namespace MeetingAssistant.Recording;

public sealed class OfflineTranscriptionBacklogHostedService : BackgroundService
{
    private static readonly TimeSpan RetryDelay = TimeSpan.FromMinutes(1);

    private readonly OfflineTranscriptionBacklogProcessor processor;
    private readonly ILogger<OfflineTranscriptionBacklogHostedService> logger;

    public OfflineTranscriptionBacklogHostedService(
        OfflineTranscriptionBacklogProcessor processor,
        ILogger<OfflineTranscriptionBacklogHostedService> logger)
    {
        this.processor = processor;
        this.logger = logger;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        while (!stoppingToken.IsCancellationRequested)
        {
            try
            {
                var processed = await processor.ProcessPendingAsync(stoppingToken);
                if (processed > 0)
                {
                    logger.LogInformation(
                        "Processed {ProcessedCount} offline transcription backlog item(s)",
                        processed);
                }
            }
            catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
            {
                return;
            }
            catch (Exception exception)
            {
                logger.LogWarning(
                    exception,
                    "Offline transcription backlog processing failed; it will be retried later");
            }

            try
            {
                await Task.Delay(RetryDelay, stoppingToken);
            }
            catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
            {
                return;
            }
        }
    }
}