(core) Billing for formula assistant

Summary:
Adding limits for AI calls and connecting those limits with a Stripe Account.

- New table in homedb called `limits`
- All calls to the AI are not routed through DocApi and measured.
- All products now contain a special key `assistantLimit`, with a default value 0
- Limit is reset every time the subscription has changed its period
- The billing page is updated with two new options that describe the AI plan
- There is a new popup that allows the user to upgrade to a higher plan
- Tiers are read directly from the Stripe product with a volume pricing model

Test Plan: Updated and added

Reviewers: georgegevoian, paulfitz

Reviewed By: georgegevoian

Subscribers: dsagal

Differential Revision: https://phab.getgrist.com/D3907

app/gen-server/entity/BillingAccount.ts

@@ -3,12 +3,13 @@ import {BillingAccountManager} from 'app/gen-server/entity/BillingAccountManager
 import {Organization} from 'app/gen-server/entity/Organization';
 import {Product} from 'app/gen-server/entity/Product';
 import {nativeValues} from 'app/gen-server/lib/values';
+import {Limit} from 'app/gen-server/entity/Limit';
 
 // This type is for billing account status information.  Intended for stuff
 // like "free trial running out in N days".
-interface BillingAccountStatus {
+export interface BillingAccountStatus {
   stripeStatus?: string;
-  currentPeriodEnd?: Date;
+  currentPeriodEnd?: string;
   message?: string;
 }
 
@@ -68,6 +69,9 @@ export class BillingAccount extends BaseEntity {
   @OneToMany(type => Organization, org => org.billingAccount)
   public orgs: Organization[];
 
+  @OneToMany(type => Limit, limit => limit.billingAccount)
+  public limits: Limit[];
+
   // A calculated column that is true if it looks like there is a paid plan.
   @Column({name: 'paid', type: 'boolean', insert: false, select: false})
   public paid?: boolean;

app/gen-server/entity/Limit.ts

@@ -0,0 +1,46 @@
+import {BaseEntity, Column, Entity, JoinColumn, ManyToOne, PrimaryGeneratedColumn} from 'typeorm';
+import {BillingAccount} from 'app/gen-server/entity/BillingAccount';
+import {nativeValues} from 'app/gen-server/lib/values';
+
+@Entity('limits')
+export class Limit extends BaseEntity {
+  @PrimaryGeneratedColumn()
+  public id: number;
+
+  @Column()
+  public limit: number;
+
+  @Column()
+  public usage: number;
+
+  @Column()
+  public type: string;
+
+  @Column({name: 'billing_account_id'})
+  public billingAccountId: number;
+
+  @ManyToOne(type => BillingAccount)
+  @JoinColumn({name: 'billing_account_id'})
+  public billingAccount: BillingAccount;
+
+  @Column({name: 'created_at', default: () => "CURRENT_TIMESTAMP"})
+  public createdAt: Date;
+
+  /**
+   * Last time the Limit.limit value was changed, by an upgrade or downgrade. Null if it has never been changed.
+   */
+  @Column({name: 'changed_at', type: nativeValues.dateTimeType, nullable: true})
+  public changedAt: Date|null;
+
+  /**
+   * Last time the Limit.usage was used (by sending a request to the model). Null if it has never been used.
+   */
+  @Column({name: 'used_at', type: nativeValues.dateTimeType, nullable: true})
+  public usedAt: Date|null;
+
+  /**
+   * Last time the Limit.usage was reset, probably by billing cycle change. Null if it has never been reset.
+   */
+  @Column({name: 'reset_at', type: nativeValues.dateTimeType, nullable: true})
+  public resetAt: Date|null;
+}

app/gen-server/entity/Product.ts

@@ -13,7 +13,11 @@ export const personalLegacyFeatures: Features = {
   // no vanity domain
   maxDocsPerOrg: 10,
   maxSharesPerDoc: 2,
-  maxWorkspacesPerOrg: 1
+  maxWorkspacesPerOrg: 1,
+  /**
+   * One time limit of 100 requests.
+   */
+  baseMaxAssistantCalls: 100,
 };
 
 /**
@@ -23,7 +27,12 @@ export const teamFeatures: Features = {
   workspaces: true,
   vanityDomain: true,
   maxSharesPerWorkspace: 0,   // all workspace shares need to be org members.
-  maxSharesPerDoc: 2
+  maxSharesPerDoc: 2,
+  /**
+   * Limit of 100 requests, but unlike for personal/free orgs the usage for this limit is reset at every billing cycle
+   * through Stripe webhook. For canceled subscription the usage is not reset, as the billing cycle is not changed.
+   */
+  baseMaxAssistantCalls: 100,
 };
 
 /**
@@ -40,6 +49,10 @@ export const teamFreeFeatures: Features = {
   baseMaxDataSizePerDocument: 5000 * 2 * 1024,  // 2KB per row
   baseMaxAttachmentsBytesPerDocument: 1 * 1024 * 1024 * 1024,  // 1GB
   gracePeriodDays: 14,
+  /**
+   * One time limit of 100 requests.
+   */
+  baseMaxAssistantCalls: 100,
 };
 
 /**
@@ -55,6 +68,7 @@ export const teamFreeFeatures: Features = {
   baseMaxDataSizePerDocument: 5000 * 2 * 1024,  // 2KB per row
   baseMaxAttachmentsBytesPerDocument: 1 * 1024 * 1024 * 1024,  // 1GB
   gracePeriodDays: 14,
+  baseMaxAssistantCalls: 100,
 };
 
 export const testDailyApiLimitFeatures = {
@@ -79,6 +93,7 @@ export const suspendedFeatures: Features = {
   maxDocsPerOrg: 0,
   maxSharesPerDoc: 0,
   maxWorkspacesPerOrg: 0,
+  baseMaxAssistantCalls: 0,
 };
 
 /**