using GB5Shared.DTO.Framework.Login;
using GB5Shared.ResponseStandard;
using PayRollDAL.DTO.Employee;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using GB5Shared.DTO.Framework.Criteria;

namespace PayRollBLL.Employee
{
    public interface IEmployeeBLL
    {
        /// <summary>
        /// Retrieves employee details for the specified employee ID and language.
        /// </summary>
        /// <param name="EmployeeId">Unique identifier of the employee.</param>
        /// <param name="LanguageId">Language ID to fetch localized data. Defaults to the system language if empty.</param>
        /// <param name="LoginDTO">User login context for security and audit.</param>
        /// <returns>JSON string containing employee details.</returns>
        /// <exception cref="Exception">Thrown when retrieval of employee data fails.</exception>
        Task<string> GetEmployee(int employeeId, string LanguageId, LoginDTO LoginDTO);
        /// <summary>
        /// Saves or updates employee information based on the given input.
        /// Handles new employee creation, version validation, translation handling,
        /// and updates to related address and contact records.
        /// </summary>
        /// <param name="employeeDTO">Employee data transfer object containing employee details.</param>
        /// <param name="languageId">Language ID to determine main or translation record.</param>
        /// <param name="loginDTO">User login context used for auditing and authorization.</param>
        /// <returns>Success message indicating the result of the operation (Save, Update, or Translation Update).</returns>
        /// <exception cref="ArgumentNullException">Thrown when required input objects are null.</exception>
        /// <exception cref="InvalidOperationException">Thrown when version control validation fails.</exception>
        /// <exception cref="Exception">Thrown for any general error during employee save operation.</exception>
        Task<string> SaveEmployee(EmployeeDTO EmployeeDTO, string languageId, LoginDTO LoginDTO);
        /// <summary>
        /// Deletes an employee and its related translation records.
        /// Ensures translation records are deleted before the main employee record.
        /// </summary>
        /// <param name="EmployeeId">Unique identifier of the employee to delete.</param>
        /// <param name="LoginDTO">User login context used for auditing and authorization.</param>
        /// <returns>
        /// A <see cref="Result{T}"/> object indicating success or failure with a descriptive message.
        /// </returns>
        /// <exception cref="Exception">Thrown when deletion of employee or related records fails.</exception>
        Task<Result<string>> DeleteEmployee(int EmployeeId, LoginDTO LoginDTO);

        Task<TransferAdvanceResultDTO> PostTransferEmployeeAdvance(
                          List<PostTransferEmployeeAdvanceDTO> PostTransferEmployeeAdvanceDTOs,
                          LoginDTO LoginDTO);

        Task<string> GetTransferEmployeeAdvance(LoginDTO LoginDTO);

        Task<string> SaveEmployeeSecretKey(int employeeId, string secretKey, LoginDTO loginDTO);
        Task<(string Json, int Total)> GetSelectListEmployee(int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO);

        /// <summary>
        /// Splits the calendar gap between an employee's DateOfJoining and a given separation date
        /// into years/months/days.
        /// </summary>
        Task<(int SeparationYears, int SeparationMonths, int SeparationDays)> GetDifferenceFromJoiningDate(
            int employeeId, string separationDate, LoginDTO loginDTO);

        /// <summary>
        /// Resolves an EmployeeCode to its EmployeeId for the manual raw-code-entry scan path.
        /// Returns -1 if no employee has that code for this tenant.
        /// </summary>
        Task<int> GetEmployeeIdByCode(string employeeCode, LoginDTO loginDTO);

