shim.js

// SPDX-License-Identifier: MIT
// Copyright © 2021 fvtt-lib-wrapper Rui Pinheiro


'use strict';

// A shim for the libWrapper library
export let libWrapper = undefined;

Hooks.once('init', () => {
	// Check if the real module is already loaded - if so, use it
	if(globalThis.libWrapper && !(globalThis.libWrapper.is_fallback ?? true)) {
		libWrapper = globalThis.libWrapper;
		return;
	}

	// Fallback implementation
	libWrapper = class {
		static get is_fallback() { return true };

		static register(module, target, fn, type="MIXED", {chain=undefined}={}) {
			const is_setter = target.endsWith('#set');
			target = !is_setter ? target : target.slice(0, -4);
			const split = target.split('.');
			const fn_name = split.pop();
			const root_nm = split.splice(0,1)[0];
			const _eval = eval; // The browser doesn't expose all global variables (e.g. 'Game') inside globalThis, but it does to an eval. We copy it to a variable to have it run in global scope.
			const obj = split.reduce((x,y)=>x[y], globalThis[root_nm] ?? _eval(root_nm));

			let iObj = obj;
			let descriptor = null;
			while(iObj) {
				descriptor = Object.getOwnPropertyDescriptor(iObj, fn_name);
				if(descriptor) break;
				iObj = Object.getPrototypeOf(iObj);
			}
			if(!descriptor || descriptor?.configurable === false) throw `libWrapper Shim: '${target}' does not exist, could not be found, or has a non-configurable descriptor.`;

			let original = null;
			const wrapper = (chain ?? type != 'OVERRIDE') ? function() { return fn.call(this, original.bind(this), ...arguments); } : function() { return fn.apply(this, arguments); };

			if(!is_setter) {
				if(descriptor.value) {
					original = descriptor.value;
					descriptor.value = wrapper;
				}
				else {
					original = descriptor.get;
					descriptor.get = wrapper;
				}
			}
			else {
				if(!descriptor.set) throw `libWrapper Shim: '${target}' does not have a setter`;
				original = descriptor.set;
				descriptor.set = wrapper;
			}

			descriptor.configurable = true;
			Object.defineProperty(obj, fn_name, descriptor);
		}
	}

	//************** USER CUSTOMIZABLE:
	// Whether to warn GM that the fallback is being used
	const WARN_FALLBACK = true;

	// Set up the ready hook that shows the "libWrapper not installed" warning dialog
	if(WARN_FALLBACK) {
		//************** USER CUSTOMIZABLE:
		// Module ID & Module Title - by default attempts to auto-detect, but you might want to hardcode your module ID and title here to avoid potential auto-detect issues
		const [MODULE_ID, MODULE_TITLE] = (()=>{
			const match = (import.meta?.url ?? Error().stack)?.match(/\/(worlds|systems|modules)\/(.+)(?=\/)/i);
			if(match?.length !== 3) return [null,null];
			const dirs = match[2].split('/');
			if(match[1] === 'worlds') return dirs.find(n => n && game.world.id === n) ? [game.world.id, game.world.title] : [null,null];
			if(match[1] === 'systems') return dirs.find(n => n && game.system.id === n) ? [game.system.id, game.system.data.title] : [null,null];
			const id = dirs.find(n => n && game.modules.has(n));
			return [id, game.modules.get(id)?.data?.title];
		})();

		if(!MODULE_ID || !MODULE_TITLE) {
			console.error("libWrapper Shim: Could not auto-detect module ID and/or title. The libWrapper fallback warning dialog will be disabled.");
			return;
		}

		Hooks.once('ready', () => {
			//************** USER CUSTOMIZABLE:
			// Title and message for the dialog shown when the real libWrapper is not installed.
			const FALLBACK_MESSAGE_TITLE = MODULE_TITLE;
			const FALLBACK_MESSAGE = `
				<p><b>'${MODULE_TITLE}' depends on the 'libWrapper' module, which is not present.</b></p>
				<p>A fallback implementation will be used, which increases the chance of compatibility issues with other modules.</p>
				<small><p>'libWrapper' is a library which provides module developers with a simple way to modify core Foundry VTT code, while reducing the likelihood of conflict with other modules.</p>
				<p>You can install it from the "Add-on Modules" tab in the <a href="javascript:game.shutDown()">Foundry VTT Setup</a>, from the <a href="https://foundryvtt.com/packages/lib-wrapper">Foundry VTT package repository</a>, or from <a href="https://github.com/ruipin/fvtt-lib-wrapper/">libWrapper's Github page</a>.</p></small>
			`;

			// Settings key used for the "Don't remind me again" setting
			const DONT_REMIND_AGAIN_KEY = "libwrapper-dont-remind-again";

			// Dialog code
			console.warn(`${MODULE_TITLE}: libWrapper not present, using fallback implementation.`);
			game.settings.register(MODULE_ID, DONT_REMIND_AGAIN_KEY, { name: '', default: false, type: Boolean, scope: 'world', config: false });
			if(game.user.isGM && !game.settings.get(MODULE_ID, DONT_REMIND_AGAIN_KEY)) {
				new Dialog({
					title: FALLBACK_MESSAGE_TITLE,
					content: FALLBACK_MESSAGE, buttons: {
						ok: { icon: '<i class="fas fa-check"></i>', label: 'Understood' },
						dont_remind: { icon: '<i class="fas fa-times"></i>', label: "Don't remind me again", callback: () => game.settings.set(MODULE_ID, DONT_REMIND_AGAIN_KEY, true) }
					}
				}).render(true);
			}
		});
	}
});