From f094395c67d71b4ecd6539cdc45e9239b3528f9f Mon Sep 17 00:00:00 2001
From: Pavel Gurov <pegurov@avito.ru>
Date: Sun, 23 Jun 2019 19:03:43 +0300
Subject: [PATCH] Add highlighting of cell in chat list when returning to
 screen

---
 TelegramUI/ChatListController.swift | 33 ++++++++++++++++++++---------
 TelegramUI/ChatListItem.swift       | 13 ++++++++++++
 TelegramUI/ChatListNode.swift       | 21 ++++++++++++++++++
 3 files changed, 57 insertions(+), 10 deletions(-)

diff --git a/TelegramUI/ChatListController.swift b/TelegramUI/ChatListController.swift
index 2b09e5c3..d5be10eb 100644
--- a/TelegramUI/ChatListController.swift
+++ b/TelegramUI/ChatListController.swift
@@ -682,9 +682,7 @@ public class ChatListController: TelegramController, KeyShortcutResponder, UIVie
                     if let layout = strongSelf.validLayout, case .regular = layout.metrics.widthClass {
                         scrollToEndIfExists = true
                     }
-                    navigateToChatController(navigationController: navigationController, context: strongSelf.context, chatLocation: .peer(peerId), scrollToEndIfExists: scrollToEndIfExists, animated: animated, completion: { [weak self] in
-                        self?.chatListDisplayNode.chatListNode.clearHighlightAnimated(true)
-                    })
+                    navigateToChatController(navigationController: navigationController, context: strongSelf.context, chatLocation: .peer(peerId), scrollToEndIfExists: scrollToEndIfExists, animated: animated)
                 }
             }
         }
@@ -694,7 +692,6 @@ public class ChatListController: TelegramController, KeyShortcutResponder, UIVie
                 if let navigationController = strongSelf.navigationController as? NavigationController {
                     let chatListController = ChatListController(context: strongSelf.context, groupId: groupId, controlsHistoryPreload: false)
                     navigationController.pushViewController(chatListController)
-                    strongSelf.chatListDisplayNode.chatListNode.clearHighlightAnimated(true)
                 }
             }
         }
@@ -1070,8 +1067,17 @@ public class ChatListController: TelegramController, KeyShortcutResponder, UIVie
             self.dismissSearchOnDisappear = false
             self.deactivateSearch(animated: false)
         }
-        
-        self.chatListDisplayNode.chatListNode.clearHighlightAnimated(true)
+    }
+    
+    override public func navigationAlongsideTransition(type: NavigationTransition) -> ((CGFloat) -> ())? {
+        switch type {
+        case .Pop:
+            return { [weak self] progress in
+                self?.chatListDisplayNode.chatListNode.updateHiglightPercent(1 - progress)
+            }
+        case .Push:
+            return nil
+        }
     }
     
     override public func containerLayoutUpdated(_ layout: ContainerViewLayout, transition: ContainedViewLayoutTransition) {
@@ -1091,10 +1097,17 @@ public class ChatListController: TelegramController, KeyShortcutResponder, UIVie
     
     override public func navigationStackConfigurationUpdated(next: [ViewController]) {
         super.navigationStackConfigurationUpdated(next: next)
-        
-        let chatLocation = (next.first as? ChatController)?.chatLocation
-        
-        self.chatListDisplayNode.chatListNode.updateSelectedChatLocation(chatLocation, progress: 1.0, transition: .immediate)
+
+        if UIDevice.current.userInterfaceIdiom != .phone {
+            let chatLocation = (navigationController?.viewControllers.last as? ChatController)?.chatLocation
+            chatListDisplayNode.chatListNode.clearHighlightAnimated(false)
+            chatListDisplayNode.chatListNode.updateSelectedChatLocation(chatLocation, progress: 1.0, transition: .immediate)
+        } else {
+            if let chatLocation = (navigationController?.viewControllers.last as? ChatController)?.chatLocation {
+                chatListDisplayNode.chatListNode.clearHighlightAnimated(false)
+                chatListDisplayNode.chatListNode.updateSelectedChatLocation(chatLocation, progress: 1.0, transition: .immediate)
+            }
+        }
     }
     
