using AccountsDAL.CustomCode.Payment;
using AccountsDAL.DTO.Payment;
using AccountsDAL.DTO.Voucher;
using GB5Shared.DTO.Framework.Criteria;
using GB5Shared.DTO.Framework.Login;
using MMDAL.DTO.CostCenterAllocation;
using Newtonsoft.Json;

namespace AccountsBLL.Payment
{
    public class PaymentBLL : IPaymentBLL
    {
        private readonly IPaymentDAL _paymentDAL;

        public PaymentBLL(IPaymentDAL paymentDAL)
        {
            _paymentDAL = paymentDAL;
        }

        public Task<string> GetSelectListPayment(int firstNumber, int maxResult, CriteriaDTO criteriaDTO, LoginDTO loginDTO)
            => _paymentDAL.GetSelectListPayment(firstNumber, maxResult, criteriaDTO, loginDTO);

        // Ported from GB4 PaymentBLL.PaymentToVoucher — a pure read-only "derive a proposed
        // Voucher preview from an existing Payment" transform, never persisted. Distinct accounts
        // (PayTo and PayFrom, excluding the -1 sentinel) each become one VoucherDetailDTO line,
        // amount summed across every detail row sharing that account.
        //
        // Preserved GB4 quirk, not "fixed": cost-center allocations are looked up against only the
        // FIRST detail row per distinct account (matching GB4's GroupBy(...).Select(g => g.First())),
        // even though the line's amount is summed across every detail row for that account — so a
        // second/third detail row sharing an account contributes to the total but its own
        // cost-center allocations (if any) are silently dropped.
        public async Task<string> GetPaymentToVoucher(int paymentId, LoginDTO loginDTO)
        {
            var header = await _paymentDAL.GetPaymentHeaderForVoucher(paymentId, loginDTO).ConfigureAwait(false);
            if (header == null)
                throw new InvalidOperationException($"Payment {paymentId} not found.");

            var details = await _paymentDAL.GetPaymentDetailsForVoucher(paymentId, loginDTO).ConfigureAwait(false);
            var costCenterAllocations = await _paymentDAL.GetCostCenterAllocationForPayment(paymentId, loginDTO).ConfigureAwait(false);
            var organizationUnit = await _paymentDAL.GetOrganizationUnitForVoucher(loginDTO.WorkOUId, loginDTO).ConfigureAwait(false);
            var costCenterApplicableCache = new Dictionary<int, bool>();

            var voucherDTO = new VoucherDTO
            {
                VoucherReferenceDate = header.PaymentReferenceDate,
                VoucherReferenceNumber = header.PaymentReferenceNumber,
                VoucherVoucherDate = header.PaymentDate,
                VoucherValidTillDate = new DateTime(9999, 12, 31),
                VoucherNarration = header.PaymentRemarks,
                VoucherPostedFromType = 7, // Payment
                VoucherPostedFromId = paymentId
            };

            short slno = 1;

            var payToFirstRows = details.Where(d => d.PayToAccountId != -1)
                                         .GroupBy(d => d.PayToAccountId)
                                         .Select(g => g.First());

            foreach (var first in payToFirstRows)
            {
                decimal amount = details.Where(d => d.PayToAccountId == first.PayToAccountId)
                                         .Sum(d => (decimal)(d.AmountRequired - d.AmountPaid));

                var voucherDetail = new VoucherDetailDTO
                {
                    VoucherAccountId = first.PayToAccountId,
                    InterOUId = loginDTO.WorkOUId,
                    InterOUCode = organizationUnit?.OUCode ?? string.Empty,
                    InterOUName = organizationUnit?.OUName ?? string.Empty,
                    VoucherAccountCode = first.PayToAccountCode,
                    VoucherAccountName = first.PayToAccountName,
                    VoucherAccountBillAllocationType = first.PayToAccountBillAllocationType,
                    VoucherAccountType = first.PayToAccountType,
                    VoucherAccountAccountGroupId = first.PayToAccountGroupId,
                    VoucherDetailDetailType = 0,
                    VoucherDetailAmount = (double)amount,
                    VoucherDetailAmountFC = (double)amount,
                    CurrencyId = first.PayToCurrencyId,
                    CurrencyCode = first.PayToCurrencyCode,
                    CurrencyName = first.PayToCurrencyName,
                    VoucherDetailCurrencyConversion = 1,
                    VoucherDetailVoucherLineNarration = first.Remarks,
                    VoucherDetailSlno = slno,
                    VoucherDetailCostCenterApplicable = await IsCostCenterApplicable(first.PayToAccountGroupId, costCenterApplicableCache, loginDTO).ConfigureAwait(false)
                };

