/// <summary>
/// Compare the specified mail address again correctMailDomainNames, and try to correct the given mailAddress.
/// </summary>
/// <param name="correctMailDomainNames">The collection of correct mail domain names.</param>
/// <param name="mailAddress">The mail address which will be corrected. It should be a valid mail address format. Otherwise, an exception will be thrown</param>
/// <returns>The corrected mail address. If empty string, it indicates the given mailAddress is already correct.</returns>
public static string CorrectMailAddress(IEnumerable <string> correctMailDomainNames, string mailAddress)
{
var correctedMailAddress = StringUtility.RemoveWhiteSpaces(mailAddress);
correctedMailAddress = StringUtility.ToDBC(correctedMailAddress);
// Simply parsing the given mailAddress
var atIndex = correctedMailAddress.IndexOf('@');
if ((atIndex <= 0) || (atIndex == (correctedMailAddress.Length - 1)))
{
throw new FormatException("The given mailAddress format is invalid. " + mailAddress);
}
var account = correctedMailAddress.Substring(0, atIndex);
var domainName = correctedMailAddress.Substring(atIndex + 1);
//var lastDotIndex = domainName.LastIndexOf('.');
//if ((lastDotIndex <= 0) || (lastDotIndex == (domainName.Length - 1)))
//{
// throw new FormatException("The given mailAddress format is invalid. " + mailAddress);
//}
//var domainNameFirst = correctedMailAddress.Substring(0, lastDotIndex);
//var domainNameSecond = correctedMailAddress.Substring(lastDotIndex + 1);
var minDistance = 99;
var minDistanceDomainName = string.Empty;
var moreThanOne = false;
foreach (var correctMailDomainName in correctMailDomainNames)
{
var distance = StringUtility.CalculateLevenshteinDistance(domainName, correctMailDomainName);
if (distance <= 0)
{
// Exactly match, return
return(ComputeCorrectMailAddressResult(mailAddress, account, correctMailDomainName));
}
if (minDistance == distance)
{
// Find one more candidate
moreThanOne = true;
}
else if (minDistance > distance)
{
minDistance = distance;
moreThanOne = false;
minDistanceDomainName = correctMailDomainName;
}
}
if (moreThanOne)
{
// If there are more than one candidates which have same distance, do not correct.
return(ComputeCorrectMailAddressResult(mailAddress, account, domainName));
}
else
{
if (minDistance < 2)
{
// Only correct 1 difference mailAddress
return(ComputeCorrectMailAddressResult(mailAddress, account, minDistanceDomainName));
}
else
{
// Do not correct
return(ComputeCorrectMailAddressResult(mailAddress, account, domainName));
}
}
}