Fix mapping task priorities from Vikunja to calDAV

Resolves #866

pkg/caldav/parsing.go

@@ -0,0 +1,134 @@
+// 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 caldav
+
+import (
+	"strconv"
+	"strings"
+	"time"
+
+	"code.vikunja.io/api/pkg/log"
+	"code.vikunja.io/api/pkg/models"
+	"github.com/laurent22/ical-go"
+)
+
+func GetCaldavTodosForTasks(list *models.List, listTasks []*models.Task) string {
+
+	// Make caldav todos from Vikunja todos
+	var caldavtodos []*Todo
+	for _, t := range listTasks {
+
+		duration := t.EndDate.Sub(t.StartDate)
+
+		caldavtodos = append(caldavtodos, &Todo{
+			Timestamp:   t.Updated,
+			UID:         t.UID,
+			Summary:     t.Title,
+			Description: t.Description,
+			Completed:   t.DoneAt,
+			// Organizer:     &t.CreatedBy, // Disabled until we figure out how this works
+			Priority: t.Priority,
+			Start:    t.StartDate,
+			End:      t.EndDate,
+			Created:  t.Created,
+			Updated:  t.Updated,
+			DueDate:  t.DueDate,
+			Duration: duration,
+		})
+	}
+
+	caldavConfig := &Config{
+		Name:   list.Title,
+		ProdID: "Vikunja Todo App",
+	}
+
+	return ParseTodos(caldavConfig, caldavtodos)
+}
+
+func ParseTaskFromVTODO(content string) (vTask *models.Task, err error) {
+	parsed, err := ical.ParseCalendar(content)
+	if err != nil {
+		return nil, err
+	}
+
+	// We put the task details in a map to be able to handle them more easily
+	task := make(map[string]string)
+	for _, c := range parsed.Children {
+		if c.Name == "VTODO" {
+			for _, entry := range c.Children {
+				task[entry.Name] = entry.Value
+			}
+			// Breaking, to only process the first task
+			break
+		}
+	}
+
+	// Parse the priority
+	var priority int64
+	if _, ok := task["PRIORITY"]; ok {
+		priorityParsed, err := strconv.ParseInt(task["PRIORITY"], 10, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		priority = parseVTODOPriority(priorityParsed)
+	}
+
+	// Parse the enddate
+	duration, _ := time.ParseDuration(task["DURATION"])
+
+	vTask = &models.Task{
+		UID:         task["UID"],
+		Title:       task["SUMMARY"],
+		Description: task["DESCRIPTION"],
+		Priority:    priority,
+		DueDate:     caldavTimeToTimestamp(task["DUE"]),
+		Updated:     caldavTimeToTimestamp(task["DTSTAMP"]),
+		StartDate:   caldavTimeToTimestamp(task["DTSTART"]),
+		DoneAt:      caldavTimeToTimestamp(task["COMPLETED"]),
+	}
+
+	if task["STATUS"] == "COMPLETED" {
+		vTask.Done = true
+	}
+
+	if duration > 0 && !vTask.StartDate.IsZero() {
+		vTask.EndDate = vTask.StartDate.Add(duration)
+	}
+
+	return
+}
+
+// https://tools.ietf.org/html/rfc5545#section-3.3.5
+func caldavTimeToTimestamp(tstring string) time.Time {
+	if tstring == "" {
+		return time.Time{}
+	}
+
+	format := DateFormat
+
+	if strings.HasSuffix(tstring, "Z") {
+		format = `20060102T150405Z`
+	}
+
+	t, err := time.Parse(format, tstring)
+	if err != nil {
+		log.Warningf("Error while parsing caldav time %s to TimeStamp: %s", tstring, err)
+		return time.Time{}
+	}
+	return t
+}