Add Calendar integration (read-only)

maintenance.go

@@ -0,0 +1,144 @@
+package main
+
+import (
+	"bytes"
+	"html/template"
+	"log"
+	"sort"
+	"time"
+)
+
+// calendarsURL is the page URL of calendarsDir ("/Calendars/").
+var calendarsURL string
+
+// maintenanceHorizon is how many days after today the header widget lists.
+const maintenanceHorizon = 7
+
+type maintItem struct {
+	When    string // "03:00" today; "Sa 27.09." or "Sa 27.09. 03:00" later
+	Summary string
+}
+
+type maintWidgetData struct {
+	Count    int // occurrences today (the badge)
+	Today    []maintItem
+	Upcoming []maintItem
+	PageURL  string
+}
+
+var maintWidgetTmpl = template.Must(template.New("widget.html").
+	Funcs(template.FuncMap{"icon": readIcon}).
+	ParseFS(assets, "assets/calendar/widget.html"))
+
+// maintenanceWidget renders the header chip and its dropdown. It is a
+// template func so layout.html can call it without every page's data struct
+// carrying it. Empty when no maintenance calendar is configured.
+func maintenanceWidget() template.HTML {
+	if calendarsDir == "" {
+		return ""
+	}
+	names := readCalendarSettings(calendarsDir).Maintenance
+	if len(names) == 0 {
+		return ""
+	}
+	now := time.Now()
+	today := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.Local)
+	tomorrow := today.AddDate(0, 0, 1)
+
+	data := maintWidgetData{PageURL: calendarsURL}
+	for _, ev := range calendarOccurrences(calendarsDir, names, today, today.AddDate(0, 0, maintenanceHorizon+1)) {
+		// Anything that started before tomorrow is due today, including
+		// multi-day events still running.
+		if ev.Start.Before(tomorrow) {
+			item := maintItem{Summary: ev.Summary}
+			if !ev.AllDay && !ev.Start.Before(today) {
+				item.When = ev.Start.Format("15:04")
+			}
+			data.Today = append(data.Today, item)
+			continue
+		}
+		when := calDayLabel(ev.Start)
+		if !ev.AllDay {
+			when += " " + ev.Start.Format("15:04")
+		}
+		data.Upcoming = append(data.Upcoming, maintItem{When: when, Summary: ev.Summary})
+	}
+	data.Count = len(data.Today)
+
+	var buf bytes.Buffer
+	if err := maintWidgetTmpl.Execute(&buf, data); err != nil {
+		log.Printf("maintenance widget template: %v", err)
+		return ""
+	}
+	return template.HTML(buf.String())
+}
+
+// maintSeriesRow is one task in the calendars page's maintenance table.
+type maintSeriesRow struct {
+	Summary string
+	Rule    string
+	Last    string // most recent occurrence before today
+	Next    string // first occurrence today or later
+	next    time.Time
+}
+
+// maintenanceWindow bounds the table's occurrence search, in days each way
+// from today. A year covers yearly tasks.
+const maintenanceWindow = 366
+
+// maintenanceSeries lists every task of the named calendars in dir: one row
+// per recurring series with its last and next date, plus upcoming single
+// events. Sorted by next date; series without a next date come last.
+func maintenanceSeries(dir string, names []string, now time.Time) []maintSeriesRow {
+	today := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.Local)
+	evs := calendarOccurrences(dir, names, today.AddDate(0, 0, -maintenanceWindow), today.AddDate(0, 0, maintenanceWindow))
+
+	type key struct{ calendar, uid string }
+	rows := map[key]*maintSeriesRow{}
+	var order []*maintSeriesRow
+	for _, ev := range evs {
+		if ev.Series == nil {
+			if ev.Start.Before(today) {
+				continue
+			}
+			order = append(order, &maintSeriesRow{
+				Summary: ev.Summary,
+				Rule:    "once",
+				Next:    calDayLabel(ev.Start),
+				next:    ev.Start,
+			})
+			continue
+		}
+		k := key{ev.Calendar, ev.Series.UID}
+		row := rows[k]
+		if row == nil {
+			row = &maintSeriesRow{Summary: ev.Series.Summary, Rule: ev.Series.Rule}
+			rows[k] = row
+			order = append(order, row)
+		}
+		// Occurrences arrive sorted by start: keep overwriting Last, take
+		// the first one from today on as Next.
+		if ev.Start.Before(today) {
+			row.Last = calDayLabel(ev.Start)
+		} else if row.next.IsZero() {
+			row.next = ev.Start
+			row.Next = calDayLabel(ev.Start)
+		}
+	}
+
+	out := make([]maintSeriesRow, 0, len(order))
+	for _, r := range order {
+		out = append(out, *r)
+	}
+	sort.SliceStable(out, func(i, j int) bool {
+		a, b := out[i].next, out[j].next
+		if a.IsZero() != b.IsZero() {
+			return b.IsZero()
+		}
+		if !a.Equal(b) {
+			return a.Before(b)
+		}
+		return out[i].Summary < out[j].Summary
+	})
+	return out
+}