From dec111f01c496311453992e9b57f135d3e1ff25a Mon Sep 17 00:00:00 2001
From: Kenta Kubo <601636+kkk669@users.noreply.github.com>
Date: Tue, 25 Apr 2023 21:42:47 +0900
Subject: [PATCH] Fix laggy TextFields (#63)

fixes #63
---
 DNSecure.xcodeproj/project.pbxproj |  4 +++
 DNSecure/Views/DetailView.swift    |  4 +--
 DNSecure/Views/DoHSections.swift   |  4 +--
 DNSecure/Views/DoTSections.swift   |  4 +--
 DNSecure/Views/LazyTextField.swift | 42 ++++++++++++++++++++++++++++++
 DNSecure/Views/RuleView.swift      | 10 +++----
 6 files changed, 57 insertions(+), 11 deletions(-)
 create mode 100644 DNSecure/Views/LazyTextField.swift

diff --git a/DNSecure.xcodeproj/project.pbxproj b/DNSecure.xcodeproj/project.pbxproj
index 5911144..70f73f7 100644
--- a/DNSecure.xcodeproj/project.pbxproj
+++ b/DNSecure.xcodeproj/project.pbxproj
@@ -29,6 +29,7 @@
 		8998041628DCDED800C8B421 /* DoTSections.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8998041528DCDED800C8B421 /* DoTSections.swift */; };
 		8998041828DCDEEF00C8B421 /* DoHSections.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8998041728DCDEEF00C8B421 /* DoHSections.swift */; };
 		89CB922125209DD100B6983C /* HowToActivateView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 89CB922025209DD100B6983C /* HowToActivateView.swift */; };
+		89E8B71A29F80164002C2AEF /* LazyTextField.swift in Sources */ = {isa = PBXBuildFile; fileRef = 89E8B71929F80164002C2AEF /* LazyTextField.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -79,6 +80,7 @@
 		8998041528DCDED800C8B421 /* DoTSections.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DoTSections.swift; sourceTree = "<group>"; };
 		8998041728DCDEEF00C8B421 /* DoHSections.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DoHSections.swift; sourceTree = "<group>"; };
 		89CB922025209DD100B6983C /* HowToActivateView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HowToActivateView.swift; sourceTree = "<group>"; };
+		89E8B71929F80164002C2AEF /* LazyTextField.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LazyTextField.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -116,6 +118,7 @@
 				894958AC2548405E009691D5 /* RuleView.swift */,
 				8998041528DCDED800C8B421 /* DoTSections.swift */,
 				8998041728DCDEEF00C8B421 /* DoHSections.swift */,
+				89E8B71929F80164002C2AEF /* LazyTextField.swift */,
 			);
 			path = Views;
 			sourceTree = "<group>";
@@ -353,6 +356,7 @@
 				8940023E24ACBD2700EBE74B /* ContentView.swift in Sources */,
 				894958AD2548405E009691D5 /* RuleView.swift in Sources */,
 				8998041828DCDEEF00C8B421 /* DoHSections.swift in Sources */,
+				89E8B71A29F80164002C2AEF /* LazyTextField.swift in Sources */,
 				890B80DF251DC6B50046BAA0 /* Presets.swift in Sources */,
 				893AA858258F996F0060B022 /* NEOnDemandRuleInterfaceType+CustomStringConvertible.swift in Sources */,
 				8940023C24ACBD2700EBE74B /* DNSecureApp.swift in Sources */,
diff --git a/DNSecure/Views/DetailView.swift b/DNSecure/Views/DetailView.swift
index f9f37ea..b3736a1 100644
--- a/DNSecure/Views/DetailView.swift
+++ b/DNSecure/Views/DetailView.swift
@@ -36,7 +36,7 @@ extension DetailView: View {
                     Toggle("Use This Server", isOn: self.$isOn)
                 }
                 Section("Name") {
-                    TextField("Name", text: self.$server.name)
+                    LazyTextField("Name", text: self.$server.name)
                 }
                 self.serverConfigurationSections
                 Section {
@@ -73,7 +73,7 @@ extension DetailView: View {
                 Toggle("Use This Server", isOn: self.$isOn)
             }
             Section("Name") {
-                TextField("Name", text: self.$server.name)
+                LazyTextField("Name", text: self.$server.name)
             }
             self.serverConfigurationSections
             Section {
diff --git a/DNSecure/Views/DoHSections.swift b/DNSecure/Views/DoHSections.swift
index 8c2a7d8..df180a1 100644
--- a/DNSecure/Views/DoHSections.swift
+++ b/DNSecure/Views/DoHSections.swift
@@ -15,7 +15,7 @@ extension DoHSections: View {
     var body: some View {
         Section {
             ForEach(0..<self.configuration.servers.count, id: \.self) { i in
-                TextField("IP address", text: self.$configuration.servers[i])
+                LazyTextField("IP address", text: self.$configuration.servers[i])
                     .textContentType(.URL)
                     .keyboardType(.numbersAndPunctuation)
                     .textInputAutocapitalization(.never)
@@ -36,7 +36,7 @@ extension DoHSections: View {
             Text("The DNS server IP addresses.")
         }
         Section {
-            TextField(
+            LazyTextField(
                 "Server URL",
                 text: .init(
                     get: { self.configuration.serverURL?.absoluteString ?? "" },
diff --git a/DNSecure/Views/DoTSections.swift b/DNSecure/Views/DoTSections.swift
index cccf0c4..c61ef20 100644
--- a/DNSecure/Views/DoTSections.swift
+++ b/DNSecure/Views/DoTSections.swift
@@ -15,7 +15,7 @@ extension DoTSections: View {
     var body: some View {
         Section {
             ForEach(0..<self.configuration.servers.count, id: \.self) { i in
-                TextField("IP address", text: self.$configuration.servers[i])
+                LazyTextField("IP address", text: self.$configuration.servers[i])
                     .textContentType(.URL)
                     .keyboardType(.numbersAndPunctuation)
                     .textInputAutocapitalization(.never)
@@ -36,7 +36,7 @@ extension DoTSections: View {
             Text("The DNS server IP addresses.")
         }
         Section {
-            TextField(
+            LazyTextField(
                 "Server Name",
                 text: .init(
                     get: { self.configuration.serverName ?? "" },
diff --git a/DNSecure/Views/LazyTextField.swift b/DNSecure/Views/LazyTextField.swift
new file mode 100644
index 0000000..f672524
--- /dev/null
+++ b/DNSecure/Views/LazyTextField.swift
@@ -0,0 +1,42 @@
+//
+//  LazyTextField.swift
+//  DNSecure
+//
+//  Created by Kenta Kubo on 4/25/23.
+//
+
+import SwiftUI
+
+struct LazyTextField {
+    private let title: String
+    @Binding private var text: String
+    @State private var localText: String
+    @FocusState private var isFocused
+
+    init(_ title: some StringProtocol, text: Binding<String>) {
+        self.title = String(title)
+        self._text = text
+        self._localText = .init(initialValue: text.wrappedValue)
+    }
+}
+
+extension LazyTextField: View {
+    var body: some View {
+        TextField(self.title, text: self.$localText)
+            .focused(self.$isFocused)
+            .onChange(of: self.isFocused) { isFocused in
+                if !isFocused {
+                    self.text = self.localText
+                }
+            }
+            .onChange(of: self.text) { text in
+                self.localText = text
+            }
+    }
+}
+
+struct LazyTextField_Previews: PreviewProvider {
+    static var previews: some View {
+        LazyTextField("Name", text: .constant(""))
+    }
+}
diff --git a/DNSecure/Views/RuleView.swift b/DNSecure/Views/RuleView.swift
index 657c529..5d46ebd 100644
--- a/DNSecure/Views/RuleView.swift
+++ b/DNSecure/Views/RuleView.swift
@@ -16,7 +16,7 @@ extension RuleView: View {
     var body: some View {
         Form {
             Section("Name") {
-                TextField("Name", text: self.$rule.name)
+                LazyTextField("Name", text: self.$rule.name)
             }
 
