Apply Mastodon poll limits in Compose view

Tusker/Screens/Compose/ComposeEmojiTextField.swift

@@ -15,15 +15,17 @@ struct ComposeEmojiTextField: UIViewRepresentable {
     
     @Binding var text: String
     let placeholder: String
+    let maxLength: Int?
     let becomeFirstResponder: Binding<Bool>?
     let focusNextView: Binding<Bool>?
     private var didChange: ((String) -> Void)? = nil
     private var didEndEditing: (() -> Void)? = nil
     private var backgroundColor: UIColor? = nil
     
-    init(text: Binding<String>, placeholder: String, becomeFirstResponder: Binding<Bool>? = nil, focusNextView: Binding<Bool>? = nil) {
+    init(text: Binding<String>, placeholder: String, maxLength: Int? = nil, becomeFirstResponder: Binding<Bool>? = nil, focusNextView: Binding<Bool>? = nil) {
         self._text = text
         self.placeholder = placeholder
+        self.maxLength = maxLength
         self.becomeFirstResponder = becomeFirstResponder
         self.focusNextView = focusNextView
         self.didChange = nil
@@ -74,6 +76,7 @@ struct ComposeEmojiTextField: UIViewRepresentable {
         } else {
             uiView.text = text
         }
+        context.coordinator.maxLength = maxLength
         context.coordinator.didChange = didChange
         context.coordinator.didEndEditing = didEndEditing
         context.coordinator.focusNextView = focusNextView
@@ -95,6 +98,7 @@ struct ComposeEmojiTextField: UIViewRepresentable {
         var text: Binding<String>!
         // break retained cycle through ComposeUIState.currentInput
         unowned var uiState: ComposeUIState!
+        var maxLength: Int?
         var didChange: ((String) -> Void)?
         var didEndEditing: (() -> Void)?
         var focusNextView: Binding<Bool>?
@@ -114,6 +118,14 @@ struct ComposeEmojiTextField: UIViewRepresentable {
             focusNextView?.wrappedValue = true
         }
         
+        func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
+            if let maxLength {
+                return ((textField.text ?? "") as NSString).replacingCharacters(in: range, with: string).count <= maxLength
+            } else {
+                return true
+            }
+        }
+        
         func textFieldDidBeginEditing(_ textField: UITextField) {
             uiState.currentInput = self
             updateAutocompleteState(textField: textField)

Tusker/Screens/Compose/ComposePollView.swift

@@ -20,6 +20,7 @@ struct ComposePollView: View {
     @ObservedObject var draft: Draft
     @ObservedObject var poll: Draft.Poll
     
+    @EnvironmentObject var mastodonController: MastodonController
     @Environment(\.colorScheme) var colorScheme: ColorScheme
     
     @State private var duration: Duration
@@ -30,6 +31,14 @@ struct ComposePollView: View {
         
         self._duration = State(initialValue: .fromTimeInterval(poll.duration) ?? .oneDay)
     }
+    
+    private var canAddOption: Bool {
+        if let pollConfig = mastodonController.instance?.pollsConfiguration {
+            return poll.options.count < pollConfig.maxOptions
+        } else {
+            return true
+        }
+    }
 
     var body: some View {
         VStack {
@@ -67,9 +76,15 @@ struct ComposePollView: View {
             .frame(height: 44 * CGFloat(poll.options.count))
             
             Button(action: self.addOption) {
-                Label("Add Option", systemImage: "plus")
+                Label {
+                    Text("Add Option")
+                } icon: {
+                    Image(systemName: "plus")
+                        .foregroundColor(.accentColor)
+                }
             }
             .buttonStyle(.borderless)
+            .disabled(!canAddOption)
             
             HStack {
                 MenuPicker(selection: $poll.multiple, options: [
@@ -155,6 +170,8 @@ struct ComposePollOption: View {
     @ObservedObject var option: Draft.Poll.Option
     let optionIndex: Int
     
+    @EnvironmentObject private var mastodonController: MastodonController
+    
     var body: some View {
         HStack(spacing: 4) {
             Checkbox(radiusFraction: poll.multiple ? 0.1 : 0.5, borderWidth: 2)
@@ -173,7 +190,7 @@ struct ComposePollOption: View {
     }
     
     private var textField: some View {
-        var field = ComposeEmojiTextField(text: $option.text, placeholder: "Option \(optionIndex + 1)")
+        var field = ComposeEmojiTextField(text: $option.text, placeholder: "Option \(optionIndex + 1)", maxLength: mastodonController.instance?.pollsConfiguration?.maxCharactersPerOption)
         return field.backgroundColor(.systemBackground)
     }