Add support for config from /.well-known/matrix/client (#126)

* Add support for config from /.well-known/matrix/client

* final fixes, refactoring, updated readme

src/components/config.ts

@@ -0,0 +1,63 @@
+import storage from "../storage";
+
+export interface Config {
+  restrictBaseUrl: string | string[];
+  asManagedUsers: string[];
+  supportURL: string;
+  menu: MenuItem[];
+}
+
+export interface MenuItem {
+  label: string;
+  icon: string;
+  url: string;
+}
+
+export const WellKnownKey = "cc.etke.synapse-admin";
+
+export const LoadConfig = (context: Config): Config => {
+  if (context.restrictBaseUrl) {
+    storage.setItem("restrict_base_url", JSON.stringify(context.restrictBaseUrl));
+  }
+
+  if (context.asManagedUsers) {
+    storage.setItem("as_managed_users", JSON.stringify(context.asManagedUsers));
+  }
+
+  let menu: MenuItem[] = [];
+  if (context.menu) {
+    menu = context.menu;
+  }
+  if (context.supportURL) {
+    const migratedSupportURL = {
+      label: "Contact support",
+      icon: "SupportAgent",
+      url: context.supportURL,
+    };
+    console.warn("supportURL config option is deprecated. Please, use the menu option instead. Automatically migrated to the new menu option:", migratedSupportURL);
+    menu.push(migratedSupportURL as MenuItem);
+  }
+  if (menu.length > 0) {
+    storage.setItem("menu", JSON.stringify(menu));
+  }
+
+  // below we try to calculate "final" config, which will contain values from context and already set values in storage
+  // because LoadConfig could be called multiple times to get config from different sources
+  let finalAsManagedUsers: string[] = [];
+  try {
+    finalAsManagedUsers = JSON.parse(storage.getItem("as_managed_users") || "");
+  } catch (e) {}
+
+  let finalMenu: MenuItem[] = [];
+  try {
+    finalMenu = JSON.parse(storage.getItem("menu") || "");
+  } catch (e) {}
+
+  return {
+    restrictBaseUrl: storage.getItem("restrict_base_url") || "",
+    asManagedUsers: finalAsManagedUsers,
+    supportURL: storage.getItem("support_url") || "",
+    menu: finalMenu,
+  } as Config;
+
+}