using GB5Shared.DTO.Framework.Criteria;
using GB5Shared.DTO.Framework.Login;
using PayRollBLL.YearlyCalendar;
using PayRollDAL.CustomeCode.TeamCalendar;
using System;
using System.Threading.Tasks;

namespace PayRollBLL.TeamCalendar
{
    public class TeamCalendarBLL : ITeamCalendarBLL
    {
        private readonly ITeamCalendarDAL _teamCalendarDAL;
        private readonly IYearlyCalendarBLL _yearlyCalendarBLL;

        public TeamCalendarBLL(
            ITeamCalendarDAL teamCalendarDAL,
            IYearlyCalendarBLL yearlyCalendarBLL)
        {
            // ── Guard: fail fast if dependencies are missing ───────────────
            _teamCalendarDAL = teamCalendarDAL ?? throw new ArgumentNullException(nameof(teamCalendarDAL));
            _yearlyCalendarBLL = yearlyCalendarBLL ?? throw new ArgumentNullException(nameof(yearlyCalendarBLL));
        }

        /// <summary>
        /// Returns calendar data as a serialized JSON string.
        ///
        /// team = true  → Multi-employee view
        ///     showAllEmployees = true  → OU-based  (all employees in given OUIDs filtered by status)
        ///     showAllEmployees = false → Hierarchy-based (junior team under employeeId filtered by level + status)
        ///
        /// team = false → Single-employee yearly calendar (calls YearlyCalendarBLL)
        /// </summary>
        public async Task<string> GetFiltersTeamCalendar(
            long employeeId,
            int employeeLevel,
            DateTime fromDate,
            DateTime toDate,
            bool showAllEmployees,
            string ouIds,
            byte employeeStatus,
            bool team,
            int firstNumber,
            int maxNumber,
            CriteriaDTO criteriaDTO,
            LoginDTO loginDTO)
        {
            // ── Input validation ───────────────────────────────────────────
            if (loginDTO == null)
                throw new ArgumentNullException(nameof(loginDTO));

            if (fromDate > toDate)
                throw new ArgumentException(
                    $"fromDate ({fromDate:yyyy-MM-dd}) must be <= toDate ({toDate:yyyy-MM-dd}).");

            if (firstNumber < 1)
                firstNumber = 1;

            if (maxNumber < firstNumber)
                maxNumber = firstNumber;

            // ── Route: Team vs Single employee ─────────────────────────────
            if (team)
            {
                /*
                 * Multi-employee calendar
                 * ─────────────────────────────────────────────────────────
                 * showAllEmployees = true  → OU based
                 *   Fetches all employees whose WORKOUID is in ouIds,
                 *   filtered by employeeStatus, paged by firstNumber/maxNumber.
                 *
                 * showAllEmployees = false → Hierarchy based
                 *   Recursive CTE from employeeId downwards,
                 *   filtered by employeeLevel + employeeStatus,
                 *   paged by firstNumber/maxNumber.
                 *
                 * In both cases:
                 *   - Calendar data is fetched via GET_TEAM_CALENDAR
                 *   - Permission data via GET_TEAM_CALENDAR_PERMISSIONS
                 *   - Both queries are scoped to the resolved employee CSV
                 *   - Results are merged and returned as JSON
                 */
                return await _teamCalendarDAL.GetFiltersTeamCalendar(
                    employeeId,
                    employeeLevel,
                    fromDate,
                    toDate,
                    showAllEmployees,
                    ouIds,
                    employeeStatus,
                    team,
                    firstNumber,
                    maxNumber,
                    criteriaDTO,
                    loginDTO);
            }
            else
            {
                /*
                 * Single-employee yearly calendar
                 * ─────────────────────────────────────────────────────────
                 * Delegates to YearlyCalendarBLL which handles the
                 * SP_employeeCalendar procedure (individual pivot query).
                 * employeeLevel, showAllEmployees, ouIds, firstNumber,
                 * maxNumber are not relevant here.
                 */
                return await _yearlyCalendarBLL.GetYearlyCalendar(
                    employeeId,
                    fromDate,
                    toDate,
                    criteriaDTO,
                    loginDTO);
            }
        }
    }
}