From d613203d13612275bb2a77c6915bd4794b50f7fb Mon Sep 17 00:00:00 2001
From: Selim Mustafaev <selim@fastmail.fm>
Date: Mon, 11 Apr 2022 00:41:01 +0300
Subject: [PATCH] Fixes for realm datasource

---
 AutoCat/Controllers/CheckController.swift |  4 ++-
 AutoCat/Utils/RxRealmDataSource.swift     | 33 ++++++++++++++++++++---
 AutoCatCore/Models/DateSection.swift      | 16 +++++++++++
 3 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/AutoCat/Controllers/CheckController.swift b/AutoCat/Controllers/CheckController.swift
index 2083859..29c1f5e 100644
--- a/AutoCat/Controllers/CheckController.swift
+++ b/AutoCat/Controllers/CheckController.swift
@@ -52,7 +52,9 @@ class CheckController: UIViewController, UITableViewDelegate, UITextFieldDelegat
         self.check.isEnabled = false
         
         DispatchQueue.main.async {
-            self.historyDataSource = RealmSectionedDataSource(table: self.history, data: realm.objects(Vehicle.self).sorted(byKeyPath: "updatedDate", ascending: false))
+            self.historyDataSource = RealmSectionedDataSource(table: self.history, data: realm.objects(Vehicle.self).sorted(byKeyPath: "updatedDate", ascending: false)) { count in
+                self.navigationItem.title = String.localizedStringWithFormat(NSLocalizedString("vehicles found", comment: ""), count)
+            }
         }
         
         self.history.delegate = self
diff --git a/AutoCat/Utils/RxRealmDataSource.swift b/AutoCat/Utils/RxRealmDataSource.swift
index 5c90c42..4dca7bb 100644
--- a/AutoCat/Utils/RxRealmDataSource.swift
+++ b/AutoCat/Utils/RxRealmDataSource.swift
@@ -18,7 +18,7 @@ class RealmSectionedDataSource<Item,Cell>: NSObject, UITableViewDataSource
     private var cellIdentifier: String
     private var filterPredicate: FilterPredicate<Item>?
     
-    init(table: UITableView, data: Results<Item>, cellIdentifier: String = String(describing: Cell.self)) {
+    init(table: UITableView, data: Results<Item>, cellIdentifier: String = String(describing: Cell.self), onSizeChanged: ((Int) -> Void)? = nil) {
         self.tv = table
         self.data = data
         self.cellIdentifier = cellIdentifier
@@ -27,11 +27,20 @@ class RealmSectionedDataSource<Item,Cell>: NSObject, UITableViewDataSource
         self.tv.reloadData()
         
         self.notificationToken = self.data.observe { changes in
+            onSizeChanged?(self.data.count)
             switch changes {
             case .initial:
                 self.reload(animated: false)
-            case .update(_, _, _, _):
-                self.reload(animated: false)
+            case .update(_, let deletions, let insertions, let modifications):
+                if deletions.isEmpty && modifications.isEmpty && insertions.count == 1 && insertions.first == 0 {
+                    // Most common use case - adding new element to the top of the list
+                    // Example - checking new number
+                    self.insertFirst()
+                } else if deletions.isEmpty && insertions.isEmpty && modifications.count == 1 && modifications.first == 0 {
+                    self.reloadFirst()
+                } else {
+                    self.reload(animated: false)
+                }
             case .error(let err):
                 print("Realm observer error: \(err)")
             }
@@ -85,6 +94,24 @@ class RealmSectionedDataSource<Item,Cell>: NSObject, UITableViewDataSource
         }
     }
     
+    func insertFirst() {
+        guard !sections.isEmpty, let item = data.first?.clone() else {
+            return
+        }
+        
+        sections[0].insert(item, at: 0)
+        tv.insertRows(at: [IndexPath(row: 0, section: 0)], with: .fade)
+    }
+    
+    func reloadFirst() {
+        guard !sections.isEmpty, let item = data.first?.clone() else {
+            return
+        }
+        
+        sections[0].replace(item, at: 0)
+        tv.reloadRows(at: [IndexPath(row: 0, section: 0)], with: .none)
+    }
+    
     func setFilterPredicate(_ predicate: FilterPredicate<Item>?) {
         self.filterPredicate = predicate
         self.reload()
diff --git a/AutoCatCore/Models/DateSection.swift b/AutoCatCore/Models/DateSection.swift
index 6d5eb90..b548ccc 100644
--- a/AutoCatCore/Models/DateSection.swift
+++ b/AutoCatCore/Models/DateSection.swift
@@ -55,6 +55,22 @@ public struct DateSection<T>: Differentiable, DifferentiableSection, Hashable wh
         self.elements.append(element)
     }
     
+    public mutating func insert(_ element: T, at index: Int) {
+        self.elements.insert(element, at: index)
+    }
+    
+    public func index(of element: T) -> Int? {
+        elements.firstIndex { $0.differenceIdentifier == element.differenceIdentifier }
+    }
+    
+    public mutating func replace(_ element: T, at index: Int) {
+        elements[index] = element
+    }
+    
+    public mutating func remove(at index: Int) {
+        elements.remove(at: index)
+    }
+    
     // MARK: - Differentiable
     
     public var differenceIdentifier: String {