refactor: move ContextExts to own folder, CommandTree / command defs to CommandMeta folder

PluralKit.Bot/CommandSystem/Context/ContextChecksExt.cs

@@ -0,0 +1,104 @@
+using Autofac;
+
+using Myriad.Extensions;
+using Myriad.Types;
+
+using PluralKit.Core;
+
+namespace PluralKit.Bot;
+
+public static class ContextChecksExt
+{
+    public static Context CheckGuildContext(this Context ctx)
+    {
+        if (ctx.Channel.GuildId != null) return ctx;
+        throw new PKError("This command can not be run in a DM.");
+    }
+
+    public static Context CheckDMContext(this Context ctx)
+    {
+        if (ctx.Channel.GuildId == null) return ctx;
+        throw new PKError("This command must be run in a DM.");
+    }
+
+    public static Context CheckSystemPrivacy(this Context ctx, PKSystem target, PrivacyLevel level)
+    {
+        if (level.CanAccess(ctx.LookupContextFor(target))) return ctx;
+        throw new PKError("You do not have permission to access this information.");
+    }
+
+    public static Context CheckOwnMember(this Context ctx, PKMember member)
+    {
+        if (member.System != ctx.System?.Id)
+            throw Errors.NotOwnMemberError;
+        return ctx;
+    }
+
+    public static Context CheckOwnGroup(this Context ctx, PKGroup group)
+    {
+        if (group.System != ctx.System?.Id)
+            throw Errors.NotOwnGroupError;
+        return ctx;
+    }
+
+    public static Context CheckSystem(this Context ctx)
+    {
+        if (ctx.System == null)
+            throw Errors.NoSystemError;
+        return ctx;
+    }
+
+    public static Context CheckNoSystem(this Context ctx)
+    {
+        if (ctx.System != null)
+            throw Errors.ExistingSystemError;
+        return ctx;
+    }
+
+    public static async Task<Context> CheckAuthorPermission(this Context ctx, PermissionSet neededPerms,
+                                                            string permissionName)
+    {
+        if ((await ctx.UserPermissions & neededPerms) != neededPerms)
+            throw new PKError(
+                $"You must have the \"{permissionName}\" permission in this server to use this command.");
+        return ctx;
+    }
+
+    public static async Task<bool> CheckPermissionsInGuildChannel(this Context ctx, Channel channel,
+                                                                  PermissionSet neededPerms)
+    {
+        var guild = await ctx.Cache.GetGuild(channel.GuildId.Value);
+        if (guild == null)
+            return false;
+
+        var guildMember = ctx.Member;
+
+        if (ctx.Guild?.Id != channel.GuildId)
+        {
+            guildMember = await ctx.Rest.GetGuildMember(channel.GuildId.Value, ctx.Author.Id);
+            if (guildMember == null)
+                return false;
+        }
+
+        var userPermissions = PermissionExtensions.PermissionsFor(guild, channel, ctx.Author.Id, guildMember);
+        if ((userPermissions & neededPerms) == 0)
+            return false;
+
+        return true;
+    }
+
+    public static bool CheckBotAdmin(this Context ctx)
+    {
+        var botConfig = ctx.Services.Resolve<BotConfig>();
+        return botConfig.AdminRole != null && ctx.Member != null &&
+               ctx.Member.Roles.Contains(botConfig.AdminRole.Value);
+    }
+
+    public static Context AssertBotAdmin(this Context ctx)
+    {
+        if (!ctx.CheckBotAdmin())
+            throw new PKError("This command is only usable by bot admins.");
+
+        return ctx;
+    }
+}