using System;
using System.Threading;
using System.Threading.Tasks;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.DTO.Promotion;
using GB5Shared.Promotion;
using Newtonsoft.Json;
using WiBLL.WiProcess;
using WiDAL.CustomCode.Promotion;
using WiDAL.DTOs;

namespace WiBLL.Promotion
{
    // ============================================================
    // WiProcessPromotionAdapter — IPromotableEntity for MWIPROCESS ("WIPROCESS"). No child rows of
    // its own. Natural key WiProcessCode (UK_MWIPROCESS_WIPROCESSCODE_TENANTID, a real unique
    // constraint, confirmed via schema). DepartmentId/DepartmentCode resolved via the new
    // IDepartmentCodeLookupDAL (small, dedicated lookup against MDEPARTMENT directly — Admin, the
    // owning module, lives in a separate Host process entirely, same reasoning as every other
    // cross-module code lookup this session).
    //
    // Registered locally inside WiModule (this module's own process, EngagementHost) — reached from
    // FrameworkBLL's RemoteHttpPromotionAdapter over HTTP via the PromotionBridge endpoints in
    // WiSL/Endpoints/Promotion. See GB5Shared/DTO/Promotion/PromotionBridgeDTOs.cs.
    // ============================================================
    public class WiProcessPromotionAdapter : IPromotableEntity
    {
        public string EntityTypeCode => "WIPROCESS";

        private readonly IWiProcessBLL _WiProcessBLL;
        private readonly IDepartmentCodeLookupDAL _DepartmentCodeLookup;
        private readonly IWiProcessCodeLookupDAL _WiProcessCodeLookup;

        public WiProcessPromotionAdapter(
            IWiProcessBLL wiProcessBLL, IDepartmentCodeLookupDAL departmentCodeLookup,
            IWiProcessCodeLookupDAL wiProcessCodeLookup)
        {
            _WiProcessBLL         = wiProcessBLL;
            _DepartmentCodeLookup = departmentCodeLookup;
            _WiProcessCodeLookup  = wiProcessCodeLookup;
        }

        private class PortablePayload
        {
            public string WiProcessCode { get; set; } = string.Empty;
            public string WiProcessName { get; set; } = string.Empty;
            public string? DepartmentCode { get; set; }
            public short DisplayOrder { get; set; }
            public string? Description { get; set; }
            public int IsActive { get; set; }
            public short SortOrder { get; set; } = 9999;
        }

        public async Task<PromotionBundleDTO> ExportForPromotionAsync(
            int originEntityId, LoginDTO login, CancellationToken ct)
        {
            var json = await _WiProcessBLL.GetById(originEntityId, login, ct).ConfigureAwait(false);
            var dto = JsonConvert.DeserializeObject<WiProcessDTO>(json)
                ?? throw new InvalidOperationException($"WiProcess {originEntityId} not found.");

            string? departmentCode = dto.DepartmentCode;
            if (string.IsNullOrWhiteSpace(departmentCode) && dto.DepartmentId != 0)
            {
                departmentCode = await _DepartmentCodeLookup.GetDepartmentCodeById(dto.DepartmentId, login, ct)
                        .ConfigureAwait(false)
                    ?? throw new InvalidOperationException(
                        $"WiProcess {originEntityId} references DepartmentId {dto.DepartmentId}, which has no DepartmentCode — cannot promote.");
            }

            var payload = new PortablePayload
            {
                WiProcessCode = dto.WiProcessCode,
                WiProcessName = dto.WiProcessName,
                DepartmentCode = departmentCode,
                DisplayOrder = dto.DisplayOrder,
                Description = dto.Description,
                IsActive = dto.IsActive,
                SortOrder = dto.SortOrder
            };

            return new PromotionBundleDTO
            {
                EntityTypeCode = EntityTypeCode,
                OriginEntityId = originEntityId,
                PayloadJson = System.Text.Json.JsonSerializer.Serialize(payload)
            };
        }

        public Task<PromotionValidationResultDTO> ValidateForPromotionAsync(
            PromotionBundleDTO bundle, CancellationToken ct)
        {
            var payload = System.Text.Json.JsonSerializer.Deserialize<PortablePayload>(bundle.PayloadJson);
            if (payload is null)
                return Task.FromResult(PromotionValidationResultDTO.Block("WiProcess payload could not be parsed."));

            var reasons = new System.Collections.Generic.List<string>();
            if (string.IsNullOrWhiteSpace(payload.WiProcessCode))
                reasons.Add("WiProcess.WiProcessCode is required to promote.");
            if (string.IsNullOrWhiteSpace(payload.DepartmentCode))
                reasons.Add("WiProcess.DepartmentId has no resolvable DepartmentCode — cannot promote.");

            var result = reasons.Count == 0
                ? PromotionValidationResultDTO.Ok()
                : new PromotionValidationResultDTO { IsPromotable = false, BlockingReasons = reasons };
            return Task.FromResult(result);
        }

        public async Task<int> ImportPromotedAsync(
            PromotionBundleDTO bundle, byte destinationSourceType, int? existingDestinationId,
            LoginDTO login, CancellationToken ct)
        {
            var payload = System.Text.Json.JsonSerializer.Deserialize<PortablePayload>(bundle.PayloadJson)
                ?? throw new InvalidOperationException("WiProcess promotion payload could not be parsed.");

            var departmentId = -1;
            if (!string.IsNullOrWhiteSpace(payload.DepartmentCode))
            {
                departmentId = await _DepartmentCodeLookup.GetDepartmentIdByCode(payload.DepartmentCode, login, ct)
                        .ConfigureAwait(false)
                    ?? throw new InvalidOperationException(
                        $"No Department with DepartmentCode '{payload.DepartmentCode}' exists at this destination.");
            }

            var resolvedId = existingDestinationId
                ?? await _WiProcessCodeLookup.GetWiProcessIdByCode(payload.WiProcessCode, login, ct).ConfigureAwait(false)
                ?? 0;

            var dto = new WiProcessDTO
            {
                WiProcessId = resolvedId,
                WiProcessCode = payload.WiProcessCode,
                WiProcessName = payload.WiProcessName,
                DepartmentId = departmentId,
                DisplayOrder = payload.DisplayOrder,
                Description = payload.Description,
                IsActive = payload.IsActive,
                SortOrder = payload.SortOrder,
                SourceType = destinationSourceType
            };

            await _WiProcessBLL.Save(dto, login, ct).ConfigureAwait(false);
            return dto.WiProcessId; // mutated in place by Save when isNew
        }
    }
}