using GB5Shared.DTO.Framework.Login;
using GoodBooks.PAY.PAYBLL.Loyalty;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace GoodBooks.PAY.PAYSL.Services
{
    // ─────────────────────────────────────────────────────────────────────────
    //  LoyaltyPointsExpiryJob
    //
    //  .NET 9 BackgroundService using PeriodicTimer.
    //  Runs once per day (configurable via PayJobs:LoyaltyExpiryIntervalHours).
    //  Calls ICustomerLoyaltyBLL.ExpirePointsAsync which:
    //    - finds all enrollments with points expiring today
    //    - inserts negative-point compensating TLOYALTYLEDGER rows (append-only)
    //    - decrements TCUSTOMERLOYALTYENROLLMENT.CURRENTPOINTS
    // ─────────────────────────────────────────────────────────────────────────
    public sealed class LoyaltyPointsExpiryJob : BackgroundService
    {
        private readonly IServiceScopeFactory              _scopeFactory;
        private readonly IConfiguration                    _config;
        private readonly ILogger<LoyaltyPointsExpiryJob>  _logger;

        public LoyaltyPointsExpiryJob(
            IServiceScopeFactory             scopeFactory,
            IConfiguration                   config,
            ILogger<LoyaltyPointsExpiryJob>  logger)
        {
            _scopeFactory = scopeFactory;
            _config       = config;
            _logger       = logger;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            int intervalHours = _config.GetValue<int>("PayJobs:LoyaltyExpiryIntervalHours", 24);

            _logger.LogInformation(
                "LoyaltyPointsExpiryJob starting — interval {IntervalHours}h", intervalHours);

            using var timer = new PeriodicTimer(TimeSpan.FromHours(intervalHours));

            while (await timer.WaitForNextTickAsync(stoppingToken))
            {
                _logger.LogInformation("LoyaltyPointsExpiryJob tick at {UtcNow:u}", DateTime.UtcNow);

                try
                {
                    using var scope = _scopeFactory.CreateScope();
                    var bll = scope.ServiceProvider.GetRequiredService<ICustomerLoyaltyBLL>();

                    var systemLogin = BuildSystemLogin();
                    await bll.ExpirePointsAsync(systemLogin, stoppingToken).ConfigureAwait(false);

                    _logger.LogInformation("LoyaltyPointsExpiryJob cycle completed at {UtcNow:u}", DateTime.UtcNow);
                }
                catch (Exception ex) when (ex is not OperationCanceledException)
                {
                    _logger.LogError(ex, "LoyaltyPointsExpiryJob cycle failed.");
                    // Continue — next tick will retry
                }
            }
        }

        private LoginDTO BuildSystemLogin() => new()
        {
            ClientId     = _config.GetValue<int>("PayJobs:SystemTenantId", -1),
            DatabaseName = _config["PayJobs:SystemDatabaseName"] ?? "GoodBooks_Main",
            UserId       = -1
        };
    }
}