Add undo scroll-to-top

Tusker.xcodeproj/project.pbxproj

@@ -117,6 +117,7 @@
 		D6B8DB342182A59300424AF7 /* UIAlertController+Visibility.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6B8DB332182A59300424AF7 /* UIAlertController+Visibility.swift */; };
 		D6BC874521961F73006163F1 /* Gifu.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = D6BC874421961F73006163F1 /* Gifu.framework */; };
 		D6BC874621961F73006163F1 /* Gifu.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = D6BC874421961F73006163F1 /* Gifu.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+		D6BC8748219738E1006163F1 /* EnhancedTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BC8747219738E1006163F1 /* EnhancedTableViewController.swift */; };
 		D6BED170212663DA00F02DA0 /* SwiftSoup.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = D6BED16E212663DA00F02DA0 /* SwiftSoup.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		D6BED174212667E900F02DA0 /* StatusTableViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BED173212667E900F02DA0 /* StatusTableViewCell.swift */; };
 		D6C693CA2161253F007D6A6D /* SilentActionPermissionsTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C693C92161253F007D6A6D /* SilentActionPermissionsTableViewController.swift */; };
@@ -313,6 +314,7 @@
 		D6A5FAFA217B86CE003DB2D9 /* OnboardingViewController.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = OnboardingViewController.xib; sourceTree = "<group>"; };
 		D6B8DB332182A59300424AF7 /* UIAlertController+Visibility.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIAlertController+Visibility.swift"; sourceTree = "<group>"; };
 		D6BC874421961F73006163F1 /* Gifu.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = Gifu.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		D6BC8747219738E1006163F1 /* EnhancedTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EnhancedTableViewController.swift; sourceTree = "<group>"; };
 		D6BED16E212663DA00F02DA0 /* SwiftSoup.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = SwiftSoup.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		D6BED173212667E900F02DA0 /* StatusTableViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StatusTableViewCell.swift; sourceTree = "<group>"; };
 		D6C693C92161253F007D6A6D /* SilentActionPermissionsTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SilentActionPermissionsTableViewController.swift; sourceTree = "<group>"; };
@@ -740,6 +742,7 @@
 				D6E0DC8D216EDF1E00369478 /* Previewing.swift */,
 				D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */,
 				D6B8DB332182A59300424AF7 /* UIAlertController+Visibility.swift */,
+				D6BC8747219738E1006163F1 /* EnhancedTableViewController.swift */,
 			);
 			path = Utilities;
 			sourceTree = "<group>";
@@ -1208,6 +1211,7 @@
 				D6F1F84D2193B56E00F5FE67 /* Cache.swift in Sources */,
 				D6757A7E2157E02600721E32 /* XCBRequestSpec.swift in Sources */,
 				D667E5F12134D5050057A976 /* UIViewController+Delegates.swift in Sources */,
+				D6BC8748219738E1006163F1 /* EnhancedTableViewController.swift in Sources */,
 				D663625F2135C75500C9CBA2 /* ConversationMainStatusTableViewCell.swift in Sources */,
 				D667E5E721349D4C0057A976 /* ProfileTableViewController.swift in Sources */,
 				D6D4DDD0212518A000E1C4BB /* AppDelegate.swift in Sources */,

Tusker/Screens/Conversation/ConversationTableViewController.swift

@@ -9,7 +9,7 @@
 import UIKit
 import Pachyderm
 
-class ConversationTableViewController: UITableViewController {
+class ConversationTableViewController: EnhancedTableViewController {
     
     let router: AppRouter
     

Tusker/Screens/Notifications/NotificationsTableViewController.swift

@@ -9,7 +9,7 @@
 import UIKit
 import Pachyderm
 
-class NotificationsTableViewController: UITableViewController {
+class NotificationsTableViewController: EnhancedTableViewController {
     
     let router: AppRouter
     

Tusker/Screens/Profile/ProfileTableViewController.swift

@@ -10,7 +10,7 @@ import UIKit
 import Pachyderm
 import SafariServices
 
-class ProfileTableViewController: UITableViewController, PreferencesAdaptive {
+class ProfileTableViewController: EnhancedTableViewController, PreferencesAdaptive {
     
     let router: AppRouter
     

Tusker/Screens/Timeline/TimelineTableViewController.swift

@@ -9,7 +9,7 @@
 import UIKit
 import Pachyderm
 
-class TimelineTableViewController: UITableViewController {
+class TimelineTableViewController: EnhancedTableViewController {
     
     let router: AppRouter
     

Tusker/Screens/Utilities/EnhancedTableViewController.swift

@@ -0,0 +1,38 @@
+//
+//  EnhancedTableViewController.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 11/10/18.
+//  Copyright © 2018 Shadowfacts. All rights reserved.
+//
+
+import UIKit
+
+class EnhancedTableViewController: UITableViewController {
+
+    var prevScrollToTopOffset: CGPoint? = nil
+
+    private var topOffset: CGPoint {
+        // when scrolled to top, the content offset is negative the height of the UI above the scroll view (i.e. the nav and status bars)
+        let barOffset = -1 * (navigationController!.navigationBar.frame.height + UIApplication.shared.statusBarFrame.height)
+        // add one so it's not technically all the way at the top, and scrollViewWShouldScrollToTop is still called to trigger undo
+        return CGPoint(x: 0, y: barOffset + 1)
+    }
+
+    override func scrollViewShouldScrollToTop(_ scrollView: UIScrollView) -> Bool {
+        if let offset = prevScrollToTopOffset {
+            tableView.setContentOffset(offset, animated: true)
+            prevScrollToTopOffset = nil
+        } else {
+            prevScrollToTopOffset = tableView.contentOffset
+            tableView.setContentOffset(topOffset, animated: true)
+        }
+        return false
+    }
+
+    override func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
+        prevScrollToTopOffset = nil
+        print(tableView.contentOffset)
+    }
+
+}