                var lineCostCenters = costCenterAllocations.Where(c => c.CostCenterAllocationObjectId == first.PaymentDetailId).ToList();
                if (lineCostCenters.Count > 0)
                    voucherDetail.VoucherCostCenterArray = lineCostCenters.Select(MapToVoucherCostCenter).ToList();

                slno++;
                voucherDTO.VoucherDetailArray.Add(voucherDetail);
            }

            var payFromFirstRows = details.Where(d => d.PayFromAccountId != -1)
                                           .GroupBy(d => d.PayFromAccountId)
                                           .Select(g => g.First());

            foreach (var first in payFromFirstRows)
            {
                decimal amount = details.Where(d => d.PayFromAccountId == first.PayFromAccountId)
                                         .Sum(d => (decimal)(d.AmountRequired - d.AmountPaid));

                var voucherDetail = new VoucherDetailDTO
                {
                    VoucherAccountId = first.PayFromAccountId,
                    InterOUId = loginDTO.WorkOUId,
                    InterOUCode = organizationUnit?.OUCode ?? string.Empty,
                    InterOUName = organizationUnit?.OUName ?? string.Empty,
                    VoucherAccountCode = first.PayFromAccountCode,
                    VoucherAccountName = first.PayFromAccountName,
                    VoucherAccountBillAllocationType = first.PayFromAccountBillAllocationType,
                    VoucherAccountType = first.PayFromAccountType,
                    VoucherAccountAccountGroupId = first.PayFromAccountGroupId,
                    VoucherDetailDetailType = 1,
                    VoucherDetailAmount = (double)amount,
                    VoucherDetailAmountFC = (double)amount,
                    CurrencyId = first.PayFromCurrencyId,
                    CurrencyCode = first.PayFromCurrencyCode,
                    CurrencyName = first.PayFromCurrencyName,
                    VoucherDetailCurrencyConversion = 1,
                    VoucherDetailVoucherLineNarration = first.Remarks,
                    VoucherDetailSlno = slno,
                    VoucherDetailCostCenterApplicable = await IsCostCenterApplicable(first.PayFromAccountGroupId, costCenterApplicableCache, loginDTO).ConfigureAwait(false)
                };

                var lineCostCenters = costCenterAllocations.Where(c => c.CostCenterAllocationObjectId == first.PaymentDetailId).ToList();
                if (lineCostCenters.Count > 0)
                    voucherDetail.VoucherCostCenterArray = lineCostCenters.Select(MapToVoucherCostCenter).ToList();

                slno++;
                voucherDTO.VoucherDetailArray.Add(voucherDetail);
            }

            return JsonConvert.SerializeObject(voucherDTO);
        }

        private async Task<int> IsCostCenterApplicable(int accountGroupId, Dictionary<int, bool> cache, LoginDTO loginDTO)
        {
            if (!cache.TryGetValue(accountGroupId, out var hasCondition))
            {
                hasCondition = await _paymentDAL.HasCostCategoryConditionForAccountGroup(accountGroupId, loginDTO).ConfigureAwait(false);
                cache[accountGroupId] = hasCondition;
            }
            // GB4: a matching MCOSTCATEGORYCONDITION means cost-center is NOT applicable (0);
            // no match means it IS applicable (1, the default).
            return hasCondition ? 0 : 1;
        }

        private static VoucherCostCenterDTO MapToVoucherCostCenter(CostCenterAllocationDTO source) => new()
        {
            VoucherCostCenterCostCategorySlno = source.CostCenterAllocationCostCategorySlno,
            CostCategoryId = source.CostCategoryId,
            CostCategoryCode = source.CostCategoryCode,
            CostCategoryName = source.CostCategoryName,
            VoucherCostCenterSlno = source.CostCenterAllocationSlno,
            CostCenterId = source.CostCenterId,
            CostCenterCode = source.CostCenterCode,
            CostCenterName = source.CostCenterName,
            VoucherCostCenterAllocatedAmount = source.CostCenterAllocationAllocatedQuantity
        };
    }
}