🚧 Scoping out some modding utils

src/util/bbmodding.ts

@@ -0,0 +1,105 @@
+type Targetable = Record<string, any>
+type TargetKey<Target extends Targetable> = keyof Target & string
+// type ModID = string
+type ModInjectionMode = 'override' | 'append' | 'prepend'
+
+// interface RegisteredFunctionMod<Target extends Targetable, Key extends TargetKey<Target>> {
+// 	id: string
+// 	mode: ModInjectionMode
+// 	cb: (
+// 		this: Target,
+// 		ctx: ModContext<Target, Key>,
+// 		...args: Parameters<Target[Key]>
+// 	) => ModFunctionReturnResult<ReturnType<Target[Key]>>
+// }
+
+interface ModContext<Target extends Targetable, Key extends TargetKey<Target>> {
+	/**
+	 * The original function that was modified.
+	 */
+	originalFunction: Target[Key]
+	/**
+	 * The key of the function that was modified.
+	 */
+	key: Key
+	/**
+	 * The id of the mod that created this function.
+	 */
+	modId: string
+	/**
+	 * The injection mode of the mod that created this function.
+	 */
+	modMode: ModInjectionMode
+}
+
+interface ModFunctionReturnResult<T> {
+	returnValue: T
+	/**
+	 * If injection mode is 'append', this will prevent the original function from running.
+	 */
+	cancelled?: boolean
+}
+
+const REGISTERED_MODS = new Map<Targetable, Map<string, any>>()
+
+function assertEntryExists<Target extends Targetable, Key extends TargetKey<Target>>(
+	target: Target,
+	key: Key
+) {
+	if (!REGISTERED_MODS.has(target)) {
+		REGISTERED_MODS.set(target, new Map())
+	}
+	if (!REGISTERED_MODS.get(target)!.has(key)) {
+		REGISTERED_MODS.get(target)!.set(key, new Map())
+	}
+}
+
+/**
+ * Registers a function mod to a target object / class.
+ * @param target The target object / class to modify.
+ * @param key The key of the function to modify.
+ * @param id The ID of the mod. Used to identify errors and conflicts.
+ * @param mode The mode of the mod. Can be `override`, `append`, or `prepend`.
+ * - `override` will replace the original function with the new one.
+ * - `append` will run the original function first, then the new one.
+ * - `prepend` will run the new function first, then the original one.
+ * @param cb The callback function to run when the target function is called.
+ */
+export function registerFunctionMod<Target extends Targetable, Key extends TargetKey<Target>>(
+	target: Target,
+	key: Key,
+	id: string,
+	mode: ModInjectionMode,
+	cb: (
+		this: Target,
+		ctx: ModContext<Target, Key>,
+		...args: Parameters<Target[Key]>
+	) => ModFunctionReturnResult<ReturnType<Target[Key]>>
+) {
+	console.log(target, key, id, mode, cb)
+	assertEntryExists(target, key)
+	const mods = REGISTERED_MODS.get(target)!.get(key)!
+	if (mods.has(id)) {
+		throw new Error(`Mod with ID "${id}" already exists for function "${key}"`)
+	}
+	mods.set(id, { id, mode, cb })
+}
+
+registerFunctionMod(Group.prototype, 'updateElement', 'my_epic_mod', 'override', function (ctx) {
+	console.log('Hello World!', ctx)
+	return { returnValue: this }
+})
+
+/**
+ * Gets all registered mods for a target object / class.
+ * @param target The target object / class to get mods for.
+ * @param key (Optional) The key of the function to get mods for.
+ */
+export function getRegisteredMods<Target extends Targetable, Key extends TargetKey<Target>>(
+	target: Target,
+	key?: Key
+) {
+	//
+}
+
+getRegisteredMods(Group.prototype)