using System.ComponentModel.DataAnnotations;
using GB5Shared.DTO.Framework.AutoNumber;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.GenerateAutoNumber;
using GB5Shared.Resource.Response;
using GB5Shared.Validation;
using TMSDAL.CustomCode.TrainingAttendance;
using TMSDAL.DTO.TrainingAttendance;
using TMSDAL.Enums;

namespace TMSBLL.TrainingAttendance
{
    public class TrainingAttendanceBLL : ITrainingAttendanceBLL
    {
        private readonly ITrainingAttendanceDAL _TrainingAttendanceDAL;
        private readonly AutoNumber _AutoNumber;
        private readonly IValidation _Validation;

        public TrainingAttendanceBLL(ITrainingAttendanceDAL trainingAttendanceDAL, AutoNumber autoNumber, IValidation validation)
        {
            _TrainingAttendanceDAL = trainingAttendanceDAL;
            _AutoNumber = autoNumber;
            _Validation = validation;
        }

        public async Task<string> GetSessionAttendance(int instanceSessionId, LoginDTO loginDTO)
        {
            try { return await _TrainingAttendanceDAL.GetSessionAttendance(instanceSessionId, loginDTO); }
            catch (Exception) { throw; }
        }

        public async Task<string> GetTrainingAttendanceList(LoginDTO loginDTO)
        {
            try { return await _TrainingAttendanceDAL.GetTrainingAttendanceList(loginDTO); }
            catch (Exception) { throw; }
        }

        public async Task<string> SaveAttendanceBulk(AttendanceBulkDTO dto, LoginDTO loginDTO)
        {
            if (dto == null) throw new ArgumentNullException(nameof(dto));

            try
            {
                if (dto.InstanceSessionId == 0)
                    throw new ValidationException("InstanceSessionId is required.");
                if (dto.Records == null || dto.Records.Count == 0)
                    throw new ValidationException("At least one attendance record is required.");

                var markedOn = DateTime.UtcNow;
                var autoNumber = await _AutoNumber.GetAutoNumber(dto.Records.Count, "TRAININGATTENDANCE", loginDTO);
                int nextId = autoNumber.StartNumber;

                foreach (var record in dto.Records)
                {
                    record.AttendanceId = nextId++;
                    record.InstanceSessionId = dto.InstanceSessionId;
                    record.RecordedById = loginDTO.UserId;
                    record.RecordedOn = markedOn;

                    if (!Enum.IsDefined(typeof(AttendanceStatus), record.AttendanceStatus))
                        throw new ValidationException($"Invalid AttendanceStatus for this AttendanceId {record.AttendanceId}.");
                }

                // Delete existing records for the session then bulk insert
                await _TrainingAttendanceDAL.DeleteSessionAttendance(dto.InstanceSessionId, loginDTO);
                await _TrainingAttendanceDAL.SaveAttendanceBulk(dto.Records, loginDTO);

                return $"{SuccessResponse.SaveSuccessMessage} {dto.Records.Count} records";
            }
            catch (ValidationException vex) { throw new Exception(vex.Message); }
            catch (Exception) { throw; }
        }
    }
}