Autocomplete custom emojis in CW field

Tusker.xcodeproj/project.pbxproj

@@ -238,6 +238,7 @@
 		D6BC9DD7232D7811002CA326 /* TimelinesPageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BC9DD6232D7811002CA326 /* TimelinesPageViewController.swift */; };
 		D6BC9DDA232D8BE5002CA326 /* SearchResultsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BC9DD9232D8BE5002CA326 /* SearchResultsViewController.swift */; };
 		D6BED174212667E900F02DA0 /* TimelineStatusTableViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6BED173212667E900F02DA0 /* TimelineStatusTableViewCell.swift */; };
+		D6C143DA253510F4007DC240 /* ComposeContentWarningTextField.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C143D9253510F4007DC240 /* ComposeContentWarningTextField.swift */; };
 		D6C693EF216192C2007D6A6D /* TuskerNavigationDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C693EE216192C2007D6A6D /* TuskerNavigationDelegate.swift */; };
 		D6C693FC2162FE6F007D6A6D /* LoadingViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C693FB2162FE6F007D6A6D /* LoadingViewController.swift */; };
 		D6C693FE2162FEEA007D6A6D /* UIViewController+Children.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6C693FD2162FEEA007D6A6D /* UIViewController+Children.swift */; };
@@ -567,6 +568,7 @@
 		D6BC9DD6232D7811002CA326 /* TimelinesPageViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelinesPageViewController.swift; sourceTree = "<group>"; };
 		D6BC9DD9232D8BE5002CA326 /* SearchResultsViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SearchResultsViewController.swift; sourceTree = "<group>"; };
 		D6BED173212667E900F02DA0 /* TimelineStatusTableViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineStatusTableViewCell.swift; sourceTree = "<group>"; };
+		D6C143D9253510F4007DC240 /* ComposeContentWarningTextField.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ComposeContentWarningTextField.swift; sourceTree = "<group>"; };
 		D6C693EE216192C2007D6A6D /* TuskerNavigationDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TuskerNavigationDelegate.swift; sourceTree = "<group>"; };
 		D6C693FB2162FE6F007D6A6D /* LoadingViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoadingViewController.swift; sourceTree = "<group>"; };
 		D6C693FD2162FEEA007D6A6D /* UIViewController+Children.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIViewController+Children.swift"; sourceTree = "<group>"; };
@@ -1004,6 +1006,7 @@
 				D62275A524F1C81800B82A16 /* ComposeReplyView.swift */,
 				D62275A724F1CA2800B82A16 /* ComposeReplyContentView.swift */,
 				D6E4267625327FB400C02E1C /* ComposeAutocompleteView.swift */,
+				D6C143D9253510F4007DC240 /* ComposeContentWarningTextField.swift */,
 			);
 			path = Compose;
 			sourceTree = "<group>";
@@ -1860,6 +1863,7 @@
 				D622757424EDF1CD00B82A16 /* ComposeAttachmentsList.swift in Sources */,
 				D6E0DC8E216EDF1E00369478 /* Previewing.swift in Sources */,
 				D6BED174212667E900F02DA0 /* TimelineStatusTableViewCell.swift in Sources */,
+				D6C143DA253510F4007DC240 /* ComposeContentWarningTextField.swift in Sources */,
 				0427033822B30F5F000D31B6 /* BehaviorPrefsView.swift in Sources */,
 				D627943923A553B600D38C68 /* UnbookmarkStatusActivity.swift in Sources */,
 				D64D0AAD2128D88B005A6F37 /* LocalData.swift in Sources */,

