Deprecate GuildActions. Fix double case posting when muting a user for message spam. Update to new mute/case style when muting a user for "other" spam.

GuildActions turned out to be a fairly pointless abstraction in the end.
It didn't really solve the problems it was meant to solve (that is,
reduce code spaghetti by having all inter-plugin calls go through a
single service, and allow easier ways to replace core plugins with
alternatives that share the same interface) any better than simply
using `this.getPlugin()` when needed, and introduced extra complexity
and made static analysis messier.

src/plugins/ZeppelinPlugin.ts

@@ -1,12 +1,15 @@
 import { IBasePluginConfig, IPluginOptions, Plugin } from "knub";
 import { PluginRuntimeError } from "../PluginRuntimeError";
 import Ajv, { ErrorObject } from "ajv";
-import { isSnowflake, isUnicodeEmoji } from "../utils";
+import { createUnknownUser, isSnowflake, isUnicodeEmoji, UnknownUser } from "../utils";
+import { Member, User } from "eris";
 
 export class ZeppelinPlugin<TConfig extends {} = IBasePluginConfig> extends Plugin<TConfig> {
   protected configSchema: any;
   protected permissionsSchema: any;
 
+  public static dependencies = [];
+
   protected throwPluginRuntimeError(message: string) {
     throw new PluginRuntimeError(message, this.runtimePluginName, this.guildId);
   }
@@ -73,4 +76,64 @@ export class ZeppelinPlugin<TConfig extends {} = IBasePluginConfig> extends Plug
   public getRegisteredCommands() {
     return this.commands.commands;
   }
+
+  /**
+   * Resolves a user from the passed string. The passed string can be a user id, a user mention, a full username (with discrim), etc.
+   */
+  async resolveUser(userResolvable: string): Promise<User | UnknownUser> {
+    if (userResolvable == null) {
+      return createUnknownUser();
+    }
+
+    let userId;
+
+    // A user mention?
+    const mentionMatch = userResolvable.match(/^<@!?(\d+)>$/);
+    if (mentionMatch) {
+      userId = mentionMatch[1];
+    }
+
+    // A non-mention, full username?
+    if (!userId) {
+      const usernameMatch = userResolvable.match(/^@?([^#]+)#(\d{4})$/);
+      if (usernameMatch) {
+        const user = this.bot.users.find(u => u.username === usernameMatch[1] && u.discriminator === usernameMatch[2]);
+        userId = user.id;
+      }
+    }
+
+    // Just a user ID?
+    if (!userId) {
+      const idMatch = userResolvable.match(/^\d+$/);
+      if (!idMatch) {
+        return null;
+      }
+
+      userId = userResolvable;
+    }
+
+    const cachedUser = this.bot.users.find(u => u.id === userId);
+    if (cachedUser) return cachedUser;
+
+    try {
+      const freshUser = await this.bot.getRESTUser(userId);
+      return freshUser;
+    } catch (e) {} // tslint:disable-line
+
+    return createUnknownUser({ id: userId });
+  }
+
+  async getMember(userId: string): Promise<Member> {
+    // See if we have the member cached...
+    let member = this.guild.members.get(userId);
+
+    // If not, fetch it from the API
+    if (!member) {
+      try {
+        member = await this.bot.getRESTGuildMember(this.guildId, userId);
+      } catch (e) {} // tslint:disable-line
+    }
+
+    return member;
+  }
 }