using GB5Shared.DTO.Framework.Login;
using Microsoft.Extensions.Logging;
using PayRollBLL.SAP.Audit;
using PayRollBLL.SAP.Builders;
using PayRollBLL.SAP.Client;
using PayRollDAL.CustomeCode.SAP;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

namespace PayRollBLL.SAP
{
    public class ITDeclarationSapBLL : IITDeclarationSapBLL
    {
        private readonly IITDeclarationSapDAL        _dal;
        private readonly ISapApiClient               _sapClient;
        private readonly ISapDeclarationAuditLog     _auditLog;
        private readonly ILogger<ITDeclarationSapBLL> _logger;

        public ITDeclarationSapBLL(
            IITDeclarationSapDAL        dal,
            ISapApiClient               sapClient,
            ISapDeclarationAuditLog     auditLog,
            ILogger<ITDeclarationSapBLL> logger)
        {
            _dal      = dal;
            _sapClient = sapClient;
            _auditLog  = auditLog;
            _logger    = logger;
        }

        public async Task<Dictionary<int, string>> GenerateSapPayloadsAsync(
            int declarationId,
            int employeeId,
            int periodId,
            int infotype,
            string date,
            string remarks,
            LoginDTO login,
            CancellationToken ct)
        {
            if (declarationId == 0 && employeeId == 0 && periodId == 0)
                throw new ArgumentException(
                    "At least one filter (DeclarationId, EmployeeId, or PeriodId) must be provided.");

            // Normalize envelope date to dd.MM.yyyy regardless of how the caller passed it
            date = NormalizeSapDate(date);

            var rows = (await _dal.GetDeclarationsAsync(
                declarationId, employeeId, periodId, login, ct)
                .ConfigureAwait(false)).ToList();

            if (rows.Count == 0)
            {
                _logger.LogInformation(
                    "No declarations found for SAP payload generation " +
                    "(DeclarationId={DeclarationId}, EmployeeId={EmployeeId}, PeriodId={PeriodId})",
                    declarationId, employeeId, periodId);
                return new Dictionary<int, string>();
            }

            var builders = infotype == 0
                ? SapInfotypeBuilderFactory.GetAll()
                : new[] { SapInfotypeBuilderFactory.Get(infotype) };

            var result = new Dictionary<int, string>();

            foreach (var builder in builders)
            {
                string json = builder.Build(rows, date, remarks);
                if (!string.IsNullOrEmpty(json))
                    result[builder.Infotype] = json;
            }

            return result;
        }

        public async Task<List<SapPushResultDTO>> PushToSapAsync(
            int declarationId,
            int employeeId,
            int periodId,
            int infotype,
            string date,
            string remarks,
            LoginDTO login,
            CancellationToken ct)
        {
            if (declarationId == 0 && employeeId == 0 && periodId == 0)
                throw new ArgumentException(
                    "At least one filter (DeclarationId, EmployeeId, or PeriodId) must be provided.");

            date = NormalizeSapDate(date);

            var builders = infotype == 0
                ? SapInfotypeBuilderFactory.GetAll()
                : new[] { SapInfotypeBuilderFactory.Get(infotype) };

            var results = new List<SapPushResultDTO>();

            var rows = (await _dal.GetDeclarationsAsync(
                declarationId, employeeId, periodId, login, ct)
                .ConfigureAwait(false)).ToList();

            // ── No declaration record found ──────────────────────────────────────────
            if (rows.Count == 0)
            {
                string noDecMsg =
                    $"No IT Declaration record found for the given filters " +
                    $"(DeclarationId={declarationId}, EmployeeId={employeeId}, PeriodId={periodId}). " +
                    "Verify the declaration exists and is not cancelled.";

                _logger.LogInformation("SAP push skipped — {Reason}", noDecMsg);

                foreach (var b in builders)
                    results.Add(NoDataResult(b, noDecMsg));

                return results;
            }

            // ── Post each infotype ───────────────────────────────────────────────────
            foreach (var builder in builders)
            {
                bool anySent = false;

