From 89edc7ed0428b31cf3364c16d7155e45cad1b544 Mon Sep 17 00:00:00 2001
From: unknown <pavlobutynez@gmail.com>
Date: Tue, 17 Dec 2024 03:16:08 +0200
Subject: [PATCH 1/3] added migration

---
 ...emove-documents-with-non-existent-users.js | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 migrations/20241216212401-remove-documents-with-non-existent-users.js

diff --git a/migrations/20241216212401-remove-documents-with-non-existent-users.js b/migrations/20241216212401-remove-documents-with-non-existent-users.js
new file mode 100644
index 00000000..678954df
--- /dev/null
+++ b/migrations/20241216212401-remove-documents-with-non-existent-users.js
@@ -0,0 +1,21 @@
+module.exports = {
+  async up(db) {
+    const allUsers = await db
+      .collection('users')
+      .find({}, { projection: { _id: 1 } })
+      .toArray()
+    const allUserIds = allUsers.map((user) => user._id.toString())
+    const collections = ['attachments', 'courses', 'lessons', 'notes', 'questions', 'quizzes', 'resourcescategories']
+    for (const collectionName of collections) {
+      const authorsFromCollection = await db.collection(collectionName).distinct('author')
+      const nonExistingUsers = await authorsFromCollection.filter((userId) => !allUserIds.includes(userId.toString()))
+
+      if (nonExistingUsers.length > 0) {
+        await db.collection(collectionName).deleteMany({ author: { $in: nonExistingUsers } })
+      }
+      console.log(`Removed ${nonExistingUsers.length} non-existing users from collection ${collectionName}`)
+    }
+  },
+
+  async down() {}
+}

From 980ef2aa515bd541270d4189e3c1094ba607a05a Mon Sep 17 00:00:00 2001
From: unknown <pavlobutynez@gmail.com>
Date: Tue, 17 Dec 2024 17:57:13 +0200
Subject: [PATCH 2/3] implemented tests for migration

---
 ...-documents-with-non-existent-users.spec.js | 62 +++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 src/test/migrations/20241216212401-remove-documents-with-non-existent-users.spec.js

diff --git a/src/test/migrations/20241216212401-remove-documents-with-non-existent-users.spec.js b/src/test/migrations/20241216212401-remove-documents-with-non-existent-users.spec.js
new file mode 100644
index 00000000..b7c0e186
--- /dev/null
+++ b/src/test/migrations/20241216212401-remove-documents-with-non-existent-users.spec.js
@@ -0,0 +1,62 @@
+const { MongoClient, ObjectId } = require('mongodb')
+
+const { up } = require('@root/migrations/20241216212401-remove-documents-with-non-existent-users')
+
+require('~/initialization/envSetup')
+const {
+  config: { MONGODB_URL }
+} = require('~/configs/config')
+
+const collections = ['attachments', 'courses', 'lessons', 'notes', 'questions', 'quizzes', 'resourcescategories']
+const existingUser = { _id: new ObjectId(), firstName: 'Test', lastName: 'User' }
+const fakeUser = new ObjectId()
+
+const url = MONGODB_URL.slice(0, MONGODB_URL.lastIndexOf('/'))
+const databaseName = MONGODB_URL.slice(MONGODB_URL.lastIndexOf('/') + 1)
+
+describe('20241216212401-remove-documents-with-non-existent-users', () => {
+  let client, database
+
+  beforeAll(() => {
+    client = new MongoClient(url)
+    database = client.db(databaseName)
+  })
+
+  afterAll(() => {
+    client.close()
+  })
+
+  it('should remove documents with non-existing users from all collections', async () => {
+    for (const collectionName of collections) {
+      await database.collection(collectionName).insertOne({ author: fakeUser.toString() })
+    }
+
+    await up(database)
+
+    for (const collectionName of collections) {
+      const docsWithNonExistingUsers = await database
+        .collection(collectionName)
+        .find({ author: fakeUser.toString() })
+        .toArray()
+      expect(docsWithNonExistingUsers).toHaveLength(0)
+    }
+  })
+
+  it('should not remove documents with existing users from all collections', async () => {
+    await database.collection('users').insertOne(existingUser)
+
+    for (const collectionName of collections) {
+      await database.collection(collectionName).insertOne({ author: existingUser._id.toString() })
+    }
+
+    await up(database)
+
+    for (const collectionName of collections) {
+      const docsWithNonExistingUsers = await database
+        .collection(collectionName)
+        .find({ author: existingUser._id.toString() })
+        .toArray()
+      expect(docsWithNonExistingUsers).toHaveLength(1)
+    }
+  })
+})

From a9f09136c633468f0ba52e0d544b487299fce8a2 Mon Sep 17 00:00:00 2001
From: unknown <pavlobutynez@gmail.com>
Date: Wed, 18 Dec 2024 14:28:37 +0200
Subject: [PATCH 3/3] removed console.log

---
 .../20241216212401-remove-documents-with-non-existent-users.js   | 1 -
 1 file changed, 1 deletion(-)

diff --git a/migrations/20241216212401-remove-documents-with-non-existent-users.js b/migrations/20241216212401-remove-documents-with-non-existent-users.js
index 678954df..701b1bcf 100644
--- a/migrations/20241216212401-remove-documents-with-non-existent-users.js
+++ b/migrations/20241216212401-remove-documents-with-non-existent-users.js
@@ -13,7 +13,6 @@ module.exports = {
       if (nonExistingUsers.length > 0) {
         await db.collection(collectionName).deleteMany({ author: { $in: nonExistingUsers } })
       }
-      console.log(`Removed ${nonExistingUsers.length} non-existing users from collection ${collectionName}`)
     }
   },