refactor: cache own user ID in IDiscordCache

- remove Cluster.User
- remove Cluster.Application (it was only being used as an alternative to Cluster.User for some reason)
- move Bot.PermissionsIn to DiscordCacheExtensions

PluralKit.Bot/Services/LogChannelService.cs

@@ -78,7 +78,7 @@ namespace PluralKit.Bot
             if (logChannel == null || logChannel.Type != Channel.ChannelType.GuildText) return null;
 
             // Check bot permissions
-            var perms = await _bot.PermissionsIn(logChannel.Id);
+            var perms = await _cache.PermissionsIn(logChannel.Id);
             if (!perms.HasFlag(PermissionSet.SendMessages | PermissionSet.EmbedLinks))
             {
                 _logger.Information(

PluralKit.Bot/Services/LoggerCleanService.cs

@@ -89,7 +89,7 @@ namespace PluralKit.Bot
             var channel = await _cache.GetChannel(msg.ChannelId);
 
             if (channel.Type != Channel.ChannelType.GuildText) return;
-            if (!(await _bot.PermissionsIn(channel.Id)).HasFlag(PermissionSet.ManageMessages)) return;
+            if (!(await _cache.PermissionsIn(channel.Id)).HasFlag(PermissionSet.ManageMessages)) return;
 
             // If this message is from a *webhook*, check if the name matches one of the bots we know
             // TODO: do we need to do a deeper webhook origin check, or would that be too hard on the rate limit?

PluralKit.Bot/Services/WebhookCacheService.cs

@@ -6,7 +6,7 @@ using System.Threading.Tasks;
 
 using App.Metrics;
 
-using Myriad.Gateway;
+using Myriad.Cache;
 using Myriad.Rest;
 using Myriad.Rest.Types.Requests;
 using Myriad.Types;
@@ -24,13 +24,13 @@ namespace PluralKit.Bot
 
         private readonly IMetrics _metrics;
         private readonly ILogger _logger;
-        private readonly Cluster _cluster;
+        private readonly IDiscordCache _cache;
 
-        public WebhookCacheService(ILogger logger, IMetrics metrics, DiscordApiClient rest, Cluster cluster)
+        public WebhookCacheService(ILogger logger, IMetrics metrics, DiscordApiClient rest, IDiscordCache cache)
         {
             _metrics = metrics;
             _rest = rest;
-            _cluster = cluster;
+            _cache = cache;
             _logger = logger.ForContext<WebhookCacheService>();
             _webhooks = new ConcurrentDictionary<ulong, Lazy<Task<Webhook>>>();
         }
@@ -86,7 +86,8 @@ namespace PluralKit.Bot
             var webhooks = await FetchChannelWebhooks(channelId);
 
             // If the channel has a webhook created by PK, just return that one
-            var ourWebhook = webhooks.FirstOrDefault(IsWebhookMine);
+            var ourUserId = await _cache.GetOwnUser();
+            var ourWebhook = webhooks.FirstOrDefault(hook => IsWebhookMine(ourUserId, hook));
             if (ourWebhook != null)
                 return ourWebhook;
 
@@ -120,7 +121,7 @@ namespace PluralKit.Bot
             return await _rest.CreateWebhook(channelId, new CreateWebhookRequest(WebhookName));
         }
 
-        private bool IsWebhookMine(Webhook arg) => arg.User?.Id == _cluster.User?.Id && arg.Name == WebhookName;
+        private bool IsWebhookMine(ulong userId, Webhook arg) => arg.User?.Id == userId && arg.Name == WebhookName;
 
         public int CacheSize => _webhooks.Count;
     }