using System.ComponentModel.DataAnnotations;
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 Newtonsoft.Json;
using TMSBLL.TxSkillUpgrade;
using TMSDAL.CustomCode.TrainingCompletion;
using TMSDAL.DTO.TrainingCompletion;
using TMSDAL.Enums;

namespace TMSBLL.TrainingCompletion
{
    public class TrainingCompletionBLL : ITrainingCompletionBLL
    {
        private readonly ITrainingCompletionDAL _TrainingCompletionDAL;
        private readonly ITxSkillUpgradeBLL _TxSkillUpgradeBLL;
        private readonly AutoNumber _AutoNumber;
        private readonly IValidation _Validation;

        public TrainingCompletionBLL(ITrainingCompletionDAL trainingCompletionDAL, ITxSkillUpgradeBLL txSkillUpgradeBLL, AutoNumber autoNumber, IValidation validation)
        {
            _TrainingCompletionDAL = trainingCompletionDAL;
            _TxSkillUpgradeBLL = txSkillUpgradeBLL;
            _AutoNumber = autoNumber;
            _Validation = validation;
        }

        public async Task<string> GetTrainingCompletion(int completionId, LoginDTO loginDTO)
        {
            try
            {
                var result = await _TrainingCompletionDAL.GetTrainingCompletion(completionId, loginDTO);
                return JsonConvert.SerializeObject(result);
            }
            catch (Exception) { throw; }
        }

        public async Task<string> GetCompletionByEnrollment(int enrollmentId, LoginDTO loginDTO)
        {
            try
            {
                var result = await _TrainingCompletionDAL.GetCompletionByEnrollment(enrollmentId, loginDTO);
                return JsonConvert.SerializeObject(result);
            }
            catch (Exception) { throw; }
        }

        public async Task<string> GetSelectList(CriteriaDTO criteriaDTO, LoginDTO login, CancellationToken ct)
        {
            try { return await _TrainingCompletionDAL.GetSelectList(criteriaDTO, login, ct); }
            catch (Exception) { throw; }
        }

        public async Task<string> SaveTrainingCompletion(TrainingCompletionDTO dto, LoginDTO loginDTO)
        {
            if (dto == null) throw new ArgumentNullException(nameof(dto));
            AutoNumberDTO? autoNumberDTO = null;

            try
            {
                if (dto.EnrollmentId == 0)
                    throw new ValidationException("EnrollmentId is required.");
                if (dto.InstanceId == 0)
                    throw new ValidationException("InstanceId is required.");
                if (dto.ProgrammeId == 0)
                    throw new ValidationException("ProgrammeId is required.");
                if (dto.EmployeeId == 0)
                    throw new ValidationException("EmployeeId is required.");
                if (!Enum.IsDefined(typeof(CompletionStatus), dto.CompletionStatus))
                    throw new ValidationException($"Invalid CompletionStatus value: {dto.CompletionStatus}.");

                dto.TenantId = loginDTO.ClientId;
                dto.ModifiedById = loginDTO.UserId;
                dto.ModifiedOn = DateTime.UtcNow;

                if (dto.TrainingCompletionId == 0)
                {
                    autoNumberDTO = await _AutoNumber.GetAutoNumber(1, "TRAININGCOMPLETION", loginDTO);
                    dto.TrainingCompletionId = autoNumberDTO.StartNumber;
                    dto.CreatedById = loginDTO.UserId;
                    dto.CreatedOn = DateTime.UtcNow;

                    await _TrainingCompletionDAL.SaveTrainingCompletion(dto, loginDTO);

                    if (dto.CompletionStatus == (byte)CompletionStatus.Completed && dto.IsPassed == 1)
                        await _TxSkillUpgradeBLL.ApplySkillMappingAsync(dto.ProgrammeId, -1, dto.EnrollmentId, loginDTO, default);

                    return string.Format(SuccessResponse.SaveSuccessWithCodeAndName, dto.TrainingCompletionCode, dto.TrainingCompletionName);
                }
                else
                {
                    await _TrainingCompletionDAL.UpdateTrainingCompletion(dto, loginDTO);

                    if (dto.CompletionStatus == (byte)CompletionStatus.Completed && dto.IsPassed == 1)
                        await _TxSkillUpgradeBLL.ApplySkillMappingAsync(dto.ProgrammeId, -1, dto.EnrollmentId, loginDTO, default);

                    return string.Format(SuccessResponse.UpdateSuccessWithCodeAndName, dto.TrainingCompletionCode, dto.TrainingCompletionName);
                }
            }
            catch (ValidationException vex) { throw new Exception(vex.Message); }
            catch (Exception)
            {
                if (autoNumberDTO != null && dto.TrainingCompletionId > 0)
                    await _AutoNumber.RollbackAutoNumber("TRAININGCOMPLETION", dto.TrainingCompletionId, loginDTO);
                throw;
            }
        }
        public async Task<string> GetTrainingCompletionList(LoginDTO loginDTO)
        {
            try { return await _TrainingCompletionDAL.GetTrainingCompletionList(loginDTO); }
            catch (Exception) { throw; }
        }

        public async Task<string> SaveCompletionBulk(CompletionBulkDTO dto, LoginDTO loginDTO)
        {
            if (dto == null) throw new ArgumentNullException(nameof(dto));
            if (dto.Records == null || dto.Records.Count == 0)
                throw new Exception("Records list cannot be empty.");

            AutoNumberDTO? autoNumberDTO = null;
            var toInsert = dto.Records.Where(r => r.TrainingCompletionId == 0).ToList();
            var toUpdate = dto.Records.Where(r => r.TrainingCompletionId != 0).ToList();

            try
            {
                if (toInsert.Count > 0)
                {
                    autoNumberDTO = await _AutoNumber.GetAutoNumber(toInsert.Count, "TRAININGCOMPLETION", loginDTO);
                    int nextId = autoNumberDTO.StartNumber;

                    foreach (var record in toInsert)
                    {
                        record.TrainingCompletionId = nextId++;
                        record.TenantId = loginDTO.ClientId;
                        record.CreatedById = loginDTO.UserId;
                        record.CreatedOn = DateTime.UtcNow;
                        record.ModifiedById = loginDTO.UserId;
                        record.ModifiedOn = DateTime.UtcNow;
                    }

                    await _TrainingCompletionDAL.SaveCompletionBulk(toInsert, loginDTO);
                }

                if (toUpdate.Count > 0)
                {
                    foreach (var record in toUpdate)
                    {
                        record.TenantId = loginDTO.ClientId;
                        record.ModifiedById = loginDTO.UserId;
                        record.ModifiedOn = DateTime.UtcNow;
                    }

                    await _TrainingCompletionDAL.UpdateCompletionBulk(toUpdate, loginDTO);
                }

                return $"Bulk operation completed. Saved: {toInsert.Count}, Updated: {toUpdate.Count}.";
            }
            catch (Exception)
            {
                if (autoNumberDTO != null && toInsert.Count > 0)
                    await _AutoNumber.RollbackAutoNumber("TRAININGCOMPLETION", autoNumberDTO.StartNumber, loginDTO);
                throw;
            }
        }
    }
}