feat(auth): refactor auth, add oidc

Thanks to all HedgeDoc team members for the time discussing,
helping with weird Nest issues, providing feedback
and suggestions!

Co-authored-by: Philip Molares <philip.molares@udo.edu>
Signed-off-by: Philip Molares <philip.molares@udo.edu>
Signed-off-by: Erik Michelson <github@erik.michelson.eu>

backend/src/users/users.service.ts

@@ -1,12 +1,14 @@
 /*
- * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ * SPDX-FileCopyrightText: 2024 The HedgeDoc developers (see AUTHORS file)
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
-import { Injectable } from '@nestjs/common';
+import { REGEX_USERNAME } from '@hedgedoc/commons';
+import { BadRequestException, Inject, Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
 
+import AuthConfiguration, { AuthConfig } from '../config/auth.config';
 import { AlreadyInDBError, NotInDBError } from '../errors/errors';
 import { ConsoleLoggerService } from '../logger/console-logger.service';
 import { Username } from '../utils/username';
@@ -22,6 +24,8 @@ import { User } from './user.entity';
 export class UsersService {
   constructor(
     private readonly logger: ConsoleLoggerService,
+    @Inject(AuthConfiguration.KEY)
+    private authConfig: AuthConfig,
     @InjectRepository(User) private userRepository: Repository<User>,
   ) {
     this.logger.setContext(UsersService.name);
@@ -32,11 +36,24 @@ export class UsersService {
    * Create a new user with a given username and displayName
    * @param {Username} username - the username the new user shall have
    * @param {string} displayName - the display name the new user shall have
+   * @param {string} [email] - the email the new user shall have
+   * @param {string} [photoUrl] - the photoUrl the new user shall have
    * @return {User} the user
+   * @throws {BadRequestException} if the username contains invalid characters or is too short
    * @throws {AlreadyInDBError} the username is already taken.
    */
-  async createUser(username: Username, displayName: string): Promise<User> {
-    const user = User.create(username, displayName);
+  async createUser(
+    username: Username,
+    displayName: string,
+    email?: string,
+    photoUrl?: string,
+  ): Promise<User> {
+    if (!REGEX_USERNAME.test(username)) {
+      throw new BadRequestException(
+        `The username '${username}' is not a valid username.`,
+      );
+    }
+    const user = User.create(username, displayName, email, photoUrl);
     try {
       return await this.userRepository.save(user);
     } catch {
@@ -66,13 +83,51 @@ export class UsersService {
 
   /**
    * @async
-   * Change the displayName of the specified user
-   * @param {User} user - the user to be changed
-   * @param displayName - the new displayName
+   * Update the given User with the given information.
+   * Use {@code null} to clear the stored value (email or profilePicture).
+   * Use {@code undefined} to keep the stored value.
+   * @param {User} user - the User to update
+   * @param {string | undefined} displayName - the displayName to update the user with
+   * @param {string | null | undefined} email - the email to update the user with
+   * @param {string | null | undefined} profilePicture - the profilePicture to update the user with
    */
-  async changeDisplayName(user: User, displayName: string): Promise<void> {
-    user.displayName = displayName;
-    await this.userRepository.save(user);
+  async updateUser(
+    user: User,
+    displayName?: string,
+    email?: string | null,
+    profilePicture?: string | null,
+  ): Promise<User> {
+    let shouldSave = false;
+    if (displayName !== undefined) {
+      user.displayName = displayName;
+      shouldSave = true;
+    }
+    if (email !== undefined) {
+      user.email = email;
+      shouldSave = true;
+    }
+    if (profilePicture !== undefined) {
+      user.photo = profilePicture;
+      shouldSave = true;
+      // ToDo: handle LDAP images (https://github.com/hedgedoc/hedgedoc/issues/5032)
+    }
+    if (shouldSave) {
+      return await this.userRepository.save(user);
+    }
+    return user;
+  }
+
+  /**
+   * @async
+   * Checks if the user with the specified username exists
+   * @param username - the username to check
+   * @return {boolean} true if the user exists, false otherwise
+   */
+  async checkIfUserExists(username: Username): Promise<boolean> {
+    const user = await this.userRepository.findOne({
+      where: { username: username },
+    });
+    return user !== null;
   }
 
   /**