Fix VoiceOver focus staying in place after navigating

Fixes #6

Gemini-iOS/BrowserNavigationController.swift

@@ -128,11 +128,13 @@ class BrowserNavigationController: UIViewController {
     
     private func onNavigate(_ operation: NavigationManager.Operation) {
         let newVC: BrowserWebViewController
+        var postAccessibilityNotification = false
         
         switch operation {
         case .go:
             backBrowserVCs.append(currentBrowserVC)
             newVC = BrowserWebViewController(navigator: navigator, url: navigator.currentURL)
+            postAccessibilityNotification = true
             
         case .reload:
             currentBrowserVC.reload()
@@ -163,6 +165,10 @@ class BrowserNavigationController: UIViewController {
             self.toolbarOffset = 0
         }
 
+        if postAccessibilityNotification {
+            // this moves focus to the nav bar, which isn't ideal, but it's better than nothing
+            UIAccessibility.post(notification: .screenChanged, argument: nil)
+        }
     }
     
     private let startEdgeNavigationSwipeDistance: CGFloat = 75

Gemini-iOS/BrowserWebViewController.swift

@@ -151,6 +151,7 @@ class BrowserWebViewController: UIViewController {
     func reload() {
         loaded = false
         loadedFallback = false
+        document = nil
         loadDocument()
     }
     
@@ -189,6 +190,10 @@ class BrowserWebViewController: UIViewController {
                     } else {
                         self.renderFallback(response: response)
                     }
+                } else if response.status.isInput {
+                    DispatchQueue.main.async {
+                        self.showInputPrompt(response: response)
+                    }
                 } else {
                     DispatchQueue.main.async {
                         self.showError(message: "Unknown error: \(response.header)")
@@ -208,6 +213,20 @@ class BrowserWebViewController: UIViewController {
         errorMessageLabel.text = message
     }
     
+    private func showInputPrompt(response: GeminiResponse) {
+        let alert = UIAlertController(title: "Input Requested", message: response.meta, preferredStyle: .alert)
+        alert.addTextField { field in
+            field.isSecureTextEntry = response.status == .sensitiveInput
+        }
+        alert.addAction(UIAlertAction(title: "Submit", style: .default, handler: { _ in
+            guard var components = URLComponents(url: self.navigator.currentURL, resolvingAgainstBaseURL: false) else { return }
+            components.query = alert.textFields!.first!.text
+            self.navigator.changeURL(components.url!)
+        }))
+        alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
+        present(alert, animated: true)
+    }
+    
     private func renderDocument(_ doc: Document) {
         self.document = doc
         
@@ -240,12 +259,18 @@ class BrowserWebViewController: UIViewController {
             
             self.loadedFallback = true
             
-            // todo: probably shouldn't assume this is UTF-8
-            self.webView.load(body, mimeType: mimeType, characterEncodingName: "utf-8", baseURL: self.url)
-            // When showing an image, the safe area insets seem to be ignored. This isn't perfect
-            // (there's a little extra space between the bottom of the nav bar and the top of the image),
-            // but it's better than the image being obscured.
-            self.webView.scrollView.contentInset = self.webView.safeAreaInsets
+            if mimeType == "text/plain",
+               let bodyText = response.bodyText {
+                let html = BrowserWebViewController.preamble +  "<pre class='plaintext'>" + bodyText + "</pre>" + BrowserWebViewController.postamble
+                self.webView.loadHTMLString(html, baseURL: Bundle.main.bundleURL)
+            } else {
+                self.webView.load(body, mimeType: mimeType, characterEncodingName: response.encodingName ?? "utf-8", baseURL: self.url)
+                
+                // When showing an image, the safe area insets seem to be ignored. This isn't perfect
+                // (there's a little extra space between the bottom of the nav bar and the top of the image),
+                // but it's better than the image being obscured.
+                self.webView.scrollView.contentInset = self.webView.safeAreaInsets
+            }
         }
     }
     
@@ -259,11 +284,21 @@ class BrowserWebViewController: UIViewController {
                 let y = result * scrollView.zoomScale - scrollView.safeAreaInsets.top
                 let maxY = scrollView.contentSize.height - scrollView.bounds.height + scrollView.safeAreaInsets.bottom
                 let finalOffsetY = min(y, maxY)
-                self.webView.scrollView.setContentOffset(CGPoint(x: 0, y: finalOffsetY), animated: true)
+                UIView.animate(withDuration: 0.25, delay: 0, options: []) {
+                    self.webView.scrollView.setContentOffset(CGPoint(x: 0, y: finalOffsetY), animated: false)
+                } completion: { _ in
+                    // calling focus() causes VoiceOver to move to that element
+                    self.webView.evaluateJavaScript("document.getElementById('l\(index)').focus();")
+                }
             }
         } else {
-            webView.evaluateJavaScript("document.getElementById('l\(index)').scrollIntoView();")
+            webView.evaluateJavaScript("""
+            const el = document.getElementById('l\(index)');
+            el.scrollIntoView();
+            el.focus();
+            """)
         }
+        
     }
     
     private static let preamble = """

