@polar-sh/adapter-utils/src/entitlement/entitlement.ts

Core package for Polar adapters

import type { Customer } from "@polar-sh/sdk/models/components/customer";
import type { WebhookBenefitGrantCreatedPayload } from "@polar-sh/sdk/models/components/webhookbenefitgrantcreatedpayload";
import type { WebhookBenefitGrantRevokedPayload } from "@polar-sh/sdk/models/components/webhookbenefitgrantrevokedpayload";

export type EntitlementProperties = Record<string, string>;

export type EntitlementHandler = (
  payload:
    | WebhookBenefitGrantCreatedPayload
    | WebhookBenefitGrantRevokedPayload,
) => Promise<void>;

export interface EntitlementContext<T extends EntitlementProperties> {
  customer: Customer;
  properties: T;
  payload:
    | WebhookBenefitGrantCreatedPayload
    | WebhookBenefitGrantRevokedPayload;
}

export class EntitlementStrategy<T extends EntitlementProperties> {
  private grantCallbacks: ((
    context: EntitlementContext<T>,
  ) => Promise<void>)[] = [];

  private revokeCallbacks: ((
    context: EntitlementContext<T>,
  ) => Promise<void>)[] = [];

  public grant(callback: (context: EntitlementContext<T>) => Promise<void>) {
    this.grantCallbacks.push(callback);
    return this;
  }

  public revoke(callback: (context: EntitlementContext<T>) => Promise<void>) {
    this.revokeCallbacks.push(callback);
    return this;
  }

  public handler(slug: string): EntitlementHandler {
    return async (
      payload:
        | WebhookBenefitGrantCreatedPayload
        | WebhookBenefitGrantRevokedPayload,
    ) => {
      if (payload.data.benefit.description === slug) {
        switch (payload.type) {
          case "benefit_grant.created":
            await Promise.all(
              this.grantCallbacks.map((callback) =>
                callback({
                  customer: payload.data.customer,
                  properties: payload.data.properties as T,
                  payload,
                }),
              ),
            );
            break;
          case "benefit_grant.revoked":
            await Promise.all(
              this.revokeCallbacks.map((callback) =>
                callback({
                  customer: payload.data.customer,
                  properties: payload.data.properties as T,
                  payload,
                }),
              ),
            );
            break;
        }
      }
    };
  }
}

export class Entitlements {
  static handlers = [] as EntitlementHandler[];

  static use<T extends EntitlementProperties = EntitlementProperties>(
    slug: string,
    strategy: EntitlementStrategy<T>,
  ) {
    this.handlers.push(strategy.handler(slug));

    return this;
  }
}