using GB5Shared.DTO.Framework.Criteria;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.GenerateAutoNumber;
using GB5Shared.Resource.Response;
using GB5Shared.Validation;
using SkillManagementDAL.CustomCode.SkillGroup;
using SkillManagementDAL.DTO.SkillGroup;
using System.Text.Json;

namespace SkillManagementBLL.SkillGroup
{
    public class SkillGroupBLL : ISkillGroupBLL
    {
        private readonly ISkillGroupDAL _dal;
        private readonly AutoNumber     _autoNumber;
        private readonly IValidation    _validation;

        public SkillGroupBLL(ISkillGroupDAL dal, AutoNumber autoNumber, IValidation validation)
        {
            _dal        = dal;
            _autoNumber = autoNumber;
            _validation = validation;
        }

        public async Task<string> GetList(int domainId, LoginDTO login, CancellationToken ct)
            => await _dal.GetList(domainId, login, ct);

        public async Task<string> GetById(int groupId, LoginDTO login, CancellationToken ct)
            => await _dal.GetById(groupId, login, ct);

        public async Task<string> GetSelectList(CriteriaDTO criteriaDTO, LoginDTO login, CancellationToken ct)
           => await _dal.GetSelectList(criteriaDTO, login, ct);

        public async Task<string> GetSkillGroupList(int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO login, CancellationToken ct = default)
        {
            // ── VALIDATION ───────────────────────────────────────────
            if (firstNumber == -1 && maxResult != -1)
                throw new ArgumentException("MaxResult must also be -1 when FirstNumber is -1.");

            if (firstNumber != -1 && maxResult == -1)
                throw new ArgumentException("FirstNumber must also be -1 when MaxResult is -1.");

            if (firstNumber != -1 && firstNumber < 1)
                throw new ArgumentException($"FirstNumber must be >= 1 or -1. Got: {firstNumber}");

            if (maxResult != -1 && maxResult < 1)
                throw new ArgumentException($"MaxResult must be >= 1 or -1. Got: {maxResult}");

            // ── FETCH DATA ───────────────────────────────────────────
            bool isAllData = firstNumber == -1 && maxResult == -1;

            List<SkillGroupDTO> data = isAllData
                ? await _dal.GetAllList(login, ct)
                : await _dal.GetPagedList(firstNumber, maxResult, login, ct);

            // ── SERIALIZE (KEY CHANGE) ────────────────────────────────
            var json = JsonSerializer.Serialize(data);

            return json;
        }


        public async Task<string> Save(SkillGroupDTO dto, LoginDTO login, CancellationToken ct)
        {
            await _validation.NotEmpty(dto.GroupCode, nameof(dto.GroupCode));
            await _validation.NotEmpty(dto.GroupName, nameof(dto.GroupName));

            if (dto.DomainId == 0)
                throw new ArgumentException("DomainId is required.");

            if (dto.DisplayOrder <= 0)
                throw new ArgumentException("DisplayOrder must be greater than 0.");

            var now = DateTime.UtcNow;

            // ✅ FK VALIDATION VIA DAL
            //var exists = await _dal.DomainExists(dto.DomainId, login.ClientId, login);

            //if (!exists)
            //    throw new Exception("Invalid DomainId");

            dto.TenantId = login.ClientId;
            dto.ModifiedById = login.UserId;
            dto.ModifiedOn = now;

            bool isNew = dto.GroupId == 0;
            GB5Shared.DTO.Framework.AutoNumber.AutoNumberDTO? an = null;

            try
            {
                if (isNew)
                {
                    an = await _autoNumber.GetNumberAsync(1, "MSKILLGROUP", login);

                    dto.GroupId = an.StartNumber;
                    dto.CreatedById = login.UserId;
                    dto.CreatedOn = now;

                    var rows = await _dal.Insert(dto, login, ct);

                    if (rows == 0)
                        throw new Exception("Insert failed");

                    return string.Format(SuccessResponse.SaveSuccessWithCodeAndName, dto.GroupCode, dto.GroupName);
                }
                else
                {
                    var rows = await _dal.Update(dto, login, ct);

                    if (rows == 0)
                        throw new Exception("Update failed");

                    return string.Format(SuccessResponse.UpdateSuccessWithCodeAndName, dto.GroupCode, dto.GroupName);
                }
            }
            catch
            {
                if (an != null && isNew)
                    await _autoNumber.RollbackAutoNumber("MSKILLGROUP", an.StartNumber, login);

                throw;
            }
        }

        public async Task<string> DeleteSkillGroup(int groupId, LoginDTO loginDTO)
        {
            var result = await _dal.DeleteSkillGroup(groupId, loginDTO);
            if (result == ErrorResponse.DeleteNotFoundMessage)
                throw new Exception(result);
            return result;
        }
    }
}