using System;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(addressLookup("42 Wallaby Way","12345"));                 // Should append zip, original missing zip

        Console.WriteLine(addressLookup("123 Some address","LKDSJFLKFJD"));         // Should not append zip, bad format

        Console.WriteLine(addressLookup("42 Wallaby Way 12345","12345"));           // Should not append zip, already in original input as exact match

        Console.WriteLine(addressLookup("123 Something","215"));                    // Should not append zip, bad format

        Console.WriteLine(addressLookup("123 Something","78945-2345"));             // Should append zip, original misssing zip and zip in good format

        Console.WriteLine(addressLookup("123 Something 78945","78945-4512"));       // Should not append zip, original has zip even if partial match

        Console.WriteLine(addressLookup("123 Something 78945-4512","78945"));       // Should not append zip, original has zip+4 already

        Console.WriteLine(addressLookup("123 Something 78945-4512","78945-4512"));  // Should not append zip, original has zip+4 already

        Console.WriteLine(addressLookup("",""));                                    // Should not break

        /************************************************************************************************

          How should it behave if both sides have a zip code but they don't match? 

          in theory we should substitute... but if they typed it and had a mistake then we shouldn't

        *************************************************************************************************/

        Console.WriteLine(addressLookup("123 Something 78945-4512","78944-4512"));  // Both have zip, but they don't match, ignore zip field in favor of original addr string

        Console.WriteLine(addressLookup("123 Something 78945","78944-4512"));       // Both have zip, but they don't match, ignore zip field in favor of original addr string                                                                                   

        Console.WriteLine(addressLookup("78945 Something","78944-4512"));           // Has what looks like it could be a zip at the front, but is actually the address. Should append zip

        Console.WriteLine("\n\n----- Different behavior ------");

        Console.WriteLine(addressLookup2("123 Something 78945-4512","78944-4512")); // Both have zip, but replace zip with the zip field as it is a valid zip

        Console.WriteLine(addressLookup2("123 Something 78945","78944-4512"));      // Both have zip, but replace zip with the zip field as it is a valid zip

        Console.WriteLine(addressLookup2("123 Something 78945","7894"));            // Both have zip, but don't replace zip with the zip field as it is invalid

        Console.WriteLine(addressLookup2("78945 Something","78944-4512"));          // Has what looks like it could be a zip at the front, but is actually the address. Should append zip

    }

    public static string addressLookup(string addr, string zip) {

        string[] geocodeAddress;

        string cleanZip = zip.Trim().ToLower();

        string firstFiveCharacters = cleanZip.Substring(0, Math.Min(5, cleanZip.Length));

        bool hasZipAsEntered = addr.ToLower().Contains(cleanZip);

        bool hasZipFirstFive = addr.ToLower().Contains(firstFiveCharacters);

        bool goodFormatZip = Regex.Match(cleanZip, @"^\d{5}(?:[-\s]\d{4})?$").Success;

        bool addrHasZipAlready = Regex.Match(addr.Trim(), @"\d{5}(?:[-\s]\d{4})?$").Success;

        if(hasZipAsEntered || hasZipFirstFive || !goodFormatZip || addrHasZipAlready) {

            geocodeAddress = new string[] { addr };

        }

        else {

            geocodeAddress = new string[] { addr, zip };

        }

        return String.Join(" ", geocodeAddress);

    }

    //Different behavior from above, this one will replace the zip in the original string with the one in the zip code field if zip code field is valid zip format

    public static string addressLookup2(string addr, string zip) {

        string[] geocodeAddress;

        string cleanZip = zip.Trim().ToLower();

        string firstFiveCharacters = cleanZip.Substring(0, Math.Min(5, cleanZip.Length));

        bool goodFormatZip = Regex.Match(cleanZip, @"^\d{5}(?:[-\s]\d{4})?$").Success;

        if(goodFormatZip) {

            addr = Regex.Replace(addr.Trim(), @"\d{5}(?:[-\s]\d{4})?$", cleanZip);

        }

        bool hasZipAsEntered = addr.ToLower().Contains(cleanZip);

        bool hasZipFirstFive = addr.ToLower().Contains(firstFiveCharacters);

        if(hasZipAsEntered || hasZipFirstFive || !goodFormatZip ) {

            geocodeAddress = new string[] { addr };

        }

        else {

            geocodeAddress = new string[] { addr, zip };

        }

        return String.Join(" ", geocodeAddress);

    }

}