feat(caldav): Sync Reminders / VALARM (#1415)

Co-authored-by: ce72 <christoph.ernst72@googlemail.com>
Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/api/pulls/1415
Reviewed-by: konrad <k@knt.li>
Co-authored-by: cernst <ce72@noreply.kolaente.de>
Co-committed-by: cernst <ce72@noreply.kolaente.de>

pkg/utils/duration.go

@@ -0,0 +1,57 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-2021 Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public Licensee as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public Licensee for more details.
+//
+// You should have received a copy of the GNU Affero General Public Licensee
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package utils
+
+import (
+	"regexp"
+	"strconv"
+	"time"
+)
+
+// ParseISO8601Duration converts a ISO8601 duration into a time.Duration
+func ParseISO8601Duration(str string) time.Duration {
+	matches := durationRegex.FindStringSubmatch(str)
+
+	if len(matches) == 0 {
+		return 0
+	}
+
+	years := parseDurationPart(matches[2], time.Hour*24*365)
+	months := parseDurationPart(matches[3], time.Hour*24*30)
+	days := parseDurationPart(matches[4], time.Hour*24)
+	hours := parseDurationPart(matches[5], time.Hour)
+	minutes := parseDurationPart(matches[6], time.Second*60)
+	seconds := parseDurationPart(matches[7], time.Second)
+
+	duration := years + months + days + hours + minutes + seconds
+
+	if matches[1] == "-" {
+		return -duration
+	}
+	return duration
+}
+
+var durationRegex = regexp.MustCompile(`([-+])?P([\d\.]+Y)?([\d\.]+M)?([\d\.]+D)?T?([\d\.]+H)?([\d\.]+M)?([\d\.]+?S)?`)
+
+func parseDurationPart(value string, unit time.Duration) time.Duration {
+	if len(value) != 0 {
+		if parsed, err := strconv.ParseFloat(value[:len(value)-1], 64); err == nil {
+			return time.Duration(float64(unit) * parsed)
+		}
+	}
+	return 0
+}

pkg/utils/duration_test.go

@@ -0,0 +1,39 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-2021 Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public Licensee as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public Licensee for more details.
+//
+// You should have received a copy of the GNU Affero General Public Licensee
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package utils
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParseISO8601Duration(t *testing.T) {
+	t.Run("full example", func(t *testing.T) {
+		dur := ParseISO8601Duration("P1DT1H1M1S")
+		expected, _ := time.ParseDuration("25h1m1s")
+
+		assert.Equal(t, expected, dur)
+	})
+	t.Run("negative duration", func(t *testing.T) {
+		dur := ParseISO8601Duration("-P1DT1H1M1S")
+		expected, _ := time.ParseDuration("-25h1m1s")
+
+		assert.Equal(t, expected, dur)
+	})
+}