using Fitness_core_BE.Infra.Tenancy;
using Fitness_core_BE.Interfaces;

namespace Fitness_core_BE.Services
{
    /// <summary>
    /// Periodically locks (and un-locks) member fingerprint access based on each client's
    /// configurable Client.LockAfterDaysOverdue setting (req 7). Reuses the existing
    /// AccessDeviceService.LockCustomer/UnlockCustomer (BlackListMember/WhiteListMember)
    /// pipeline — this job only decides *who* should be locked, not *how*.
    ///
    /// This is a background service with no HttpContext, so TenantConnectionResolver's normal
    /// per-request tenant resolution can never apply here -- a DI-scoped TenantDbContext always
    /// resolves to the same single fallback schema regardless of which client is being checked.
    /// Every client's overdue-check therefore opens its OWN schema directly via
    /// TenantSchemaIterator instead of using the scope's injected TenantDbContext.
    ///
    /// The per-client algorithm itself lives in OverdueLockRunner so
    /// AdminBackgroundJobsController's manual "trigger now" endpoint can call the exact same
    /// code path instead of duplicating it -- this class only owns the 6-hour loop and the
    /// central-only client lookup.
    /// </summary>
    public class OverdueLockJob : BackgroundService
    {
        private static readonly TimeSpan Interval = TimeSpan.FromHours(6);

        private readonly IServiceScopeFactory _scopeFactory;
        private readonly ILogger<OverdueLockJob> _logger;

        public OverdueLockJob(IServiceScopeFactory scopeFactory, ILogger<OverdueLockJob> logger)
        {
            _scopeFactory = scopeFactory;
            _logger = logger;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            while (!stoppingToken.IsCancellationRequested)
            {
                try
                {
                    await RunOnceAsync(stoppingToken);
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "OverdueLockJob run failed.");
                }

                try
                {
                    await Task.Delay(Interval, stoppingToken);
                }
                catch (TaskCanceledException)
                {
                    // Shutting down.
                }
            }
        }

        private async Task RunOnceAsync(CancellationToken ct)
        {
            using var scope = _scopeFactory.CreateScope();
            var iterator = scope.ServiceProvider.GetRequiredService<TenantSchemaIterator>();
            var runner = scope.ServiceProvider.GetRequiredService<OverdueLockRunner>();

            var now = DateTime.UtcNow;

            // Central-only lookup -- safe to use the scope's normal DI-resolved repository,
            // since GetClientsWithOverdueLockPolicyAsync only ever touches CentralDbContext.
            var bootstrapRepo = scope.ServiceProvider.GetRequiredService<IOverdueLockRepository>();
            var clients = await bootstrapRepo.GetClientsWithOverdueLockPolicyAsync(ct);

            foreach (var client in clients)
            {
                try
                {
                    await runner.RunForClientAsync(client, now, iterator, ct);
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "OverdueLockJob failed for client {ClientId}.", client.ClientId);
                }
            }
        }
    }
}