using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        List<OutgoingPaymentApprovalDetails> inputs = new List<OutgoingPaymentApprovalDetails>()

        {

            new OutgoingPaymentApprovalDetails() { OriginatorId = 1, Name = "Name1", DocumentId = "DocumentId1", Amount = 1.0, DebitAccountNo = "DebitAccountNo1", CreditAccountNo = "CreditAccountNo1"},

            new OutgoingPaymentApprovalDetails() { OriginatorId = 1, Name = "Name1", DocumentId = "DocumentId1", Amount = 2.0, DebitAccountNo = "DebitAccountNo2", CreditAccountNo = "CreditAccountNo2"},

            new OutgoingPaymentApprovalDetails() { OriginatorId = 1, Name = "Name1", DocumentId = "DocumentId2", Amount = 3.0, DebitAccountNo = "DebitAccountNo3", CreditAccountNo = "CreditAccountNo3"},

            new OutgoingPaymentApprovalDetails() { OriginatorId = 1, Name = "Name1", DocumentId = "DocumentId2", Amount = 4.0, DebitAccountNo = "DebitAccountNo4", CreditAccountNo = "CreditAccountNo4"},

            new OutgoingPaymentApprovalDetails() { OriginatorId = 2, Name = "Name2", DocumentId = "DocumentId3", Amount = 5.0, DebitAccountNo = "DebitAccountNo5", CreditAccountNo = "CreditAccountNo5"},

            new OutgoingPaymentApprovalDetails() { OriginatorId = 3, Name = "Name3", DocumentId = "DocumentId4", Amount = 6.0, DebitAccountNo = "DebitAccountNo6", CreditAccountNo = "CreditAccountNo6"},

            new OutgoingPaymentApprovalDetails() { OriginatorId = 3, Name = "Name3", DocumentId = "DocumentId5", Amount = 7.0, DebitAccountNo = "DebitAccountNo7", CreditAccountNo = "CreditAccountNo7"},

        };

        var originalDetails = inputs.GroupBy(g => g.OriginatorId).Select(g => new OriginatorDetails() 

                                                                         { 

                                                                             OriginatorId = g.Key, 

                                                                             Name = g.First().Name, 

                                                                             DocumentDetails = g.GroupBy(d => d.DocumentId)

                                                                                 .Select(d => new DocumentDetails() 

                                                                                         {

                                                                                             DocumentId = d.Key,

                                                                                             TransactionDetails = d.Select(t => new TransactionDetails() { DebitAccountNo = t.DebitAccountNo, CreditAccountNo = t.CreditAccountNo, Amount = t.Amount.ToString() }).ToList()

                                                                                         })

                                                                                 .ToList() });

        var serializedString = JsonConvert.SerializeObject(originalDetails);

        Console.WriteLine(serializedString);

        Console.WriteLine("Hello World");

    }

}

​

public class OriginatorDetails

{

     public int OriginatorId { get; set; }

     public string Name { get; set; }

     public List<DocumentDetails> DocumentDetails { get; set; }

​

}

​

public class DocumentDetails

{

   public string DocumentId { get; set; }

   public List<TransactionDetails> TransactionDetails { get; set; }

}

public class TransactionDetails

{

   public string Amount { get; set; }

   public string DebitAccountNo { get; set; }

   public string CreditAccountNo { get; set; }

}

​

public class OutgoingPaymentApprovalDetails

 {

    public int OriginatorId { get; set; }

​

    public string Name { get; set; }

​

    public string DocumentId { get; set; }

​

    public string DebtorName { get; set; }

​

    public string Currency { get; set; }

​

    public double Amount { get; set; }

​

    public string Description { get; set; }

​

    public string DebitAccountNo { get; set; }

​

    public string CreditAccountNo { get; set; }

}