// 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);
		}
	}
});