feat: WebKit message handlers

[buzsh]

TODO

Example Syntax

declare global {
  interface Window {
    webkit: {
      messageHandlers: {
        copilotMessageProcessed: {
          postMessage: (message: string) => void;
        };
        copilotSidebarHidden: {
          postMessage: (message: string) => void;
        };
        copilotPopupHidden: {
          postMessage: (message: string) => void;
        };
      };
    };
    sendMessageToCopilot: (message: string) => void;
    showCopilotSidebar: () => void;
    hideCopilotSidebar: () => void;
    showCopilotPopup: () => void;
    hideCopilotPopup: () => void;
  }
}

• Parse webkit message handlers
• Generate separate enum for typesafe ScriptMessageHandlers
• Generate WebView extensions for typesafe ScriptMessageHandlers
• Generate view modifiers for typesafe ScriptMessageHandlers

Additional Ideas

• Pass types through postMessage functions
• Swift extensions for verifying types

Testing

• Ensure duplicate postMessage names cannot be created

More Examples

Boolean

declare global {
  interface Window {
    webkit: {
      messageHandlers: {
        copilotSidebarHidden: {
          postMessage: (isHidden: boolean) => void;
        };
      };
    };
  }
}

// Sending a boolean message
window.webkit.messageHandlers.copilotSidebarHidden.postMessage(true);

↓

func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
  if message.name == "copilotSidebarHidden" {
    if let isHidden = message.body as? Bool, isHidden {
      // Do something when the sidebar is hidden
    }
  }
}

Multiple Parameter Types

interface SidebarStatus {
  isHidden: boolean;
  timestamp: number;
}

declare global {
  interface Window {
    webkit: {
      messageHandlers: {
        copilotSidebarHidden: {
          postMessage: (status: SidebarStatus) => void;
        };
      };
    };
  }
}

// Sending an object message
window.webkit.messageHandlers.copilotSidebarHidden.postMessage({ isHidden: true, timestamp: Date.now() });

↓

func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
  if message.name == "copilotSidebarHidden" {
    if let status = message.body as? [String: Any],
       let isHidden = status["isHidden"] as? Bool,
       let timestamp = status["timestamp"] as? Double {
      // Do something with isHidden and timestamp
    }
  }
}

Different Method Name

declare global {
  interface Window {
    webkit: {
      messageHandlers: {
        handleSidebarStatus: {
          sendStatus: (status: string) => void;
        };
      };
    };
  }
}

// Sending a string message
window.webkit.messageHandlers.handleSidebarStatus.sendStatus("hidden");

↓

func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
  if message.name == "handleSidebarStatus" {
    if let status = message.body as? String, status == "hidden" {
      // Do something when the sidebar status is "hidden"
    }
  }
}

Generative: interface

interface SidebarStatus {
  isHidden: boolean;
  progress: number;
}

↓

struct SidebarStatus: Codable {
  let isHidden: Bool
  let progress: Double
}

Usage

let status = SidebarStatus(isHidden: true, progress: 0.75)

Conversion

interface SidebarStatus {
  isHidden: boolean;
  progress: number;
}

declare global {
  interface Window {
    webkit: {
      messageHandlers: {
        copilotSidebarHidden: {
          postMessage: (status: SidebarStatus) => void;
        };
      };
    };
  }
}

// Sending an object message
window.webkit.messageHandlers.copilotSidebarHidden.postMessage({ isHidden: true, progress: 0.75 });

↓

struct SidebarStatus: Codable {
  let isHidden: Bool
  let progress: Double
}

func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
  if message.name == "copilotSidebarHidden" {
    if let data = message.body as? [String: Any] {
      do {
        let jsonData = try JSONSerialization.data(withJSONObject: data, options: [])
        let status = try JSONDecoder().decode(SidebarStatus.self, from: jsonData)
        // Use the status struct
        print("Sidebar is hidden: \(status.isHidden), progress: \(status.progress)")
      } catch {
        print("Failed to decode SidebarStatus: \(error)")
      }
    }
  }
}