dev: Added initial version of the grpc api. Added relevant dummy settings to creds (they have no effect rn)

dev: Yt searches now INTERNALLY return multiple results but there is no way right now to paginate plain text results
dev: moved some stuff around

src/NadekoBot/_common/Impl/RemoteGrpcCoordinator.cs

@@ -0,0 +1,132 @@
+#nullable disable
+using Grpc.Core;
+using Grpc.Net.Client;
+using NadekoBot.Common.ModuleBehaviors;
+using NadekoBot.Coordinator;
+
+namespace NadekoBot.Services;
+
+public class RemoteGrpcCoordinator : ICoordinator, IReadyExecutor
+{
+    private readonly Coordinator.Coordinator.CoordinatorClient _coordClient;
+    private readonly DiscordSocketClient _client;
+
+    public RemoteGrpcCoordinator(IBotCredentials creds, DiscordSocketClient client)
+    {
+        var coordUrl = string.IsNullOrWhiteSpace(creds.CoordinatorUrl) ? "http://localhost:3442" : creds.CoordinatorUrl;
+
+        var channel = GrpcChannel.ForAddress(coordUrl);
+        _coordClient = new(channel);
+        _client = client;
+    }
+
+    public bool RestartBot()
+    {
+        _coordClient.RestartAllShards(new());
+
+        return true;
+    }
+
+    public void Die(bool graceful)
+        => _coordClient.Die(new()
+        {
+            Graceful = graceful
+        });
+
+    public bool RestartShard(int shardId)
+    {
+        _coordClient.RestartShard(new()
+        {
+            ShardId = shardId
+        });
+
+        return true;
+    }
+
+    public IList<ShardStatus> GetAllShardStatuses()
+    {
+        var res = _coordClient.GetAllStatuses(new());
+
+        return res.Statuses.ToArray()
+                  .Map(s => new ShardStatus
+                  {
+                      ConnectionState = FromCoordConnState(s.State),
+                      GuildCount = s.GuildCount,
+                      ShardId = s.ShardId,
+                      LastUpdate = s.LastUpdate.ToDateTime()
+                  });
+    }
+
+    public int GetGuildCount()
+    {
+        var res = _coordClient.GetAllStatuses(new());
+
+        return res.Statuses.Sum(x => x.GuildCount);
+    }
+
+    public async Task Reload()
+        => await _coordClient.ReloadAsync(new());
+
+    public Task OnReadyAsync()
+    {
+        Task.Run(async () =>
+        {
+            var gracefulImminent = false;
+            while (true)
+            {
+                try
+                {
+                    var reply = await _coordClient.HeartbeatAsync(new()
+                        {
+                            State = ToCoordConnState(_client.ConnectionState),
+                            GuildCount =
+                                _client.ConnectionState == ConnectionState.Connected ? _client.Guilds.Count : 0,
+                            ShardId = _client.ShardId
+                        },
+                        deadline: DateTime.UtcNow + TimeSpan.FromSeconds(10));
+                    gracefulImminent = reply.GracefulImminent;
+                }
+                catch (RpcException ex)
+                {
+                    if (!gracefulImminent)
+                    {
+                        Log.Warning(ex,
+                            "Hearbeat failed and graceful shutdown was not expected: {Message}",
+                            ex.Message);
+                        break;
+                    }
+
+                    Log.Information("Coordinator is restarting gracefully. Waiting...");
+                    await Task.Delay(30_000);
+                }
+                catch (Exception ex)
+                {
+                    Log.Error(ex, "Unexpected heartbeat exception: {Message}", ex.Message);
+                    break;
+                }
+
+                await Task.Delay(7500);
+            }
+
+            Environment.Exit(5);
+        });
+
+        return Task.CompletedTask;
+    }
+
+    private ConnState ToCoordConnState(ConnectionState state)
+        => state switch
+        {
+            ConnectionState.Connecting => ConnState.Connecting,
+            ConnectionState.Connected => ConnState.Connected,
+            _ => ConnState.Disconnected
+        };
+
+    private ConnectionState FromCoordConnState(ConnState state)
+        => state switch
+        {
+            ConnState.Connecting => ConnectionState.Connecting,
+            ConnState.Connected => ConnectionState.Connected,
+            _ => ConnectionState.Disconnected
+        };
+}