using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace Admin.NET.Plugin.AiDOP.DataPlatform.HotWatch;

/// <summary>热回读后台：默认每 5 秒一轮，Concurrent 由单实例循环保证不叠加。</summary>
public sealed class MdpHotWatchWorker : BackgroundService
{
    private static readonly TimeSpan Interval = TimeSpan.FromSeconds(5);

    private readonly IServiceScopeFactory _scopeFactory;
    private readonly ILogger _logger;

    public MdpHotWatchWorker(IServiceScopeFactory scopeFactory, ILoggerFactory loggerFactory)
    {
        _scopeFactory = scopeFactory;
        _logger = loggerFactory.CreateLogger(nameof(MdpHotWatchWorker));
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        // 启动稍延后，避免与应用引导抢资源
        try { await Task.Delay(TimeSpan.FromSeconds(15), stoppingToken); }
        catch (OperationCanceledException) { return; }

        while (!stoppingToken.IsCancellationRequested)
        {
            try
            {
                using var scope = _scopeFactory.CreateScope();
                var svc = scope.ServiceProvider.GetRequiredService<MdpHotWatchService>();
                var (polled, changed, terminated) = await svc.PollOnceAsync(100, stoppingToken);
                if (changed + terminated > 0)
                    _logger.LogInformation(
                        "[MdpHotWatchWorker] polled={Polled} changed={Changed} terminated={Terminated}",
                        polled, changed, terminated);
            }
            catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
            {
                break;
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "[MdpHotWatchWorker] poll failed");
            }

            try { await Task.Delay(Interval, stoppingToken); }
            catch (OperationCanceledException) { break; }
        }
    }
}