1 files changed, 59 insertions, 0 deletions
diff --git a/src/Enmarcha.Backend/Extensions/StopScheduleExtensions.cs b/src/Enmarcha.Backend/Extensions/StopScheduleExtensions.cs
new file mode 100644
index 0000000..bbf0e4b
--- /dev/null
+++ b/src/Enmarcha.Backend/Extensions/StopScheduleExtensions.cs
@@ -0,0 +1,59 @@
+using Enmarcha.Backend.Types;
+using static Enmarcha.Backend.Types.StopArrivals.Types;
+
+namespace Enmarcha.Backend.Extensions;
+
+public static class StopScheduleExtensions
+{
+    public static DateTime? StartingDateTime(this StopArrivals.Types.ScheduledArrival stop, DateTime baseDate)
+    {
+        return ParseGtfsTime(stop.StartingTime, baseDate);
+    }
+
+    public static DateTime? CallingDateTime(this StopArrivals.Types.ScheduledArrival stop, DateTime baseDate)
+    {
+        return ParseGtfsTime(stop.CallingTime, baseDate);
+    }
+
+    /// <summary>
+    /// Parse GTFS time format (HH:MM:SS) which can have hours >= 24 for services past midnight
+    /// </summary>
+    private static DateTime? ParseGtfsTime(string timeStr, DateTime baseDate)
+    {
+        if (string.IsNullOrWhiteSpace(timeStr))
+        {
+            return null;
+        }
+
+        var parts = timeStr.Split(':');
+        if (parts.Length != 3)
+        {
+            return null;
+        }
+
+        if (!int.TryParse(parts[0], out var hours) ||
+            !int.TryParse(parts[1], out var minutes) ||
+            !int.TryParse(parts[2], out var seconds))
+        {
+            return null;
+        }
+
+        // Handle GTFS times that exceed 24 hours (e.g., 25:30:00 for 1:30 AM next day)
+        var days = hours / 24;
+        var normalizedHours = hours % 24;
+
+        try
+        {
+            var dt = baseDate
+                .AddDays(days)
+                .AddHours(normalizedHours)
+                .AddMinutes(minutes)
+                .AddSeconds(seconds);
+            return dt.AddSeconds(60 - dt.Second);
+        }
+        catch
+        {
+            return null;
+        }
+    }
+}