const MINIMUM_PHONE_NUMBER_LENGTH = 9;

const PHONE_OK = 0;
const PHONE_ERROR_EMPTY_PHONE = 1;
const PHONE_ERROR_INVALID_CHARS = 2;
const PHONE_ERROR_PHONE_SHORT_LENGTH = 3;
const PHONE_ERROR_PHONE_IS_FICTIVE = 4;

function IsPhoneTextNumber(str) 
{
	var result = (str != null);	
	result = result && (str.length != 0);
	result = result && (str.match(/[0-9]/i));
	return result;
}

function GetFixedPhoneNumber(phone_number)
{
	var result = "";	
	if (phone_number) {
		for (var i = 0; i < phone_number.length; i++) {
			if (IsPhoneTextNumber(phone_number.charAt(i))) {
				result += phone_number.charAt(i);
			}		  
		}
	}
	return result;
}

function CheckPhoneEmpty(phone_number)
{
	var result = (phone_number != null);
	if (result) {	
		phone_number = phone_number.trim();
		result = result && (phone_number.length > 0);	
	}
	return result;	
}

function CheckPhoneChars(phone_number)
{
	if (phone_number) {		
		var phone_regex = /^[0-9\+\-\ \(\)]+$/;		
		if (phone_regex.test(phone_number)) {
			return true;		
		}				
	}
	return false;	
}

function CheckPhoneLength(phone_number)
{
	phone_number = GetFixedPhoneNumber(phone_number);
	if (phone_number) {		
		return (phone_number.length >= MINIMUM_PHONE_NUMBER_LENGTH);	
	}
	return false;
}

function IsStringFilledWithDigit(phone, digit)
{				
	phone = phone.split(digit).join('');	
	return (phone.length == 0);
}	

 function IsPhoneFilledBySingleDigit(phone)
{	
	for (var i = 0; i <= 9; i++)
	{		
		if (IsStringFilledWithDigit(phone, i))				
			return true;		
	}	
	return false;	
}

function CheckFictivePhoneNumber(phone)
{
	phone = GetFixedPhoneNumber(phone);
	var result = (!IsPhoneFilledBySingleDigit(phone));	
	return result;
}

function ValidatePhoneNumber(phone_number)
{		
	if (!CheckPhoneEmpty(phone_number))
		return PHONE_ERROR_EMPTY_PHONE;
	if (!CheckPhoneChars(phone_number))
		return PHONE_ERROR_INVALID_CHARS;
	if (!CheckPhoneLength(phone_number))
		return PHONE_ERROR_PHONE_SHORT_LENGTH;
	if (!CheckFictivePhoneNumber(phone_number))
		return PHONE_ERROR_PHONE_IS_FICTIVE;		
	return PHONE_OK;
}

function PhoneValidationStatusToDescription(status)
{
	switch (status) 
	{
		case PHONE_OK: return "OK";
		case PHONE_ERROR_EMPTY_PHONE: return "Номер телефона не может быть пустым";
		case PHONE_ERROR_INVALID_CHARS: return "Номер телефона содержит некорректные символы";
		case PHONE_ERROR_PHONE_IS_FICTIVE: return "Номер телефона не может состоять из одной цифры";
		case PHONE_ERROR_PHONE_SHORT_LENGTH: return "Слишком короткий номер телефона";
	}
	return "Неизвестная ошибка";
}

function IsValidPhoneNumber(phone_number)
{
	var phone_validate_result = ValidatePhoneNumber(phone_number);
	return (phone_validate_result == PHONE_OK);	
}