fix(Statement Deletion): Fixes store recounts when clients have no LR…

…S attached (#1515 - [LL-322](https://learningpool.atlassian.net/browse/LL-322))

#1515
https://learningpool.atlassian.net/browse/LL-322

api/src/routes/HttpRoutes.js

@@ -58,8 +58,6 @@ import personaRESTHandler from 'api/routes/personas/personaRESTHandler';
 import personaIdentifierRESTHandler from 'api/routes/personas/personaIdentifierRESTHandler';
 import UserOrganisationsRouter from 'api/routes/userOrganisations/router';
 import UserOrganisationSettingsRouter from 'api/routes/userOrganisationSettings/router';
-import getLrsFromAuthInfo from 'lib/services/auth/authInfoSelectors/getLrsFromAuthInfo';
-import { decrementStatementCount } from 'lib/services/lrs';
 
 // CONSTANTS
 import * as routes from 'lib/constants/routes';
@@ -359,18 +357,8 @@ restify.serve(router, Statement, {
       return res.send('No ID sent', 400);
     }
     next();
-    return;
   },
   preUpdate: (req, res) => res.sendStatus(405),
-  postDelete: (req, _, next) => {
-    // Update LRS.statementCount
-    const authInfo = getAuthFromRequest(req);
-    const lrsId = getLrsFromAuthInfo(authInfo);
-
-    decrementStatementCount(lrsId)
-      .then(() => next())
-      .catch(err => next(err));
-  },
 });
 restify.serve(router, StatementForwarding);
 restify.serve(router, QueryBuilderCache);

lib/models/lrs.js

@@ -9,6 +9,40 @@ import * as scopes from 'lib/constants/scopes';
 import addCRUDFunctions from 'lib/models/plugins/addCRUDFunctions';
 import auditRemove from 'lib/models/plugins/auditRemove';
 
+/**
+ * Plain object structure without mongoose model methods
+ *
+ * @typedef {object} Lrs
+ *  @property {string} title
+ *  @property {string} description
+ *  @property {*} owner_id TODO: define type
+ *  @property {*} organisation TODO: define type
+ *  @property {number} statementCount
+ */
+
+/** @typedef {module:mongoose.Model<Lrs>} lrsModel */
+
+/**
+ * @param {lrsModel} lrsModel
+ * @returns {Promise<void>}
+ */
+const createDefaultClient = async (lrsModel) => {
+  if (!lrsModel.title) {
+    lrsModel.title = 'New xAPI store';
+  }
+  const ClientModel = getConnection().model('Client');
+  const client = new ClientModel({
+    organisation: lrsModel.organisation,
+    lrs_id: lrsModel._id,
+    scopes: [scopes.XAPI_ALL],
+    title: `${lrsModel.title} client`
+  });
+  await client.save((err) => {
+    assert.ifError(err);
+  });
+};
+
+/** @class LrsSchema */
 const schema = new mongoose.Schema({
   title: { type: String },
   description: { type: String },
@@ -20,22 +54,9 @@ schema.plugin(filterByOrg);
 schema.plugin(timestamps);
 schema.plugin(addCRUDFunctions);
 
-schema.pre('save', function preSave(next) {
-  // make a default client
+schema.pre('save', async function preSave(next) {
   if (this.isNew) {
-    if (!this.title) {
-      this.title = 'New xAPI store';
-    }
-    const Client = getConnection().model('Client');
-    const client = new Client({
-      organisation: this.organisation,
-      lrs_id: this._id,
-      scopes: [scopes.XAPI_ALL],
-      title: `${this.title} client`
-    });
-    client.save((err) => {
-      assert.ifError(err);
-    });
+    await createDefaultClient(this);
   }
   next();
 });
@@ -49,6 +70,10 @@ schema.plugin(auditRemove, {
   auditName: 'LRSAudit'
 });
 
+/**
+ * @param {lrsModel} lrs
+ * @returns {Promise<void>}
+ */
 schema.statics.updateStatementCount = async (lrs) => {
   const Statement = getConnection().model('Statement');
 
@@ -58,10 +83,14 @@ schema.statics.updateStatementCount = async (lrs) => {
   });
 };
 
-schema.statics.decrementStatementCount = async (lrs) => {
+/**
+ * @param {string} lrsId
+ * @returns {Promise<void>}
+ */
+schema.statics.decrementStatementCount = async (lrsId) => {
   getConnection()
     .model('Lrs')
-    .update({ _id: lrs._id }, { $inc: { statementCount: -1 } })
+    .update({ _id: lrsId }, { $inc: { statementCount: -1 } })
     .exec();
 };
 

lib/models/statement.js

@@ -23,6 +23,7 @@ import getScopeFilter from 'lib/services/auth/filters/getScopeFilter';
 import filterByOrg from 'lib/models/plugins/filterByOrg';
 import decodeDot from 'lib/helpers/decodeDot';
 import logger from 'lib/logger';
+import Lrs from 'lib/models/lrs';
 
 const ALLOW_AGGREGATION_DISK_USE = boolean(defaultTo(process.env.ALLOW_AGGREGATION_DISK_USE, true));
 const AGGREGATION_CACHE_SECONDS = defaultTo(Number(process.env.AGGREGATION_CACHE_SECONDS), 300);
@@ -94,6 +95,11 @@ schema.plugin(scopeChecks);
 schema.plugin(filterByOrg);
 schema.plugin(addCRUDFunctions);
 
+schema.post('remove', async (statement, next) => {
+  await Lrs.decrementStatementCount(statement.lrs_id);
+  next();
+});
+
 /**
  * @param {*} - {
  *                pipeline

lib/services/lrs.js

@@ -6,10 +6,3 @@ export const updateStatementCountsInOrg = async (organisationId) => {
   const lrsList = await Lrs.find({ organisation: organisationId });
   await Promise.map(lrsList, Lrs.updateStatementCount);
 };
-
-export const decrementStatementCount = async (lrsId) => {
-  const lrs = await Lrs.findOne({ _id: lrsId });
-  if (lrs) {
-    await Lrs.decrementStatementCount(lrs);
-  }
-};