OIDC: Persist details in session storage, create store (#11302)

* utils to persist clientId and issuer after oidc authentication

* add dep oidc-client-ts

* persist issuer and clientId after successful oidc auth

* add OidcClientStore

* comments and tidy

* format

test/utils/oidc/persistOidcSettings-test.ts

@@ -0,0 +1,63 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {
+    getStoredOidcClientId,
+    getStoredOidcTokenIssuer,
+    persistOidcAuthenticatedSettings,
+} from "../../../src/utils/oidc/persistOidcSettings";
+
+describe("persist OIDC settings", () => {
+    beforeEach(() => {
+        jest.spyOn(sessionStorage.__proto__, "getItem").mockClear().mockReturnValue(null);
+
+        jest.spyOn(sessionStorage.__proto__, "setItem").mockClear();
+    });
+
+    const clientId = "test-client-id";
+    const issuer = "https://auth.org/";
+
+    describe("persistOidcAuthenticatedSettings", () => {
+        it("should set clientId and issuer in session storage", () => {
+            persistOidcAuthenticatedSettings(clientId, issuer);
+            expect(sessionStorage.setItem).toHaveBeenCalledWith("mx_oidc_client_id", clientId);
+            expect(sessionStorage.setItem).toHaveBeenCalledWith("mx_oidc_token_issuer", issuer);
+        });
+    });
+
+    describe("getStoredOidcTokenIssuer()", () => {
+        it("should return issuer from session storage", () => {
+            jest.spyOn(sessionStorage.__proto__, "getItem").mockReturnValue(issuer);
+            expect(getStoredOidcTokenIssuer()).toEqual(issuer);
+            expect(sessionStorage.getItem).toHaveBeenCalledWith("mx_oidc_token_issuer");
+        });
+
+        it("should return undefined when no issuer in session storage", () => {
+            expect(getStoredOidcTokenIssuer()).toBeUndefined();
+        });
+    });
+
+    describe("Name of the group", () => {
+        it("should return clientId from session storage", () => {
+            jest.spyOn(sessionStorage.__proto__, "getItem").mockReturnValue(clientId);
+            expect(getStoredOidcClientId()).toEqual(clientId);
+            expect(sessionStorage.getItem).toHaveBeenCalledWith("mx_oidc_client_id");
+        });
+        it("should throw when no clientId in session storage", () => {
+            expect(() => getStoredOidcClientId()).toThrow("Oidc client id not found in storage");
+        });
+    });
+});