Add offsetNow function

Author: svilenmarkov

docs/custom-api.md

@@ -375,6 +375,7 @@ The following helper functions provided by Glance are available:
 - `toInt(f float) int`: Converts a float to an integer.
 - `toRelativeTime(t time.Time) template.HTMLAttr`: Converts Time to a relative time such as 2h, 1d, etc which dynamically updates. **NOTE:** the value of this function should be used as an attribute in an HTML tag, e.g. `<span {{ toRelativeTime .Time }}></span>`.
 - `now() time.Time`: Returns the current time.
+- `offsetNow(offset string) time.Time`: Returns the current time with an offset. The offset can be positive or negative and must be in the format "3h" "-1h" or "2h30m10s".
 - `duration(str string) time.Duration`: Parses a string such as `1h`, `1d`, `5h30m`, etc into a `time.Duration`.
 - `parseTime(layout string, s string) time.Time`: Parses a string into time.Time. The layout must be provided in Go's [date format](https://pkg.go.dev/time#pkg-constants). You can alternatively use these values instead of the literal format: "unix", "RFC3339", "RFC3339Nano", "DateTime", "DateOnly".
 - `parseRelativeTime(layout string, s string) time.Time`: A shorthand for `{{ .String "date" | parseTime "rfc3339" | toRelativeTime }}`.

internal/glance/widget-custom-api.go

@@ -435,6 +435,13 @@ var customAPITemplateFuncs = func() template.FuncMap {
 		"now": func() time.Time {
 			return time.Now()
 		},
+		"offsetNow": func(offset string) time.Time {
+			d, err := time.ParseDuration(offset)
+			if err != nil {
+				return time.Now()
+			}
+			return time.Now().Add(d)
+		},
 		"duration": func(str string) time.Duration {
 			d, err := time.ParseDuration(str)
 			if err != nil {