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

namespace SkillManagementBLL.SkillProcessStageMap
{
    public class SkillProcessStageMapBLL : ISkillProcessStageMapBLL
    {
        private readonly ISkillProcessStageMapDAL _dal;
        private readonly AutoNumber               _autoNumber;

        public SkillProcessStageMapBLL(ISkillProcessStageMapDAL dal, AutoNumber autoNumber)
        {
            _dal        = dal;
            _autoNumber = autoNumber;
        }

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

        public async Task<string> Save(IEnumerable<SkillProcessStageMapDTO> maps, int skillId, LoginDTO login, CancellationToken ct)
        {
            if (skillId == 0)
                throw new ArgumentException("SkillId is required.");

            var mapList = maps.ToList();
            if (!mapList.Any())
                return "No mappings provided.";

            // Resolve MinLevelRequired from SkillLevelId where the frontend
            // sends the MSKILLLEVEL.SLEVELID but not the SLNO (1-4).
            foreach (var m in mapList)
            {
                if (m.SkillLevelId != 0 && (m.MinLevelRequired == 0 || m.MinLevelRequired > 4))
                    m.MinLevelRequired = await _dal.GetSlNoBySkillLevelId(m.SkillLevelId, login);
            }

            // Identify new maps (MapId = 0)
            var newMaps = mapList.Where(m => m.MapId == 0).ToList();
            if (newMaps.Any())
            {
                var an = await _autoNumber.GetNumberAsync(newMaps.Count, "MROUTINGSKILL", login);
                int nextId = an.StartNumber;
                foreach (var m in newMaps)
                {
                    m.MapId = nextId++;
                    m.SkillId = skillId;
                }
            }

            // Call DAL layer to handle insert/update/delete
            var affectedRows = await _dal.Save(mapList, skillId, login, ct);

            // mapList only carries IDs/codes from the client — SkillName/RoutingName
            // are join-only display fields, so re-fetch the saved rows to get them
            // for the response message.
            var savedJson = await _dal.GetBySkill(skillId, login, ct);
            var saved = System.Text.Json.JsonSerializer.Deserialize<List<SkillProcessStageMapDTO>>(
                savedJson, new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
            var first = saved?.FirstOrDefault();

            return string.Format(SuccessResponse.MapSuccessWithSkillAndRouting, first?.SkillName, first?.RoutingName);
        }

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


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

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

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

            return json;
        }
    }
}