DummyProducerService.cs

namespace MultiEventsConsumer;

internal partial class DummyProducerService(IEventPublisher publisher, ILogger<DummyProducerService> logger) : BackgroundService
{
    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        // Wait for bus to be ready
        await Task.Delay(TimeSpan.FromSeconds(8), stoppingToken);

        // Generate random vehicle Ids
        var rnd = new Random(DateTimeOffset.UtcNow.Millisecond);
        var vehicles = Enumerable.Range(0, 5).Select(_ => GenerateRandomString(rnd)).ToList();

        // Find the number of possible combinations
        var kinds = Enum.GetValues<DoorKind>().ToList();
        var states = Enum.GetValues<DoorState>().ToList();
        var combinations = vehicles.Count * kinds.Count * states.Count;

        // Select a portion of the combinations
        var times = rnd.Next(1, combinations);
        logger.LogInformation("Selected {Times} of {Combinations} combinations.", times, combinations);

        var delay = TimeSpan.FromSeconds(15);

        for (var i = 0; i < times; i++)
        {
            // Select vehicle, door kind and door state randomly
            var vehicle = vehicles[rnd.Next(0, combinations) * 1 % vehicles.Count];
            var kind = kinds[rnd.Next(0, combinations) * i % kinds.Count];
            var state = states[rnd.Next(0, combinations) * i % states.Count];

            // Publish event depending on the door state
            if (state == DoorState.Closed)
            {
                var evt = new DoorClosed
                {
                    VehicleId = vehicle,
                    Closed = DateTimeOffset.UtcNow,
                    Kind = kind,
                };

                await publisher.PublishAsync(evt, cancellationToken: stoppingToken);
            }
            else
            {
                var evt = new DoorOpened
                {
                    VehicleId = vehicle,
                    Opened = DateTimeOffset.UtcNow,
                    Kind = kind,
                };

                await publisher.PublishAsync(evt, cancellationToken: stoppingToken);
            }

            await Task.Delay(delay, stoppingToken);
        }

        logger.LogInformation("Finished producing dummy data!");
    }

    private static string GenerateRandomString(Random random)
    {
        var bys = new byte[20];
        random.NextBytes(bys);
        var result = Convert.ToBase64String(bys);
        return AlphaNumeric().Replace(result, "");
    }

    [System.Text.RegularExpressions.GeneratedRegex("[^A-Za-z0-9]")]
    private static partial System.Text.RegularExpressions.Regex AlphaNumeric();
}