Tusker/Screens/Compose/ComposeContentWarningTextField.swift

@@ -0,0 +1,148 @@
+//
+//  ComposeContentWarningTextField.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 10/12/20.
+//  Copyright © 2020 Shadowfacts. All rights reserved.
+//
+
+import SwiftUI
+
+struct ComposeContentWarningTextField: UIViewRepresentable {
+    typealias UIViewType = UITextField
+    
+    @Binding var text: String
+    
+    @EnvironmentObject private var uiState: ComposeUIState
+    
+    func makeUIView(context: Context) -> UITextField {
+        let view = UITextField()
+        
+        view.placeholder = "Write your warning here"
+        view.borderStyle = .roundedRect
+        
+        view.delegate = context.coordinator
+        view.addTarget(context.coordinator, action: #selector(Coordinator.didChange(_:)), for: .editingChanged)
+        
+        context.coordinator.textField = view
+        context.coordinator.uiState = uiState
+        context.coordinator.text = $text
+        
+        return view
+    }
+    
+    func updateUIView(_ uiView: UITextField, context: Context) {
+        uiView.text = text
+    }
+    
+    func makeCoordinator() -> Coordinator {
+        return Coordinator()
+    }
+    
+    class Coordinator: NSObject, UITextFieldDelegate, ComposeAutocompleteHandler {
+        weak var textField: UITextField?
+        var text: Binding<String>!
+        var uiState: ComposeUIState!
+        
+        @objc func didChange(_ textField: UITextField) {
+            text.wrappedValue = textField.text ?? ""
+        }
+        
+        func textFieldDidBeginEditing(_ textField: UITextField) {
+            uiState.autocompleteHandler = self
+            updateAutocompleteState(textField: textField)
+        }
+        
+        func textFieldDidEndEditing(_ textField: UITextField) {
+            uiState.autocompleteHandler = nil
+            updateAutocompleteState(textField: textField)
+        }
+        
+        func textFieldDidChangeSelection(_ textField: UITextField) {
+            updateAutocompleteState(textField: textField)
+        }
+        
+        func autocomplete(with string: String) {
+            guard let textField = textField,
+                  let text = textField.text,
+                  let selectedRange = textField.selectedTextRange,
+                  let lastWordStartIndex = findAutocompleteLastWord(textField: textField) else {
+                return
+            }
+            
+            let selectedRangeStartUTF16 = textField.offset(from: textField.beginningOfDocument, to: selectedRange.start)
+            let characterBeforeCursorIndex = text.utf16.index(text.startIndex, offsetBy: selectedRangeStartUTF16)
+            
+            textField.text!.replaceSubrange(lastWordStartIndex..<characterBeforeCursorIndex, with: string)
+            didChange(textField)
+        }
+        
+        private func updateAutocompleteState(textField: UITextField) {
+            guard let selectedRange = textField.selectedTextRange,
+                  let text = textField.text,
+                  let lastWordStartIndex = findAutocompleteLastWord(textField: textField) else {
+                uiState.autocompleteState = nil
+                return
+            }
+            
+            if lastWordStartIndex > text.startIndex {
+                let c = text[text.index(before: lastWordStartIndex)]
+                if isPermittedForAutocomplete(c) || c == ":" {
+                    uiState.autocompleteState = nil
+                    return
+                }
+            }
+            
+            let selectedRangeStartUTF16 = textField.offset(from: textField.beginningOfDocument, to: selectedRange.start)
+            let cursorIndex = text.utf16.index(text.startIndex, offsetBy: selectedRangeStartUTF16)
+
+            if lastWordStartIndex >= text.startIndex {
+                let lastWord = text[lastWordStartIndex..<cursorIndex]
+                let exceptFirst = lastWord[lastWord.index(after: lastWord.startIndex)...]
+                
+                if lastWord.first == ":" {
+                    uiState.autocompleteState = .emoji(String(exceptFirst))
+                } else {
+                    uiState.autocompleteState = nil
+                }
+            } else {
+                uiState.autocompleteState = nil
+            }
+        }
+        
+        private func isPermittedForAutocomplete(_ c: Character) -> Bool {
+            return (c >= "a" && c <= "z") || (c >= "A" && c <= "Z") || (c >= "0" && c <= "9") || c == "_"
+        }
+        
+        private func findAutocompleteLastWord(textField: UITextField) -> String.Index? {
+            guard textField.isFirstResponder,
+                  let selectedRange = textField.selectedTextRange,
+                  selectedRange.isEmpty,
+                  let text = textField.text,
+                  !text.isEmpty else {
+                return nil
+            }
+            
+            let selectedRangeStartUTF16 = textField.offset(from: textField.beginningOfDocument, to: selectedRange.start)
+            let cursorIndex = text.utf16.index(text.startIndex, offsetBy: selectedRangeStartUTF16)
+            
+            var lastWordStartIndex = text.index(before: cursorIndex)
+            while true {
+                let c = text[lastWordStartIndex]
+                
+                if !isPermittedForAutocomplete(c) {
+                    break
+                }
+                
+                if lastWordStartIndex > text.startIndex {
+                    lastWordStartIndex = text.index(before: lastWordStartIndex)
+                } else {
+                    break
+                }
+            }
+            
+            return lastWordStartIndex
+        }
+    }
+    
+}

Tusker/Screens/Compose/ComposeView.swift

@@ -114,8 +114,7 @@ struct ComposeView: View {
             header
             
             if draft.contentWarningEnabled {
-                TextField("Write your warning here", text: $draft.contentWarning)
+                ComposeContentWarningTextField(text: $draft.contentWarning)
-                    .textFieldStyle(RoundedBorderTextFieldStyle())
             }
             
             MainComposeTextView(

Tusker/Screens/Compose/MainComposeTextView.swift

@@ -218,11 +218,13 @@ struct MainComposeWrappedTextView: UIViewRepresentable {
             uiState.delegate?.keyboardDidHide(accessoryView: textView!.inputAccessoryView!, notification: notification)
         }
         
-        func textViewDidEndEditing(_ textView: UITextView) {
+        func textViewDidBeginEditing(_ textView: UITextView) {
+            uiState.autocompleteHandler = self
             updateAutocompleteState()
         }
         
-        func textViewDidBeginEditing(_ textView: UITextView) {
+        func textViewDidEndEditing(_ textView: UITextView) {
+            uiState.autocompleteHandler = nil
             updateAutocompleteState()
         }
         
@@ -312,7 +314,7 @@ struct MainComposeWrappedTextView: UIViewRepresentable {
             var lastWordStartIndex = text.index(before: characterBeforeCursorIndex)
             var foundFirstAtSign = false
             while true {
-                let c = textView.text[lastWordStartIndex]
+                let c = text[lastWordStartIndex]
                 
                 if !isPermittedForAutocomplete(c) {
                     if foundFirstAtSign {