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

namespace ComplianceBLL.ComplianceAlert;

public class ComplianceAlertBLL(
    IComplianceAlertDAL dal,
    ILogger<ComplianceAlertBLL> logger) : IComplianceAlertBLL
{
    public async Task<string> GetActiveAlertsAsync(
        string gstin, int page, int pageSize, LoginDTO login, CancellationToken ct)
    {
        var (items, total) = await dal.GetActiveAlertsAsync(gstin, page, pageSize, login, ct);
        return JsonSerializer.Serialize(new { Items = items, Total = total, Page = page, PageSize = pageSize });
    }

    public async Task<string> DismissAlertAsync(int alertId, LoginDTO login, CancellationToken ct)
    {
        await dal.DismissAlertAsync(alertId, login.UserId, login, ct);
        logger.LogInformation("Alert {AlertId} dismissed by user {UserId}", alertId, login.UserId);
        return JsonSerializer.Serialize(new { Message = SuccessResponse.UpdateSuccess });
    }

    public async Task<string> GetAlertConfigAsync(string gstin, LoginDTO login, CancellationToken ct)
    {
        var config = await dal.GetAlertConfigAsync(gstin, login, ct)
            ?? new AlertConfigDTO { GSTIN = gstin };
        return JsonSerializer.Serialize(config);
    }

    public async Task<string> SaveAlertConfigAsync(AlertConfigDTO dto, LoginDTO login, CancellationToken ct)
    {
        var id = await dal.UpsertAlertConfigAsync(dto, login, ct);
        logger.LogInformation("Alert config {Id} saved for GSTIN {GSTIN}", id, dto.GSTIN);
        return JsonSerializer.Serialize(new { AlertConfigId = id, Message = SuccessResponse.SaveSuccess });
    }

    public async Task RunAlertCheckAsync(LoginDTO login, CancellationToken ct)
    {
        logger.LogInformation("Running compliance alert check for client {ClientId}", login.ClientId);

        await Task.WhenAll(
            CheckFilingDeadlinesAsync(login, ct),
            CheckEWBExpiriesAsync(login, ct),
            CheckMissingIRNsAsync(login, ct),
            CheckRejectedArtifactsAsync(login, ct)
        );

        logger.LogInformation("Compliance alert check completed for client {ClientId}", login.ClientId);
    }

    private async Task CheckFilingDeadlinesAsync(LoginDTO login, CancellationToken ct)
    {
        var pending = await dal.GetPendingFilingGSTINsAsync(login, ct);
        foreach (var row in pending)
        {
            var alert = new ComplianceAlertDTO
            {
                AlertType    = "FilingDeadline",
                GSTIN        = (string)row.GSTIN,
                ReturnPeriod = $"{(int)row.PERIODMONTH:D2}{(int)row.PERIODYEAR}",
                AlertMessage = $"{(string)row.RETURNTYPE} filing deadline approaching for period {(int)row.PERIODMONTH:D2}/{(int)row.PERIODYEAR}",
                Severity     = "Warning"
            };
            await dal.UpsertAlertAsync(alert, login, ct);
        }
        logger.LogInformation("Filing deadline alerts processed: {Count}", pending.Count);
    }

    private async Task CheckEWBExpiriesAsync(LoginDTO login, CancellationToken ct)
    {
        var expiring = await dal.GetExpiringEWBsAsync(login, ct);
        foreach (var row in expiring)
        {
            var alert = new ComplianceAlertDTO
            {
                AlertType    = "EWBExpiry",
                GSTIN        = (string)row.GSTIN,
                AlertMessage = $"E-Way Bill {(string)row.EWAYBILLNUMBER} expires on {((DateTime)row.VALIDUPTO):dd-MMM-yyyy HH:mm}",
                Severity     = "Critical"
            };
            await dal.UpsertAlertAsync(alert, login, ct);
        }
        logger.LogInformation("EWB expiry alerts processed: {Count}", expiring.Count);
    }

    private async Task CheckMissingIRNsAsync(LoginDTO login, CancellationToken ct)
    {
        var missing = await dal.GetInvoicesWithoutIRNAsync(login, ct);
        foreach (var row in missing)
        {
            var alert = new ComplianceAlertDTO
            {
                AlertType    = "IRNPending",
                GSTIN        = (string)row.GSTIN,
                ReturnPeriod = (string)row.RETURNPERIOD,
                AlertMessage = $"Invoice {(string)row.INVOICENUMBER} dated {((DateTime)row.INVOICEDATE):dd-MMM-yyyy} has no IRN",
                Severity     = "Warning"
            };
            await dal.UpsertAlertAsync(alert, login, ct);
        }
        logger.LogInformation("Missing IRN alerts processed: {Count}", missing.Count);
    }

    private async Task CheckRejectedArtifactsAsync(LoginDTO login, CancellationToken ct)
    {
        var rejected = await dal.GetOldRejectedArtifactsAsync(login, ct);
        foreach (var row in rejected)
        {
            var alert = new ComplianceAlertDTO
            {
                AlertType    = "SubmissionFailed",
                GSTIN        = (string)row.GSTIN,
                ReturnPeriod = (string?)row.RETURNPERIOD,
                ArtifactId   = (int)row.ARTIFACTID,
                AlertMessage = $"Compliance submission failed and remains in REJECTED state since {((DateTime)row.CREATEDON):dd-MMM-yyyy}",
                Severity     = "Critical"
            };
            await dal.UpsertAlertAsync(alert, login, ct);
        }
        logger.LogInformation("Submission failed alerts processed: {Count}", rejected.Count);
    }
}