feat: User flags (#3353)

* feat: Add user flags concept, for tracking bits on a user

* feat: Example flag usage for user invite resend abuse

server/models/User.ts

@@ -40,6 +40,14 @@ import Encrypted, {
 } from "./decorators/Encrypted";
 import Fix from "./decorators/Fix";
 
+/**
+ * Flags that are available for setting on the user.
+ */
+export enum UserFlag {
+  InviteSent = "inviteSent",
+  InviteReminderSent = "inviteReminderSent",
+}
+
 @Scopes(() => ({
   withAuthentications: {
     include: [
@@ -101,6 +109,9 @@ class User extends ParanoidModel {
   @Column
   suspendedAt: Date | null;
 
+  @Column(DataType.JSONB)
+  flags: { [key in UserFlag]?: number } | null;
+
   @Default(process.env.DEFAULT_LANGUAGE)
   @IsIn([languages])
   @Column
@@ -162,6 +173,52 @@ class User extends ParanoidModel {
 
   // instance methods
 
+  /**
+   * User flags are for storing information on a user record that is not visible
+   * to the user itself.
+   *
+   * @param flag The flag to set
+   * @param value Set the flag to true/false
+   * @returns The current user flags
+   */
+  public setFlag = (flag: UserFlag, value = true) => {
+    if (!this.flags) {
+      this.flags = {};
+    }
+    this.flags[flag] = value ? 1 : 0;
+    this.changed("flags", true);
+
+    return this.flags;
+  };
+
+  /**
+   * Returns the content of the given user flag.
+   *
+   * @param flag The flag to retrieve
+   * @returns The flag value
+   */
+  public getFlag = (flag: UserFlag) => {
+    return this.flags?.[flag] ?? 0;
+  };
+
+  /**
+   * User flags are for storing information on a user record that is not visible
+   * to the user itself.
+   *
+   * @param flag The flag to set
+   * @param value The amount to increment by, defaults to 1
+   * @returns The current user flags
+   */
+  public incrementFlag = (flag: UserFlag, value = 1) => {
+    if (!this.flags) {
+      this.flags = {};
+    }
+    this.flags[flag] = (this.flags[flag] ?? 0) + value;
+    this.changed("flags", true);
+
+    return this.flags;
+  };
+
   collectionIds = async (options = {}) => {
     const collectionStubs = await Collection.scope({
       method: ["withMembership", this.id],