From 95af59f3642cce7846aaa86e47617a204e18eb89 Mon Sep 17 00:00:00 2001
From: JeffreyCA <jeffreyca16@gmail.com>
Date: Sat, 4 Dec 2021 22:37:20 -0800
Subject: [PATCH 1/2] Prevent duplicate posts from showing in feed

---
 App/Feed/FeedViewModel.swift | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/App/Feed/FeedViewModel.swift b/App/Feed/FeedViewModel.swift
index e5337303..0702a70f 100644
--- a/App/Feed/FeedViewModel.swift
+++ b/App/Feed/FeedViewModel.swift
@@ -11,6 +11,7 @@ import PromiseKit
 
 class FeedViewModel {
     var posts: [Post] = []
+    var postIds: Set<Int> = Set()
     var postType: PostType = .news
     var pageIndex = 1
     var isFetching = false
@@ -29,13 +30,17 @@ class FeedViewModel {
         return firstly {
             HackersKit.shared.getPosts(type: postType, page: pageIndex)
         }.done { posts in
-            self.posts.append(contentsOf: posts)
+            let newPosts = posts.filter { !self.postIds.contains($0.id) }
+            let newPostIds = newPosts.map { $0.id }
+            self.posts.append(contentsOf: newPosts)
+            self.postIds.formUnion(newPostIds)
             self.isFetching = false
         }
     }
 
     func reset() {
         posts = []
+        postIds = Set()
         pageIndex = 1
         isFetching = false
     }

From 5089154ae43d3b24b488fdcb0a3d9569a8a232fb Mon Sep 17 00:00:00 2001
From: JeffreyCA <jeffreyca16@gmail.com>
Date: Sat, 4 Dec 2021 22:38:28 -0800
Subject: [PATCH 2/2] Fix next page fetching for "New" and "Jobs" posts

---
 App/Feed/FeedViewModel.swift                        | 10 ++++++++--
 .../HackersKit/HackersKit+PostsList.swift           | 13 +++++++++----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/App/Feed/FeedViewModel.swift b/App/Feed/FeedViewModel.swift
index 0702a70f..ee75bfc3 100644
--- a/App/Feed/FeedViewModel.swift
+++ b/App/Feed/FeedViewModel.swift
@@ -14,6 +14,7 @@ class FeedViewModel {
     var postIds: Set<Int> = Set()
     var postType: PostType = .news
     var pageIndex = 1
+    var lastPostId = 0
     var isFetching = false
 
     func fetchFeed(fetchNextPage: Bool = false) -> Promise<Void> {
@@ -22,13 +23,17 @@ class FeedViewModel {
         }
 
         if fetchNextPage {
-            pageIndex += 1
+            if postType == .newest || postType == .jobs {
+                lastPostId = posts.last?.id ?? lastPostId
+            } else {
+                pageIndex += 1
+            }
         }
 
         isFetching = true
 
         return firstly {
-            HackersKit.shared.getPosts(type: postType, page: pageIndex)
+            HackersKit.shared.getPosts(type: postType, page: pageIndex, nextId: lastPostId)
         }.done { posts in
             let newPosts = posts.filter { !self.postIds.contains($0.id) }
             let newPostIds = newPosts.map { $0.id }
@@ -42,6 +47,7 @@ class FeedViewModel {
         posts = []
         postIds = Set()
         pageIndex = 1
+        lastPostId = 0
         isFetching = false
     }
 
diff --git a/Shared Frameworks/HackersKit/HackersKit+PostsList.swift b/Shared Frameworks/HackersKit/HackersKit+PostsList.swift
index 30fe361c..8f73afc4 100644
--- a/Shared Frameworks/HackersKit/HackersKit+PostsList.swift	
+++ b/Shared Frameworks/HackersKit/HackersKit+PostsList.swift	
@@ -11,9 +11,9 @@ import PromiseKit
 import SwiftSoup
 
 extension HackersKit {
-    func getPosts(type: PostType, page: Int = 1) -> Promise<[Post]> {
+    func getPosts(type: PostType, page: Int = 1, nextId: Int = 0) -> Promise<[Post]> {
         firstly {
-            fetchPostsHtml(type: type, page: page)
+            fetchPostsHtml(type: type, page: page, nextId: nextId)
         }.map { html in
             try HtmlParser.postsTableElement(from: html)
         }.compactMap { tableElement in
@@ -21,8 +21,13 @@ extension HackersKit {
         }
     }
 
-    private func fetchPostsHtml(type: PostType, page: Int) -> Promise<String> {
-        let url = URL(string: "https://news.ycombinator.com/\(type.rawValue)?p=\(page)")!
+    private func fetchPostsHtml(type: PostType, page: Int, nextId: Int) -> Promise<String> {
+        var url: URL
+        if type == .newest || type == .jobs {
+            url = URL(string: "https://news.ycombinator.com/\(type.rawValue)?next=\(nextId)")!
+        } else {
+            url = URL(string: "https://news.ycombinator.com/\(type.rawValue)?p=\(page)")!
+        }
         return fetchHtml(url: url)
     }
 }