using GB5Shared.DTO.Framework.Login;
using Microsoft.Extensions.Logging;
using MMDAL.CustomCode.InventoryReports;
using MMDAL.DTO.InventoryReports;
using System.Linq;

namespace MMBLL.InventoryReports
{
    public class InventoryReportsBLL : IInventoryReportsBLL
    {
        // Default BizTransactionClassId for "Purchase Order" -- see InventoryReportsQB's own
        // comment for provenance. Used when the caller doesn't override it.
        public const int DefaultSupplyBizTransactionClassId = -1499999975;

        // Default staleness threshold for the Non-Moving report -- matches legacy's own default
        // (StockPositionDAL.GetNonMovingReport's "int Age = 15").
        public const int DefaultNonMovingAgeDays = 15;

        public const int DefaultStockMovementPeriodDays = 30;
        public const int DefaultTopMoversCount = 10;
        public const int DefaultStockHoldingTrendPeriodDays = 90;

        private readonly IInventoryReportsDAL _inventoryReportsDAL;
        private readonly ILogger<InventoryReportsBLL> _logger;

        public InventoryReportsBLL(IInventoryReportsDAL inventoryReportsDAL, ILogger<InventoryReportsBLL> logger)
        {
            _inventoryReportsDAL = inventoryReportsDAL;
            _logger = logger;
        }

        public async Task<List<ReorderBreachReportDTO>> GetReorderBreachReport(
            int ouId, int? storeId, int? itemCategoryId, int supplyBizTransactionClassId,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            var resolvedClassId = supplyBizTransactionClassId != 0
                ? supplyBizTransactionClassId
                : DefaultSupplyBizTransactionClassId;

            try
            {
                return await _inventoryReportsDAL.GetReorderBreachReport(
                    ouId, storeId, itemCategoryId, resolvedClassId, loginDTO, ct).ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "GetReorderBreachReport failed for OUId {OuId}", ouId);
                throw;
            }
        }

        public async Task<List<StockAgeingReportDTO>> GetStockAgeingReport(
            int ouId, int? itemCategoryId, DateTime? asOnDate,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            try
            {
                return await _inventoryReportsDAL.GetStockAgeingReport(
                    ouId, itemCategoryId, asOnDate ?? DateTime.UtcNow.Date, loginDTO, ct).ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "GetStockAgeingReport failed for OUId {OuId}", ouId);
                throw;
            }
        }

        public async Task<List<NonMovingReportDTO>> GetNonMovingReport(
            int ouId, int? itemCategoryId, int? ageDays, DateTime? asOnDate,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            try
            {
                return await _inventoryReportsDAL.GetNonMovingReport(
                    ouId, itemCategoryId, ageDays ?? DefaultNonMovingAgeDays,
                    asOnDate ?? DateTime.UtcNow.Date, loginDTO, ct).ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "GetNonMovingReport failed for OUId {OuId}", ouId);
                throw;
            }
        }

        public async Task<StockMovementDashboardDTO> GetStockMovementDashboard(
            int ouId, DateTime? periodFromDate, DateTime? periodToDate, int? topN,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            var resolvedToDate = periodToDate ?? DateTime.UtcNow.Date;
            var resolvedFromDate = periodFromDate ?? resolvedToDate.AddDays(-DefaultStockMovementPeriodDays);

            try
            {
                return await _inventoryReportsDAL.GetStockMovementDashboard(
                    ouId, resolvedFromDate, resolvedToDate, topN ?? DefaultTopMoversCount,
                    loginDTO, ct).ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "GetStockMovementDashboard failed for OUId {OuId}", ouId);
                throw;
            }
        }

        public async Task<StockOverviewDashboardDTO> GetStockOverviewDashboard(
            int ouId, LoginDTO loginDTO, CancellationToken ct = default)
        {
            try
            {
                return await _inventoryReportsDAL.GetStockOverviewDashboard(ouId, loginDTO, ct)
                    .ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "GetStockOverviewDashboard failed for OUId {OuId}", ouId);
                throw;
            }
        }

        public async Task<List<StockHoldingTrendDTO>> GetStockHoldingTrend(
            int ouId, int? itemId, DateTime? periodFromDate, DateTime? periodToDate,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            var resolvedToDate = periodToDate ?? DateTime.UtcNow.Date;
            var resolvedFromDate = periodFromDate ?? resolvedToDate.AddDays(-DefaultStockHoldingTrendPeriodDays);

            try
            {
                return await _inventoryReportsDAL.GetStockHoldingTrend(
                    ouId, itemId, resolvedFromDate, resolvedToDate, loginDTO, ct).ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "GetStockHoldingTrend failed for OUId {OuId}", ouId);
                throw;
            }
        }

        public async Task<List<SubcontractorMaterialTrackerDTO>> GetSubcontractorMaterialTracker(
            int ouId, LoginDTO loginDTO, CancellationToken ct = default)
        {
            try
            {
                return await _inventoryReportsDAL.GetSubcontractorMaterialTracker(ouId, loginDTO, ct)
                    .ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "GetSubcontractorMaterialTracker failed for OUId {OuId}", ouId);
                throw;
            }
        }

        // Composes numbers from three different sources rather than issuing one query -- see
        // InventoryKPISummaryDTO.cs for the full reasoning. Reorder Breach and Obsolete Stock
        // reuse the already-built Stock Overview / Ageing tiles' own BLL methods rather than
        // recomputing the same predicate a third time.
        public async Task<InventoryKPISummaryDTO> GetInventoryKPISummary(
            int ouId, int tenantId, DateTime? periodFromDate, DateTime? periodToDate,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            var resolvedToDate = periodToDate ?? DateTime.UtcNow.Date;
            var resolvedFromDate = periodFromDate ?? resolvedToDate.AddDays(-DefaultStockMovementPeriodDays);
            var fromDateId = int.Parse(resolvedFromDate.ToString("yyyyMMdd"));
            var toDateId = int.Parse(resolvedToDate.ToString("yyyyMMdd"));

            try
            {
                var totalStockValueTask = _inventoryReportsDAL.GetTotalStockValue(ouId, loginDTO, ct);
                var movementValueTask = _inventoryReportsDAL.GetMovementValueFromFact(
                    ouId, tenantId, fromDateId, toDateId, loginDTO, ct);
                var overviewTask = GetStockOverviewDashboard(ouId, loginDTO, ct);
                var ageingTask = GetStockAgeingReport(ouId, null, resolvedToDate, loginDTO, ct);

                await Task.WhenAll(totalStockValueTask, movementValueTask, overviewTask, ageingTask)
                    .ConfigureAwait(false);

                return new InventoryKPISummaryDTO
                {
                    TotalStockValue = totalStockValueTask.Result,
                    TotalMovementInValue = movementValueTask.Result.TotalMovementInValue,
                    TotalMovementOutValue = movementValueTask.Result.TotalMovementOutValue,
                    ReorderBreachCount = overviewTask.Result.Alerts.ReorderBreachCount,
                    ObsoleteStockValue = ageingTask.Result.Sum(r => r.Age4Value)
                };
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "GetInventoryKPISummary failed for OUId {OuId}", ouId);
                throw;
            }
        }
    }
}