add -a and -b flags

main.go

@@ -34,28 +34,38 @@ func formula(p float64) int64 {
 	return int64(yearsAgo * 31556926)
 }
 
-func (db *TimelineDB) closestEvents(t int64, n int) ([]EventsRow, error) {
+func (db *TimelineDB) closestEvents(t int64, n int, after bool, before bool) ([]EventsRow, error) {
+	ulimit := int64(math.MaxInt64)
+	llimit := int64(math.MinInt64)
+	if after && before {
+		return nil, errors.New("after and before can't both be true")
+	} else if after {
+		llimit = t
+	} else if before {
+		ulimit = t
+	}
+
 	query := `
 	select description, timestamp, yearknown, monthknown, dayknown, hourknown, minuteknown, secondknown
 	from events
-	where timestamp is not null
+	where timestamp between ? and ?
 	order by abs(? - timestamp) asc
 	limit ?
 	`
 
-	events := make([]EventsRow, n)
 	stmt, err := db.Prepare(query)
 	if err != nil {
-		return events, err
+		return nil, err
 	}
 	defer stmt.Close()
 
-	rows, err := stmt.Query(t, n)
+	rows, err := stmt.Query(llimit, ulimit, t, n)
 	if err != nil {
-		return events, err
+		return nil, err
 	}
 	defer rows.Close()
 
+	events := make([]EventsRow, n)
 	i := 0
 	for ; rows.Next(); i++ {
 		var event EventsRow
@@ -96,8 +106,14 @@ func (event *EventsRow) Output() (int64, string, string, error) {
 func main() {
 	percent := flag.Float64("p", -1, "percentage")
 	nevents := flag.Int("n", 1, "number of events")
+	after := flag.Bool("a", false, "only return events occurring after computed timestamp")
+	before := flag.Bool("b", false, "only return events occurring before computed timestamp")
 	flag.Parse()
 
+	if *after && *before {
+		log.Fatal("cannot pass both -a and -b")
+	}
+
 	if *percent < 0 || *percent > 1 {
 		log.Fatal("invalid percentage")
 	} else if *nevents < 0 {
@@ -114,7 +130,7 @@ func main() {
 	}
 	defer db.Close()
 
-	events, err := db.closestEvents(t, *nevents)
+	events, err := db.closestEvents(t, *nevents, *after, *before)
 	if err != nil {
 		log.Fatal(err)
 	}