Improve duration format of overdue tasks in reminders

pkg/utils/humanize_duration.go

@@ -0,0 +1,66 @@
+// 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 (
+	"fmt"
+	"math"
+	"strings"
+	"time"
+)
+
+// HumanizeDuration formats a time.Duration in a human-friendly format.
+// Based on https://gist.github.com/harshavardhana/327e0577c4fed9211f65
+func HumanizeDuration(duration time.Duration) string {
+	years := int64(duration.Hours() / 24 / 365)
+	days := int64(duration.Hours()/24) - years*365
+	weeks := days / 7
+	days -= weeks * 7
+
+	hours := int64(math.Mod(duration.Hours(), 24))
+	minutes := int64(math.Mod(duration.Minutes(), 60))
+
+	chunks := []struct {
+		singularName string
+		amount       int64
+	}{
+		{"year", years},
+		{"week", weeks},
+		{"day", days},
+		{"hour", hours},
+		{"minute", minutes},
+	}
+
+	parts := []string{}
+
+	for _, chunk := range chunks {
+		switch chunk.amount {
+		case 0:
+			continue
+		case 1:
+			parts = append(parts, fmt.Sprintf("one %s", chunk.singularName))
+		default:
+			parts = append(parts, fmt.Sprintf("%d %ss", chunk.amount, chunk.singularName))
+		}
+	}
+
+	if len(parts) > 1 {
+		return strings.Join(parts[:len(parts)-1], ", ") + " and " + parts[len(parts)-1]
+	}
+
+	return strings.Join(parts, ", ")
+}