noptin_locate_ip_address( string $ip_address = '' )

function noptin_locate_ip_address( $ip_address = '' ) {

	// Prepare ip address.
	if ( empty( $ip_address ) ) {
		$ip_address = noptin_get_user_ip();
	}

	// Ensure that it is valid.
	if (  empty( $ip_address ) || ! rest_is_ip_address( $ip_address ) ) {
		return false;
	}

	// Try fetching from the cache.
	$transient_name = md5( "noptin_geolocation_cache_$ip_address" );

	if ( get_transient( $transient_name ) ) {
		return get_transient( $transient_name );
	}

	// Retrieve API key.
	$api_key = get_noptin_option( 'ipgeolocation_io_api_key' );

	if ( empty( $api_key ) ) {
		return noptin_locate_ip_address_alt( $ip_address );
	}

	// Geolocate the ip.
	$url      = add_query_arg(
		array(
			'apiKey' => $api_key,
			'ip'     => $ip_address,
			'fields' => 'city,continent_name,country_name,state_prov,zipcode,country_flag,currency,time_zone,latitude,longitude,calling_code',
		),
		'https://api.ipgeolocation.io/ipgeo'
	);
	$response = wp_remote_get( $url );

	if ( is_wp_error( $response ) ) {
		return false;
	}

	$geo = json_decode( wp_remote_retrieve_body( $response ), true );
	if ( empty( $geo ) ) {
		log_noptin_message( __( 'Error fetching GeoLocation information.', 'newsletter-optin-box' ) );
		return false;
	}

	if ( ! empty( $geo['time_zone'] ) ) {
		$geo['time zone'] = $geo['time_zone']['name'] . ' GMT ' . $geo['time_zone']['offset'];
	}

	if ( ! empty( $geo['currency'] ) ) {
		$geo['currency'] = $geo['currency']['name'];
	}

	if ( ! empty( $geo['continent_name'] ) ) {
		$geo['continent'] = $geo['continent_name'];
		unset( $geo['continent_name'] );
	}

	if ( ! empty( $geo['country_name'] ) ) {
		$geo['country'] 		= $geo['country_name'];
		unset( $geo['country_name'] );
	}

	if ( ! empty( $geo['state_prov'] ) ) {
		$geo['state'] 			= $geo['state_prov'];
		unset( $geo['state_prov'] );
	}

	$fields = noptin_clean( $geo );
	set_transient( $transient_name, $fields, HOUR_IN_SECONDS );
	return $fields;

}