From 4298c9e982bcc9047bcbf2983b217c29a4aae1a4 Mon Sep 17 00:00:00 2001
From: Paul-Louis Hery <paullouis.hery@gmail.com>
Date: Thu, 15 Jun 2023 18:58:00 +0200
Subject: [PATCH] feat(workers): Only add new followers to cache

---
 unfollow-ninja-server/src/dao/dao.ts           |  3 +++
 .../src/workers/checkAllFollowers.ts           | 18 +++++++++++-------
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/unfollow-ninja-server/src/dao/dao.ts b/unfollow-ninja-server/src/dao/dao.ts
index 3e1e238..c721b33 100644
--- a/unfollow-ninja-server/src/dao/dao.ts
+++ b/unfollow-ninja-server/src/dao/dao.ts
@@ -196,6 +196,9 @@ export default class Dao {
     }
 
     public async addTwittosToCache(twittosInfo: ITwittoInfo[]): Promise<void> {
+        if (twittosInfo.length === 0) {
+            return;
+        }
         await this.CachedUsername.bulkCreate(
             twittosInfo
                 .filter((twittoInfo) => !(twittoInfo.username.length > 20 && twittoInfo.username.startsWith('erased_')))
diff --git a/unfollow-ninja-server/src/workers/checkAllFollowers.ts b/unfollow-ninja-server/src/workers/checkAllFollowers.ts
index 6322e2e..4899951 100644
--- a/unfollow-ninja-server/src/workers/checkAllFollowers.ts
+++ b/unfollow-ninja-server/src/workers/checkAllFollowers.ts
@@ -122,6 +122,9 @@ async function checkFollowers(userId: string, dao: Dao, queue: Queue) {
     let cursor = null;
     let followers: string[] = [];
 
+    const formerFollowers: string[] = await userDao.getFollowers();
+    const formerFollowersSet = new Set(formerFollowers);
+
     // For big account (>150k), maybe we got the 150k first accounts previously, we'll continue the scrapping
     const scrappedFollowers = await userDao.getTemporaryFollowerList();
     if (scrappedFollowers) {
@@ -152,10 +155,12 @@ async function checkFollowers(userId: string, dao: Dao, queue: Queue) {
                 followers.push(...result.data.data.map((user) => user.id));
                 try {
                     await dao.addTwittosToCache(
-                        result.data.data.map((user) => ({
-                            id: user.id,
-                            username: user.username,
-                        }))
+                        result.data.data
+                            .filter((user) => !formerFollowersSet.has(user.id))
+                            .map((user) => ({
+                                id: user.id,
+                                username: user.username,
+                            }))
                     );
                 } catch (error) {
                     const username: string = (await dao.getCachedUsername(userId).catch(() => userId)) || userId;
@@ -183,7 +188,7 @@ async function checkFollowers(userId: string, dao: Dao, queue: Queue) {
             ); // minus 30s because we can trigger it a bit before the ideal time
         }
 
-        await detectUnfollows(userId, followers, dao, queue);
+        await detectUnfollows(userId, followers, formerFollowers, dao, queue);
     } catch (err) {
         if (!(err instanceof ApiResponseError)) {
             // network error
@@ -213,11 +218,10 @@ async function checkFollowers(userId: string, dao: Dao, queue: Queue) {
     }
 }
 
-async function detectUnfollows(userId: string, followers: string[], dao: Dao, queue: Queue) {
+async function detectUnfollows(userId: string, followers: string[], formerFollowers: string[], dao: Dao, queue: Queue) {
     const userDao = dao.getUserDao(userId);
 
     let newUser = false;
-    let formerFollowers: string[] = await userDao.getFollowers();
     if (formerFollowers === null) {
         newUser = true;
         formerFollowers = [];