Serge Bazanski | 8ef457f | 2021-07-11 14:42:38 +0000 | [diff] [blame] | 1 | package calendar |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "fmt" |
| 6 | "io" |
| 7 | "net/http" |
| 8 | "sort" |
| 9 | "time" |
| 10 | _ "time/tzdata" |
| 11 | |
| 12 | ics "github.com/arran4/golang-ical" |
| 13 | "github.com/golang/glog" |
| 14 | ) |
| 15 | |
| 16 | const ( |
| 17 | // eventsURL is the calendar from which we load public Hackerspace events. |
| 18 | eventsURL = "https://owncloud.hackerspace.pl/remote.php/dav/public-calendars/g8toktZrA9fyAHNi/?export" |
| 19 | ) |
| 20 | |
| 21 | // eventsBySooner sorts upcoming events so the one that happens the soonest |
| 22 | // will be first in the list. |
| 23 | type eventBySooner []*UpcomingEvent |
| 24 | |
| 25 | func (e eventBySooner) Len() int { return len(e) } |
| 26 | func (e eventBySooner) Swap(i, j int) { e[i], e[j] = e[j], e[i] } |
| 27 | func (e eventBySooner) Less(i, j int) bool { |
| 28 | a, b := e[i], e[j] |
| 29 | if a.Start.Time == b.Start.Time { |
| 30 | if a.End.Time == b.End.Time { |
| 31 | return a.UID < b.UID |
| 32 | } |
| 33 | return a.End.Time.Before(b.End.Time) |
| 34 | } |
| 35 | return a.Start.Time.Before(b.Start.Time) |
| 36 | } |
| 37 | |
| 38 | // parseUpcomingEvents generates a list of upcoming events from an open ICS/iCal file. |
| 39 | func parseUpcomingEvents(now time.Time, data io.Reader) ([]*UpcomingEvent, error) { |
| 40 | cal, err := ics.ParseCalendar(data) |
| 41 | if err != nil { |
| 42 | return nil, fmt.Errorf("ParseCalendar(%q): %w", err) |
| 43 | } |
| 44 | |
| 45 | var out []*UpcomingEvent |
| 46 | for _, event := range cal.Events() { |
| 47 | uidProp := event.GetProperty(ics.ComponentPropertyUniqueId) |
| 48 | if uidProp == nil || uidProp.Value == "" { |
| 49 | glog.Errorf("Event with no UID, ignoring: %+v", event) |
| 50 | continue |
| 51 | } |
| 52 | uid := uidProp.Value |
| 53 | |
| 54 | summaryProp := event.GetProperty(ics.ComponentPropertySummary) |
| 55 | if summaryProp == nil || summaryProp.Value == "" { |
| 56 | glog.Errorf("Event %s has no summary, ignoring", uid) |
| 57 | } |
| 58 | summary := summaryProp.Value |
| 59 | |
| 60 | status := event.GetProperty(ics.ComponentPropertyStatus) |
| 61 | tentative := false |
| 62 | if status != nil { |
| 63 | if status.Value == string(ics.ObjectStatusCancelled) { |
| 64 | // NextCloud only has CONFIRMED, CANCELELD and TENTATIVE for |
| 65 | // events. We drop everything CANCELELD and keep things that are |
| 66 | // TENTATIVE. |
| 67 | continue |
| 68 | } |
| 69 | if status.Value == string(ics.ObjectStatusTentative) { |
| 70 | tentative = true |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | start, err := parseICSTime(event.GetProperty(ics.ComponentPropertyDtStart)) |
| 75 | if err != nil { |
| 76 | glog.Errorf("Event %s has unparseable DTSTART, ignoring: %v", uid, err) |
| 77 | continue |
| 78 | } |
| 79 | end, err := parseICSTime(event.GetProperty(ics.ComponentPropertyDtEnd)) |
| 80 | if err != nil { |
| 81 | glog.Errorf("Event %s has unparseable DTEND, ignoring: %v", uid, err) |
| 82 | continue |
| 83 | } |
| 84 | |
| 85 | if (start.WholeDay && !end.WholeDay) || (!start.WholeDay && end.WholeDay) { |
| 86 | glog.Errorf("Event %s has whole-day inconsistencies, start: %s, end: %s, ignoring", uid, start, end) |
| 87 | } |
| 88 | |
| 89 | u := &UpcomingEvent{ |
| 90 | UID: uid, |
| 91 | Summary: summary, |
| 92 | Start: start, |
| 93 | End: end, |
| 94 | Tentative: tentative, |
| 95 | } |
| 96 | if u.Elapsed(now) { |
| 97 | continue |
| 98 | } |
| 99 | |
| 100 | out = append(out, u) |
| 101 | } |
| 102 | sort.Sort(eventBySooner(out)) |
| 103 | return out, nil |
| 104 | } |
| 105 | |
| 106 | // GetUpcomingEvents returns all public Hackerspace events that are upcoming |
| 107 | // relative to the given time 'now' as per the Warsaw Hackerspace public |
| 108 | // calender (from owncloud.hackerspace.pl). |
| 109 | func GetUpcomingEvents(ctx context.Context, now time.Time) ([]*UpcomingEvent, error) { |
| 110 | r, err := http.NewRequestWithContext(ctx, "GET", eventsURL, nil) |
| 111 | if err != nil { |
| 112 | return nil, fmt.Errorf("NewRequest(%q): %w", eventsURL, err) |
| 113 | } |
| 114 | res, err := http.DefaultClient.Do(r) |
| 115 | if err != nil { |
| 116 | return nil, fmt.Errorf("Do(%q): %w", eventsURL, err) |
| 117 | } |
| 118 | defer res.Body.Close() |
| 119 | return parseUpcomingEvents(now, res.Body) |
| 120 | } |