remove post from user progress when it is deleted

database/firestore.indexes.json

@@ -396,6 +396,50 @@
         }
       ]
     },
+    {
+      "collectionGroup": "progress",
+      "fieldPath": "examples",
+      "indexes": [
+        {
+          "order": "ASCENDING",
+          "queryScope": "COLLECTION"
+        },
+        {
+          "order": "DESCENDING",
+          "queryScope": "COLLECTION"
+        },
+        {
+          "arrayConfig": "CONTAINS",
+          "queryScope": "COLLECTION"
+        },
+        {
+          "arrayConfig": "CONTAINS",
+          "queryScope": "COLLECTION_GROUP"
+        }
+      ]
+    },
+    {
+      "collectionGroup": "progress",
+      "fieldPath": "lessons",
+      "indexes": [
+        {
+          "order": "ASCENDING",
+          "queryScope": "COLLECTION"
+        },
+        {
+          "order": "DESCENDING",
+          "queryScope": "COLLECTION"
+        },
+        {
+          "arrayConfig": "CONTAINS",
+          "queryScope": "COLLECTION"
+        },
+        {
+          "arrayConfig": "CONTAINS",
+          "queryScope": "COLLECTION_GROUP"
+        }
+      ]
+    },
     {
       "collectionGroup": "timeline",
       "fieldPath": "id",

functions/src/posts/onDelete/__tests__/removeFromProgress.spec.ts

@@ -0,0 +1,68 @@
+import functions from 'firebase-functions-test';
+import * as admin from 'firebase-admin';
+
+const testEnv = functions();
+const db = admin.firestore();
+
+import { onDeletePostRemoveFromProgress } from '../removeFromProgress';
+
+const post1 = { ref: { update: jest.fn().mockReturnValue('post1Ref') } };
+const post2 = { ref: { update: jest.fn().mockReturnValue('post2Ref') } };
+
+beforeAll(() => {
+  spyOn(Promise, 'all').and.returnValue('removed');
+});
+
+test('return when there is no chapterId', async (done) => {
+  const data = { chapterId: null };
+  const snap = { data: () => data };
+  const wrapped = testEnv.wrap(onDeletePostRemoveFromProgress);
+  const req = await wrapped(snap);
+
+  expect(req).toBe(false);
+  expect(db.collectionGroup).not.toHaveBeenCalled();
+  expect(Promise.all).not.toHaveBeenCalled();
+  done();
+});
+
+test('remove examples', async (done) => {
+  spyOn(db.collectionGroup('').where('', '==', ''), 'get').and.returnValue({
+    docs: [post1, post2],
+  });
+
+  const data = { category: 'examples', chapterId: 'chapterId' };
+  const snap = { data: () => data, id: 'exampleId' };
+  const wrapped = testEnv.wrap(onDeletePostRemoveFromProgress);
+  const req = await wrapped(snap);
+
+  expect(req).toBe('removed');
+  expect(db.collectionGroup).toHaveBeenCalledWith('progress');
+  expect(db.collectionGroup('').where).toHaveBeenCalledWith(
+    'examples',
+    'array-contains',
+    'exampleId',
+  );
+  expect(Promise.all).toHaveBeenCalledWith(['post1Ref', 'post2Ref']);
+  done();
+});
+
+test('remove lessons', async (done) => {
+  spyOn(db.collectionGroup('').where('', '==', ''), 'get').and.returnValue({
+    docs: [post1, post2],
+  });
+
+  const data = { category: 'lessons', chapterId: 'chapterId' };
+  const snap = { data: () => data, id: 'lessonId' };
+  const wrapped = testEnv.wrap(onDeletePostRemoveFromProgress);
+  const req = await wrapped(snap);
+
+  expect(req).toBe('removed');
+  expect(db.collectionGroup).toHaveBeenCalledWith('progress');
+  expect(db.collectionGroup('').where).toHaveBeenCalledWith(
+    'lessons',
+    'array-contains',
+    'lessonId',
+  );
+  expect(Promise.all).toHaveBeenCalledWith(['post1Ref', 'post2Ref']);
+  done();
+});

functions/src/posts/onDelete/index.ts

@@ -1,2 +1,3 @@
 export * from './addToActivity';
+export * from './removeFromProgress';
 export * from './removeFromTimeline';

functions/src/posts/onDelete/removeFromProgress.ts

@@ -0,0 +1,33 @@
+import * as functions from 'firebase-functions';
+import * as admin from 'firebase-admin';
+import { Post } from '@zoonk/models';
+
+const db = admin.firestore();
+
+/**
+ * When an example or lesson is deleted, we should remove it
+ * from the chapter progress.
+ */
+export const onDeletePostRemoveFromProgress = functions.firestore
+  .document('posts/{id}')
+  .onDelete(async (snap) => {
+    const { category, chapterId } = snap.data() as Post.Response;
+
+    // We only track progress for chapter posts.
+    if (!chapterId) return false;
+
+    // Get all users who read this post.
+    const users = await db
+      .collectionGroup('progress')
+      .where(category, 'array-contains', snap.id)
+      .get();
+
+    // Remove this post from every user.
+    const requests = users.docs.map((user) => {
+      return user.ref.update({
+        [category]: admin.firestore.FieldValue.arrayRemove(snap.id),
+      });
+    });
+
+    return Promise.all(requests);
+  });