Add context management

src/application.js

@@ -2,6 +2,7 @@ import Frame from './frame.js';
 import Layer from './layer.js';
 import Anim from './anim.js';
 import { Birb, Animations } from './birb.js';
+import { getContext } from './context.js';
 
 import {
 	Directions,
@@ -270,34 +271,9 @@ Promise.all([
 	/** @type {StickyNote[]} */
 	let stickyNotes = [];
 
-	/**
-	 * @returns {boolean} Whether the script is running in a userscript extension context
-	 */
-	function isUserScript() {
-		// @ts-expect-error
-		return typeof GM_getValue === "function";
-	}
-
-	function isTestEnvironment() {
-		return window.location.hostname === "127.0.0.1"
-			|| window.location.hostname === "localhost"
-			|| window.location.hostname.startsWith("192.168.");
-	}
-
 	function load() {
 		/** @type {Record<string, any>} */
-		let saveData = {};
-
-		if (isUserScript()) {
-			log("Loading save data from UserScript storage");
-			// @ts-expect-error
-			saveData = GM_getValue("birbSaveData", {}) ?? {};
-		} else if (isTestEnvironment()) {
-			log("Test environment detected, loading save data from localStorage");
-			saveData = JSON.parse(localStorage.getItem("birbSaveData") ?? "{}");
-		} else {
-			log("Not a UserScript");
-		}
+		let saveData = getContext().getSaveData();
 
 		debug("Loaded data: " + JSON.stringify(saveData));
 
@@ -340,29 +316,11 @@ Promise.all([
 			}));
 		}
 
-		if (isUserScript()) {
-			log("Saving data to UserScript storage");
-			// @ts-expect-error
-			GM_setValue("birbSaveData", saveData);
-		} else if (isTestEnvironment()) {
-			log("Test environment detected, saving data to localStorage");
-			localStorage.setItem("birbSaveData", JSON.stringify(saveData));
-		} else {
-			log("Not a UserScript");
-		}
+		getContext().putSaveData(saveData);
 	}
 
 	function resetSaveData() {
-		if (isUserScript()) {
-			log("Resetting save data in UserScript storage");
-			// @ts-expect-error
-			GM_deleteValue("birbSaveData");
-		} else if (isTestEnvironment()) {
-			log("Test environment detected, resetting save data in localStorage");
-			localStorage.removeItem("birbSaveData");
-		} else {
-			log("Not a UserScript");
-		}
+		getContext().resetSaveData();
 		load();
 	}
 

src/context.js

@@ -0,0 +1,119 @@
+
+import { debug, log, error } from "./shared.js";
+
+/**
+ * @typedef {import('./application.js').BirbSaveData} BirbSaveData
+ */
+
+/**
+ * @abstract
+ */
+export class Context {
+
+	/**
+	 * @abstract
+	 * @returns {boolean} Whether this context is applicable
+	 */
+	isContextActive() {
+		throw new Error("Method not implemented");
+	}
+
+	/**
+	 * @abstract
+	 * @returns {BirbSaveData|{}}
+	 */
+	getSaveData() {
+		throw new Error("Method not implemented");
+	}
+
+	/**
+	 * @abstract
+	 * @param {BirbSaveData} saveData
+	 */
+	putSaveData(saveData) {
+		throw new Error("Method not implemented");
+	}
+
+	/**
+	 * @abstract
+	 */
+	resetSaveData() {
+		throw new Error("Method not implemented");
+	}
+}
+
+export class LocalContext extends Context {
+
+	isContextActive() {
+		return window.location.hostname === "127.0.0.1"
+			|| window.location.hostname === "localhost"
+			|| window.location.hostname.startsWith("192.168.");
+	}
+
+	getSaveData() {
+		log("Loading save data from localStorage");
+		return JSON.parse(localStorage.getItem("birbSaveData") ?? "{}");
+	}
+
+	/**
+	 * @override
+	 * @param {BirbSaveData} saveData
+	 */
+	putSaveData(saveData) {
+		log("Saving data to localStorage");
+		localStorage.setItem("birbSaveData", JSON.stringify(saveData));
+	}
+
+	resetSaveData() {
+		log("Resetting save data in localStorage");
+		localStorage.removeItem("birbSaveData");
+	}
+}
+
+export class UserScriptContext extends Context {
+
+	isContextActive() {
+		// @ts-expect-error
+		return typeof GM_getValue === "function";
+	}
+
+	getSaveData() {
+		log("Loading save data from UserScript storage");
+		/** @type {BirbSaveData|{}} */
+		let saveData = {};
+		// @ts-expect-error
+		saveData = GM_getValue("birbSaveData", {}) ?? {};
+		return saveData;
+	}
+
+	/**
+	 * @override
+	 * @param {BirbSaveData} saveData
+	 */
+	putSaveData(saveData) {
+		log("Saving data to UserScript storage");
+		// @ts-expect-error
+		GM_setValue("birbSaveData", saveData);
+	}
+
+	resetSaveData() {
+		log("Resetting save data in UserScript storage");
+		// @ts-expect-error
+		GM_deleteValue("birbSaveData");
+	}
+}
+
+const CONTEXTS = [
+	new LocalContext(),
+	new UserScriptContext(),
+];
+
+export function getContext() {
+	for (const context of CONTEXTS) {
+		if (context.isContextActive()) {
+			return context;
+		}
+	}
+	error("No applicable context found, defaulting to LocalContext");
+	return CONTEXTS[0];
+}