Migrate existing code

Services/Dhcp/DhcpQueueWorker.cs

@@ -0,0 +1,44 @@
+using System.Threading.Channels;
+
+using DotNetDDI.Services.Dns;
+
+using Microsoft.Extensions.Hosting;
+
+namespace DotNetDDI.Services.Dhcp;
+
+public class DhcpQueueWorker : BackgroundService
+{
+	private readonly ChannelReader<DhcpLeaseChange> _channelReader;
+	private readonly DnsRepository _repository;
+
+	public DhcpQueueWorker(DhcpLeaseQueue queue, DnsRepository repository)
+	{
+		_channelReader = queue.Reader;
+		_repository = repository;
+	}
+
+	protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+	{
+		while (await _channelReader.WaitToReadAsync(stoppingToken).ConfigureAwait(false))
+		{
+			while (_channelReader.TryRead(out var lease))
+			{
+				DnsRecordIdentifier identifier = lease.Identifier switch
+				{
+					DhcpLeaseClientIdentifier clientId => new DnsRecordClientIdentifier(clientId.ClientId),
+					DhcpLeaseHWAddrIdentifier hwAddr => new DnsRecordHWAddrIdentifier(hwAddr.HWAddr),
+					_ => throw new ArgumentException(nameof(lease.Identifier))
+				};
+
+				TimeSpan lifetime = lease.Lifetime.TotalSeconds switch
+				{
+					<= 1800 => TimeSpan.FromSeconds(600),
+					>= 10800 => TimeSpan.FromSeconds(3600),
+					{ } seconds => TimeSpan.FromSeconds(seconds / 3)
+				};
+
+				await _repository.Record(new DnsRecord(lease.Address, lease.FQDN, identifier, lifetime), stoppingToken).ConfigureAwait(false);
+			}
+		}
+	}
+}