[Global] Basic commands api implementation (#9)

* [Global] Basic commands api implementation

* [Commands] Return unregister method when registering command

* [Commands] Code cleanup pass

Co-authored-by: Beef <beefers@riseup.net>

src/lib/commands.ts

@@ -0,0 +1,26 @@
+import { ApplicationCommand } from "@types";
+import { findByProps } from "@metro/filters";
+import { after } from "@lib/patcher";
+
+const commandsModule = findByProps("getBuiltInCommands")
+
+let commands: ApplicationCommand[] = [];
+
+after("getBuiltInCommands", commandsModule, (args, res) => res.concat(commands));
+
+export function registerCommand(command: ApplicationCommand): () => void {
+	// Get built in commands
+	const builtInCommands = commandsModule.getBuiltInCommands(1, true, false);
+	builtInCommands.sort(function (a: ApplicationCommand, b: ApplicationCommand) { return parseInt(b.id!) - parseInt(a.id!) });
+
+	const lastCommand = builtInCommands[builtInCommands.length - 1];
+
+	// Override the new command's id to the last command id - 1
+	command.id = (parseInt(lastCommand.id, 10) - 1).toString();
+
+	// Add it to the commands array
+	commands.push(command);
+
+	// Return command id so it can be unregistered
+	return () => commands = commands.filter(({ id }) => id !== command.id);
+}