(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/common/ActiveDocAPI.ts

@@ -1,5 +1,4 @@
 import {ActionGroup} from 'app/common/ActionGroup';
-import {AssistanceRequest, AssistanceResponse} from 'app/common/AssistancePrompts';
 import {BulkAddRecord, CellValue, TableDataAction, UserAction} from 'app/common/DocActions';
 import {FormulaProperties} from 'app/common/GranularAccessClause';
 import {UIRowId} from 'app/common/TableData';
@@ -320,11 +319,6 @@ export interface ActiveDocAPI {
    */
   getFormulaError(tableId: string, colId: string, rowId: number): Promise<CellValue>;
 
-  /**
-   * Generates a formula code based on the AI suggestions, it also modifies the column and sets it type to a formula.
-   */
-  getAssistance(request: AssistanceRequest): Promise<AssistanceResponse>;
-
   /**
    * Fetch content at a url.
    */

app/common/ApiError.ts

@@ -2,15 +2,17 @@
  * A tip for fixing an error.
  */
 export interface ApiTip {
-  action: 'add-members' | 'upgrade' |'ask-for-help';
+  action: 'add-members' | 'upgrade' | 'ask-for-help' | 'manage';
   message: string;
 }
 
+export type LimitType = 'collaborators' | 'docs' | 'workspaces' | 'assistant';
+
 /**
  * Documentation of a limit relevant to an API error.
  */
 export interface ApiLimit {
-  quantity: 'collaborators' | 'docs' | 'workspaces';  // what are we counting
+  quantity: LimitType;  // what are we counting
   subquantity?: string;    // a nuance to what we are counting
   maximum: number;         // maximum allowed
   value: number;           // current value of quantity for user

app/common/BillingAPI.ts

@@ -43,6 +43,16 @@ export interface IBillingPlan {
   active: boolean;
 }
 
+export interface ILimitTier {
+  name?: string;
+  volume: number;
+  price: number;
+  flatFee: number;
+  type: string;
+  planId: string;
+  interval: string; // probably 'month'|'year';
+}
+
 // Utility type that requires all properties to be non-nullish.
 // type NonNullableProperties<T> = { [P in keyof T]: Required<NonNullable<T[P]>>; };
 
@@ -69,6 +79,7 @@ export interface IBillingDiscount {
 export interface IBillingSubscription {
   // All standard plan options.
   plans: IBillingPlan[];
+  tiers: ILimitTier[];
   // Index in the plans array of the plan currently in effect.
   planIndex: number;
   // Index in the plans array of the plan to be in effect after the current period end.
@@ -111,6 +122,14 @@ export interface IBillingSubscription {
   lastInvoiceUrl?: string;    // URL of the Stripe-hosted page with the last invoice.
   lastChargeError?: string;   // The last charge error, if any, to show in case of a bad status.
   lastChargeTime?: number;    // The time of the last charge attempt.
+  limit?: ILimit|null;
+}
+
+export interface ILimit {
+  limitValue: number;
+  currentUsage: number;
+  type: string; // Limit type, for now only assistant is supported.
+  price: number; // If this is 0, it means it is a free plan.
 }
 
 export interface IBillingOrgSettings {
@@ -139,6 +158,7 @@ export interface BillingAPI {
   downgradePlan(planName: string): Promise<void>;
   renewPlan(): string;
   customerPortal(): string;
+  updateAssistantPlan(tier: number): Promise<void>;
 }
 
 export class BillingAPIImpl extends BaseAPI implements BillingAPI {
@@ -230,6 +250,13 @@ export class BillingAPIImpl extends BaseAPI implements BillingAPI {
     return `${this._url}/api/billing/renew`;
   }
 
+  public async updateAssistantPlan(tier: number): Promise<void> {
+    await this.request(`${this._url}/api/billing/upgrade-assistant`, {
+      method: 'POST',
+      body: JSON.stringify({ tier })
+    });
+  }
+
   /**
    * Checks if current org has active subscription for a Stripe plan.
    */

app/common/Features.ts

@@ -58,6 +58,11 @@ export interface Features {
                                                 // for attached files in a document
 
   gracePeriodDays?: number;  // Duration of the grace period in days, before entering delete-only mode
+
+  baseMaxAssistantCalls?: number; // Maximum number of AI assistant calls. Defaults to 0 if not set, use -1 to indicate
+                                  // unbound limit. This is total limit, not per month or per day, it is used as a seed
+                                  // value for the limits table. To create a per-month limit, there must be a separate
+                                  // task that resets the usage in the limits table.
 }
 
 // Check whether it is possible to add members at the org level.  There's no flag

app/common/UserAPI.ts

@@ -1,5 +1,6 @@
 import {ActionSummary} from 'app/common/ActionSummary';
 import {ApplyUAResult, ForkResult, PermissionDataWithExtraUsers, QueryFilters} from 'app/common/ActiveDocAPI';
+import {AssistanceRequest, AssistanceResponse} from 'app/common/AssistancePrompts';
 import {BaseAPI, IOptions} from 'app/common/BaseAPI';
 import {BillingAPI, BillingAPIImpl} from 'app/common/BillingAPI';
 import {BrowserSettings} from 'app/common/BrowserSettings';
@@ -462,6 +463,8 @@ export interface DocAPI {
   // Update webhook
   updateWebhook(webhook: WebhookUpdate): Promise<void>;
   flushWebhooks(): Promise<void>;
+
+  getAssistance(params: AssistanceRequest): Promise<AssistanceResponse>;
 }
 
 // Operations that are supported by a doc worker.
@@ -1012,6 +1015,13 @@ export class DocAPIImpl extends BaseAPI implements DocAPI {
     return response.data[0];
   }
 
+  public async getAssistance(params: AssistanceRequest): Promise<AssistanceResponse> {
+    return await this.requestJson(`${this._url}/assistant`, {
+      method: 'POST',
+      body: JSON.stringify(params),
+    });
+  }
+
   private _getRecords(tableId: string, endpoint: 'data' | 'records', options?: GetRowsParams): Promise<any> {
     const url = new URL(`${this._url}/tables/${tableId}/${endpoint}`);
     if (options?.filters) {