Initial Commit

sort.go

@@ -0,0 +1,83 @@
+package timertxt
+
+import (
+	"errors"
+	"sort"
+	"time"
+)
+
+// Flags for defining sort element and order.
+const (
+	SORT_START_DATE_ASC = iota
+	SORT_START_DATE_DESC
+	SORT_FINISH_DATE_ASC
+	SORT_FINISH_DATE_DESC
+)
+
+// Sort allows a TimerList to be sorted by certain predefined fields.
+// See constants SORT_* for fields and sort order.
+func (timerlist *TimerList) Sort(sortFlag int) error {
+	switch sortFlag {
+	case SORT_START_DATE_ASC, SORT_START_DATE_DESC:
+		timerlist.sortByStartDate(sortFlag)
+	case SORT_FINISH_DATE_ASC, SORT_FINISH_DATE_DESC:
+		timerlist.sortByFinishDate(sortFlag)
+	default:
+		return errors.New("Unrecognized sort option")
+	}
+	return nil
+}
+
+type timerlistSort struct {
+	timerlists TimerList
+	by         func(t1, t2 *Timer) bool
+}
+
+func (ts *timerlistSort) Len() int {
+	return len(ts.timerlists)
+}
+
+func (ts *timerlistSort) Swap(l, r int) {
+	ts.timerlists[l], ts.timerlists[r] = ts.timerlists[r], ts.timerlists[l]
+}
+
+func (ts *timerlistSort) Less(l, r int) bool {
+	return ts.by(&ts.timerlists[l], &ts.timerlists[r])
+}
+
+func (timerlist *TimerList) sortBy(by func(t1, t2 *Timer) bool) *TimerList {
+	ts := &timerlistSort{
+		timerlists: *timerlist,
+		by:         by,
+	}
+	sort.Sort(ts)
+	return timerlist
+}
+
+func sortByDate(asc bool, date1, date2 time.Time) bool {
+	if asc { // ASC
+		if !date1.IsZero() && !date2.IsZero() {
+			return date1.Before(date2)
+		}
+		return !date2.IsZero()
+	}
+	// DESC
+	if !date1.IsZero() && !date2.IsZero() {
+		return date1.After(date2)
+	}
+	return date2.IsZero()
+}
+
+func (timerlist *TimerList) sortByStartDate(order int) *TimerList {
+	timerlist.sortBy(func(t1, t2 *Timer) bool {
+		return sortByDate(order == SORT_START_DATE_ASC, t1.StartDate, t2.StartDate)
+	})
+	return timerlist
+}
+
+func (timerlist *TimerList) sortByFinishDate(order int) *TimerList {
+	timerlist.sortBy(func(t1, t2 *Timer) bool {
+		return sortByDate(order == SORT_FINISH_DATE_ASC, t1.FinishDate, t2.FinishDate)
+	})
+	return timerlist
+}