                // BuildAll returns one SapSubtypePayload per sub-type (e.g. 584 returns two).
                foreach (var sub in builder.BuildAll(rows, date, remarks))
                {
                    anySent = true;

                    // ── Audit: log what we are about to send ─────────────────────────
                    _auditLog.LogRequest(
                        sub.Infotype,
                        declarationId, employeeId, periodId,
                        sub.EndpointPath, sub.Description, sub.Json);

                    var apiResult = await _sapClient
                        .PostAsync(sub.EndpointPath, sub.MsgNavProperty, sub.Json, ct)
                        .ConfigureAwait(false);

                    // ── Audit: log what SAP returned ─────────────────────────────────
                    _auditLog.LogResponse(
                        sub.Infotype,
                        sub.EndpointPath, sub.Description,
                        apiResult.StatusCode, apiResult.IsSuccess,
                        apiResult.Message, apiResult.ResponseBody);

                    JsonElement? sentPayload = null;
                    try { sentPayload = JsonDocument.Parse(sub.Json).RootElement.Clone(); } catch { }

                    results.Add(new SapPushResultDTO(
                        sub.Infotype,
                        sub.Description,
                        sub.EndpointPath,
                        apiResult.IsSuccess,
                        apiResult.StatusCode,
                        apiResult.ResponseBody,
                        apiResult.Message,
                        sentPayload));

                    _logger.LogInformation(
                        "SAP push infotype {Infotype} ({Description}): success={Success}, status={Status}, message={Message}",
                        sub.Infotype, sub.Description, apiResult.IsSuccess, apiResult.StatusCode, apiResult.Message);
                }

                // ── No payload built for this infotype — explain why ─────────────────
                if (!anySent)
                {
                    string noDataMsg = string.IsNullOrEmpty(builder.EndpointPath)
                        ? $"Infotype {builder.Infotype} ({builder.DisplayName}): " +
                          "SAP service endpoint is not yet configured — pending confirmation from the SAP team. " +
                          "Nothing was posted."
                        : $"Infotype {builder.Infotype} ({builder.DisplayName}): " +
                          "No matching declaration detail records found for this employee / period. " +
                          "Nothing was posted to SAP.";

                    _logger.LogInformation(
                        "SAP push infotype {Infotype} — no payload generated. {Reason}",
                        builder.Infotype, noDataMsg);

                    // Always write to audit log so every call is fully traceable
                    _auditLog.LogRequest(builder.Infotype, declarationId, employeeId, periodId,
                        builder.EndpointPath, builder.DisplayName,
                        "(no matching data — nothing sent to SAP)");
                    _auditLog.LogResponse(builder.Infotype, builder.EndpointPath, builder.DisplayName,
                        0, false, noDataMsg, string.Empty);

                    results.Add(NoDataResult(builder, noDataMsg));
                }
            }

            return results;
        }

        private static SapPushResultDTO NoDataResult(ISapInfotypeBuilder builder, string message) =>
            new(builder.Infotype,
                builder.DisplayName,
                builder.EndpointPath,
                false, 0, string.Empty,
                message,
                null);

        // Accepts any common date format and returns dd.MM.yyyy as required by SAP envelope.
        // Handles: "01-Apr-2025", "01/04/2025", "2025-04-01", "01.04.2025" (passthrough).
        private static string NormalizeSapDate(string date)
        {
            if (string.IsNullOrWhiteSpace(date))
                return DateTime.Today.ToString("dd.MM.yyyy");

            string[] formats =
            {
                "dd-MMM-yyyy", "dd/MM/yyyy", "yyyy-MM-dd",
                "dd.MM.yyyy",  "d-MMM-yyyy", "d/M/yyyy"
            };

            return DateTime.TryParseExact(date, formats,
                System.Globalization.CultureInfo.InvariantCulture,
                System.Globalization.DateTimeStyles.None, out var parsed)
                ? parsed.ToString("dd.MM.yyyy")
                : date;   // unknown format — pass through as-is
        }
    }
}