using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

​

    public static void Main(string[] args)

    {

        var FieldList = new List<string>

        {

            "Case.Owner.Name",

            "Case.Owner.ProfilePic",

            "Case.CaseNo",

            "Case.FieldOfLaw.Name",

            "Case.CaseType.Name",

            "Case.CaseSubType.Name",

            "Client.Policy.PolicyNo",

        };

​

        Parser graphQL = new Parser();

        var result = graphQL.Parse(FieldList);

        Console.Write(result);

    }

}

​

public class Parser

{

    public Parser() { }

​

    public string Parse(List<string> fieldList)

    {

        var fieldPaths = fieldList.Select(x => x.Split('.').ToList());

        var groups = fieldPaths.GroupBy(x => x.First(), x => x.Skip(1));

        return ParseGroups(groups, 1);

    }

​

    private string ParseGroups(IEnumerable<IGrouping<string, IEnumerable<string>>> groups, int level)

    {

        string indent = new string('\t', level - 1);

​

        var groupResults = groups.Select(g =>

            !g.First().Any() ? 

                $"\t{indent}{g.Key}: null" :

                $"\t{indent}{g.Key}: " + string.Join(", \n", ParseGroups(g.GroupBy(x => x.First(), x => x.Skip(1)), level + 1))

        );

​

        return indent + "{\n" + string.Join(", \n", groupResults) + "\n" + indent + "}";

    }

}