Notes

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Threading.Tasks;

public class YourClassName
{
// Define a data structure to store last invoice numbers for each combination
private Dictionary<string, int> lastInvoiceNumbers = new Dictionary<string, int>();

/// <summary>
/// Get Salaried Employee List For Invoice
/// </summary>
/// <param name="startDate"></param>
/// <param name="endDate"></param>
/// <param name="companyId"></param>
/// <returns></returns>
public async Task<InvoiceMasterModelForSalariedEmployee> GetSalariedEmployeeListForInvoice(string startDate, string endDate, string companyId)
{
try
{
InvoiceMasterModelForSalariedEmployee invoiceMasterModelForSalariedEmployee = new();
List<InvoiceModelForSalariedEmployee> invoiceModelListForSalariedEmployee = new();
DateTime.TryParseExact(startDate, AppConstants.DateFormat, CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTime parsedStartDate);
DateTime.TryParseExact(endDate, AppConstants.DateFormat, CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTime parsedEndDate);
var currentDate = DateTime.Now;
var empForms = await helperRepository.GetDivisionCodesAsync();
var invoiceSalaryHelper = await helperRepository.GetInvoiceSalaryHelperAsync();
var getExternalConsultingSalaryList = await helperRepository.GetCandidatesRecordModelForInvoice();

foreach (var item in getExternalConsultingSalaryList.DistinctBy(x => new { x.CandidateId, x.BillingStartId, x.BillingRecId }))
{
if (string.IsNullOrEmpty(item.SalaryEndDate) || item.SalaryEndDate.CompareTo(currentDate.ToString("MM-dd-yyyy")) >= 0)
{
if (item.SalaryApproved == AppConstants.One)
{
if (!IsExcludedCompany(item.CompanyId))
{
if (IsValidDivision(item.Division))
{
if (companyId != "0")
{
if (item.CompanyId == companyId)
{
if (item.Division == AppConstants.USA1099DivisionCode && item.SalaryPer != "H")
{
InvoiceModelForSalariedEmployee invoiceModelForSalariedEmployee = CreateInvoiceForSalariedEmployee(item, startDate, endDate, parsedStartDate, parsedEndDate, empForms, invoiceSalaryHelper);
invoiceModelListForSalariedEmployee.Add(invoiceModelForSalariedEmployee);
}
else if (item.Division != AppConstants.USA1099DivisionCode)
{
InvoiceModelForSalariedEmployee invoiceModelForSalariedEmployee = CreateInvoiceForSalariedEmployee(item, startDate, endDate, parsedStartDate, parsedEndDate, empForms, invoiceSalaryHelper);
invoiceModelListForSalariedEmployee.Add(invoiceModelForSalariedEmployee);
}
}
}
}
}
}
}
}

invoiceMasterModelForSalariedEmployee.InvoiceModelListForSalariedEmployee = invoiceModelListForSalariedEmployee;
return invoiceMasterModelForSalariedEmployee;
}
catch (Exception exception)
{
Log.Error($"Error in GetSalariedEmployeeListForInvoice: {exception.Message}");
throw;
}
}

// Method to check if the company is excluded
private bool IsExcludedCompany(string companyId)
{
List<string> excludedCompanies = new List<string> { "5509748", "10175435", "5508844", "9511343" };
return excludedCompanies.Contains(companyId);
}

// Method to check if the division is valid
private bool IsValidDivision(string division)
{
List<string> validDivisions = new List<string> { AppConstants.ECSalaryDivisionCode, AppConstants.W2SalaryDivisionCode, AppConstants.USA1099DivisionCode };
return validDivisions.Contains(division);
}

/// <summary>
/// Create External Consulting Salary For Invoice
/// </summary>
/// <param name="item"></param>
/// <param name="startDate"></param>
/// <param name="endDate"></param>
/// <param name="parsedStartDate"></param>
/// <param name="parsedEndDate"></param>
/// <returns></returns>
private InvoiceModelForSalariedEmployee CreateInvoiceForSalariedEmployee(CandidatesRecordModel item, string startDate, string endDate,
DateTime parsedStartDate, DateTime parsedEndDate, List<DivisionCode> empForms, List<InvoiceSalaryHelper> invoiceSalaryHelper)
{
try
{
InvoiceModelForSalariedEmployee invoiceModelForSalariedEmployee = new();

// Generate invoice number
string invoiceNumber = GenerateInvoiceNumber(item.CompanyId, item.PONumber, item.ClientContact);
invoiceModelForSalariedEmployee.InvoiceNumber = invoiceNumber;

// Other parts of the method remain unchanged...
// (Implementation of creating the invoice model continues here)

return invoiceModelForSalariedEmployee;
}
catch (Exception exception)
{
Log.Error($"Error in CreateInvoiceForSalariedEmployee: {exception.Message}");
throw;
}
}

// Method to generate invoice number
private string GenerateInvoiceNumber(string companyId, string poNumber, string clientContact)
{
string key = $"{companyId}-{poNumber}-{clientContact}";

if (lastInvoiceNumbers.ContainsKey(key))
{
// Increment last invoice number by 1
lastInvoiceNumbers[key]++;
}
else
{
// Start invoice number from 1000 for new combination
lastInvoiceNumbers[key] = 1000;
}

return lastInvoiceNumbers[key].ToString();
}
}