using System.Text.Json;
using ComplianceDAL.CustomCode.ComplianceAnalytics;
using ComplianceDAL.DTO.Analytics;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.Resource.Response;
using Microsoft.Extensions.Logging;

namespace ComplianceBLL.ComplianceAnalytics;

public class ComplianceAnalyticsBLL(
    IComplianceAnalyticsDAL dal,
    ILogger<ComplianceAnalyticsBLL> logger) : IComplianceAnalyticsBLL
{
    public async Task<string> GetGSTSummaryAsync(
        string gstin, string returnPeriod, LoginDTO login, CancellationToken ct)
    {
        try
        {
            var summary = await dal.GetGSTSummaryAsync(gstin, returnPeriod, login, ct);
            return JsonSerializer.Serialize(summary);
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "GetGSTSummary failed for GSTIN {GSTIN} period {Period}", gstin, returnPeriod);
            throw;
        }
    }

    public async Task<string> GetOUWiseGSTSummaryAsync(
        string returnPeriod, string gstin, LoginDTO login, CancellationToken ct)
    {
        try
        {
            var rows = await dal.GetOUWiseSummaryAsync(returnPeriod, gstin, login, ct);
            return JsonSerializer.Serialize(rows);
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "GetOUWiseGSTSummary failed for period {Period}", returnPeriod);
            throw;
        }
    }

    public async Task<string> GetHSNSummaryAsync(
        string returnPeriod, string gstin, LoginDTO login, CancellationToken ct)
    {
        try
        {
            var rows = await dal.GetHSNSummaryAsync(returnPeriod, gstin, login, ct);
            return JsonSerializer.Serialize(rows);
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "GetHSNSummary failed for period {Period}", returnPeriod);
            throw;
        }
    }

    public async Task<string> GetFilingStatusSummaryAsync(
        int periodYear, string gstin, LoginDTO login, CancellationToken ct)
    {
        try
        {
            var rows = await dal.GetFilingStatusSummaryAsync(periodYear, gstin, login, ct);
            return JsonSerializer.Serialize(rows);
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "GetFilingStatusSummary failed for year {Year}", periodYear);
            throw;
        }
    }

    public async Task<string> GetExceptionReportAsync(
        string returnPeriod, int page, int pageSize, LoginDTO login, CancellationToken ct)
    {
        try
        {
            var (items, total) = await dal.GetExceptionReportAsync(returnPeriod, page, pageSize, login, ct);
            return JsonSerializer.Serialize(new { Items = items, Total = total, Page = page, PageSize = pageSize });
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "GetExceptionReport failed for period {Period}", returnPeriod);
            throw;
        }
    }

    public async Task<string> RecomputePeriodSummaryAsync(
        RecomputeSummaryRequestDTO request, LoginDTO login, CancellationToken ct)
    {
        try
        {
            var returnPeriod = $"{request.PeriodMonth:D2}{request.PeriodYear}";

            var (taxable, igst, cgst, sgst, cess, docs) =
                await dal.GetOutwardAggregateAsync(request.GSTIN, returnPeriod, login, ct);

            var (itcIgst, itcCgst, itcSgst) =
                await dal.GetInwardITCAggregateAsync(request.GSTIN, returnPeriod, login, ct);

            var dto = new PeriodSummaryDTO
            {
                GSTIN            = request.GSTIN,
                PeriodYear       = request.PeriodYear,
                PeriodMonth      = request.PeriodMonth,
                SummaryType      = request.SummaryType,
                TotalTaxableValue= taxable,
                TotalIGST        = igst,
                TotalCGST        = cgst,
                TotalSGST        = sgst,
                TotalCess        = cess,
                TotalITCIGST     = itcIgst,
                TotalITCCGST     = itcCgst,
                TotalITCSGST     = itcSgst,
                TotalDocuments   = docs,
                InvalidDocuments = 0
            };

            var summaryId = await dal.UpsertPeriodSummaryAsync(dto, login, ct);
            logger.LogInformation("Period summary {SummaryId} recomputed for GSTIN {GSTIN} {Month}/{Year}",
                summaryId, request.GSTIN, request.PeriodMonth, request.PeriodYear);

            return JsonSerializer.Serialize(new { SummaryId = summaryId, Message = SuccessResponse.UpdateSuccess });
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "RecomputePeriodSummary failed for GSTIN {GSTIN}", request.GSTIN);
            throw;
        }
    }
}