using GB5Shared.DTO.Framework.AutoNumber;
using GB5Shared.DTO.Framework.Criteria;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.GenerateAutoNumber;
using GB5Shared.Resource.Response;
using GB5Shared.Validation;
using PayRollDAL.CustomeCode.EmployeeTransfer;
using PayRollDAL.DTO.EmployeeTransfer;
using System;
using System.ComponentModel.DataAnnotations;
using System.Threading.Tasks;

namespace PayRollBLL.EmployeeTransfer
{
    public class EmployeeTransferBLL : IEmployeeTransferBLL
    {
        private readonly IEmployeeTransferDAL _employeeTransferDAL;
        private readonly AutoNumber _autoNumber;
        private readonly IValidation _validation;

        public EmployeeTransferBLL(
            IEmployeeTransferDAL employeeTransferDAL,
            AutoNumber autoNumber,
            IValidation validation)
        {
            _employeeTransferDAL = employeeTransferDAL;
            _autoNumber = autoNumber;
            _validation = validation;
        }

        public async Task<string> GetEmployeeTransfer(int employeeTransferId, LoginDTO loginDTO)
        {
            try
            {
                return await _employeeTransferDAL.GetEmployeeTransfer(employeeTransferId, loginDTO);
            }
            catch (Exception)
            {
                throw;
            }
        }

        // Save (insert or update) — branches on EmployeeTransferId being 0 (new).
        //
        // TEMPLOYEETRANSFERDETAIL.EMPLOYEETRANSFERDETAILID is application-assigned (GB4
        // NHibernate generator="assigned", not IDENTITY), so detail rows need their own
        // autonumber allocation too — not just the header. On update, existing detail rows
        // are always deleted and re-inserted (see EmployeeTransferDAL.UpdateEmployeeTransfer),
        // so fresh detail ids are allocated there as well.
        //
        // A single autonumber call is made per save (count = 1 + detailCount for a new header,
        // or just detailCount for an update) so a single RollbackAutoNumber call can undo the
        // whole allocation on failure — RollbackAutoNumber only reverts the most recent block.
        public async Task<string> SaveEmployeeTransfer(EmployeeTransferDTO employeeTransferDTO, LoginDTO loginDTO)
        {
            if (employeeTransferDTO == null)
                throw new ArgumentNullException(nameof(employeeTransferDTO));

            AutoNumberDTO? autoNumberDTO = null;

            try
            {
                await _validation.NotEmpty(employeeTransferDTO.EmployeeTransferTransferNumber, nameof(employeeTransferDTO.EmployeeTransferTransferNumber));

                int detailCount = employeeTransferDTO.EmployeeTransferDetailArray?.Count ?? 0;

                employeeTransferDTO.EmployeeTransferModifiedById = loginDTO.UserId;
                employeeTransferDTO.EmployeeTransferModifiedOn = DateTime.UtcNow;

                bool isNew = employeeTransferDTO.EmployeeTransferId == 0;

                if (isNew)
                {
                    autoNumberDTO = await _autoNumber.GetAutoNumber(1 + detailCount, "EmployeeTransfer", loginDTO);

                    employeeTransferDTO.EmployeeTransferId = autoNumberDTO.StartNumber;
                    employeeTransferDTO.EmployeeTransferCreatedById = loginDTO.UserId;
                    employeeTransferDTO.EmployeeTransferCreatedOn = DateTime.UtcNow;

                    AssignDetailIds(employeeTransferDTO, autoNumberDTO.StartNumber + 1);

                    ApplyDateStringFormats(employeeTransferDTO);

                    await _employeeTransferDAL.SaveEmployeeTransfer(employeeTransferDTO, loginDTO);

                    return $"{SuccessResponse.SaveSuccessMessage} {employeeTransferDTO.EmployeeTransferId}";
                }
                else
                {
                    if (detailCount > 0)
                    {
                        autoNumberDTO = await _autoNumber.GetAutoNumber(detailCount, "EmployeeTransfer", loginDTO);
                        AssignDetailIds(employeeTransferDTO, autoNumberDTO.StartNumber);
                    }

                    ApplyDateStringFormats(employeeTransferDTO);

                    await _employeeTransferDAL.UpdateEmployeeTransfer(employeeTransferDTO, loginDTO);

                    return $"{SuccessResponse.UpdateSuccessMessage} {employeeTransferDTO.EmployeeTransferId}";
                }
            }
            catch (ValidationException vex)
            {
                throw new Exception(vex.Message);
            }
            catch (Exception)
            {
                if (autoNumberDTO != null)
                {
                    await _autoNumber.RollbackAutoNumber("EmployeeTransfer", autoNumberDTO.StartNumber, loginDTO);
                }

                throw;
            }
        }

        public async Task<int> DeleteEmployeeTransfer(int employeeTransferId, LoginDTO loginDTO)
        {
            try
            {
                return await _employeeTransferDAL.DeleteEmployeeTransfer(employeeTransferId, loginDTO);
            }
            catch (Exception)
            {
                throw;
            }
        }

        public async Task<string> GetSelectListEmployeeTransfer(
            int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO, bool isCount = false)
        {
            try
            {
                return await _employeeTransferDAL.GetSelectListEmployeeTransfer(firstNumber, maxResult, criteriaDTO, loginDTO, isCount);
            }
            catch (Exception)
            {
                throw;
            }
        }

        public async Task<string> GetEmployeeTransferList(
            int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO, bool isCount = false)
        {
            try
            {
                return await _employeeTransferDAL.GetEmployeeTransferListAsync(firstNumber, maxResult, criteriaDTO, loginDTO, isCount);
            }
            catch (Exception)
            {
                throw;
            }
        }

        // ── Helpers ────────────────────────────────────────────────────────

        private static void AssignDetailIds(EmployeeTransferDTO dto, int startId)
        {
            if (dto.EmployeeTransferDetailArray == null || dto.EmployeeTransferDetailArray.Count == 0)
                return;

            int id = startId;
            int slNo = 1;

            foreach (EmployeeTransferDetailDTO detail in dto.EmployeeTransferDetailArray)
            {
                detail.EmployeeTransferDetailId = id++;
                detail.EmployeeTransferId = dto.EmployeeTransferId;
                detail.EmployeeTransferDetailSlNo = slNo++;
            }
        }

        private static void ApplyDateStringFormats(EmployeeTransferDTO dto)
        {
            if (dto.EmployeeTransferTransferDate != default)
                dto.EmployeeTransferTransferDateStringFormat = dto.EmployeeTransferTransferDate.ToString("dd-MMM-yyyy");

            if (dto.EmployeeTransferEffectiveFrom != default)
                dto.EmployeeTransferEffectiveFromStringFormat = dto.EmployeeTransferEffectiveFrom.ToString("dd-MMM-yyyy");
        }
    }
}