package feed import ( "errors" "fmt" "net/url" "regexp" "slices" "strings" "time" ) var ( ErrNoContent = errors.New("failed to retrieve any content") ErrPartialContent = errors.New("failed to retrieve some of the content") ) func percentChange(current, previous float64) float64 { return (current/previous - 1) * 100 } func extractDomainFromUrl(u string) string { if u == "" { return "" } parsed, err := url.Parse(u) if err != nil { return "" } return strings.TrimPrefix(strings.ToLower(parsed.Host), "www.") } func SvgPolylineCoordsFromYValues(width float64, height float64, values []float64) string { if len(values) < 2 { return "" } verticalPadding := height * 0.02 height -= verticalPadding * 2 coordinates := make([]string, len(values)) distanceBetweenPoints := width / float64(len(values)-1) min := slices.Min(values) max := slices.Max(values) for i := range values { coordinates[i] = fmt.Sprintf( "%.2f,%.2f", float64(i)*distanceBetweenPoints, ((max-values[i])/(max-min))*height+verticalPadding, ) } return strings.Join(coordinates, " ") } func maybeCopySliceWithoutZeroValues[T int | float64](values []T) []T { if len(values) == 0 { return values } for i := range values { if values[i] != 0 { continue } c := make([]T, 0, len(values)-1) for i := range values { if values[i] != 0 { c = append(c, values[i]) } } return c } return values } var urlSchemePattern = regexp.MustCompile(`^[a-z]+:\/\/`) func stripURLScheme(url string) string { return urlSchemePattern.ReplaceAllString(url, "") } func limitStringLength(s string, max int) (string, bool) { asRunes := []rune(s) if len(asRunes) > max { return string(asRunes[:max]), true } return s, false } func parseRFC3339Time(t string) time.Time { parsed, err := time.Parse(time.RFC3339, t) if err != nil { return time.Now() } return parsed }