     @objc func editPressed() {
diff --git a/TelegramUI/ChatListItem.swift b/TelegramUI/ChatListItem.swift
index 815fdc66..03700e03 100644
--- a/TelegramUI/ChatListItem.swift
+++ b/TelegramUI/ChatListItem.swift
@@ -502,6 +502,17 @@ class ChatListItemNode: ItemListRevealOptionsItemNode {
         self.updateIsHighlighted(transition: (animated && !highlighted) ? .animated(duration: 0.3, curve: .easeInOut) : .immediate)
     }
     
+    override func setHighlightedPercent(_ percent: CGFloat) -> Bool {
+        guard isHighlighted else { return false }
+        
+        if percent == 0 {
+            setHighlighted(false, at: .zero, animated: true)
+        } else {
+            self.highlightedBackgroundNode.alpha = 2 * (1 - 1 / (1 + percent))
+        }
+        return isHighlighted
+    }
+    
     func updateIsHighlighted(transition: ContainedViewLayoutTransition) {
         var reallyHighlighted = self.isHighlighted
         if let item = self.item {
@@ -513,6 +524,7 @@ class ChatListItemNode: ItemListRevealOptionsItemNode {
         }
         
         if reallyHighlighted {
+            self.isHighlighted = true
             if self.highlightedBackgroundNode.supernode == nil {
                 self.insertSubnode(self.highlightedBackgroundNode, aboveSubnode: self.separatorNode)
                 self.highlightedBackgroundNode.alpha = 0.0
@@ -524,6 +536,7 @@ class ChatListItemNode: ItemListRevealOptionsItemNode {
                 self.onlineNode.setImage(PresentationResourcesChatList.recentStatusOnlineIcon(item.presentationData.theme, state: .highlighted))
             }
         } else {
+            self.isHighlighted = false
             if self.highlightedBackgroundNode.supernode != nil {
                 transition.updateAlpha(layer: self.highlightedBackgroundNode.layer, alpha: 0.0, completion: { [weak self] completed in
                     if let strongSelf = self {
diff --git a/TelegramUI/ChatListNode.swift b/TelegramUI/ChatListNode.swift
index 6f66b9a3..f9d7c355 100644
--- a/TelegramUI/ChatListNode.swift
+++ b/TelegramUI/ChatListNode.swift
@@ -1419,11 +1419,32 @@ final class ChatListNode: ListView {
         
         self.forEachItemNode { itemNode in
             if let itemNode = itemNode as? ChatListItemNode {
+                _ = itemNode.setHighlightedPercent(0)
                 itemNode.updateIsHighlighted(transition: transition)
             }
         }
     }
     
+    private var nodeCurrentlyBeingAnimated: ChatListItemNode?
+    override public func updateHiglightPercent(_ percent: CGFloat) {
+        if percent == 0, let interaction = self.interaction {
+            interaction.highlightedChatLocation = nil
+        }
+        if percent == 0 || percent == 1 {
+            nodeCurrentlyBeingAnimated = nil
+        }
+        
+        if let currentlyAnimatedNode = nodeCurrentlyBeingAnimated {
+            _ = currentlyAnimatedNode.setHighlightedPercent(percent)
+        } else {
+            self.forEachItemNode { itemNode in
+                if let itemNode = itemNode as? ChatListItemNode, itemNode.setHighlightedPercent(percent) {
+                    nodeCurrentlyBeingAnimated = itemNode
+                }
+            }
+        }
+    }
+    
     private func currentlyVisibleLatestChatListIndex() -> ChatListIndex? {
         guard let chatListView = (self.opaqueTransactionState as? ChatListOpaqueTransactionState)?.chatListView else {
             return nil