Add joinwatch slash command (#183)

Commands/InteractionCommands/JoinwatchInteractions.cs

@@ -0,0 +1,40 @@
+namespace Cliptok.Commands.InteractionCommands
+{
+    internal class JoinwatchInteractions : ApplicationCommandModule
+    {
+        [SlashCommand("joinwatch", "Watch for joins and leaves of a given user. Output goes to #investigations.", defaultPermission: false)]
+        [SlashRequireHomeserverPerm(ServerPermLevel.TrialModerator)]
+        public async Task JoinwatchSlashCmd(InteractionContext ctx,
+            [Option("user", "The user to watch for joins and leaves of.")] DiscordUser user,
+            [Option("note", "An optional note for context.")] string note = "")
+        {
+            var joinWatchlist = await Program.db.ListRangeAsync("joinWatchedUsers");
+
+            if (joinWatchlist.Contains(user.Id))
+            {
+                if (note != "")
+                {
+                    // User is already joinwatched, just update note
+                    await Program.db.HashSetAsync("joinWatchedUsersNotes", user.Id, note);
+                    await ctx.RespondAsync($"{Program.cfgjson.Emoji.Success} Successfully updated the note for {user.Mention}. Run again with no note to unwatch.");
+                    return;
+                }
+
+                // User is already joinwatched, unwatch
+                Program.db.ListRemove("joinWatchedUsers", joinWatchlist.First(x => x == user.Id));
+                await Program.db.HashDeleteAsync("joinWatchedUsersNotes", user.Id);
+                await ctx.RespondAsync($"{Program.cfgjson.Emoji.Success} Successfully unwatched {user.Mention}, since they were already in the list.");
+            }
+            else
+            {
+                // User is not joinwatched, watch
+                await Program.db.ListRightPushAsync("joinWatchedUsers", user.Id);
+                if (note != "")
+                    await Program.db.HashSetAsync("joinWatchedUsersNotes", user.Id, note);
+                await ctx.RespondAsync($"{Program.cfgjson.Emoji.Success} Now watching for joins/leaves of {user.Mention} to send to the investigations channel"
+                    + (note == "" ? "!" : $" with the following note:\n>>> {note}"));
+            }
+        }
+    }
+
+}