Added @tryghost/members-payments module

refs https://github.com/TryGhost/Team/issues/1166

This is a new module which will eventually handle all payment related
things. This allows the Offers module to focus exclusively on the Ghost
concepts, and the Payments module will handle the association between
Offer & Stripe Coupon, Tier & Stripe Product, Cadence & Stripe Price.

This decoupling allows us to not have to consider the lack of Stripe
data for an Offer, which is the case after a Stripe Disconnect. Instead
all of the population/repopulation/lazy-creating can be handled here.

ghost/payments/.eslintrc.js

@@ -0,0 +1,6 @@
+module.exports = {
+    plugins: ['ghost'],
+    extends: [
+        'plugin:ghost/node'
+    ]
+};

ghost/payments/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2013-2021 Ghost Foundation
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

ghost/payments/README.md

@@ -0,0 +1,34 @@
+# Payments
+
+## Install
+
+`npm install @tryghost/payments --save`
+
+or
+
+`yarn add @tryghost/payments`
+
+
+## Usage
+
+
+## Develop
+
+This is a mono repository, managed with [lerna](https://lernajs.io/).
+
+Follow the instructions for the top-level repo.
+1. `git clone` this repo & `cd` into it as usual
+2. Run `yarn` to install top-level dependencies.
+
+
+## Run
+
+- `yarn dev`
+
+
+## Test
+
+- `yarn lint` run just eslint
+- `yarn test` run lint and tests
+
+

ghost/payments/index.js

@@ -0,0 +1 @@
+module.exports = require('./lib/payments');

ghost/payments/lib/payments.js

@@ -0,0 +1,68 @@
+class PaymentsService {
+    /**
+     * @param {object} deps
+     * @param {any} deps.Offer
+     * @param {import('@tryghost/members-offers/lib/application/OffersAPI')} deps.offersAPI
+     * @param {any} deps.stripeAPIService
+     */
+    constructor(deps) {
+        /** @private */
+        this.OfferModel = deps.Offer;
+        /** @private */
+        this.offersAPI = deps.offersAPI;
+        /** @private */
+        this.stripeAPIService = deps.stripeAPIService;
+    }
+
+    /**
+     * @param {string} offerId
+     *
+     * @returns {Promise<{id: string}>}
+     */
+    async getCouponForOffer(offerId) {
+        const row = await this.OfferModel.where({id: offerId}).query().select('stripe_coupon_id').first();
+        if (!row) {
+            return null;
+        }
+        if (!row.stripe_coupon_id) {
+            const offer = await this.offersAPI.getOffer({id: offerId});
+            await this.createCouponForOffer(offer);
+            return this.getCouponForOffer(offerId);
+        }
+        return {
+            id: row.stripe_coupon_id
+        };
+    }
+
+    /**
+     * @param {import('@tryghost/members-offers/lib/application/OfferMapper').OfferDTO} offer
+     */
+    async createCouponForOffer(offer) {
+        /** @type {import('stripe').Stripe.CouponCreateParams} */
+        const couponData = {
+            name: offer.name,
+            duration: offer.duration
+        };
+
+        if (offer.duration === 'repeating') {
+            couponData.duration_in_months = offer.duration_in_months;
+        }
+
+        if (offer.type === 'percent') {
+            couponData.percent_off = offer.amount;
+        } else {
+            couponData.amount_off = offer.amount;
+            couponData.currency = offer.currency;
+        }
+
+        const coupon = await this.stripeAPIService.createCoupon(couponData);
+
+        await this.OfferModel.edit({
+            stripe_coupon_id: coupon.id
+        }, {
+            id: offer.id
+        });
+    }
+}
+
+module.exports = PaymentsService;

ghost/payments/package.json

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+{
+  "name": "@tryghost/members-payments",
+  "version": "0.0.0",
+  "repository": "https://github.com/TryGhost/Members/tree/main/packages/payments",
+  "author": "Ghost Foundation",
+  "license": "MIT",
+  "main": "index.js",
+  "scripts": {
+    "dev": "echo \"Implement me!\"",
+    "test": "NODE_ENV=testing c8 --check-coverage mocha './test/**/*.test.js'",
+    "lint": "eslint . --ext .js --cache",
+    "posttest": "yarn lint"
+  },
+  "files": [
+    "index.js",
+    "lib"
+  ],
+  "publishConfig": {
+    "access": "public"
+  },
+  "devDependencies": {
+    "c8": "7.10.0",
+    "mocha": "9.1.3",
+    "should": "13.2.3",
+    "sinon": "11.1.2"
+  },
+  "dependencies": {}
+}

ghost/payments/test/.eslintrc.js

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+module.exports = {
+    plugins: ['ghost'],
+    extends: [
+        'plugin:ghost/test'
+    ]
+};

ghost/payments/test/hello.test.js

@@ -0,0 +1,10 @@
+// Switch these lines once there are useful utils
+// const testUtils = require('./utils');
+require('./utils');
+
+describe('Hello world', function () {
+    it('Runs a test', function () {
+        // TODO: Write me!
+        'hello'.should.eql('hello');
+    });
+});

ghost/payments/test/utils/assertions.js

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+/**
+ * Custom Should Assertions
+ *
+ * Add any custom assertions to this file.
+ */
+
+// Example Assertion
+// should.Assertion.add('ExampleAssertion', function () {
+//     this.params = {operator: 'to be a valid Example Assertion'};
+//     this.obj.should.be.an.Object;
+// });

ghost/payments/test/utils/index.js

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+/**
+ * Test Utilities
+ *
+ * Shared utils for writing tests
+ */
+
+// Require overrides - these add globals for tests
+require('./overrides');
+
+// Require assertions - adds custom should assertions
+require('./assertions');

ghost/payments/test/utils/overrides.js

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+// This file is required before any test is run
+
+// Taken from the should wiki, this is how to make should global
+// Should is a global in our eslint test config
+global.should = require('should').noConflict();
+should.extend();
+
+// Sinon is a simple case
+// Sinon is a global in our eslint test config
+global.sinon = require('sinon');