Add an iPhone client sharing the macOS app's SwiftUI code

mac/Sources/Byre/Pages.swift

@@ -1,4 +1,3 @@
-import AppKit
 import Foundation
 import Network
 import Observation
@@ -268,6 +267,7 @@ final class Pages {
         return String(describing: value)
     }
 
+    #if os(macOS)
     func capture(_ view: WKWebView) async throws -> Data {
         guard unsafe view.window != nil, !view.isHiddenOrHasHiddenAncestor else {
             throw ApiError(status: 0, message: "the tab isn't on screen: the human has the page view closed or another tab showing")
@@ -278,6 +278,7 @@ final class Pages {
         }
         return png
     }
+    #endif
 
     func close() {
         listener?.close()
@@ -546,34 +547,67 @@ private final class PageDelegate: NSObject, WKUIDelegate, WKNavigationDelegate {
     }
 
     func webView(_ webView: WKWebView, runJavaScriptAlertPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo) async {
-        _ = await ask(webView, frame, message, buttons: ["OK"], field: nil)
+        _ = await ask(webView, frame, message, cancel: false, field: nil)
     }
 
     func webView(_ webView: WKWebView, runJavaScriptConfirmPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo) async -> Bool {
-        await ask(webView, frame, message, buttons: ["OK", "Cancel"], field: nil) == .alertFirstButtonReturn
+        await ask(webView, frame, message, cancel: true, field: nil) != nil
     }
 
     func webView(_ webView: WKWebView, runJavaScriptTextInputPanelWithPrompt prompt: String, defaultText: String?, initiatedByFrame frame: WKFrameInfo) async -> String? {
-        let field = NSTextField(frame: NSRect(x: 0, y: 0, width: 300, height: 24))
-        field.stringValue = defaultText ?? ""
-        guard await ask(webView, frame, prompt, buttons: ["OK", "Cancel"], field: field) == .alertFirstButtonReturn else {
-            return nil
-        }
-        return field.stringValue
+        await ask(webView, frame, prompt, cancel: true, field: defaultText ?? "")
     }
 
-    private func ask(_ webView: WKWebView, _ frame: WKFrameInfo, _ message: String, buttons: [String], field: NSTextField?) async -> NSApplication.ModalResponse {
+    // Returns nil when the human cancels, otherwise the field's text ("" without a field).
+    private func ask(_ webView: WKWebView, _ frame: WKFrameInfo, _ message: String, cancel: Bool, field: String?) async -> String? {
+        let title = frame.securityOrigin.host.isEmpty ? "This page says" : "\(frame.securityOrigin.host) says"
+        #if os(macOS)
         guard let window = unsafe webView.window, !webView.isHiddenOrHasHiddenAncestor else {
-            return .cancel
+            return nil
         }
         let alert = NSAlert()
-        alert.messageText = frame.securityOrigin.host.isEmpty ? "This page says" : "\(frame.securityOrigin.host) says"
+        alert.messageText = title
         alert.informativeText = message
-        for title in buttons {
-            alert.addButton(withTitle: title)
+        alert.addButton(withTitle: "OK")
+        if cancel {
+            alert.addButton(withTitle: "Cancel")
         }
-        alert.accessoryView = field
-        return await alert.beginSheetModal(for: window)
+        let input = field.map { text in
+            let f = NSTextField(frame: NSRect(x: 0, y: 0, width: 300, height: 24))
+            f.stringValue = text
+            return f
+        }
+        alert.accessoryView = input
+        guard await alert.beginSheetModal(for: window) == .alertFirstButtonReturn else {
+            return nil
+        }
+        return input?.stringValue ?? ""
+        #else
+        guard let window = webView.window, !webView.isHidden, var top = window.rootViewController else {
+            return nil
+        }
+        while let presented = top.presentedViewController {
+            top = presented
+        }
+        let presenter = top
+        return await withCheckedContinuation { c in
+            let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
+            if let field {
+                alert.addTextField { f in
+                    f.text = field
+                }
+            }
+            alert.addAction(UIAlertAction(title: "OK", style: .default) { [weak alert] _ in
+                c.resume(returning: alert?.textFields?.first?.text ?? "")
+            })
+            if cancel {
+                alert.addAction(UIAlertAction(title: "Cancel", style: .cancel) { _ in
+                    c.resume(returning: nil)
+                })
+            }
+            presenter.present(alert, animated: true)
+        }
+        #endif
     }
 
     func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
@@ -589,7 +623,8 @@ private final class PageDelegate: NSObject, WKUIDelegate, WKNavigationDelegate {
     }
 }
 
-private struct WebPage: NSViewRepresentable {
+@MainActor
+private struct WebPage {
     let view: WKWebView
     let reloads: Int
     let shown: Bool
@@ -603,20 +638,41 @@ private struct WebPage: NSViewRepresentable {
         Coordinator()
     }
 
-    func makeNSView(context: Context) -> WKWebView {
-        context.coordinator.reloads = reloads
+    private func make(_ c: Coordinator) -> WKWebView {
+        c.reloads = reloads
         if refresh, !view.isLoading {
             view.reload()
         }
         return view
     }
 
-    func updateNSView(_ view: WKWebView, context: Context) {
+    private func update(_ view: WKWebView, _ c: Coordinator) {
         view.isHidden = !shown
-        let c = context.coordinator
         if c.reloads != reloads {
             c.reloads = reloads
             view.reload()
         }
     }
 }
+
+#if os(macOS)
+extension WebPage: NSViewRepresentable {
+    func makeNSView(context: Context) -> WKWebView {
+        make(context.coordinator)
+    }
+
+    func updateNSView(_ view: WKWebView, context: Context) {
+        update(view, context.coordinator)
+    }
+}
+#else
+extension WebPage: UIViewRepresentable {
+    func makeUIView(context: Context) -> WKWebView {
+        make(context.coordinator)
+    }
+
+    func updateUIView(_ view: WKWebView, context: Context) {
+        update(view, context.coordinator)
+    }
+}
+#endif