        /// <summary>
        /// Builds the employee reporting-chain org tree (JSON) for the given scope (CriteriaDTO
        /// attributes: OUId, EmployeeId). Root scoping mirrors the legacy GB4
        /// EmployeeHierarchyDashboard recursive-CTE semantics using a flat query + in-memory tree build.
        /// </summary>
        Task<string> GetEmployeeHierarchy(CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        /// <summary>
        /// Assembles the HRMS dashboard (JSON) — headcount breakups, pay cost, attrition,
        /// attendance/shift summaries, and the embedded org hierarchy widget. The legacy
        /// workflow-pending-approvals widget is intentionally omitted (no GB5 Activiti equivalent).
        /// </summary>
        Task<string> GetHRMSDashboard(CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        /// <summary>
        /// Paged composite employee profile report — returns typed rows (not JSON) since this
        /// backs a BaseReportEndpoint (export/streaming support), matching the AccountReports
        /// report-BLL convention rather than this module's usual JSON-string return.
        /// </summary>
        Task<(List<EmployeeProfileReportDTO> Items, int Total)> GetEmployeeProfileReport(
            int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        /// <summary>
        /// Migrated from GB4 EmployeeBLL.EmployeePostingSelectionList — MM posting/allocation
        /// history for a given employee (TPOSTINGPOSITION), with an optional FromInventory
        /// variant. See IEmployeeDAL.EmployeePostingSelectionList for full parity notes.
        /// </summary>
        Task<(List<EmployeePostingSelectListDTO> Items, int Total)> EmployeePostingSelectionList(
            int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        Task<(List<EmployeeVsShiftPatternDTO> Items, int Total)> GetEmployeeVsShiftPattern(
            int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        /// <summary>
        /// GB4 parity: EmployeeBLL.GetEmployeeVsShiftPatternNew (route Get/Employee/Vs/ShiftPattern/Load).
        /// Distinct from GetEmployeeVsShiftPattern — per-shift-pattern-day DayType/NumberofDays rows.
        /// </summary>
        Task<(List<EmployeeVsShiftPatternNewDTO> Items, int Total)> GetEmployeeVsShiftPatternNew(
            int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        Task<List<EmployeeVersionPickListDTO>> GetEmployeeVersionPicklist(
            int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        Task<List<EmployeeBasedLegecyInformationDTO>> LegecyBasedEmployeeInformation(
            int employeeId, LoginDTO loginDTO, CancellationToken ct);

        Task<List<EmployeeVersionInPayProcessDTO>> GetEmployeeVersionInPayProcess(
            CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        Task<EmployeeVersionDTO?> GetEmployeeVersion(int employeeVersionId, LoginDTO loginDTO, CancellationToken ct);

        Task<List<DuplicateEmployeeDTO>> GetDuplicateEmployee(CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);

        /// <summary>
        /// GB4 EmployeeBLL.DeleteEmployeeVersion — two hard business-rule guards, deletes the version,
        /// then rolls MEMPLOYEE/MEMPLOYEEADDON back to the new latest remaining version. Runs inside
        /// one transaction (see TLeaveBLL.SaveTLeave for the reference transaction pattern).
        /// </summary>
        Task<string> DeleteEmployeeVersion(int employeeVersionId, LoginDTO loginDTO, CancellationToken ct);

        /// <summary>
        /// GB4 parity: EmployeeBLL.RegisterDeletion — validates via PayProcessBLL.IsUpdatePossible
        /// equivalent (blocks if a pay process has already run for this employee/period), then deletes
        /// future TDAILYATTENDANCE rows from EffectiveFrom onward.
        /// </summary>
        Task<bool> RegisterDeletion(int employeeId, DateTime effectiveFrom, LoginDTO loginDTO, CancellationToken ct);

        /// <summary>
        /// GB4 parity: EmployeeBLL.UpdateEmployeeShiftPattern — loops the existing single-item
        /// DAL save across the batch inside one manual transaction (no single owning entity DTO).
        /// </summary>
        Task<string> UpdateEmployeeShiftPattern(List<EmployeeShiftPatternDTO> employeeShiftPatternDTOs, LoginDTO loginDTO, CancellationToken ct);

        /// <summary>
        /// GB4 parity: EmployeeBLL.GetJOBDetailReport / EmployeeQueryBuilder.GET_EMPLOYEE_JOB_DETAIL —
        /// wide paged job-opening report (TJOB + GCM masters + party/employee/department joins).
        /// </summary>
        Task<(List<PayRollDAL.DTO.Job.JOBDetailReportDTO> Items, int Total)> GetJOBDetailReport(
            int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO, CancellationToken ct);
    }
}