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

namespace SkillManagementBLL.RoleSkillRequirement
{
    public class RoleSkillRequirementBLL : IRoleSkillRequirementBLL
    {
        private readonly IRoleSkillRequirementDAL _dal;
        private readonly AutoNumber               _autoNumber;

        public RoleSkillRequirementBLL(IRoleSkillRequirementDAL dal, AutoNumber autoNumber)
        {
            _dal        = dal;
            _autoNumber = autoNumber;
        }

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

        public async Task<string> GetBySkill(int SkillId, LoginDTO login, CancellationToken ct)
            => await _dal.GetBySkill(SkillId, login, ct);
        public async Task<string> GetByReq(int ReqId, LoginDTO login, CancellationToken ct)
            => await _dal.GetByReq(ReqId, login, ct);

        public async Task<string> Save(IEnumerable<RoleSkillRequirementDTO> reqs, int roleId, string? roleCode, string? roleName, LoginDTO login, CancellationToken ct)
        {
            var reqList = reqs.ToList();

            if (reqList.Count == 0)
                throw new ArgumentException("At least one skill requirement is required.");

            foreach (var r in reqList)
            {
                if (r.SkillId == 0)
                    throw new ArgumentException("SkillId is required for each requirement.");
                if (r.Category > 3)
                    throw new ArgumentException("Category must be 0 (Core), 1 (Technical), 2 (Specialist), or 3 (Optional).");
                if (r.MinLevNo < 1)
                    throw new ArgumentException("MinLevNo must be at least 1.");
            }

            // RoleId == 0 means new role — generate an ID for the group
            int finalRoleId = roleId;
            if (finalRoleId == 0)
            {
                var roleAn = await _autoNumber.GetAutoNumber(1, "MJOBROLESKILL", login);
                finalRoleId = roleAn.StartNumber;
            }

            // Assign a fresh ReqId to each requirement that doesn't already have one
            foreach (var r in reqList.Where(x => x.ReqId == 0))
            {
                var an = await _autoNumber.GetAutoNumber(1, "MJOBROLESKILL", login);
                r.ReqId = an.StartNumber;
            }

            // Stamp RoleId, RoleCode, RoleName on every row
            foreach (var r in reqList)
            {
                r.RoleId   = finalRoleId;
                r.RoleCode = roleCode;
                r.RoleName = roleName;
            }

            await _dal.Save(reqList, finalRoleId, login, ct);

            return string.Format(SuccessResponse.SaveSuccessWithCodeAndName, roleCode, roleName);
        }

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

        public async Task<string> DeleteById(int reqId, LoginDTO login, CancellationToken ct)
        {
            var rows = await _dal.DeleteById(reqId, login, ct);
            if (rows == 0)
                throw new Exception(ErrorResponse.DeleteNotFoundMessage);
            return SuccessResponse.DeleteSuccessMessage;
        }

        public async Task<string> GetRoleSkillRequirementList(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<RoleSkillRequirementDTO> data = isAllData
                ? await _dal.GetAllList(login, ct)
                : await _dal.GetPagedList(firstNumber, maxResult, login, ct);

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

            return json;
        }
    }
}