Add logic to add tempBasal from pump history after filtering

We filter the pump history to improve algorithmic performance, but if
there aren't any temp basals within our filtered history we need to
pull the most recent one from the full history and add it to our
filtered history. This change ensures that the `lastTemp` field is
consistent with JS.

Trio/Sources/APS/OpenAPSSwift/Iob/IobGenerator.swift

@@ -15,7 +15,24 @@ struct IobGenerator {
 
         // we have to keep all of our suspend/resume events due to a hardcoded
         // DIA value in dealing with suspended pumps in JS
-        let pumpHistory = history.filter({ $0.timestamp >= lastDia || $0.isSuspendOrResume() }).map({ $0.computedEvent() })
+        var pumpHistory = history.filter({ $0.timestamp >= lastDia || $0.isSuspendOrResume() }).map({ $0.computedEvent() })
+
+        // To make sure that lastTemp is filled in correctly, we need to check
+        // if there aren't any tempBasal events in the DIA-filtered list.
+        // If not, find the most recent one from the full history and add it.
+        if pumpHistory.filter({ $0.type == .tempBasal }).isEmpty {
+            // Find the most recent TempBasal event from before the DIA cutoff
+            let olderTempBasals = history.filter({ $0.type == .tempBasal && $0.timestamp < lastDia })
+            if let lastTempBasal = olderTempBasals.max(by: { $0.timestamp < $1.timestamp }) {
+                // Find its matching TempBasalDuration (same timestamp)
+                if let matchingDuration = history
+                    .first(where: { $0.type == .tempBasalDuration && $0.timestamp == lastTempBasal.timestamp })
+                {
+                    pumpHistory.append(lastTempBasal.computedEvent())
+                    pumpHistory.append(matchingDuration.computedEvent())
+                }
+            }
+        }
 
         let treatments = try IobHistory.calcTempTreatments(
             history: pumpHistory,