instant.FromUtc(2023, 1, 9, 0, 0);
+
+        time.Clock = new FakeClock(now);
+
+        var actual = op
+            .Run(input)
+            .Select(
+                a => string.Format(
+                    "{0} -- {1} -- {2}",
+                    a.Get<UPath>().ToString(),
+                    a.Has<Instant>()
+                        ? time
+                            .ToDateTime(a.Get<Instant>())
+                            .ToString("yyyy-MM-dd")
+                        : "none",
+                    a.Get<TestModel>().Access))
+            .ToList();
+
+        var expected = new List<string>
+        {
+            "/chapter-11.md -- 2023-01-01 -- public",
+            "/chapter-12.md -- 2023-01-08 -- public",
+            "/chapter-13.md -- none -- private",
+        };
+
+        TestHelper.CompareObjects(expected, actual);
+    }
+
     [Fact]
     public void SequencedScheduleWorks()
     {