[GH57] Receive notifications of upcoming events (#58)

* Receive notifications of upcoming events

* Fix compile error

* Update error on subject empty, use user timezone on event reminder, simplify time operations, extract event rendering and extract statusSyncJobInterval to mscalendar

* Revert debug change

* Improve timezone fetching and error messages

* Simplify no subject message

* Change "No subject" for "Subject: unkwnonw"

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>
Co-authored-by: mattermod <mattermod@users.noreply.github.com>

server/jobs/status_sync_job.go

@@ -4,22 +4,17 @@
 package jobs
 
 import (
-	"time"
-
 	"github.com/mattermost/mattermost-plugin-mscalendar/server/mscalendar"
 )
 
 // Unique id for the status sync job
 const statusSyncJobID = "status_sync"
 
-// Run status sync job every 5 minutes
-const statusSyncJobInterval = 5 * time.Minute
-
 // NewStatusSyncJob creates a RegisteredJob with the parameters specific to the StatusSyncJob
 func NewStatusSyncJob() RegisteredJob {
 	return RegisteredJob{
 		id:                statusSyncJobID,
-		interval:          statusSyncJobInterval,
+		interval:          mscalendar.StatusSyncJobInterval,
 		work:              runStatusSyncJob,
 		isEnabledByConfig: isStatusSyncJobEnabled,
 	}

server/mscalendar/availability.go

@@ -7,14 +7,18 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/mattermost/mattermost-plugin-mscalendar/server/mscalendar/views"
 	"github.com/mattermost/mattermost-plugin-mscalendar/server/remote"
 	"github.com/mattermost/mattermost-plugin-mscalendar/server/store"
 	"github.com/mattermost/mattermost-plugin-mscalendar/server/utils"
 	"github.com/pkg/errors"
 )
 
 const (
-	availabilityTimeWindowSize = 15
+	availabilityTimeWindowSize      = 15
+	StatusSyncJobInterval           = 5 * time.Minute
+	upcomingEventNotificationTime   = 10 * time.Minute
+	upcomingEventNotificationWindow = (StatusSyncJobInterval * 9) / 10 //90% of the interval
 )
 
 type Availability interface {
@@ -105,6 +109,8 @@ func (m *mscalendar) setUserStatuses(users store.UserIndex, schedules []*remote.
 		}
 
 		mattermostUserID := usersByEmail[s.ScheduleID].MattermostUserID
+
+		m.notifyUpcomingEvent(mattermostUserID, s.ScheduleItems)
 		status, ok := statusMap[mattermostUserID]
 		if !ok {
 			continue
@@ -119,6 +125,37 @@ func (m *mscalendar) setUserStatuses(users store.UserIndex, schedules []*remote.
 	return utils.JSONBlock(schedules), nil
 }
 
+func (m *mscalendar) notifyUpcomingEvent(mattermostUserID string, items []remote.ScheduleItem) {
+	var timezone string
+	for _, scheduleItem := range items {
+		upcomingTime := time.Now().Add(upcomingEventNotificationTime)
+		start := scheduleItem.Start.Time()
+		diff := start.Sub(upcomingTime)
+
+		if (diff < upcomingEventNotificationWindow) && (diff > -upcomingEventNotificationWindow) {
+			var err error
+			if timezone == "" {
+				timezone, err = m.GetTimezoneByID(mattermostUserID)
+				if err != nil {
+					m.Logger.Errorf("notifyUpcomingEvent error getting timezone, err=%s", err.Error())
+					return
+				}
+			}
+
+			message, err := views.RenderScheduleItem(scheduleItem, timezone)
+			if err != nil {
+				m.Logger.Errorf("notifyUpcomingEvent error rendering schedule item, err=", err.Error())
+				continue
+			}
+			err = m.Poster.DM(mattermostUserID, message)
+			if err != nil {
+				m.Logger.Errorf("notifyUpcomingEvent error creating DM, err=", err.Error())
+				continue
+			}
+		}
+	}
+}
+
 func (m *mscalendar) GetAvailabilities(remoteUserID string, scheduleIDs []string) ([]*remote.ScheduleInformation, error) {
 	err := m.Filter(withClient)
 	if err != nil {

server/mscalendar/user.go

@@ -94,6 +94,10 @@ func (m *mscalendar) GetTimezone(user *User) (string, error) {
 	return settings.TimeZone, nil
 }
 
+func (m *mscalendar) GetTimezoneByID(mattermostUserID string) (string, error) {
+	return m.GetTimezone(NewUser(mattermostUserID))
+}
+
 func (user *User) String() string {
 	if user.MattermostUser != nil {
 		return fmt.Sprintf("@%s", user.MattermostUser.Username)

server/mscalendar/views/calendar.go

@@ -64,3 +64,22 @@ func groupEventsByDate(events []*remote.Event) [][]*remote.Event {
 	}
 	return result
 }
+
+func RenderScheduleItem(s remote.ScheduleItem, timezone string) (string, error) {
+	message := "You have an upcoming event:"
+	start := s.Start.In(timezone).Time()
+	end := s.End.In(timezone).Time()
+
+	message += fmt.Sprintf("\n%s-%s (%s)", start.Format(time.Kitchen), end.Format(time.Kitchen), timezone)
+	if s.Subject == "" {
+		message += "\nSubject: unknown"
+	} else {
+		message += fmt.Sprintf("\nSubject: %s", s.Subject)
+	}
+
+	if s.Location != "" {
+		message += fmt.Sprintf("\nLocation: %s", s.Location)
+	}
+
+	return message, nil
+}

server/remote/schedule.go

@@ -9,6 +9,13 @@ const (
 	AvailabilityViewBusy             = '2'
 	AvailabilityViewOutOfOffice      = '3'
 	AvailabilityViewWorkingElsewhere = '4'
+
+	ScheduleStatusFree             = "free"
+	ScheduleStatusTentative        = "tentative"
+	ScheduleStatusBusy             = "busy"
+	ScheduleStatusOof              = "oof"
+	ScheduleStatusWorkingElsewhere = "workingElsewhere"
+	ScheduleStatusUnknown          = "unknown"
 )
 
 type ScheduleInformationError struct {
@@ -29,7 +36,16 @@ type ScheduleInformation struct {
 
 	Error *ScheduleInformationError `json:"error"`
 
-	// ScheduleItems []interface{} `json:"scheduleItems,omitempty"`
+	ScheduleItems []ScheduleItem `json:"scheduleItems,omitempty"`
 	// WorkingHours interface{} `json:"workingHours,omitempty"`
 	// Error *FreeBusyError `json:"error,omitempty"`
 }
+
+type ScheduleItem struct {
+	IsPrivate bool
+	Status    string
+	Subject   string
+	Location  string
+	Start     DateTime
+	End       DateTime
+}