func IsNationalPrefixPresentIfRequired()

in matcher.go [47:85]
27 lines of code
7 McCabe index (conditional complexity)

func IsNationalPrefixPresentIfRequired(number *PhoneNumber) bool {
	// First, check how we deduced the country code. If it was written
	// in international format, then the national prefix is not required.
	if number.GetCountryCodeSource() != PhoneNumber_FROM_DEFAULT_COUNTRY {
		return true
	}
	var phoneNumberRegion = GetRegionCodeForCountryCode(int(number.GetCountryCode()))
	var metadata = getMetadataForRegion(phoneNumberRegion)
	if metadata == nil {
		return true
	}
	// Check if a national prefix should be present when formatting this number.
	var nationalNumber = GetNationalSignificantNumber(number)
	var formatRule = chooseFormattingPatternForNumber(
		metadata.GetNumberFormat(), nationalNumber)
	// To do this, we check that a national prefix formatting rule was
	// present and that it wasn't just the first-group symbol ($1) with
	// punctuation.
	if (formatRule != nil) && len(formatRule.GetNationalPrefixFormattingRule()) > 0 {
		if formatRule.GetNationalPrefixOptionalWhenFormatting() {
			// The national-prefix is optional in these cases, so we
			// don't need to check if it was present.
			return true
		}
		if formattingRuleHasFirstGroupOnly(
			formatRule.GetNationalPrefixFormattingRule()) {
			// National Prefix not needed for this number.
			return true
		}
		// Normalize the remainder.
		var rawInputCopy = NormalizeDigitsOnly(number.GetRawInput())
		var rawInput = NewBuilderString(rawInputCopy)
		// Check if we found a national prefix and/or carrier code at
		// the start of the raw input, and return the result.
		return maybeStripNationalPrefixAndCarrierCode(
			rawInput, metadata, NewBuilder(nil))
	}
	return true
}