Support for XEP-0082.

Parsing of times with an offset does not work for now (should it ?)

stanza/datetime_profiles.go

@@ -0,0 +1,70 @@
+package stanza
+
+import (
+	"errors"
+	"strings"
+	"time"
+)
+
+// Helper structures and functions to manage dates and timestamps as defined in
+// XEP-0082: XMPP Date and Time Profiles (https://xmpp.org/extensions/xep-0082.html)
+
+const dateLayoutXEP0082 = "2006-01-02"
+const timeLayoutXEP0082 = "15:04:05+00:00"
+
+var InvalidDateInput = errors.New("could not parse date. Input might not be in a supported format")
+var InvalidDateOutput = errors.New("could not format date as desired")
+
+type JabberDate struct {
+	value time.Time
+}
+
+func (d JabberDate) DateToString() string {
+	return d.value.Format(dateLayoutXEP0082)
+}
+
+func (d JabberDate) DateTimeToString(nanos bool) string {
+	if nanos {
+		return d.value.Format(time.RFC3339Nano)
+	}
+	return d.value.Format(time.RFC3339)
+}
+
+func (d JabberDate) TimeToString(nanos bool) (string, error) {
+	if nanos {
+		spl := strings.Split(d.value.Format(time.RFC3339Nano), "T")
+		if len(spl) != 2 {
+			return "", InvalidDateOutput
+		}
+		return spl[1], nil
+	}
+	spl := strings.Split(d.value.Format(time.RFC3339), "T")
+	if len(spl) != 2 {
+		return "", InvalidDateOutput
+	}
+	return spl[1], nil
+}
+
+func NewJabberDateFromString(strDate string) (JabberDate, error) {
+	t, err := time.Parse(time.RFC3339, strDate)
+	if err == nil {
+		return JabberDate{value: t}, nil
+	}
+
+	t, err = time.Parse(time.RFC3339Nano, strDate)
+	if err == nil {
+		return JabberDate{value: t}, nil
+	}
+
+	t, err = time.Parse(dateLayoutXEP0082, strDate)
+	if err == nil {
+		return JabberDate{value: t}, nil
+	}
+
+	t, err = time.Parse(timeLayoutXEP0082, strDate)
+	if err == nil {
+		return JabberDate{value: t}, nil
+	}
+
+	return JabberDate{}, InvalidDateInput
+}