Gemini-iOS/NavigationBarView.swift

@@ -39,6 +39,7 @@ class NavigationBarView: UIView {
         textField = UITextField()
         textField.text = navigator.displayURL
         textField.borderStyle = .roundedRect
+        textField.textContentType = .URL
         textField.keyboardType = .URL
         textField.returnKeyType = .go
         textField.autocapitalizationType = .none

Gemini-iOS/Resources/browser.css

@@ -14,6 +14,11 @@ pre {
     tab-size: 4;
 }
 
+pre.plaintext {
+    word-wrap: break-word;
+    white-space: pre-wrap;
+}
+
 h1, h2, h3 {
     line-height: 1;
     font-weight: normal;

GeminiProtocol/GeminiProtocol.swift

@@ -14,6 +14,8 @@ class GeminiProtocol: NWProtocolFramerImplementation {
     
     private var tempStatusCode: GeminiResponseHeader.StatusCode?
     private var tempMeta: String?
+    private var lastAttemptedMetaLength: Int?
+    private var lastFoundCR = false
     
     required init(framer: NWProtocolFramer.Instance) {
     }
@@ -45,13 +47,21 @@ class GeminiProtocol: NWProtocolFramerImplementation {
             return 3
         }
         
-        var attemptedMetaLength: Int?
         if tempMeta == nil {
-            // Minimum length is 2 bytes, spec does not say meta string is required
-            _ = framer.parseInput(minimumIncompleteLength: 2, maximumLength: 1024 + 2) { (buffer, isComplete) -> Int in
+            let min: Int
+            // if we previously tried to get the meta but failed (because the <CR><LF> was not found,
+            // the minimum amount we need before trying to parse is at least 1 or 2 (depending on whether we found the <CR>) bytes more
+            if let lastAttemptedMetaLength = lastAttemptedMetaLength {
+                min = lastAttemptedMetaLength + (lastFoundCR ? 1 : 2)
+            } else {
+                // Minimum length is 2 bytes, spec does not say meta string is required
+                min = 2
+            }
+            _ = framer.parseInput(minimumIncompleteLength: min, maximumLength: 1024 + 2) { (buffer, isComplete) -> Int in
                 guard let buffer = buffer,
                       buffer.count >= 2 else { return 0 }
-                attemptedMetaLength = buffer.count
+                print("got count: \(buffer.count)")
+                self.lastAttemptedMetaLength = buffer.count
                 
                 let lastPossibleCRIndex = buffer.index(before: buffer.index(before: buffer.endIndex))
                 var index = buffer.startIndex
@@ -66,6 +76,10 @@ class GeminiProtocol: NWProtocolFramerImplementation {
                 }
                 
                 if !found {
+                    if buffer[index] == 13 {
+                        // if we found <CR>, but not <LF>, save that info so that next time we only wait for 1 more byte instead of 2
+                        self.lastFoundCR = true
+                    }
                     if buffer.count < 1026 {
                         return 0
                     } else {
@@ -78,8 +92,8 @@ class GeminiProtocol: NWProtocolFramerImplementation {
             }
         }
         guard let meta = tempMeta else {
-            if let attempted = attemptedMetaLength {
-                return attempted + 1
+            if let attempted = self.lastAttemptedMetaLength {
+                return attempted + (lastFoundCR ? 1 : 2)
             } else {
                 return 2
             }

GeminiProtocol/GeminiResponse.swift

@@ -38,10 +38,17 @@ public struct GeminiResponse {
         return UTType.types(tag: mimeType, tagClass: .mimeType, conformingTo: nil).first
     }
     
+    public var encodingName: String? {
+        guard let parameters = mimeTypeParameters else {
+            return nil
+        }
+        return parameters["charset"]
+    }
+    
     public var bodyText: String? {
-        guard let body = body, let parameters = mimeTypeParameters else { return nil }
+        guard let body = body else { return nil }
         let encoding: String.Encoding
-        switch parameters["charset"]?.lowercased() {
+        switch encodingName?.lowercased() {
         case nil, "utf-8":
             // The Gemini spec defines UTF-8 to be the default charset.
             encoding = .utf8