Add context management

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];
+}