Filter outlook discussions with retained outlooks

internal/app/service.go

@@ -85,6 +85,7 @@ func (s *Service) LatestConvectiveOutlook(ctx context.Context, filter OutlookFil
 		}
 	}
 	out.Outlooks = outlooks
+	out.Discussions = filterOutlookDiscussions(out.Discussions, out.Outlooks)
 	return out, nil
 }
 
@@ -123,6 +124,12 @@ func cloneOutlookRun(run *model.WeatherOutlookRun) *model.WeatherOutlookRun {
 			out.Outlooks[i] = cloneOutlook(run.Outlooks[i])
 		}
 	}
+	if run.Discussions != nil {
+		out.Discussions = make([]model.WeatherOutlookDiscussion, len(run.Discussions))
+		for i := range run.Discussions {
+			out.Discussions[i] = cloneOutlookDiscussion(run.Discussions[i])
+		}
+	}
 	return &out
 }
 
@@ -135,6 +142,31 @@ func cloneOutlook(outlook model.WeatherOutlook) model.WeatherOutlook {
 	return out
 }
 
+func cloneOutlookDiscussion(discussion model.WeatherOutlookDiscussion) model.WeatherOutlookDiscussion {
+	out := discussion
+	out.UpdatedAt = copyTime(discussion.UpdatedAt)
+	return out
+}
+
+func filterOutlookDiscussions(discussions []model.WeatherOutlookDiscussion, outlooks []model.WeatherOutlook) []model.WeatherOutlookDiscussion {
+	if len(outlooks) == 0 {
+		return []model.WeatherOutlookDiscussion{}
+	}
+
+	retainedDays := make(map[int]struct{}, len(outlooks))
+	for _, outlook := range outlooks {
+		retainedDays[outlook.Day] = struct{}{}
+	}
+
+	out := discussions[:0]
+	for _, discussion := range discussions {
+		if _, ok := retainedDays[discussion.Day]; ok {
+			out = append(out, discussion)
+		}
+	}
+	return out
+}
+
 func copyFloat64(value *float64) *float64 {
 	if value == nil {
 		return nil