func FormatNumberForMobileDialing()

in phonenumbers.go [1282:1383]
63 lines of code
25 McCabe index (conditional complexity)

func FormatNumberForMobileDialing(
	number *PhoneNumber,
	regionCallingFrom string,
	withFormatting bool) string {

	countryCallingCode := int(number.GetCountryCode())
	if !hasValidCountryCallingCode(countryCallingCode) {
		return number.GetRawInput() // go impl defaults to ""
	}

	formattedNumber := ""
	// Clear the extension, as that part cannot normally be dialed
	// together with the main number.
	var numberNoExt = &PhoneNumber{}
	proto.Merge(numberNoExt, number)
	numberNoExt.Extension = nil // can we assume this is safe? (no nil-pointer?)
	regionCode := GetRegionCodeForCountryCode(countryCallingCode)
	numberType := GetNumberType(numberNoExt)
	isValidNumber := numberType != UNKNOWN
	if regionCallingFrom == regionCode {
		isFixedLineOrMobile :=
			numberType == FIXED_LINE ||
				numberType == MOBILE ||
				numberType == FIXED_LINE_OR_MOBILE
		// Carrier codes may be needed in some countries. We handle this here.
		if regionCode == "CO" && numberType == FIXED_LINE {
			formattedNumber =
				FormatNationalNumberWithCarrierCode(
					numberNoExt, COLOMBIA_MOBILE_TO_FIXED_LINE_PREFIX)
		} else if regionCode == "BR" && isFixedLineOrMobile {
			if numberNoExt.GetPreferredDomesticCarrierCode() != "" {
				formattedNumber =
					FormatNationalNumberWithPreferredCarrierCode(numberNoExt, "")
			} else {
				// Brazilian fixed line and mobile numbers need to be dialed
				// with a carrier code when called within Brazil. Without
				// that, most of the carriers won't connect the call.
				// Because of that, we return an empty string here.
				formattedNumber = ""
			}
		} else if isValidNumber && regionCode == "HU" {
			// The national format for HU numbers doesn't contain the
			// national prefix, because that is how numbers are normally
			// written down. However, the national prefix is obligatory when
			// dialing from a mobile phone, except for short numbers. As a
			// result, we add it back here
			// if it is a valid regular length phone number.
			formattedNumber =
				GetNddPrefixForRegion(regionCode, true /* strip non-digits */) +
					" " + Format(numberNoExt, NATIONAL)
		} else if countryCallingCode == NANPA_COUNTRY_CODE {
			// For NANPA countries, we output international format for
			// numbers that can be dialed internationally, since that
			// always works, except for numbers which might potentially be
			// short numbers, which are always dialled in national format.
			regionMetadata := getMetadataForRegion(regionCallingFrom)
			if canBeInternationallyDialled(numberNoExt) && testNumberLength(GetNationalSignificantNumber(numberNoExt), regionMetadata, UNKNOWN) != TOO_SHORT {
				formattedNumber = Format(numberNoExt, INTERNATIONAL)
			} else {
				formattedNumber = Format(numberNoExt, NATIONAL)
			}
		} else {
			// For non-geographical countries, and Mexican and Chilean fixed
			// line and mobile numbers, we output international format for
			// numbers that can be dialed internationally as that always
			// works.

			// MX fixed line and mobile numbers should always be formatted
			// in international format, even when dialed within MX. For
			// national format to work, a carrier code needs to be used,
			// and the correct carrier code depends on if the caller and
			// callee are from the same local area. It is trickier to get
			// that to work correctly than using international format, which
			// is tested to work fine on all carriers. CL fixed line
			// numbers need the national prefix when dialing in the national
			// format, but don't have it when used for display. The reverse
			// is true for mobile numbers. As a result, we output them in
			// the international format to make it work.
			if regionCode == REGION_CODE_FOR_NON_GEO_ENTITY ||
				((regionCode == "MX" || regionCode == "CL" || regionCode == "UZ") &&
					isFixedLineOrMobile) &&
					canBeInternationallyDialled(numberNoExt) {
				formattedNumber = Format(numberNoExt, INTERNATIONAL)
			} else {
				formattedNumber = Format(numberNoExt, NATIONAL)
			}
		}
	} else if isValidNumber && canBeInternationallyDialled(numberNoExt) {
		// We assume that short numbers are not diallable from outside
		// their region, so if a number is not a valid regular length
		// phone number, we treat it as if it cannot be internationally
		// dialled.
		if withFormatting {
			return Format(numberNoExt, INTERNATIONAL)
		}
		return Format(numberNoExt, E164)
	}
	if withFormatting {
		return formattedNumber
	}
	return normalizeDiallableCharsOnly(formattedNumber)
}