             Section {
@@ -42,7 +42,7 @@ extension RuleView: View {
             if self.rule.interfaceType.ssidIsUsed {
                 Section {
                     ForEach(0..<self.rule.ssidMatch.count, id: \.self) { i in
-                        TextField(
+                        LazyTextField(
                             "SSID",
                             // self.$rule.ssidMatch[i] causes crash on deletion
                             text: .init(
@@ -71,7 +71,7 @@ extension RuleView: View {
 
             Section {
                 ForEach(0..<self.rule.dnsSearchDomainMatch.count, id: \.self) { i in
-                    TextField(
+                    LazyTextField(
                         "Search Domain",
                         // self.$rule.dnsSearchDomainMatch[i] causes crash on deletion
                         text: .init(
@@ -97,7 +97,7 @@ extension RuleView: View {
 
             Section {
                 ForEach(0..<self.rule.dnsServerAddressMatch.count, id: \.self) { i in
-                    TextField(
+                    LazyTextField(
                         "IP Address",
                         // self.$rule.dnsServerAddressMatch[i] causes crash on deletion
                         text: .init(
@@ -122,7 +122,7 @@ extension RuleView: View {
             }
 
             Section {
-                TextField(
+                LazyTextField(
                     "Probe URL",
                     text: .init(
                         get: { self.rule.probeURL?.absoluteString ?? "" },