fix(bug): Fixed DTStart bug in rrule processing. (#1468)

* fix(bug): Fixed DTStart bug in rrule processing.

Right now we kind of guess the dtstart, but several months ago I added
some code to set a marker for a usable dtstart on the record itself.
This way we can use that more accurately.

* chore: Improved tests

* fix(bug): Fixed bug with forecasting calculation.

* chore: Fixing timezone issues :(

* chore: Fixed dtstart issue in pkg models too

pkg/controller/funding_schedules.go

@@ -124,6 +124,7 @@ func (c *Controller) postFundingSchedules(ctx echo.Context) error {
 
 	// It has never occurred so this needs to be nil.
 	fundingSchedule.LastOccurrence = nil
+	fundingSchedule.DateStarted = fundingSchedule.NextOccurrence
 
 	if err = repo.CreateFundingSchedule(c.getContext(ctx), &fundingSchedule); err != nil {
 		return c.wrapPgError(ctx, err, "failed to create funding schedule")

pkg/controller/spending.go

@@ -137,6 +137,7 @@ func (c *Controller) postSpending(ctx echo.Context) error {
 	}
 
 	spending.NextRecurrence = nextRecurrence
+	spending.DateStarted = nextRecurrence
 
 	// Once we have all that data we can calculate the new expenses next contribution amount.
 	if err = spending.CalculateNextContribution(

pkg/forecast/fixtures/elliots-funding-20230705.json

@@ -0,0 +1,10 @@
+[
+  {
+    "fundingScheduleId": 1,
+    "rule": "FREQ=MONTHLY;INTERVAL=1;BYMONTHDAY=15,-1",
+    "excludeWeekends": true,
+    "lastOccurrence": "2023-06-30T05:00:00Z",
+    "nextOccurrence": "2023-07-14T05:00:00Z",
+    "dateStarted": "2023-02-28T06:00:00Z"
+  }
+]